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Sample records for hexaploid wheat population

  1. The origin of spelt and free-threshing hexaploid wheat.

    PubMed

    Dvorak, Jan; Deal, Karin R; Luo, Ming-Cheng; You, Frank M; von Borstel, Keith; Dehghani, Hamid

    2012-01-01

    It is widely believed that hexaploid wheat originated via hybridization of hulled tetraploid emmer with Aegilops tauschii (genomes DD) and that the nascent hexaploid was spelt, from which free-threshing wheat evolved by mutations. To reassess the role of spelt in the evolution of Triticum aestivum, 4 disomic substitution lines of Ae. tauschii chromosome 2D in Chinese Spring wheat were developed and one of them was used to map the Tg locus, which controls glume tenacity in Ae. tauschii, relative to simple sequence repeat (SSR) and expressed sequence tag loci on wheat chromosome 2D. The segregation of SSR markers was used to assess the presence of Tg alleles in 11 accessions of spelt, both from Europe and from Asia. Ten of them had an inactive tg allele in the D genome and most had an active Tg allele in the B genome. This is consistent with spelt being derived from free-threshing hexaploid wheat by hybridization of free-threshing wheat with hulled emmer. It is proposed that the tetraploid parent of hexaploid wheat was not hulled emmer but a free-threshing form of tetraploid wheat.

  2. Genetic structure of Argentinean hexaploid wheat germplasm

    PubMed Central

    Vanzetti, Leonardo S.; Yerkovich, Nadia; Chialvo, Eugenia; Lombardo, Lucio; Vaschetto, Luis; Helguera, Marcelo

    2013-01-01

    The identification of genetically homogeneous groups of individuals is an ancient issue in population genetics and in the case of crops like wheat, it can be valuable information for breeding programs, genetic mapping and germplasm resources. In this work we determined the genetic structure of a set of 102 Argentinean bread wheat (Triticum aestivum L.) elite cultivars using 38 biochemical and molecular markers (functional, closely linked to genes and neutral ones) distributed throughout 18 wheat chromosomes. Genetic relationships among these lines were examined using model-based clustering methods. In the analysis three subpopulations were identified which correspond largely to the origin of the germplasm used by the main breeding programs in Argentina. PMID:24130447

  3. Factors Affecting the Radiosensitivity of Hexaploid Wheat to γ-Irradiation: Radiosensitivity of Hexaploid Wheat (Triticum aestivum L.)

    PubMed Central

    Zhao, Linshu; Guo, Huijun; Xie, Yongdun; Zhao, Shirong; Song, Xiyun; Han, Longzhi; Liu, Luxiang

    2016-01-01

    Understanding the radiosensitivity of plants, an important factor in crop mutation breeding programs, requires a thorough investigation of the factors that contribute to this trait. In this study, we used the highly radiosensitive wheat (Triticum aestivum L.) variety HY1 and J411, a γ-irradiation-insensitive control, which were screened from a natural population, to examine the factors affecting radiosensitivity, including free radical content and total antioxidant capacity, as well as the expression of TaKu70 and TaKu80 (DNA repair-related genes) as measured by real-time PCR. We also investigated the alternative splicing of this gene in the wild-type wheat ecotype by sequence analysis. Free radical contents and total antioxidant capacity significantly increased upon exposure of HY1 wheat to γ-irradiation in a dose-dependent manner. By contrast, in J411, the free radical contents exhibited a similar trend, but the total antioxidant capacity exhibited a downward trend upon increasing γ-irradiation. Additionally, we detected dose-dependent increases in TaKu70 and TaKu80 expression levels in γ-irradiated HY1, while in J411, TaKu70 expression levels increased, followed by a decline. We also detected alternative splicing of TaKu70 mRNA, namely, intron retention, in HY1 but not in J411. Our findings indicate that γ-irradiation induces oxidative stress and DNA damage in hexaploid wheat, resulting in growth retardation of seedlings, and they suggest that TaKu70 may play a causal role in radiosensitivity in HY1. Further studies are required to exploit these factors to improve radiosensitivity in other wheat varieties. PMID:27551965

  4. Synthetic hexaploids: Harnessing species of the primary gene pool for wheat improvement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incorporation of genetic diversity into elite wheat cultivars has long been recognized as a means of improving wheat productivity and securing the global wheat supply. Synthetic hexaploid wheat (SHW) recreated from its two progenitor species, the tetraploid, Triticum turgidum and its diploid wild r...

  5. Characterization of a Wheat Breeders' Array suitable for high-throughput SNP genotyping of global accessions of hexaploid bread wheat (Triticum aestivum).

    PubMed

    Allen, Alexandra M; Winfield, Mark O; Burridge, Amanda J; Downie, Rowena C; Benbow, Harriet R; Barker, Gary L A; Wilkinson, Paul A; Coghill, Jane; Waterfall, Christy; Davassi, Alessandro; Scopes, Geoff; Pirani, Ali; Webster, Teresa; Brew, Fiona; Bloor, Claire; Griffiths, Simon; Bentley, Alison R; Alda, Mark; Jack, Peter; Phillips, Andrew L; Edwards, Keith J

    2017-03-01

    Targeted selection and inbreeding have resulted in a lack of genetic diversity in elite hexaploid bread wheat accessions. Reduced diversity can be a limiting factor in the breeding of high yielding varieties and crucially can mean reduced resilience in the face of changing climate and resource pressures. Recent technological advances have enabled the development of molecular markers for use in the assessment and utilization of genetic diversity in hexaploid wheat. Starting with a large collection of 819 571 previously characterized wheat markers, here we describe the identification of 35 143 single nucleotide polymorphism-based markers, which are highly suited to the genotyping of elite hexaploid wheat accessions. To assess their suitability, the markers have been validated using a commercial high-density Affymetrix Axiom(®) genotyping array (the Wheat Breeders' Array), in a high-throughput 384 microplate configuration, to characterize a diverse global collection of wheat accessions including landraces and elite lines derived from commercial breeding communities. We demonstrate that the Wheat Breeders' Array is also suitable for generating high-density genetic maps of previously uncharacterized populations and for characterizing novel genetic diversity produced by mutagenesis. To facilitate the use of the array by the wheat community, the markers, the associated sequence and the genotype information have been made available through the interactive web site 'CerealsDB'.

  6. Effects of durum wheat background on the expression of hexaploid wheat-derived Fusarium head blight resistance genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple Fusarium head blight (FHB) resistance sources have been identified in common wheat, but an effective source of resistance to FHB has not found in durum wheat. Here we report preliminary results on the effects of durum background on the expression of hexaploid wheat-derived FHB resistance g...

  7. Registration of hard kernel puroindoline allele nearisogenic line hexaploid wheat genetic stocks.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven puroindoline allele near-isogenic line (NIL) hexaploid wheat (Triticum aestivum L.) genetic stocks (GS-xxxx – GS-xxxx; PI 644080 – PI 644086) were developed by Dr. Craig F. Morris at the USDA-ARS Western Wheat Quality Laboratory, Pullman, Washington. As they incorporate the first seven known ...

  8. Genetic diversity among synthetic hexaploid wheat accessions with resistance to several fungal diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic hexaploid wheat (SHW) is known to be an excellent vehicle for transferring large genetic variations especially the many useful traits present in the D genome of Aegilops tauschii Coss (2n=2x=14, DD) for improvement of cultivated wheat (Triticum aestivum L., 2n=6x=42, AABBDD). The objectiv...

  9. Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew.

    PubMed

    Wang, Yanpeng; Cheng, Xi; Shan, Qiwei; Zhang, Yi; Liu, Jinxing; Gao, Caixia; Qiu, Jin-Long

    2014-09-01

    Sequence-specific nucleases have been applied to engineer targeted modifications in polyploid genomes, but simultaneous modification of multiple homoeoalleles has not been reported. Here we use transcription activator-like effector nuclease (TALEN) and clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (refs. 4,5) technologies in hexaploid bread wheat to introduce targeted mutations in the three homoeoalleles that encode MILDEW-RESISTANCE LOCUS (MLO) proteins. Genetic redundancy has prevented evaluation of whether mutation of all three MLO alleles in bread wheat might confer resistance to powdery mildew, a trait not found in natural populations. We show that TALEN-induced mutation of all three TaMLO homoeologs in the same plant confers heritable broad-spectrum resistance to powdery mildew. We further use CRISPR-Cas9 technology to generate transgenic wheat plants that carry mutations in the TaMLO-A1 allele. We also demonstrate the feasibility of engineering targeted DNA insertion in bread wheat through nonhomologous end joining of the double-strand breaks caused by TALENs. Our findings provide a methodological framework to improve polyploid crops.

  10. A whole-genome shotgun approach for assembling and anchoring the hexaploid bread wheat genome

    SciTech Connect

    Chapman, Jarrod A.; Mascher, Martin; Buluc, Aydin; Barry, Kerrie; Georganas, Evangelos; Session, Adam; Strnadova, Veronika; Jenkins, Jerry; Sehgal, Sunish; Oliker, Leonid; Schmutz, Jeremy; Yelick, Katherine A.; Scholz, Uwe; Waugh, Robbie; Poland, Jesse A.; Muehlbauer, Gary J.; Stein, Nils; Rokhsar, Daniel S.

    2015-01-31

    We report that polyploid species have long been thought to be recalcitrant to whole-genome assembly. By combining high-throughput sequencing, recent developments in parallel computing, and genetic mapping, we derive, de novo, a sequence assembly representing 9.1 Gbp of the highly repetitive 16 Gbp genome of hexaploid wheat, Triticum aestivum, and assign 7.1 Gb of this assembly to chromosomal locations. The genome representation and accuracy of our assembly is comparable or even exceeds that of a chromosome-by-chromosome shotgun assembly. Our assembly and mapping strategy uses only short read sequencing technology and is applicable to any species where it is possible to construct a mapping population.

  11. A whole-genome shotgun approach for assembling and anchoring the hexaploid bread wheat genome

    DOE PAGES

    Chapman, Jarrod A.; Mascher, Martin; Buluc, Aydin; ...

    2015-01-31

    We report that polyploid species have long been thought to be recalcitrant to whole-genome assembly. By combining high-throughput sequencing, recent developments in parallel computing, and genetic mapping, we derive, de novo, a sequence assembly representing 9.1 Gbp of the highly repetitive 16 Gbp genome of hexaploid wheat, Triticum aestivum, and assign 7.1 Gb of this assembly to chromosomal locations. The genome representation and accuracy of our assembly is comparable or even exceeds that of a chromosome-by-chromosome shotgun assembly. Our assembly and mapping strategy uses only short read sequencing technology and is applicable to any species where it is possible tomore » construct a mapping population.« less

  12. Construction and characterization of a bacterial artificial chromosome library for hexaploid wheat line 92R137

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For map-based cloning of genes conferring important traits in the hexaploid wheat line 92R137, a bacterial artificial chromosome (BAC) library, including two sub libraries, was constructed using the genomic DNA of 92R137 digested with restriction enzymes HindIII and BamHI. The BAC library was compos...

  13. Segregation analysis of heading traits in hexaploid wheat utilizing recombinant inbred lines.

    PubMed

    Shindo, C; Tsujimoto, H; Sasakuma, T

    2003-01-01

    The purpose of this study was to analyze the genetic segregation of heading traits in wheat using recombinant inbred lines (RILs) of hexaploid wheat, derived from Triticum aestivum cv. Chinese Spring and T. spelta var. duhameliamum. The population was examined under controlled environmental conditions as well as in the field. This strategy differentiated the effect of three genetic factors (vernalization requirement, photoperiod sensitivity and narrow-sense earliness) and identified their interactions. Correlation analysis showed that photoperiod sensitivity and narrow-sense earliness are critical for heading time in the field. Single-marker analysis using 322 molecular markers segregating among RIL detected a total of 38 linked markers for each genetic factor and heading in the field. In interval analysis, two Vrn genes (Vrn-B1 and Vrn-D1) and Ppd-B1 were mapped on chromosomes 5B, 5D and 2B, respectively. It was noticed that Vrn-B1 on 5B from the spelt wheat conferred a strong-spring habit equivalent to the homologous Vrn-A1. Quantitative trait locus analysis also showed that Ppd-B1 was not detected under the short-day condition without vernalization treatment, and that there were two types of genes for photoperiod sensitivity, dependent on and independent of vernalization treatment.

  14. High-density SNP genotyping array for hexaploid wheat and its secondary and tertiary gene pool.

    PubMed

    Winfield, Mark O; Allen, Alexandra M; Burridge, Amanda J; Barker, Gary L A; Benbow, Harriet R; Wilkinson, Paul A; Coghill, Jane; Waterfall, Christy; Davassi, Alessandro; Scopes, Geoff; Pirani, Ali; Webster, Teresa; Brew, Fiona; Bloor, Claire; King, Julie; West, Claire; Griffiths, Simon; King, Ian; Bentley, Alison R; Edwards, Keith J

    2016-05-01

    In wheat, a lack of genetic diversity between breeding lines has been recognized as a significant block to future yield increases. Species belonging to bread wheat's secondary and tertiary gene pools harbour a much greater level of genetic variability, and are an important source of genes to broaden its genetic base. Introgression of novel genes from progenitors and related species has been widely employed to improve the agronomic characteristics of hexaploid wheat, but this approach has been hampered by a lack of markers that can be used to track introduced chromosome segments. Here, we describe the identification of a large number of single nucleotide polymorphisms that can be used to genotype hexaploid wheat and to identify and track introgressions from a variety of sources. We have validated these markers using an ultra-high-density Axiom(®) genotyping array to characterize a range of diploid, tetraploid and hexaploid wheat accessions and wheat relatives. To facilitate the use of these, both the markers and the associated sequence and genotype information have been made available through an interactive web site.

  15. High Transferability of Homoeolog-Specific Markers between Bread Wheat and Newly Synthesized Hexaploid Wheat Lines

    PubMed Central

    Zeng, Deying; Luo, Jiangtao; Li, Zenglin; Chen, Gang; Zhang, Lianquan; Ning, Shunzong; Yuan, Zhongwei; Zheng, Youliang; Hao, Ming; Liu, Dengcai

    2016-01-01

    Bread wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) has a complex allohexaploid genome, which makes it difficult to differentiate between the homoeologous sequences and assign them to the chromosome A, B, or D subgenomes. The chromosome-based draft genome sequence of the ‘Chinese Spring’ common wheat cultivar enables the large-scale development of polymerase chain reaction (PCR)-based markers specific for homoeologs. Based on high-confidence ‘Chinese Spring’ genes with known functions, we developed 183 putative homoeolog-specific markers for chromosomes 4B and 7B. These markers were used in PCR assays for the 4B and 7B nullisomes and their euploid synthetic hexaploid wheat (SHW) line that was newly generated from a hybridization between Triticum turgidum (AABB) and the wild diploid species Aegilops tauschii (DD). Up to 64% of the markers for chromosomes 4B or 7B in the SHW background were confirmed to be homoeolog-specific. Thus, these markers were highly transferable between the ‘Chinese Spring’ bread wheat and SHW lines. Homoeolog-specific markers designed using genes with known functions may be useful for genetic investigations involving homoeologous chromosome tracking and homoeolog expression and interaction analyses. PMID:27611704

  16. Divergent Development of Hexaploid Triticale by a Wheat – Rye –Psathyrostachys huashanica Trigeneric Hybrid Method

    PubMed Central

    Huang, Juan; Wang, Yujie; Li, Daiyan; Diao, Chengdou; Zhu, Wei; Tang, Yao; Wang, Yi; Fan, Xing; Zeng, Jian; Xu, Lili; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong

    2016-01-01

    Hexaploid triticale is an important forage crop and a promising energy plant. Some forms were previously reported for developing the hexaploid triticale, such as crossing tetraploid wheat or hexaploid wheat with rye, crossing hexaploid triticale and/or hexaploid wheat with octoploid triticale, and spontaneously appearing in the selfed progenies of octoploid triticale. In the present study, we developed an effective method for production of diverse types of hexaploid triticale via wheat—rye—Psathyrostachys huashanica trigeneric hybrid. Genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) karyotyping revealed that D genome chromosomes were completely eliminated and the whole A, B, and R genome chromosomes were retained in three lines. More interestingly, the composite genome of the line K14-489-2 consisted of complete A and B genomes and chromosomes 1D, 2R, 3R, 4R, 5R, 6R, and 7R, that of line K14-491-2 was 12 A-genome (1A-6A), 14 B-genome (1B-7B), 12 R-genome (1R-3R, 5R-7R), and chromosomes 1D and 3D, and that of the line K14-547-1 had 26A/B and 14R chromosomes, plus one pair of centric 6BL/2DS translocations. This finding implies that some of D genome chromosomes can be spontaneously and stably incorporated into the hexaploid triticale. Additionally, a variety of high-molecular-weight glutenin subunits (HMW-GS) compositions were detected in the six hexaploid triticale lines, respectively. Besides, compared with its recurrent triticale parent Zhongsi828, these lines showed high level of resistance to stripe rust (Puccinia striiformis f. sp. tritici, Pst) pathogens prevalent in China, including V26/Gui 22. These new hexaploid triticales not only enhanced diversification of triticale but also could be utilized as valuable germplasm for wheat improvement. PMID:27182983

  17. Structural and molecular basis of starch viscosity in hexaploid wheat.

    PubMed

    Ral, J-P; Cavanagh, C R; Larroque, O; Regina, A; Morell, M K

    2008-06-11

    Wheat starch is considered to have a low paste viscosity relative to other starches. Consequently, wheat starch is not preferred for many applications as compared to other high paste viscosity starches. Increasing the viscosity of wheat starch is expected to increase the functionality of a range of wheat flour-based products in which the texture is an important aspect of consumer acceptance (e.g., pasta, and instant and yellow alkaline noodles). To understand the molecular basis of starch viscosity, we have undertaken a comprehensive structural and rheological analysis of starches from a genetically diverse set of wheat genotypes, which revealed significant variation in starch traits including starch granule protein content, starch-associated lipid content and composition, phosphate content, and the structures of the amylose and amylopectin fractions. Statistical analysis highlighted the association between amylopectin chains of 18-25 glucose residues and starch pasting properties. Principal component analysis also identified an association between monoesterified phosphate and starch pasting properties in wheat despite the low starch-phosphate level in wheat as compared to tuber starches. We also found a strong negative correlation between the phosphate ester content and the starch content in flour. Previously observed associations between internal starch granule fatty acids and the swelling peak time and pasting temperature have been confirmed. This study has highlighted a range of parameters associated with increased starch viscosity that could be used in prebreeding/breeding programs to modify wheat starch pasting properties.

  18. Synthetic hexaploids derived from under-exploited tetraploids as a new resource for disease resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic hexaploid wheat (SHW) (2n = 6x = 42, genome AABBDD), which is developed from the hybridization between tetraploid wheat (Triticum turgidum L., 2n = 4x = 28, genome AABB) and Aegilops tauschii Coss. (2n = 2x = 14, genome DD), is a useful bridging germplasm for the introgression of desirable...

  19. Genotype dependent burst of transposable element expression in crowns of hexaploid wheat (Triticum aestivum L.) during cold acclimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The expression of 1,613 transposable elements (TEs) represented in the Affymetix Wheat Genome Chip was examined during cold treatment in crowns of 4 hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throug...

  20. Genome interplay in the grain transcriptome of hexaploid bread wheat.

    PubMed

    Pfeifer, Matthias; Kugler, Karl G; Sandve, Simen R; Zhan, Bujie; Rudi, Heidi; Hvidsten, Torgeir R; Mayer, Klaus F X; Olsen, Odd-Arne

    2014-07-18

    Allohexaploid bread wheat (Triticum aestivum L.) provides approximately 20% of calories consumed by humans. Lack of genome sequence for the three homeologous and highly similar bread wheat genomes (A, B, and D) has impeded expression analysis of the grain transcriptome. We used previously unknown genome information to analyze the cell type-specific expression of homeologous genes in the developing wheat grain and identified distinct co-expression clusters reflecting the spatiotemporal progression during endosperm development. We observed no global but cell type- and stage-dependent genome dominance, organization of the wheat genome into transcriptionally active chromosomal regions, and asymmetric expression in gene families related to baking quality. Our findings give insight into the transcriptional dynamics and genome interplay among individual grain cell types in a polyploid cereal genome.

  1. Analysis of Breeding Systems, Ploidy, and the Role of Hexaploids in Three Hypericum perforatum L. Populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hexaploid seeds are produced by predominantly tetraploid populations of Hypericum perforatum, but the fate of hexaploid seedlings and their reproductive behavior have not been closely examined. We used flow cytometry to analyze single seeds and individual plant samples of three accessions of H. per...

  2. Proteomic analysis of amphiphilic proteins of hexaploid wheat kernels.

    PubMed

    Amiour, Nardjis; Merlino, Marielle; Leroy, Philippe; Branlard, Gérard

    2002-06-01

    Wheat proteins and specially gluten proteins have been well studied and are closely associated with baking products. Amphiphilic proteins (proteins that are soluble using nonionic detergent Triton X-114 ) also play an important role in wheat quality. Some of them, like puroindolines, are lipid binding proteins, and are strongly linked to dough foaming properties and to fine crumb texture. However many amphiphilic proteins are still unknown and both their physiological and technological functions remain to be analysed. In order to explore these proteins, proteomic analysis was carried out using 81 F9 lines, progeny obtained from an interspecific cross "W7984"x"Opata", and already used to built a map of more than 2000 molecular markers (International Triticeae Mapping Initiative, ITMImap). Two-dimensional electrophoresis (immobilized pH gradient (pH 6-11)x sodium dodecyl sulfate-polyacrylamide gel electrophoresis) was performed on amphiphilic proteins with three to five replicates for each line. Silver stained gels were analysed using Melanie 3 software. Genetic determinism was carried out on 170 spots segregating between the two parental hexaploïd wheats. Many of these spots were mapped on different chromosomes of the ITMImap. Spots of interest were identified using matrix-assisted laser desorption/ionization-time of flight and some of them were partly sequenced using electrospray ionization-tandem mass spectrometry. This proteomic approach provided some very useful information about some proteic components linked to bread wheat quality and particularly to kernel hardness.

  3. A whole-genome, radiation hybrid mapping resource of hexaploid wheat.

    PubMed

    Tiwari, Vijay K; Heesacker, Adam; Riera-Lizarazu, Oscar; Gunn, Hilary; Wang, Shichen; Wang, Yi; Gu, Young Q; Paux, Etienne; Koo, Dal-Hoe; Kumar, Ajay; Luo, Ming-Cheng; Lazo, Gerard; Zemetra, Robert; Akhunov, Eduard; Friebe, Bernd; Poland, Jesse; Gill, Bikram S; Kianian, Shahryar; Leonard, Jeffrey M

    2016-04-01

    Generating a contiguous, ordered reference sequence of a complex genome such as hexaploid wheat (2n = 6x = 42; approximately 17 GB) is a challenging task due to its large, highly repetitive, and allopolyploid genome. In wheat, ordering of whole-genome or hierarchical shotgun sequencing contigs is primarily based on recombination and comparative genomics-based approaches. However, comparative genomics approaches are limited to syntenic inference and recombination is suppressed within the pericentromeric regions of wheat chromosomes, thus, precise ordering of physical maps and sequenced contigs across the whole-genome using these approaches is nearly impossible. We developed a whole-genome radiation hybrid (WGRH) resource and tested it by genotyping a set of 115 randomly selected lines on a high-density single nucleotide polymorphism (SNP) array. At the whole-genome level, 26 299 SNP markers were mapped on the RH panel and provided an average mapping resolution of approximately 248 Kb/cR1500 with a total map length of 6866 cR1500 . The 7296 unique mapping bins provided a five- to eight-fold higher resolution than genetic maps used in similar studies. Most strikingly, the RH map had uniform bin resolution across the entire chromosome(s), including pericentromeric regions. Our research provides a valuable and low-cost resource for anchoring and ordering sequenced BAC and next generation sequencing (NGS) contigs. The WGRH developed for reference wheat line Chinese Spring (CS-WGRH), will be useful for anchoring and ordering sequenced BAC and NGS based contigs for assembling a high-quality, reference sequence of hexaploid wheat. Additionally, this study provides an excellent model for developing similar resources for other polyploid species.

  4. Progress towards the construction of a sequence-ready physical map of the 3AS chromosome arm of hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The large genome size (~17 Gb), polyploid nature, and repetitive sequence content (>90%) of hexaploid wheat (Triticum aestivum) present a challenge for constructing physical maps, which are fundamental resources to aid genomic sequencing and annotation, and gene cloning. One approach to reduce the c...

  5. Identification and characterization of genes on a single subgenome in the hexaploid wheat (Triticum aestivum L.) genotype 'Chinese Spring'.

    PubMed

    Ma, Jian; Zheng, Zhi; Stiller, Jiri; Lan, Xiu-Jin; Liu, Yaxi; Deng, Mei; Wang, Penghao; Pu, Zhien; Chen, Guangdeng; Jiang, Qian-Tao; Wei, Yuming; Zheng, You-Liang

    2017-03-01

    Gene loss during the formation of hexaploid bread wheat has been repeatedly reported. However, our knowledge on genome-wide analysis of the genes present on a single subgenome (SSG) in bread wheat is still limited. In this study, by analysing the 'Chinese Spring' chromosome arm shotgun sequences together with high-confidence gene models, we detected 433 genes on a SSG. Greater gene loss was observed in A and D subgenomes compared with B subgenome. More than 79% of the orthologs for these SSG genes were detected in diploid and tetraploid relatives of hexaploid wheat. Unexpectedly, no bias in expression breadth or in the distribution patterns of GO (gene ontology) terms for these genes was detected among the high-confidence genes. Further, network and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses indicated that most of these genes were not functionally related to each other. Interestingly, 30.7% of these SSG genes were most highly expressed in root, showing biased distribution given the distribution of the whole high-confidence genes. Collectively, these results facilitate our understanding of the loss of the genes that were retained in a SSG during the formation of hexaploid wheat.

  6. Non-gridded library: a new approach for BAC (bacterial artificial chromosome) exploitation in hexaploid wheat (Triticum aestivum).

    PubMed

    Ma, Z; Weining, S; Sharp, P J; Liu, C

    2000-12-15

    The feasibility of exploiting non-gridded bacterial artificial chromosome (BAC) libraries and some major factors affecting the efficiency of handling such libraries were studied in hexaploid wheat. Even for a bacterial culture containing only 55% recombinants, some 2000 BAC clones with inserts ranging from 45 to 245 kb could be pooled. The pooled BAC clones could be amplified by culturing for up to 6 h without losing any target clones. These results imply that even for hexaploid wheat, which has an extremely large genome, some 250 pools are sufficient for a BAC library that should satisfy many research objectives. This non-gridded strategy would dramatically reduce the cost and make robotic equipment non-essential in exploiting BAC technology. To construct a representative library and to minimise clone competition, thawing and re-freezing ligation mixtures and bacterial cultures should be avoided in BAC library construction and application.

  7. High-efficiency gene targeting in hexaploid wheat using DNA replicons and CRISPR/Cas9.

    PubMed

    Gil-Humanes, Javier; Wang, Yanpeng; Liang, Zhen; Shan, Qiwei; Ozuna, Carmen V; Sánchez-León, Susana; Baltes, Nicholas J; Starker, Colby; Barro, Francisco; Gao, Caixia; Voytas, Daniel F

    2017-03-01

    The ability to edit plant genomes through gene targeting (GT) requires efficient methods to deliver both sequence-specific nucleases (SSNs) and repair templates to plant cells. This is typically achieved using Agrobacterium T-DNA, biolistics or by stably integrating nuclease-encoding cassettes and repair templates into the plant genome. In dicotyledonous plants, such as Nicotinana tabacum (tobacco) and Solanum lycopersicum (tomato), greater than 10-fold enhancements in GT frequencies have been achieved using DNA virus-based replicons. These replicons transiently amplify to high copy numbers in plant cells to deliver abundant SSNs and repair templates to achieve targeted gene modification. In the present work, we developed a replicon-based system for genome engineering of cereal crops using a deconstructed version of the wheat dwarf virus (WDV). In wheat cells, the replicons achieve a 110-fold increase in expression of a reporter gene relative to non-replicating controls. Furthermore, replicons carrying CRISPR/Cas9 nucleases and repair templates achieved GT at an endogenous ubiquitin locus at frequencies 12-fold greater than non-viral delivery methods. The use of a strong promoter to express Cas9 was critical to attain these high GT frequencies. We also demonstrate gene-targeted integration by homologous recombination (HR) in all three of the homoeoalleles (A, B and D) of the hexaploid wheat genome, and we show that with the WDV replicons, multiplexed GT within the same wheat cell can be achieved at frequencies of ~1%. In conclusion, high frequencies of GT using WDV-based DNA replicons will make it possible to edit complex cereal genomes without the need to integrate GT reagents into the genome.

  8. Molecular cloning and characterization of two novel genes from hexaploid wheat that encode double PR-1 domains coupled with a receptor-like protein kinase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hexaploid wheat (Triticum aestivum L.) contains at least 23 TaPr-1 genes encoding the group 1 pathogenesis-related (PR-1) proteins as identified in our previous work. Here we report the cloning and characterization of TaPr-1-rk1 and TaPr-1-rk2, two novel genes closely related to the wheat PR-1 famil...

  9. Using the Hexaploid Nature of Wheat To Create Variability in Starch Characteristics.

    PubMed

    Inokuma, Takayuki; Vrinten, Patricia; Shimbata, Tomoya; Sunohara, Ai; Ito, Hiroyuki; Saito, Mika; Taniguchi, Yoshinori; Nakamura, Toshiki

    2016-02-03

    In hexaploid crops, such as bread wheat, it should be possible to fine-tune phenotypic traits by identifying wild-type and null genes from each of the three genomes and combining them in a calculated manner. Here, we demonstrate this with gene combinations for two starch synthesis genes, SSIIa and GBSSI. Lines with inactive copies of both enzymes show a very dramatic change in phenotype, so to create intermediate phenotypes, we used marker-assisted selection to develop near-isogenic lines (NILs) carrying homozygous combinations of null alleles. For both genes, gene dosage effects follow the order B > D ≥ A; therefore, we completed detailed analysis of starch characteristics for NIL 3-3, which is null for the B-genome copy of the SSIIa and GBSSI genes, and NIL 5-5, which has null mutations in the B- and D-genome-encoded copies of both of these genes. The effects of the combinations on phenotypic traits followed the order expected on the basis of genotype, with NIL 5-5 showing the largest differences from the wild type, while NIL 3-3 characteristics were intermediate between NIL 5-5 and the wild type. Differences among genotypes were significant for many starch characteristics, including percent amylose, chain length distribution, gelatinization temperature, retrogradation, and pasting properties, and these differences appeared to translate into improvements in end-product quality, since bread made from type 5-5 flour showed a 3 day lag in staling.

  10. HMW and LMW glutenin alleles among putative tetraploid and hexaploid European spelt wheat (Triticum spelta L.) progenitors.

    PubMed

    Yan, Y; Hsam, S L K; Yu, J Z; Jiang, Y; Ohtsuka, I; Zeller, F J

    2003-11-01

    The allelic compositions of high- and low-molecular-weight subunits of glutenins (HMW-GS and LMW-GS) among European spelt ( Triticum spelta L.) and related hexaploid and tetraploid Triticum species were investigated by one- and two-dimensional polyacrylamide-gel electrophoresis (PAGE) and capillary electrophoresis (CE). A total of seven novel glutenin alleles (designated A1a*, B1d*, B1g*, B1f*, B1j*, D1a* at Glu-1 and A3h at the Glu-3 loci, respectively) in European spelt wheat were detected by SDS-PAGE, which were confirmed further by employing A-PAGE and CE methods. Particularly, two HMW-GS alleles, Glu-B1d* coding the subunits 6.1 and 22.1, and Glu-B1f* coding the subunits 13 and 22*, were found to occur in European spelt with frequencies of 32.34% and 5.11%, respectively. These two alleles were present in cultivated emmer (Triticum dicoccum), but they were not observed in bread wheat (Triticum aestivum L.). The allele Glu-B1g* coding for 13* and 19* subunits found in spelt wheat was also detected in club wheat (Triticum compactum L.). Additionally, two alleles coding for LMW-GS, Glu-A3h and Glu-B3d, occurred with high frequencies in spelt, club and cultivated emmer wheat, whereas these were not found or present with very low frequencies in bread wheat. Our results strongly support the secondary origin hypothesis, namely European spelt wheat originated from hybridization between cultivated emmer and club wheat. This is also confirmed experimentally by the artificial synthesis of spelt through crossing between old European emmer wheat, T. dicoccum and club wheat, T. compactum.

  11. Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci

    PubMed Central

    Salentijn, Elma MJ; Goryunova, Svetlana V; Bas, Noor; van der Meer, Ingrid M; van den Broeck, Hetty C; Bastien, Thomas; Gilissen, Luud JWJ; Smulders, Marinus JM

    2009-01-01

    Background Α-gliadins form a multigene protein family encoded by multiple α-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The α-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic α-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences. Results We detected large differences in relative expression levels of α-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus'). Conclusion Here, we have shown that large differences exist in relative expression levels of α-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a

  12. Generation of marker-free transgenic hexaploid wheat via an Agrobacterium-mediated co-transformation strategy in commercial Chinese wheat varieties.

    PubMed

    Wang, Ke; Liu, Huiyun; Du, Lipu; Ye, Xingguo

    2016-11-10

    Genotype specificity is a big problem lagging the development of efficient hexaploid wheat transformation system. Increasingly, the biosecurity of genetically modified organisms is garnering public attention, so the generation of marker-free transgenic plants is very important to the eventual potential commercial release of transgenic wheat. In this study, 15 commercial Chinese hexaploid wheat varieties were successfully transformed via an Agrobacterium-mediated method, with efficiency of up to 37.7%, as confirmed by the use of Quickstix strips, histochemical staining, PCR analysis and Southern blotting. Of particular interest, marker-free transgenic wheat plants from various commercial Chinese varieties and their F1 hybrids were successfully obtained for the first time, with a frequency of 4.3%, using a plasmid harbouring two independent T-DNA regions. The average co-integration frequency of the gus and the bar genes located on the two independent T-DNA regions was 49.0% in T0 plants. We further found that the efficiency of generating marker-free plants was related to the number of bar gene copies integrated in the genome. Marker-free transgenic wheat plants were identified in the progeny of three transgenic lines that had only one or two bar gene copies. Moreover, silencing of the bar gene was detected in 30.7% of T1 positive plants, but the gus gene was never found to be silenced in T1 plants. Bisulphite genomic sequencing suggested that DNA methylation in the 35S promoter of the bar gene regulatory region might be the main reason for bar gene silencing in the transgenic plants.

  13. Types and rates of sequence evolution at the high-molecular-weight glutenin locus in hexaploid wheat and its ancestral genomes.

    PubMed

    Gu, Yong Qiang; Salse, Jérôme; Coleman-Derr, Devin; Dupin, Adeline; Crossman, Curt; Lazo, Gerard R; Huo, Naxin; Belcram, Harry; Ravel, Catherine; Charmet, Gilles; Charles, Mathieu; Anderson, Olin D; Chalhoub, Boulos

    2006-11-01

    The Glu-1 locus, encoding the high-molecular-weight glutenin protein subunits, controls bread-making quality in hexaploid wheat (Triticum aestivum) and represents a recently evolved region unique to Triticeae genomes. To understand the molecular evolution of this locus region, three orthologous Glu-1 regions from the three subgenomes of a single hexaploid wheat species were sequenced, totaling 729 kb of sequence. Comparing each Glu-1 region with its corresponding homologous region from the D genome of diploid wheat, Aegilops tauschii, and the A and B genomes of tetraploid wheat, Triticum turgidum, revealed that, in addition to the conservation of microsynteny in the genic regions, sequences in the intergenic regions, composed of blocks of nested retroelements, are also generally conserved, although a few nonshared retroelements that differentiate the homologous Glu-1 regions were detected in each pair of the A and D genomes. Analysis of the indel frequency and the rate of nucleotide substitution, which represent the most frequent types of sequence changes in the Glu-1 regions, demonstrated that the two A genomes are significantly more divergent than the two B genomes, further supporting the hypothesis that hexaploid wheat may have more than one tetraploid ancestor.

  14. AB-QTL analysis in winter wheat: I. Synthetic hexaploid wheat (T. turgidum ssp. dicoccoides x T. tauschii) as a source of favourable alleles for milling and baking quality traits.

    PubMed

    Kunert, Antje; Naz, Ali Ahmad; Dedeck, Oliver; Pillen, Klaus; Léon, Jens

    2007-09-01

    The advanced backcross QTL (AB-QTL) strategy was utilised to locate quantitative trait loci (QTLs) for baking quality traits in two BC(2)F(3) populations of winter wheat. The backcrosses are derived from two German winter wheat cultivars, Batis and Zentos, and two synthetic, hexaploid wheat accessions, Syn022 and Syn086. The synthetics originate from hybridisations of wild emmer (T. turgidum spp. dicoccoides) and T. tauschii, rather than from durum wheat and T. tauschii and thus allowed for the first time to test for exotic QTL effects on wheat genomes A and B in addition to genome D. The investigated quality traits comprised hectolitre weight, grain hardness, flour yield Type 550, falling number, grain protein content, sedimentation volume and baking volume. One hundred and forty-nine SSR markers were applied to genotype a total of 400 BC(2)F(3) lines. For QTL detection, a mixed-model ANOVA was conducted, including the effects DNA marker, BC(2)F(3) line, environment and marker x environment interaction. Overall 38 QTLs significant for a marker main effect were detected. The exotic allele improved trait performance at 14 QTLs (36.8%), while the elite genotype contributed the favourable effect at 24 QTLs (63.2%). The favourable exotic alleles were mainly associated with grain protein content, though the greatest improvement of trait performance due to the exotic alleles was achieved for the traits falling number and sedimentation volume. At the QTL on chromosome 4B the exotic allele increased the falling number by 19.6% and at the QTL on chromosome 6D the exotic allele led to an increase of the sedimentation volume by 21.7%. The results indicate that synthetic wheat derived from wild emmer x T. tauschii carries favourable QTL alleles for baking quality traits, which might be useful for breeding improved wheat varieties by marker-assisted selection.

  15. Isolation and characterization of EMS-induced Dy10 and Ax1 high molecular weight glutenin subunit deficient mutant lines of elite hexaploid wheat (Triticum aestivum L.) cv. Summit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mixing properties of the dough are critical in the production of bread and other food products derived from wheat. The high molecular weight glutenin subunits (HMW-GS) are major determinants of wheat dough processing qualities. The different alleles of the HMW-GS genes in hexaploid wheat vary ...

  16. Tandemly Duplicated Safener-Induced Glutathione S-Transferase Genes from Triticum tauschii Contribute to Genome- and Organ-Specific Expression in Hexaploid Wheat1

    PubMed Central

    Xu, Fangxiu; Lagudah, Evans S.; Moose, Stephen P.; Riechers, Dean E.

    2002-01-01

    Glutathione S-transferase (GST) gene expression was examined in several Triticum species, differing in genome constitution and ploidy level, to determine genome contribution to GST expression in cultivated, hexaploid bread wheat (Triticum aestivum). Two tandemly duplicated tau class GST genes (TtGSTU1 and TtGSTU2) were isolated from a single bacterial artificial chromosome clone in a library constructed from the diploid wheat and D genome progenitor to cultivated wheat, Triticum tauschii. The genes are very similar in genomic structure and their encoded proteins are 95% identical. Gene-specific reverse transcriptase-polymerase chain reaction analysis revealed differential transcript accumulation of TtGSTU1 and TtGSTU2 in roots and shoots. Expression of both genes was induced by herbicide safeners, 2,4-dichlorophenoxyacetic acid and abscisic acid, in the shoots of T. tauschii; however, expression of TtGSTU1 was always higher than TtGSTU2. In untreated seedlings, TtGSTU1 was expressed in both shoots and roots, whereas TtGSTU2 expression was only detected in roots. RNA gel-blot analysis of ditelosomic, aneuploid lines that are deficient for 6AS, 6BS, or 6DS chromosome arms of cultivated, hexaploid bread wheat showed differential genome contribution to safener-induced GST expression in shoots compared with roots. The GST genes from the D genome of hexaploid wheat contribute most to safener-induced expression in the shoots, whereas GSTs from the B and D genomes contribute to safener-induced expression in the roots. PMID:12226515

  17. Tandemly duplicated Safener-induced glutathione S-transferase genes from Triticum tauschii contribute to genome- and organ-specific expression in hexaploid wheat.

    PubMed

    Xu, Fangxiu; Lagudah, Evans S; Moose, Stephen P; Riechers, Dean E

    2002-09-01

    Glutathione S-transferase (GST) gene expression was examined in several Triticum species, differing in genome constitution and ploidy level, to determine genome contribution to GST expression in cultivated, hexaploid bread wheat (Triticum aestivum). Two tandemly duplicated tau class GST genes (TtGSTU1 and TtGSTU2) were isolated from a single bacterial artificial chromosome clone in a library constructed from the diploid wheat and D genome progenitor to cultivated wheat, Triticum tauschii. The genes are very similar in genomic structure and their encoded proteins are 95% identical. Gene-specific reverse transcriptase-polymerase chain reaction analysis revealed differential transcript accumulation of TtGSTU1 and TtGSTU2 in roots and shoots. Expression of both genes was induced by herbicide safeners, 2,4-dichlorophenoxyacetic acid and abscisic acid, in the shoots of T. tauschii; however, expression of TtGSTU1 was always higher than TtGSTU2. In untreated seedlings, TtGSTU1 was expressed in both shoots and roots, whereas TtGSTU2 expression was only detected in roots. RNA gel-blot analysis of ditelosomic, aneuploid lines that are deficient for 6AS, 6BS, or 6DS chromosome arms of cultivated, hexaploid bread wheat showed differential genome contribution to safener-induced GST expression in shoots compared with roots. The GST genes from the D genome of hexaploid wheat contribute most to safener-induced expression in the shoots, whereas GSTs from the B and D genomes contribute to safener-induced expression in the roots.

  18. Chromatin modification contributes to the expression divergence of three TaGS2 homoeologs in hexaploid wheat

    PubMed Central

    Zhang, Wei; Fan, Xiaoli; Gao, Yingjie; Liu, Lei; Sun, Lijing; Su, Qiannan; Han, Jie; Zhang, Na; Cui, Fa; Ji, Jun; Tong, Yiping; Li, Junming

    2017-01-01

    Plastic glutamine synthetase (GS2) is responsible for ammonium assimilation. The reason that TaGS2 homoeologs in hexaploid wheat experience different selection pressures in the breeding process remains unclear. TaGS2 were minimally expressed in roots but predominantly expressed in leaves, and TaGS2-B had higher expression than TaGS2-A and TaGS2-D. ChIP assays revealed that the activation of TaGS2-B expression in leaves was correlated with increased H3K4 trimethylation. The transcriptional silencing of TaGS2 in roots was correlated with greater cytosine methylation and less H3K4 trimethylation. Micrococcal nuclease and DNase I accessibility experiments indicated that the promoter region was more resistant to digestion in roots than leaves, which indicated that the closed nucleosome conformation of the promoter region was important to the transcription initiation for the spatial-temporal expression of TaGS2. In contrast, the transcribed regions possess different nuclease accessibilities of three TaGS2 homoeologs in the same tissue, suggesting that nucleosome conformation of the transcribed region was part of the fine adjustment of TaGS2 homoeologs. This study provides evidence that histone modification, DNA methylation and nuclease accessibility coordinated the control of the transcription of TaGS2 homoeologs. Our results provided important evidence that TaGS2-B experienced the strongest selection pressures during the breeding process. PMID:28300215

  19. Chromatin modification contributes to the expression divergence of three TaGS2 homoeologs in hexaploid wheat.

    PubMed

    Zhang, Wei; Fan, Xiaoli; Gao, Yingjie; Liu, Lei; Sun, Lijing; Su, Qiannan; Han, Jie; Zhang, Na; Cui, Fa; Ji, Jun; Tong, Yiping; Li, Junming

    2017-03-16

    Plastic glutamine synthetase (GS2) is responsible for ammonium assimilation. The reason that TaGS2 homoeologs in hexaploid wheat experience different selection pressures in the breeding process remains unclear. TaGS2 were minimally expressed in roots but predominantly expressed in leaves, and TaGS2-B had higher expression than TaGS2-A and TaGS2-D. ChIP assays revealed that the activation of TaGS2-B expression in leaves was correlated with increased H3K4 trimethylation. The transcriptional silencing of TaGS2 in roots was correlated with greater cytosine methylation and less H3K4 trimethylation. Micrococcal nuclease and DNase I accessibility experiments indicated that the promoter region was more resistant to digestion in roots than leaves, which indicated that the closed nucleosome conformation of the promoter region was important to the transcription initiation for the spatial-temporal expression of TaGS2. In contrast, the transcribed regions possess different nuclease accessibilities of three TaGS2 homoeologs in the same tissue, suggesting that nucleosome conformation of the transcribed region was part of the fine adjustment of TaGS2 homoeologs. This study provides evidence that histone modification, DNA methylation and nuclease accessibility coordinated the control of the transcription of TaGS2 homoeologs. Our results provided important evidence that TaGS2-B experienced the strongest selection pressures during the breeding process.

  20. Genome-wide identification and expression characterization of ABCC-MRP transporters in hexaploid wheat

    PubMed Central

    Bhati, Kaushal K.; Sharma, Shivani; Aggarwal, Sipla; Kaur, Mandeep; Shukla, Vishnu; Kaur, Jagdeep; Mantri, Shrikant; Pandey, Ajay K.

    2015-01-01

    The ABCC multidrug resistance associated proteins (ABCC-MRP), a subclass of ABC transporters are involved in multiple physiological processes that include cellular homeostasis, metal detoxification, and transport of glutathione-conjugates. Although they are well-studied in humans, yeast, and Arabidopsis, limited efforts have been made to address their possible role in crop like wheat. In the present work, 18 wheat ABCC-MRP proteins were identified that showed the uniform distribution with sub-families from rice and Arabidopsis. Organ-specific quantitative expression analysis of wheat ABCC genes indicated significantly higher accumulation in roots (TaABCC2, TaABCC3, and TaABCC11 and TaABCC12), stem (TaABCC1), leaves (TaABCC16 and TaABCC17), flag leaf (TaABCC14 and TaABCC15), and seeds (TaABCC6, TaABCC8, TaABCC12, TaABCC13, and TaABCC17) implicating their role in the respective tissues. Differential transcript expression patterns were observed for TaABCC genes during grain maturation speculating their role during seed development. Hormone treatment experiments indicated that some of the ABCC genes could be transcriptionally regulated during seed development. In the presence of Cd or hydrogen peroxide, distinct molecular expression of wheat ABCC genes was observed in the wheat seedlings, suggesting their possible role during heavy metal generated oxidative stress. Functional characterization of the wheat transporter, TaABCC13 a homolog of maize LPA1 confirms its role in glutathione-mediated detoxification pathway and is able to utilize adenine biosynthetic intermediates as a substrate. This is the first comprehensive inventory of wheat ABCC-MRP gene subfamily. PMID:26191068

  1. Genome-wide identification and expression characterization of ABCC-MRP transporters in hexaploid wheat.

    PubMed

    Bhati, Kaushal K; Sharma, Shivani; Aggarwal, Sipla; Kaur, Mandeep; Shukla, Vishnu; Kaur, Jagdeep; Mantri, Shrikant; Pandey, Ajay K

    2015-01-01

    The ABCC multidrug resistance associated proteins (ABCC-MRP), a subclass of ABC transporters are involved in multiple physiological processes that include cellular homeostasis, metal detoxification, and transport of glutathione-conjugates. Although they are well-studied in humans, yeast, and Arabidopsis, limited efforts have been made to address their possible role in crop like wheat. In the present work, 18 wheat ABCC-MRP proteins were identified that showed the uniform distribution with sub-families from rice and Arabidopsis. Organ-specific quantitative expression analysis of wheat ABCC genes indicated significantly higher accumulation in roots (TaABCC2, TaABCC3, and TaABCC11 and TaABCC12), stem (TaABCC1), leaves (TaABCC16 and TaABCC17), flag leaf (TaABCC14 and TaABCC15), and seeds (TaABCC6, TaABCC8, TaABCC12, TaABCC13, and TaABCC17) implicating their role in the respective tissues. Differential transcript expression patterns were observed for TaABCC genes during grain maturation speculating their role during seed development. Hormone treatment experiments indicated that some of the ABCC genes could be transcriptionally regulated during seed development. In the presence of Cd or hydrogen peroxide, distinct molecular expression of wheat ABCC genes was observed in the wheat seedlings, suggesting their possible role during heavy metal generated oxidative stress. Functional characterization of the wheat transporter, TaABCC13 a homolog of maize LPA1 confirms its role in glutathione-mediated detoxification pathway and is able to utilize adenine biosynthetic intermediates as a substrate. This is the first comprehensive inventory of wheat ABCC-MRP gene subfamily.

  2. Rmg8, a New Gene for Resistance to Triticum Isolates of Pyricularia oryzae in Hexaploid Wheat.

    PubMed

    Anh, Vu Lan; Anh, Nguyen Tuan; Tagle, Analiza Grubanzo; Vy, Trinh Thi Phuong; Inoue, Yoshihiro; Takumi, Shigeo; Chuma, Izumi; Tosa, Yukio

    2015-12-01

    Blast, caused by Pyricularia oryzae, is one of the major diseases of wheat in South America. We identified a new gene for resistance to Triticum isolates of P. oryzae in common wheat 'S-615', and designated it "resistance to Magnaporthe grisea 8" (Rmg8). Rmg8 was assigned to chromosome 2B through molecular mapping with simple-sequence repeat markers. To identify an avirulence gene corresponding to Rmg8, Triticum isolate Br48 (avirulent on S-615) was crossed with 200R29 (virulent on S-615), an F1 progeny derived from a cross between an Eleusine isolate (MZ5-1-6) and Br48. Segregation analysis of their progeny revealed that avirulence of Br48 on S-615 was conditioned by a single gene, which was designated AVR-Rmg8. AVR-Rmg8 was closely linked to AVR-Rmg7, which corresponded to Rmg7 located on chromosome 2A of tetraploid wheat.

  3. Genetic maps of stem rust resistance gene Sr35 in diploid and hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Puccinia graminis f. sp. tritici is the causal agent of stem rust of wheat. A new race designated TTKSK (also known as Ug99) has recently spread through East Africa, Yemen and on to Iran. TTKSK and its variants (TTKST and TTTSK) are virulent to most of the stem rust resistance genes currently deploy...

  4. Breeding and Characterization of Hexaploid Wheats with Nil Levels of Grain Polyphenol Oxidase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenol oxidase (PPO) is a ubiquitous enzyme in plants, responsible for many browning reactions and reduction of food product quality. In common (bread) wheat, PPO occurs in the external layers of grain, often is carried into flour via milling, and can be responsible for the discoloration of whe...

  5. Dryland Wheat Domestication Changed the Development of Aboveground Architecture for a Well-Structured Canopy

    PubMed Central

    Li, Pu-Fang; Cheng, Zheng-Guo; Ma, Bao-Luo; Palta, Jairo A.; Kong, Hai-Yan; Mo, Fei; Wang, Jian-Yong; Zhu, Ying; Lv, Guang-Chao; Batool, Asfa; Bai, Xue; Li, Feng-Min; Xiong, You-Cai

    2014-01-01

    We examined three different-ploidy wheat species to elucidate the development of aboveground architecture and its domesticated mechanism under environment-controlled field conditions. Architecture parameters including leaf, stem, spike and canopy morphology were measured together with biomass allocation, leaf net photosynthetic rate and instantaneous water use efficiency (WUEi). Canopy biomass density was decreased from diploid to tetraploid wheat, but increased to maximum in hexaploid wheat. Population yield in hexaploid wheat was higher than in diploid wheat, but the population fitness and individual competition ability was higher in diploid wheats. Plant architecture was modified from a compact type in diploid wheats to an incompact type in tetraploid wheats, and then to a more compact type of hexaploid wheats. Biomass accumulation, population yield, harvest index and the seed to leaf ratio increased from diploid to tetraploid and hexaploid, associated with heavier specific internode weight and greater canopy biomass density in hexaploid and tetraploid than in diploid wheat. Leaf photosynthetic rate and WUEi were decreased from diploid to tetraploid and increased from tetraploid to hexaploid due to more compact leaf type in hexaploid and diploid than in tetraploid. Grain yield formation and WUEi were closely associated with spatial stance of leaves and stems. We conclude that the ideotype of dryland wheats could be based on spatial reconstruction of leaf type and further exertion of leaf photosynthetic rate. PMID:25181037

  6. Genome-Wide Association Mapping of Anther Extrusion in Hexaploid Spring Wheat

    PubMed Central

    Muqaddasi, Quddoos H.; Lohwasser, Ulrike; Nagel, Manuela; Börner, Andreas; Pillen, Klaus; Röder, Marion S.

    2016-01-01

    In a number of crop species hybrids are able to outperform line varieties. The anthers of the autogamous bread wheat plant are normally extruded post anthesis, a trait which is unfavourable for the production of F1 hybrid grain. Higher anther extrusion (AE) promotes cross fertilization for more efficient hybrid seed production. Therefore, this study aimed at the genetic dissection of AE by genome wide association studies (GWAS) and determination of the main effect QTL. We applied GWAS approach to identify DArT markers potentially linked to AE to unfold its genetic basis in a panel of spring wheat accessions. Phenotypic data were collected for three years and best linear unbiased estimate (BLUE) values were calculated across all years. The extent of the AE correlation between growing years and BLUE values ranged from r = +0.56 (2013 vs 2015) to 0.91 (2014 vs BLUE values). The broad sense heritability was 0.84 across all years. Six accessions displayed stable AE >80% across all the years. Genotyping data included 2,575 DArT markers (with minimum of 0.05 minor allele frequency applied). AE was influenced both by genotype and by the growing environment. In all, 131 significant marker trait associations (MTAs) (|log10 (P)| >FDR) were established for AE. AE behaved as a quantitative trait, with five consistently significant markers (significant across at least two years with a significant BLUE value) contributing a minor to modest proportion (4.29% to 8.61%) of the phenotypic variance and affecting the trait either positively or negatively. For this reason, there is potential for breeding for improved AE by gene pyramiding. The consistently significant markers linked to AE could be helpful for marker assisted selection to transfer AE to high yielding varieties allowing to promote the exploitation of hybrid-heterosis in the key crop wheat. PMID:27191600

  7. Fine mapping and marker development for the crossability gene SKr on chromosome 5BS of hexaploid wheat (Triticum aestivum L.).

    PubMed

    Alfares, Walid; Bouguennec, Annaig; Balfourier, François; Gay, Georges; Bergès, Hélène; Vautrin, Sonia; Sourdille, Pierre; Bernard, Michel; Feuillet, Catherine

    2009-10-01

    Most elite wheat varieties cannot be crossed with related species thereby restricting greatly the germplasm that can be used for alien introgression in breeding programs. Inhibition to crossability is controlled genetically and a number of QTL have been identified to date, including the major gene Kr1 on 5BL and SKr, a strong QTL affecting crossability between wheat and rye on chromosome 5BS. In this study, we used a recombinant SSD population originating from a cross between the poorly crossable cultivar Courtot (Ct) and the crossable line MP98 to characterize the major dominant effect of SKr and map the gene at the distal end of the chromosome near the 5B homeologous GSP locus. Colinearity with barley and rice was used to saturate the SKr region with new markers and establish orthologous relationships with a 54-kb region on rice chromosome 12. In total, five markers were mapped within a genetic interval of 0.3 cM and 400 kb of BAC contigs were established on both sides of the gene to lay the foundation for map-based cloning of SKr. Two SSR markers completely linked to SKr were used to evaluate a collection of crossable wheat progenies originating from primary triticale breeding programs. The results confirm the major effect of SKr on crossability and the usefulness of the two markers for the efficient introgression of crossability in elite wheat varieties.

  8. A genome-wide analysis of the auxin/indole-3-acetic acid gene family in hexaploid bread wheat (Triticum aestivum L.).

    PubMed

    Qiao, Linyi; Zhang, Xiaojun; Han, Xiao; Zhang, Lei; Li, Xin; Zhan, Haixian; Ma, Jian; Luo, Peigao; Zhang, Wenping; Cui, Lei; Li, Xiaoyan; Chang, Zhijian

    2015-01-01

    The Auxin/indole-3-acetic acid (Aux/IAA) gene family plays key roles in the primary auxin-response process and controls a number of important traits in plants. However, the characteristics of the Aux/IAA gene family in hexaploid bread wheat (Triticum aestivum L.) have long been unknown. In this study, a comprehensive identification of the Aux/IAA gene family was performed using the latest draft genome sequence of the bread wheat "Chinese Spring." Thirty-four Aux/IAA genes were identified, 30 of which have duplicated genes on the A, B or D sub-genome, with a total of 84 Aux/IAA sequences. These predicted Aux/IAA genes were non-randomly distributed in all the wheat chromosomes except for chromosome 2D. The information of wheat Aux/IAA proteins is also described. Based on an analysis of phylogeny, expression and adaptive evolution, we prove that the Aux/IAA family in wheat has been replicated twice in the two allopolyploidization events of bread wheat, when the tandem duplication also occurred. The duplicated genes have undergone an evolutionary process of purifying selection, resulting in the high conservation of copy genes among sub-genomes and functional redundancy among several members of the TaIAA family. However, functional divergence probably existed in most TaIAA members due to the diversity of the functional domain and expression pattern. Our research provides useful information for further research into the function of Aux/IAA genes in wheat.

  9. Mapping QTLs for Fusarium Head Blight Resistance in an Interspecific Wheat Population

    PubMed Central

    Giancaspro, Angelica; Giove, Stefania L.; Zito, Daniela; Blanco, A.; Gadaleta, Agata

    2016-01-01

    Fusarium head blight (scab) is one of the most widespread and damaging diseases of wheat, causing grain yield and quality losses and production of harmful mycotoxins. Development of resistant varieties is hampered by lack of effective resistance sources in the tetraploid wheat primary gene pool. Here we dissected the genetic basis of resistance in a new durum wheat (Triticum turgidum ssp. durum) Recombinant inbred lines (RILs) population obtained by crossing an hexaploid resistant line and a durum susceptible cultivar. A total of 135 RILs were used for constituting a genetic linkage map and mapping loci for head blight incidence, severity, and disease-related plant morphological traits (plant height, spike compactness, and awn length). The new genetic map accounted for 4,366 single nucleotide polymorphism markers assembled in 52 linkage groups covering a total length of 4,227.37 cM. Major quantitative trait loci (QTL) for scab incidence and severity were mapped on chromosomes 2AS, 3AL, and 2AS, 2BS, 4BL, respectively. Plant height loci were identified on 3A, 3B, and 4B, while major QTL for ear compactness were found on 4A, 5A, 5B, 6A, and 7A. In this work, resistance to Fusarium was transferred from hexaploid to durum wheat, and correlations between the disease and morphological traits were assessed. PMID:27746787

  10. Molecular cloning and characterization of two novel genes from hexaploid wheat that encode double PR-1 domains coupled with a receptor-like protein kinase.

    PubMed

    Lu, Shunwen; Faris, Justin D; Edwards, Michael C

    2017-04-01

    Hexaploid wheat (Triticum aestivum L.) contains at least 23 TaPr-1 genes encoding the group 1 pathogenesis-related (PR-1) proteins as identified in our previous work. Here, we report the cloning and characterization of TaPr-1-rk1 and TaPr-1-rk2, two novel genes closely related to the wheat PR-1 family. The two TaPr-1-rk genes are located on homoeologous chromosomes 3D and 3A, respectively, and each contains a large open reading frame (7385 or 6060 bp) that is interrupted by seven introns and subjected to alternative splicing (AS) with five or six isoforms of mRNA transcripts. The deduced full-length TaPR-1-RK1 and TaPR-1-RK2 proteins (95% identity) contain two repeat PR-1 domains, the second of which is fused via a transmembrane helix to a serine/threonine kinase catalytic (STKc) domain characteristic of receptor-like protein kinases. Phylogenetic analysis indicated that the two PR-1 domains of the TaPR-1-RK proteins form sister clades with their homologues identified in other monocot plants and are well separated from stand-alone PR-1 proteins, whereas the STKc domains may have originated from cysteine-rich receptor-like kinases (CRKs). Reverse-transcriptase-PCR analysis revealed that the TaPr-1-rk genes are predominantly expressed in wheat leaves and their expression levels are elevated in response to pathogen attack, such as infection by barley stripe mosaic virus (BSMV), and also to stress conditions, most obviously, to soil salinity. This is the first report of PR-1-CRK hybrid proteins in wheat. The data may shed new insights into the function/evolutionary origin of the PR-1 family and the STKc-mediated defense/stress response pathways in plants.

  11. The impact of photoperiod insensitive Ppd-1a mutations on the photoperiod pathway across the three genomes of hexaploid wheat (Triticum aestivum).

    PubMed

    Shaw, Lindsay M; Turner, Adrian S; Laurie, David A

    2012-07-01

    Flowering time is a trait that has been extensively altered during wheat domestication, enabling it to be highly productive in diverse environments and providing a rich source of variation for studying adaptation mechanisms. Hexaploid wheat is ancestrally a long-day plant, but many environments require varieties with photoperiod insensitivity (PI) that can flower in short days. PI results from mutations in the Ppd-1 gene on the A, B or D genomes, with individual mutations conferring different degrees of earliness. The basis of this is poorly understood. Using a common genetic background, the effects of A, B and D genome PI mutations on genes of the circadian clock and photoperiod pathway were studied using genome-specific expression assays. Ppd-1 PI mutations did not affect the clock or immediate clock outputs, but affected TaCO1 and TaFT1, with a reduction in TaCO1 expression as TaFT1 expression increased. Therefore, although Ppd-1 is related to PRR genes of the Arabidopsis circadian clock, Ppd-1 affects flowering by an alternative route, most likely by upregulating TaFT1 with a feedback effect that reduces TaCO1 expression. Individual genes in the circadian clock and photoperiod pathway were predominantly expressed from one genome, and there was no genome specificity in Ppd-1 action. Lines combining PI mutations on two or three genomes had enhanced earliness with higher levels, but not earlier induction, of TaFT1, showing that there is a direct quantitative relationship between Ppd-1 mutations, TaFT1 expression and flowering.

  12. Molecular characterization of the puroindoline-a and b alleles in synthetic hexaploid wheats and in silico functional and structural insights into Pina-D1.

    PubMed

    Ali, Iftikhar; Sardar, Zainab; Rasheed, Awais; Mahmood, Tariq

    2015-07-07

    Kernel hardness determined by two tightly linked Puroindoline genes, Pina-D1 and Pinb-D1, located on chromosome 5DS define commercially important characteristics, uses, major grades and export markets of wheat. This study was conducted to characterize Pina-D1 and Pinb-D1 alleles, in fifteen synthetic hexaploid wheats (SHWs) and its relation with grain hardness. Additionally, in silico functional analyses of puroindoline-a protein was conducted for better understanding of their putative importance in grain quality. Six different Pina-D1 alleles were identified in the SHWs, of which three i.e. Pina-D1a, Pina-D1c and Pina-D1d were already known whereas the other three had new sequence polymorphisms and were designated as Pina-D1w, Pina-D1x and Pina-D1y. Three different Pinb-D1 alleles were identified which have been reported earlier and no novel sequence polymorphism was detected. It was concluded that despite some primary, secondary and 3D structure variations, ligand binding sites and disulfide bonds discrepancies, the main features of PINA, i.e. the tryptophan-rich domain, the cysteine backbone, the signal peptide and basic identity of the proteins were all conserved. In silico analysis showed that puroindolines having binding capacity with small parts of prolamins causing celiac disease of human, however their potential role is not obvious. Conclusively, the new Pina-D1 alleles with modest effect on grain hardness, and insight into their functional and structural characteristics are important findings and their putative role in celiac disease require further studies to validate.

  13. Genome-wide comparative diversity uncovers multiple targets of selection for improvement in hexaploid wheat landrace and cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Domesticated crops have experienced strong human-driven selection aimed at the development of improved varieties adapted to local conditions. To detect regions of the wheat genome subject to selection during improvement, we developed a high-throughput array to interrogate 9,000 gene-associated DNA m...

  14. Genome-wide association mapping for resistance to leaf and stripe rust in winter-habit hexaploid wheat landraces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf rust, caused by Puccinia triticina (Pt), and stripe rust, caused by P. striiformis f. sp. tritici (Pst), are destructive foliar diseases of wheat worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst re...

  15. mlo-based powdery mildew resistance in hexaploid bread wheat generated by a non-transgenic TILLING approach.

    PubMed

    Acevedo-Garcia, Johanna; Spencer, David; Thieron, Hannah; Reinstädler, Anja; Hammond-Kosack, Kim; Phillips, Andrew L; Panstruga, Ralph

    2017-03-01

    Wheat is one of the most widely grown cereal crops in the world and is an important food grain source for humans. However, wheat yields can be reduced by many abiotic and biotic stress factors, including powdery mildew disease caused by Blumeria graminis f.sp. tritici (Bgt). Generating resistant varieties is thus a major effort in plant breeding. Here, we took advantage of the non-transgenic Targeting Induced Lesions IN Genomes (TILLING) technology to select partial loss-of-function alleles of TaMlo, the orthologue of the barley Mlo (Mildew resistance locus o) gene. Natural and induced loss-of-function alleles (mlo) of barley Mlo are known to confer durable broad-spectrum powdery mildew resistance, typically at the expense of pleiotropic phenotypes such as premature leaf senescence. We identified 16 missense mutations in the three wheat TaMlo homoeologues, TaMlo-A1, TaMlo-B1 and TaMlo-D1 that each lead to single amino acid exchanges. Using transient gene expression assays in barley single cells, we functionally analysed the different missense mutants and identified the most promising candidates affecting powdery mildew susceptibility. By stacking of selected mutant alleles we generated four independent lines with non-conservative mutations in each of the three TaMlo homoeologues. Homozygous triple mutant lines and surprisingly also some of the homozygous double mutant lines showed enhanced, yet incomplete, Bgt resistance without the occurrence of discernible pleiotropic phenotypes. These lines thus represent an important step towards the production of commercial non-transgenic, powdery mildew-resistant bread wheat varieties.

  16. Registration of ‘Dy10-DLC’ wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dy10-DLC wheat (Triticum aestivum) was developed by USDA-ARS at the Western Regional Research Center in Albany, CA. Dy10-DLC was identified from an EMS-mutagenized population of an elite hexaploid wheat variety Summit by screening M3 seeds for altered storage protein profiles using one-dimensiona...

  17. Mapping and validation of Yr48 and other QTL conferring partial resistance to broadly virulent post-2000 North American races of stripe rust in hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mapping population of 188 recombinant inbred lines developed from a cross between UC1110, an adapted California spring wheat, and PI610750, a synthetic derivative from CIMMYT's wide-cross program, was evaluated for its response to current California races of stripe rust (Puccinia striiformis f.sp....

  18. Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease

    PubMed Central

    de Jong, Hein C.; Salentijn, Elma M. J.; Dekking, Liesbeth; Bosch, Dirk; Hamer, Rob J.; Gilissen, Ludovicus J. W. J.; van der Meer, Ingrid M.; Smulders, Marinus J. M.

    2010-01-01

    Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-α9 and Glia-α20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-α9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-α20 was included as a technical reference. Overall, the presence of the Glia-α9 epitope was higher in the modern varieties, whereas the presence of the Glia-α20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of ‘low CD toxic’ as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD. PMID:20664999

  19. [Influence of D genome of wheat on expression of novel type spike branching in hybrid populations of 171ACS line].

    PubMed

    Alieva, A J; Aminov, N Kh

    2013-11-01

    A 171ACS line (AABBDD, 2n = 6x = 42) has been crossed with the tetra- (AABB and AAGG, 2n = 4x = 28) and octoploid (AAAABBGG, 2n = 8x = 56) wheat species without the D genome, as well as with hexaploid (AABBDD and AAGGDD, 2n = 6x = 42) wheat species and tetra- (AADD, 2n = 4x = 28) and hexaploid (AADDSS, 2n = 6x = 42) amphidiploids that have the D genome. The inheritance of a novel type of spike branching in these obtained hybrid populations F1-F3 was studied. According to the results of a morphogenetic analysis of hybrid populations derived from crossings between 171ACS and wheat species without the D genome, the novel type of branching was found to be controlled by a single recessive gene (although a phenotype of the 171ACS line gives a handle for a doubt about occurrence of the second gene) and the 171ACS line is a source of gene of the novel type branching. However, not a single branched spike plant was observed in hybrid populations that were produced by crosses of the 171ACS line with wheat species, as well as with amphidiploids that have the D genome. This result also experimentally confirmed the inhibitor effect of chromosomes of the D genome on the expression of the spike-branching trait. The appearance of branched spike forms, together with normal spiked plants in hybrid populations of the 171ACS line and T. araraticum Jakubz. (AAGG) or T. fungicidum Zhuk. (AAAABBGG) confirmed that, as opposed to the D genome, neither genome G nor genome B demonstrated the inhibition of the expression of the spike-branching trait. In conclusion, keeping in mind that branching is exhibited in hybrid progenies obtained from crosses between the 171ACS line and wheat species with AABB and AAGG genomes, it can be said that this gene belongs to the A genome.

  20. Population- and genome-specific patterns of linkage disequilibrium and SNP variation in spring and winter wheat (Triticum aestivum L.)

    PubMed Central

    2010-01-01

    higher extent of LD in the wheat D-genome versus the A- and B-genomes likely reflects the episodes of recent introgression and population bottleneck accompanying the origin of hexaploid wheat. The assessment of LD and population structure in this assembled panel of diverse lines provides critical information for the development of genetic resources for genome-wide association mapping of agronomically important traits in wheat. PMID:21190581

  1. Wheat in the Mediterranean revisited – tetraploid wheat landraces assessed with elite bread wheat Single Nucleotide Polymorphism markers

    PubMed Central

    2014-01-01

    Background Single Nucleotide Polymorphism (SNP) panels recently developed for the assessment of genetic diversity in wheat are primarily based on elite varieties, mostly those of bread wheat. The usefulness of such SNP panels for studying wheat evolution and domestication has not yet been fully explored and ascertainment bias issues can potentially affect their applicability when studying landraces and tetraploid ancestors of bread wheat. We here evaluate whether population structure and evolutionary history can be assessed in tetraploid landrace wheats using SNP markers previously developed for the analysis of elite cultivars of hexaploid wheat. Results We genotyped more than 100 tetraploid wheat landraces and wild emmer wheat accessions, some of which had previously been screened with SSR markers, for an existing SNP panel and obtained publically available genotypes for the same SNPs for hexaploid wheat varieties and landraces. Results showed that quantification of genetic diversity can be affected by ascertainment bias but that the effects of ascertainment bias can at least partly be alleviated by merging SNPs to haplotypes. Analyses of population structure and genetic differentiation show strong subdivision between the tetraploid wheat subspecies, except for durum and rivet that are not separable. A more detailed population structure of durum landraces could be obtained than with SSR markers. The results also suggest an emmer, rather than durum, ancestry of bread wheat and with gene flow from wild emmer. Conclusions SNP markers developed for elite cultivars show great potential for inferring population structure and can address evolutionary questions in landrace wheat. Issues of marker genome specificity and mapping need, however, to be addressed. Ascertainment bias does not seem to interfere with the ability of a SNP marker system developed for elite bread wheat accessions to detect population structure in other types of wheat. PMID:24885044

  2. Molecular mapping of genes Yr64 and Yr65 for stripe rust resistance in hexaploid derivatives of durum wheat accessions PI 331260 and PI 480016

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide and resistance is the best control strategy. Durum wheat accessions PI 331260 and PI 480016 were resistant to all tested Pst races. To transfer the resistance genes to common ...

  3. The specific isolation of complete 5S rDNA units from chromosome 1A of hexaploid, tetraploid, and diploid wheat species using PCR with head-to-head oriented primers.

    PubMed

    Van Campenhout, S; Stappen, J V; Volckaert, G

    2001-08-01

    The presence of 5S rDNA units on chromosome 1A of Triticum aestivum was shown by the development of a specific PCR test, using head-to-head oriented primers. This primer set allowed the amplification of complete 5S DNA units and was used to isolate SS-Rrna-A1 sequences from polyploid and diploid wheat species. Multiple-alignment and parsimony analyses of the 132 sequences divided the sequences into four types. The isolates from T. aestivum and the tetraploid species (T. dicoccoides, T. dicoccum, T durum, T. araraticum, and T timopheevi) were all of one type, which was shown to be closely related to the type mainly characteristic for T. urartu. The other two types were isolated exclusively from the diploid species T. monococcum, T aegilopoides, T. thaoudar, and T. sinskajae and the hexaploid species T. zhukovski. Triticum monococcum was the only species for which representatives of each of the four sequence types were found to be present. Further, we discuss the possible multicluster arrangement of the 5S-Rrna-A1 array.

  4. A 3,000-loci transcription map of chromosome 3B unravels the structural and functional features of gene islands in hexaploid wheat.

    PubMed

    Rustenholz, Camille; Choulet, Frédéric; Laugier, Christel; Safár, Jan; Simková, Hana; Dolezel, Jaroslav; Magni, Federica; Scalabrin, Simone; Cattonaro, Federica; Vautrin, Sonia; Bellec, Arnaud; Bergès, Hélène; Feuillet, Catherine; Paux, Etienne

    2011-12-01

    To improve our understanding of the organization and regulation of the wheat (Triticum aestivum) gene space, we established a transcription map of a wheat chromosome (3B) by hybridizing a newly developed wheat expression microarray with bacterial artificial chromosome pools from a new version of the 3B physical map as well as with cDNA probes derived from 15 RNA samples. Mapping data for almost 3,000 genes showed that the gene space spans the whole chromosome 3B with a 2-fold increase of gene density toward the telomeres due to an increase in the number of genes in islands. Comparative analyses with rice (Oryza sativa) and Brachypodium distachyon revealed that these gene islands are composed mainly of genes likely originating from interchromosomal gene duplications. Gene Ontology and expression profile analyses for the 3,000 genes located along the chromosome revealed that the gene islands are enriched significantly in genes sharing the same function or expression profile, thereby suggesting that genes in islands acquired shared regulation during evolution. Only a small fraction of these clusters of cofunctional and coexpressed genes was conserved with rice and B. distachyon, indicating a recent origin. Finally, genes with the same expression profiles in remote islands (coregulation islands) were identified suggesting long-distance regulation of gene expression along the chromosomes in wheat.

  5. Copy number and haplotype variation at the VRN-A1 and central FR-A2 loci are associated with frost tolerance in hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Frost tolerance is a key trait to ensure winter wheat survival. Natural variation for this trait is mainly associated with allelic differences at the VERNALIZATION 1 (VRN1) and FROST RESISTANCE 2 (FR2) loci. VRN1 regulates the transition between vegetative and reproductive stages and FR2, a locus in...

  6. A genome-wide association study of resistance to stripe rust (Puccinia striiformis f. sp. tritici) in a worldwide collection of hexaploid spring wheat (Triticum aestivum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New races of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, show high virulence to previously deployed resistance genes and are causing large yield losses worldwide. To identify new sources of resistance we performed a genome-wide association study (GWAS) using...

  7. Niche differentiation between diploid and hexaploid Aster amellus.

    PubMed

    Raabová, Jana; Fischer, Markus; Münzbergová, Zuzana

    2008-12-01

    The maintenance of separated diploid and polyploid populations within a contact zone is possible due to both prezygotic and postzygotic isolation mechanisms. Niche differentiation between two cytotypes may be an important prezygotic isolating mechanism and can be studied using reciprocal transplant experiments. We investigated niche differentiation between diploid and hexaploid Aster amellus in their contact zone in the Czech Republic. Diploid populations are confined to habitats with low productivity, whereas hexaploid populations occur in habitats with both low and high productivity. Thus, we chose three diploid populations and six hexaploid populations, three in each of the two different habitat types. We analyzed habitat characteristics and carried out reciprocal transplant experiments in the field using both seeds and adult plants. Sites of diploid and hexaploid populations differed significantly in vegetation and soil properties. The mean number of juveniles was higher at sites of home ploidy level than at sites of foreign ploidy level, suggesting niche differentiation between the two cytotypes. On the other hand, transplanted adult plants survived at all sites and juvenile plants were able to establish at some sites of the foreign cytotype. Furthermore, the mean number of juveniles, survival, and flowering percentages were higher at home sites than at foreign sites, indicating local adaptation. We conclude that niche differentiation between the two cytotypes and local adaptation within each cytotype may contribute to the maintenance of diploid and hexaploid populations of A. amellus in their contact zone. Moreover, further factors, such as differences in flowering phenology and exclusion of minority cytotypes, should also be considered.

  8. A Genome-Wide Association Study of Resistance to Stripe Rust (Puccinia striiformis f. sp. tritici) in a Worldwide Collection of Hexaploid Spring Wheat (Triticum aestivum L.)

    PubMed Central

    Maccaferri, Marco; Zhang, Junli; Bulli, Peter; Abate, Zewdie; Chao, Shiaoman; Cantu, Dario; Bossolini, Eligio; Chen, Xianming; Pumphrey, Michael; Dubcovsky, Jorge

    2015-01-01

    New races of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, show high virulence to previously deployed resistance genes and are responsible for large yield losses worldwide. To identify new sources of resistance we performed a genome-wide association study (GWAS) using a worldwide collection of 1000 spring wheat accessions. Adult plants were evaluated under field conditions in six environments in the western United States, and seedlings were tested with four Pst races. A single-nucleotide polymorphism (SNP) Infinium 9K-assay provided 4585 SNPs suitable for GWAS. High correlations among environments and high heritabilities were observed for stripe rust infection type and severity. Greater levels of Pst resistance were observed in a subpopulation from Southern Asia than in other groups. GWAS identified 97 loci that were significant for at least three environments, including 10 with an experiment-wise adjusted Bonferroni probability < 0.10. These 10 quantitative trait loci (QTL) explained 15% of the phenotypic variation in infection type, a percentage that increased to 45% when all QTL were considered. Three of these 10 QTL were mapped far from previously identified Pst resistance genes and QTL, and likely represent new resistance loci. The other seven QTL mapped close to known resistance genes and allelism tests will be required to test their relationships. In summary, this study provides an integrated view of stripe rust resistance resources in spring wheat and identifies new resistance loci that will be useful to diversify the current set of resistance genes deployed to control this devastating disease. PMID:25609748

  9. A genome-wide association study of resistance to stripe rust (Puccinia striiformis f. sp. tritici) in a worldwide collection of hexaploid spring wheat (Triticum aestivum L.).

    PubMed

    Maccaferri, Marco; Zhang, Junli; Bulli, Peter; Abate, Zewdie; Chao, Shiaoman; Cantu, Dario; Bossolini, Eligio; Chen, Xianming; Pumphrey, Michael; Dubcovsky, Jorge

    2015-01-20

    New races of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, show high virulence to previously deployed resistance genes and are responsible for large yield losses worldwide. To identify new sources of resistance we performed a genome-wide association study (GWAS) using a worldwide collection of 1000 spring wheat accessions. Adult plants were evaluated under field conditions in six environments in the western United States, and seedlings were tested with four Pst races. A single-nucleotide polymorphism (SNP) Infinium 9K-assay provided 4585 SNPs suitable for GWAS. High correlations among environments and high heritabilities were observed for stripe rust infection type and severity. Greater levels of Pst resistance were observed in a subpopulation from Southern Asia than in other groups. GWAS identified 97 loci that were significant for at least three environments, including 10 with an experiment-wise adjusted Bonferroni probability < 0.10. These 10 quantitative trait loci (QTL) explained 15% of the phenotypic variation in infection type, a percentage that increased to 45% when all QTL were considered. Three of these 10 QTL were mapped far from previously identified Pst resistance genes and QTL, and likely represent new resistance loci. The other seven QTL mapped close to known resistance genes and allelism tests will be required to test their relationships. In summary, this study provides an integrated view of stripe rust resistance resources in spring wheat and identifies new resistance loci that will be useful to diversify the current set of resistance genes deployed to control this devastating disease.

  10. Population Density and Distribution of Wheat Bugs Infesting Durum Wheat in Sardinia, Italy

    PubMed Central

    Salis, Luigi; Goula, Marta; Izquierdo, Jordi; Gordún, Elena

    2013-01-01

    Wheat is a very important crop in Italy, and is infested by wheat bugs belonging to the genera Eurygaster (Hemiptera: Scutellaridae) and Aelia (Hemiptera: Pentatomidae). Many wheat bug infestations have been reported in the north, south, and center of Italy, both in the past as well as recently. The present study was carried out in Sardinia, Italy, during two years (2007 and 2008). The objective of this study was to determine the species and distribution of wheat bugs in durum wheat fields in Sardinia, and to estimate their population density in order to know the incidence of the pest on the island. Sampling took place twice a year (May and June) in three zones, representative of durum wheat cropping in the island. Four species of wheat bugs were found; the predominant species was Eurygaster austriaca (Schrank), followed by Aelia germari (Kuster), Eurygaster maura L., and Aelia acuminata L. The average density of wheat bugs was low (1.1 individuals/m2), but in certain areas it was above the damage threshold (4 individuals/m2). For this reason, the conclusion of the study is that this pest should be monitored in order to control outbreaks and prevent their further spread. PMID:23906035

  11. Population density and distribution of wheat bugs infesting durum wheat in Sardinia, Italy.

    PubMed

    Salis, Luigi; Goula, Marta; Izquierdo, Jordi; Gordún, Elena

    2013-01-01

    Wheat is a very important crop in Italy, and is infested by wheat bugs belonging to the genera Eurygaster (Hemiptera: Scutellaridae) and Aelia (Hemiptera: Pentatomidae). Many wheat bug infestations have been reported in the north, south, and center of Italy, both in the past as well as recently. The present study was carried out in Sardinia, Italy, during two years (2007 and 2008). The objective of this study was to determine the species and distribution of wheat bugs in durum wheat fields in Sardinia, and to estimate their population density in order to know the incidence of the pest on the island. Sampling took place twice a year (May and June) in three zones, representative of durum wheat cropping in the island. Four species of wheat bugs were found; the predominant species was Eurygaster austriaca (Schrank), followed by Aelia germari (Kuster), Eurygaster maura L., and Aelia acuminata L. The average density of wheat bugs was low (1.1 individuals/m²), but in certain areas it was above the damage threshold (4 individuals/m²). For this reason, the conclusion of the study is that this pest should be monitored in order to control outbreaks and prevent their further spread.

  12. Molecular characterization of the celiac disease epitope domains in α-gliadin genes in Aegilops tauschii and hexaploid wheats (Triticum aestivum L.).

    PubMed

    Xie, Zhenze; Wang, Congyan; Wang, Ke; Wang, Shunli; Li, Xiaohui; Zhang, Zhao; Ma, Wujun; Yan, Yueming

    2010-11-01

    Nineteen novel full-ORF α-gliadin genes and 32 pseudogenes containing at least one stop codon were cloned and sequenced from three Aegilops tauschii accessions (T15, T43 and T26) and two bread wheat cultivars (Gaocheng 8901 and Zhongyou 9507). Analysis of three typical α-gliadin genes (Gli-At4, Gli-G1 and Gli-Z4) revealed some InDels and a considerable number of SNPs among them. Most of the pseudogenes were resulted from C to T change, leading to the generation of TAG or TAA in-frame stop codon. The putative proteins of both Gli-At3 and Gli-Z7 genes contained an extra cysteine residue in the unique domain II. Analysis of toxic epitodes among 19 deduced α-gliadins demonstrated that 14 of these contained 1-5 T cell stimulatory toxic epitopes while the other 5 did not contain any toxic epitopes. The glutamine residues in two specific ployglutamine domains ranged from 7 to 27, indicating a high variation in length. According to the numbers of 4 T cell stimulatory toxic epitopes and glutamine residues in the two ployglutamine domains among the 19 α-gliadin genes, 2 were assigned to chromosome 6A, 5 to chromosome 6B and 12 to chromosome 6D. These results were consistent with those from wheat cv. Chinese Spring nulli-tetrasomic and phylogenetic analysis. Secondary structure prediction showed that all α-gliadins had high content of β-strands and most of the α-helixes and β-strands were present in two unique domains. Phylogenetic analysis demonstrated that α-gliadin genes had a high homology with γ-gliadin, B-hordein, and LMW-GS genes and they diverged at approximate 39 MYA. Finally, the five α-gliadin genes were successfully expressed in E. coli, and their expression amount reached to the maximum after 4 h induced by IPTG, indicating that the α-gliadin genes can express in a high level under the control of T(7) promoter.

  13. Effect of Allelic Variation at the Glu-3/Gli-1 Loci on Breadmaking Quality Parameters in Hexaploid Wheat (Triticum aestivum L.)

    PubMed Central

    Bonafede, Marcos D.; Tranquilli, Gabriela; Pflüger, Laura A.; Peña, Roberto J.; Dubcovsky, Jorge

    2016-01-01

    Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program we developed a set of nine near isogenic lines (NILs) including different Glu-A3/GliA-1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3iMan alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3iChu were consistently associated with weak gluten and low quality values. The value of different Glu3/Gli-1 allele combinations to improve breadmaking quality is discussed. PMID:27818572

  14. Effect of Allelic Variation at the Glu-3/Gli-1 Loci on Breadmaking Quality Parameters in Hexaploid Wheat (Triticum aestivum L.).

    PubMed

    Bonafede, Marcos D; Tranquilli, Gabriela; Pflüger, Laura A; Peña, Roberto J; Dubcovsky, Jorge

    2015-03-01

    Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program we developed a set of nine near isogenic lines (NILs) including different Glu-A3/GliA-1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3iMan alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3iChu were consistently associated with weak gluten and low quality values. The value of different Glu3/Gli-1 allele combinations to improve breadmaking quality is discussed.

  15. Application of population sequencing (POPSEQ) for ordering and inputting genotyping-by-sequencing markers in hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The advancement of next-generation sequencing technologies in conjunction with new bioinformatics tools enabled fine-tuning of sequence-based high resolution mapping strategies for complex genomes. Although genotyping-by-sequencing (GBS) provides a large number of markers, its application for assoc...

  16. Genomic dissection of drought resistance in durum wheat x wild emmer wheat recombinant inbreed line population.

    PubMed

    Peleg, Zvi; Fahima, Tzion; Krugman, Tamar; Abbo, Shahal; Yakir, Dan; Korol, Abraham B; Saranga, Yehoshua

    2009-07-01

    Drought is the major factor limiting wheat productivity worldwide. The gene pool of wild emmer wheat, Triticum turgidum ssp. dicoccoides, harbours a rich allelic repertoire for morpho-physiological traits conferring drought resistance. The genetic and physiological bases of drought responses were studied here in a tetraploid wheat population of 152 recombinant inbreed lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc# G18-16), under contrasting water availabilities. Wide genetic variation was found among RILs for all studied traits. A total of 110 quantitative trait loci (QTLs) were mapped for 11 traits, with LOD score range of 3.0-35.4. Several QTLs showed environmental specificity, accounting for productivity and related traits under water-limited (20 QTLs) or well-watered conditions (15 QTLs), and in terms of drought susceptibility index (22 QTLs). Major genomic regions controlling productivity and related traits were identified on chromosomes 2B, 4A, 5A and 7B. QTLs for productivity were associated with QTLs for drought-adaptive traits, suggesting the involvement of several strategies in wheat adaptation to drought stress. Fifteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. The identified QTLs may facilitate the use of wild alleles for improvement of drought resistance in elite wheat cultivars.

  17. Uncovering hidden variation in polyploid wheat

    PubMed Central

    Krasileva, Ksenia V.; Vasquez-Gross, Hans A.; Howell, Tyson; Bailey, Paul; Paraiso, Francine; Clissold, Leah; Simmonds, James; Ramirez-Gonzalez, Ricardo H.; Wang, Xiaodong; Borrill, Philippa; Fosker, Christine; Ayling, Sarah; Phillips, Andrew L.; Uauy, Cristobal

    2017-01-01

    Comprehensive reverse genetic resources, which have been key to understanding gene function in diploid model organisms, are missing in many polyploid crops. Young polyploid species such as wheat, which was domesticated less than 10,000 y ago, have high levels of sequence identity among subgenomes that mask the effects of recessive alleles. Such redundancy reduces the probability of selection of favorable mutations during natural or human selection, but also allows wheat to tolerate high densities of induced mutations. Here we exploited this property to sequence and catalog more than 10 million mutations in the protein-coding regions of 2,735 mutant lines of tetraploid and hexaploid wheat. We detected, on average, 2,705 and 5,351 mutations per tetraploid and hexaploid line, respectively, which resulted in 35–40 mutations per kb in each population. With these mutation densities, we identified an average of 23–24 missense and truncation alleles per gene, with at least one truncation or deleterious missense mutation in more than 90% of the captured wheat genes per population. This public collection of mutant seed stocks and sequence data enables rapid identification of mutations in the different copies of the wheat genes, which can be combined to uncover previously hidden variation. Polyploidy is a central phenomenon in plant evolution, and many crop species have undergone recent genome duplication events. Therefore, the general strategy and methods developed herein can benefit other polyploid crops. PMID:28096351

  18. Triticale powdery mildew: population characterization and wheat gene efficiency.

    PubMed

    Bouguennec, Annaig; Trottet, Maxime; du Cheyron, Philippe; Lonnet, Philippe

    2014-01-01

    Powdery mildew has emerged on triticale in the early 2000s in many locations, probably due to a host range expansion of the wheat formae speciales, Blumeria graminis f.sp. tritici. Many triticale cultivars are highly susceptible to powdery mildew, mainly in seedling stage, revealing a probably narrow genetic basis for powdery mildew resistance genes (Pm). Moreover, as Blumeria graminis is an obligate biotrophic fungus, it is very time consuming and difficult to maintain powdery mildew isolates for a non-specialized laboratory and populations can evolve. In order to identify wheat Pm genes efficient against natural populations of powdery mildew, wheat differential hosts and triticale seedlings were inoculated below susceptible triticale crop naturally contaminated by mildew, in several locations and several years. Symptoms on seedlings were measured after approximately two weeks of incubation in favorable fungus growth conditions. According to these data, we classified the Pm genes presents in our wheat differential hosts set in 3 classes: Pm already overcame by triticale powdery mildew, Pm having variable effects and Pm still efficient against triticale mildew. Data on triticale seedlings allowed us to identify some few triticale cultivars resistant to Blumeria graminis in seedling stage. We will try to identify Pm genes present in those cultivars next year by testing them with the characterized isolates of powdery mildew from Gent University. Nevertheless, interspecific crossing of wheat, resistant to powdery mildew in seedling stage, and rye have been initiated to introduce potentially interesting genes for resistance in triticale.

  19. Genetic basis of triticale breeding (x triticale). IV. Embryo culture for synthesizing primary hexaploid triticales

    SciTech Connect

    Gordei, I.A.; Khodortsova, L.F.

    1986-07-01

    Results are reported on enhancing the efficiency of embryo culture for synthesizing primary hexaploid triticales (AABBRR, 2n = 42). The antioxidant tomatoside has a positive effect on the reduction of progamous incompatibility of wheat with rye and increases the output of wheat-rye amphihaploids. It has been established that irradiation of embryos, cultured on nutrient medium, with helium-neon laser, increases significantly (P < 0.01) the regeneration frequency of the wheat-rye hybrid embryos. The highest frequency (40%) of amphidiploids was obtained by treating the plants with 0.15% colchicine through roots during the tillering phase. Hexaploid triticales from 11 cross combinations between tetraploid wheats (AABB, 2n = 28) and diploid rye (RR, 2n = 14) formed the initial material for breeding.

  20. Genetic mapping of race-specific stem rust resistance in the synthetic hexaploid W7984 x Opata M85 mapping population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stem rust (caused by Puccinia graminis f. sp. tritici) has historically caused severe yield losses of wheat (Triticum aestivum) worldwide and has been one of the most feared diseases of wheat and barley (Hordeum vulgare). Stem rust has been controlled successfully through the use of resistant varie...

  1. Cytotype distribution at a diploid–hexaploid contact zone in Aster amellus (Asteraceae)

    PubMed Central

    Castro, S.; Loureiro, J.; Procházka, T.; Münzbergová, Z.

    2012-01-01

    Background and Aims The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. Methods Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4′,6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. Key Results The diploid–hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. Conclusions The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to

  2. Change in biotypic diversity of Russian wheat aphid (Hemiptera: Aphididae) populations in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A key component of Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing Dn4 gene. Biotypic diversity in RWA populations has not been...

  3. Modeling spatial variation of Russian wheat aphid overwintering population densities in Colorado winter wheat.

    PubMed

    Merrill, Scott C; Holtzer, Thomas O; Peairs, Frank B; Lester, Philip J

    2009-04-01

    The Russian wheat aphid, Diuraphis noxia (Kurdjumov), is a pest of small grain crops that has caused hundreds of millions of dollars of damage since it was first reported in the United States in 1986. Much is known about D. noxia population dynamics during the spring and early summer when most of the crop damage occurs, whereas little is known about the system during the overwintering period. Using a spatially explicit model developed from field observations in a wheat/fallow agro-ecosystem, we sought for predictable variation in overwintering success of D. noxia based on environmental factors such as topography and soil type. Successful modeling of densities of D. noxia would facilitate early control efforts targeting locations where D. noxia successfully overwintered. D. noxia density data were collected over 3 yr at two sites in eastern Colorado. The model incorporates georeferenced data from soil surveys, topography, and satellite imagery as predictor variables. Our approach links an information theoretic approach for model inference and model selection to landscape ecology, allowing for the examination of multiple candidate models and variables within each of the candidate models. Results were used to create trend surface models for D. noxia density in winter wheat agroecosystems. The model has the potential for use in site specific pesticide applications. Using site specific pesticide applications, pesticide inputs could be reduced by an estimated 30%, reducing input costs to the producer, increasing natural enemy refuges, reducing environmental contamination, augmenting pesticide resistance management practices, and reducing exposure of agricultural workers.

  4. Virulence structure of the eastern U.S. wheat powdery mildew population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the population structure of wheat powdery mildew in the eastern 2 U.S., and the most recent report on virulence in this pathogen population involved isolates 3 collected in 1993-94. In the present study, wheat leaves naturally infected with powdery mildew 4 were collected from ...

  5. Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species.

    PubMed

    Yu, Q; Ahmad-Hamdani, M S; Han, H; Christoffers, M J; Powles, S B

    2013-03-01

    Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids.

  6. Evolutionary history of the mitochondrial genome in Mycosphaerella populations infecting bread wheat, durum wheat and wild grasses.

    PubMed

    Torriani, Stefano F F; Brunner, Patrick C; McDonald, Bruce A

    2011-02-01

    Plant pathogens emerge in agro-ecosystems following different evolutionary mechanisms over different time scales. Previous analyses based on sequence variation at six nuclear loci indicated that Mycosphaerella graminicola diverged from an ancestral population adapted to wild grasses during the process of wheat domestication approximately 10,500 years ago. We tested this hypothesis by conducting coalescence analyses based on four mitochondrial loci using 143 isolates that included four closely related pathogen species originating from four continents. Pathogen isolates from bread and durum wheat were included to evaluate the emergence of specificity towards these hosts in M. graminicola. Although mitochondrial and nuclear genomes differed greatly in degree of genetic variability, their coalescence was remarkably congruent, supporting the proposed origin of M. graminicola through host tracking. The coalescence analysis was unable to trace M. graminicola host specificity through recent evolutionary time, indicating that the specificity towards durum or bread wheat emerged following the domestication of the pathogen on wheat.

  7. Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States.

    PubMed

    Puterka, G J; Giles, K L; Brown, M J; Nicholson, S J; Hammon, R W; Peairs, F B; Randolph, T L; Michaels, G J; Bynum, E D; Springer, T L; Armstrong, J S; Mornhinweg, D W

    2015-04-01

    A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex. Our objectives were to determine the biotypic diversity in the Central Great Plains and Colorado Plateau at regional (2010, 2011, 2013) and local (2012) levels and detect the presence of new Russian wheat aphid biotypes. Regional and within-field aphid collections were screened against Russian wheat aphid-resistant wheat genotypes containing genes Dn3, Dn4, Dn6, Dn7, Dn9, CI2401; and resistant barley STARS 9301B. In 2010, all aphid collections from Texas were avirulent to the Dn4 resistance gene in wheat. Regional results revealed Dn4 avirulent RWA6 was widespread (55-84%) in populations infesting wheat in both regions. Biotypes RWA1, 2, and 3/7 were equally represented with percentages<20% each while RWA8 was rarely detected. Combining percentages of RWA1, 6, and 8 across regions to estimate avirulence to Dn4 gene revealed high percentages for both 2011 (64-80%) and 2013 (69-90%). In contrast, the biotype structure at the local level differed where biotype percentages varied up to ≥2-fold between fields. No new biotypes were detected; therefore, Dn7, CI2401, and STARS9301B remained resistant to all known Russian wheat aphid biotypes. This study documents a shift to Dn4 avirulent biotypes and serves as a valuable baseline for biotypic diversity in Russian wheat aphid populations prior to the deployment of new Russian wheat aphid-resistant wheat cultivars.

  8. Fertility of a spontaneous hexaploid male Siberian sturgeon, Acipenser baerii

    PubMed Central

    2014-01-01

    Background Evolution of sturgeons and paddlefishes (order Acipenseriformes) is inherently connected with polyploidization events which resulted in differentiation of ploidy levels and chromosome numbers of present acipenseriform species. Moreover, allopolyploidization as well as autopolyploidization seems to be an ongoing process in these fishes and individuals with abnormal ploidy levels were occasionally observed within sturgeon populations. Here, we reported occurrence of Siberian sturgeon (Acipenser baerii) male with abnormal ploidy level for this species, accessed its ploidy level and chromosome number and investigate its potential sterility or fertility in comparison with normal individuals of sterlet (A. ruthenus), Russian sturgeon (A. gueldenstaedtii) and Siberian sturgeon (A. baerii). Results Acipenser ruthenus possessed 120 chromosomes, exhibiting recent diploidy (2n), A. gueldenstaedtii and A. baerii had ~245 chromosomes representing recent tetraploidy (4n), and A. baerii male with abnormal ploidy level had ~ 368 chromosomes, indicating recent hexaploidy (6n). Genealogy assessed from the mtDNA control region did not reveal genome markers of other sturgeon species and this individual was supposed to originate from spontaneous 1.5 fold increment in number of chromosome sets with respect to the number most frequently found in nature for this species. Following hormone stimulation, the spontaneous hexaploid male produced normal sperm with ability for fertilization. Fertilization of A. baerii and A. gueldenstaedtii ova from normal 4n level females with sperm of the hexaploid male produced viable, non-malformed pentaploid (5n) progeny with a ploidy level intermediate to those of the parents. Conclusion This study firstly described occurrence of hexaploid individual of A. baerii and confirmed its autopolyploid origin. In addition to that, the first detailed evidence about fertility of spontaneous hexaploid sturgeon was provided. If 1.5 fold increment in

  9. Exceptionally High Levels of Genetic Diversity in Wheat Curl Mite (Acari: Eriophyidae) Populations from Turkey.

    PubMed

    Szydło, W; Hein, G; Denizhan, E; Skoracka, A

    2015-08-01

    Recent research on the wheat curl mite species complex has revealed extensive genetic diversity that has distinguished several genetic lineages infesting bread wheat (Triticum aestivum L.) and other cereals worldwide. Turkey is the historical region of wheat and barley (Hordeum vulgare L.) domestication and diversification. The close relationship between these grasses and the wheat curl mite provoked the question of the genetic diversity of the wheat curl mite in this region. The scope of the study was to investigate genetic differentiation within the wheat curl mite species complex on grasses in Turkey. Twenty-one wheat curl mite populations from 16 grass species from nine genera (Agropyron sp., Aegilops sp., Bromus sp., Elymus sp., Eremopyrum sp., Hordeum sp., Poa sp., Secale sp., and Triticum sp.) were sampled in eastern and southeastern Turkey for genetic analyses. Two molecular markers were amplified: the cytochrome oxidase subunit I coding region of mtDNA (COI) and the D2 region of 28S rDNA. Phylogenetic analyses revealed high genetic variation of the wheat curl mite in Turkey, primarily on Bromus and Hordeum spp., and exceptionally high diversity of populations associated with bread wheat. Three wheat-infesting wheat curl mite lineages known to occur on other continents of the world, including North and South America, Australia and Europe, were found in Turkey, and at least two new genetic lineages were discovered. These regions of Turkey exhibit rich wheat curl mite diversity on native grass species. The possible implications for further studies on the wheat curl mite are discussed.

  10. Diets of differentially processed wheat alter ruminal fermentation parameters and microbial populations in beef cattle.

    PubMed

    Jiang, S Z; Yang, Z B; Yang, W R; Li, Z; Zhang, C Y; Liu, X M; Wan, F C

    2015-11-01

    The influences of differently processed wheat products on rumen fermentation, microbial populations, and serum biochemistry profiles in beef cattle were studied. Four ruminally cannulated Limousin × Luxi beef cattle (400 ± 10 kg) were used in the experiment with a 4 × 4 Latin square design. The experimental diets contained (on a DM basis) 60% corn silage as a forage source and 40% concentrate with 4 differently processed wheat products (extruded, pulverized, crushed, and rolled wheat). Concentrations of ruminal NH-N and microbial protein (MCP) in cattle fed crushed and rolled wheat were greater ( < 0.05) than the corresponding values in cattle fed pulverized and extruded wheat. Ruminal concentrations of total VFA and acetate and the ratio of acetate to propionate decreased ( < 0.05) with increased geometric mean particle size (geometric mean diameter) of processed wheat, except for extruded wheat; cattle fed extruded wheat had the lowest concentrations of total VFA and acetate among all treatments. The relative abundance of , , ciliated protozoa, and was lower in cattle fed the pulverized wheat diet than in the other 3 diets ( < 0.05), whereas the relative abundance of was decreased in cattle fed extruded wheat compared with cattle fed crushed and rolled wheat ( < 0.05). No treatment effect was obtained for serum enzyme activity and protein concentration ( > 0.05). Our findings suggest that the method of wheat processing could have a significant effect on ruminal fermentation parameters and microbial populations in beef cattle and that crushed and rolled processing is better in terms of ruminal NH-N and MCP content, acetate-to-propionate ratio, and relative abundance of rumen microorganisms.

  11. [Population dynamics of ground carabid beetles and spiders in a wheat field along the wheat-alfalfa interface and their response to alfalfa mowing].

    PubMed

    Liu, Wen-Hui; Hu, Yi-Jun; Hu, Wen-Chao; Hong, Bo; Guan, Xiao-Qing; Ma, Shi-Yu; He, Da-Han

    2014-09-01

    Taking the wheat-alfalfa and wheat-wheat interfaces as model systems, sampling points were set by the method of pitfall trapping in the wheat field at the distances of 3 m, 6 m, 9 m, 12 m, 15 m, 18 m, 21 m, 24 m, and 27 m from the interface. The species composition and abundance of ground carabid beetles and spiders captured in pitfalls were investigated. The results showed that, to some extent there was an edge effect on species diversity and abundance of ground carabid beetles and spiders along the two interfaces. A marked edge effect was observed between 15 m and 18 m along the alfalfa-wheat interface, while no edge effect was found at a distance over 20 m. The edge effect along the wheat-wheat interface was weaker in comparison to the alfalfa-wheat interface. Alfalfa mowing resulted in the migration of a large number of ground carabid beetles and spiders to the adjacent wheat filed. During ten days since mowing, both species and abundance of ground carabid beetles and spiders increased in wheat filed within the distance of 20 m along the alfalfa-wheat interface. The spatial distribution of species diversity of ground beetles and spiders, together with the population abundance of the dominant Chlaenius pallipes and Pardosa astrigera, were depicted, which could directly indicate the migrating process of natural enemy from alfalfa to wheat field.

  12. Wheat Landrace Genome Diversity.

    PubMed

    Wingen, Luzie U; West, Claire; Leverington-Waite, Michelle; Collier, Sarah; Orford, Simon; Goram, Richard; Yang, Cai-Yun; King, Julie; Allen, Alexandra M; Burridge, Amanda; Edwards, Keith J; Griffiths, Simon

    2017-04-01

    Understanding the genomic complexity of bread wheat (Triticum aestivum L.) is a cornerstone in the quest to unravel the processes of domestication and the following adaptation of domesticated wheat to a wide variety of environments across the globe. Additionally, it is of importance for future improvement of the crop, particularly in the light of climate change. Focusing on the adaptation after domestication, a nested association mapping (NAM) panel of 60 segregating biparental populations was developed, mainly involving landrace accessions from the core set of the Watkins hexaploid wheat collection optimized for genetic diversity. A modern spring elite variety, "Paragon," was used as common reference parent. Genetic maps were constructed following identical rules to make them comparable. In total, 1611 linkage groups were identified, based on recombination from an estimated 126,300 crossover events over the whole NAM panel. A consensus map, named landrace consensus map (LRC), was constructed and contained 2498 genetic loci. These newly developed genetics tools were used to investigate the rules underlying genome fluidity or rigidity, e.g., by comparing marker distances and marker orders. In general, marker order was highly correlated, which provides support for strong synteny between bread wheat accessions. However, many exceptional cases of incongruent linkage groups and increased marker distances were also found. Segregation distortion was detected for many markers, sometimes as hot spots present in different populations. Furthermore, evidence for translocations in at least 36 of the maps was found. These translocations fell, in general, into many different translocation classes, but a few translocation classes were found in several accessions, the most frequent one being the well-known T5B:7B translocation. Loci involved in recombination rate, which is an interesting trait for plant breeding, were identified by QTL analyses using the crossover counts as a trait

  13. Wheat Landrace Genome Diversity

    PubMed Central

    Wingen, Luzie U.; West, Claire; Leverington-Waite, Michelle; Collier, Sarah; Orford, Simon; Goram, Richard; Yang, Cai-Yun; King, Julie; Allen, Alexandra M.; Burridge, Amanda; Edwards, Keith J.; Griffiths, Simon

    2017-01-01

    Understanding the genomic complexity of bread wheat (Triticum aestivum L.) is a cornerstone in the quest to unravel the processes of domestication and the following adaptation of domesticated wheat to a wide variety of environments across the globe. Additionally, it is of importance for future improvement of the crop, particularly in the light of climate change. Focusing on the adaptation after domestication, a nested association mapping (NAM) panel of 60 segregating biparental populations was developed, mainly involving landrace accessions from the core set of the Watkins hexaploid wheat collection optimized for genetic diversity. A modern spring elite variety, “Paragon,” was used as common reference parent. Genetic maps were constructed following identical rules to make them comparable. In total, 1611 linkage groups were identified, based on recombination from an estimated 126,300 crossover events over the whole NAM panel. A consensus map, named landrace consensus map (LRC), was constructed and contained 2498 genetic loci. These newly developed genetics tools were used to investigate the rules underlying genome fluidity or rigidity, e.g., by comparing marker distances and marker orders. In general, marker order was highly correlated, which provides support for strong synteny between bread wheat accessions. However, many exceptional cases of incongruent linkage groups and increased marker distances were also found. Segregation distortion was detected for many markers, sometimes as hot spots present in different populations. Furthermore, evidence for translocations in at least 36 of the maps was found. These translocations fell, in general, into many different translocation classes, but a few translocation classes were found in several accessions, the most frequent one being the well-known T5B:7B translocation. Loci involved in recombination rate, which is an interesting trait for plant breeding, were identified by QTL analyses using the crossover counts as a

  14. Biotypic diversity in Colorado Russian wheat aphid (Hemiptera: Aphididae) populations.

    PubMed

    Weiland, Aubrey A; Peairs, Frank B; Randolph, Terri L; Rudolph, Jeffrey B; Haley, Scott D; Puterka, Gary J

    2008-04-01

    The biotypic diversity of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), was assessed in five isolates collected in Colorado. Three isolates, RWA 1, RWA 2, and an isolate from Montezuma County, CO, designated RWA 6, were originally collected from cultivated wheat, Triticum aestivum L., and obtained from established colonies at Colorado State University. The fourth isolate, designated RWA 7, was collected from Canada wildrye, Elymus canadensis L., in Baca County, CO. The fifth isolate, designated RWA 8, was collected from crested wheatgrass, Agropyron cristatum (L.) Gaertn., in Montezuma County, CO. The four isolates were characterized in a standard seedling assay, by using 24 plant differentials, 22 wheat lines and two barley, Hordeum vulgare L., lines. RWA 1 was the least virulent of the isolates, killing only the four susceptible entries. RWA 8 also killed only the four susceptible entries, but it expressed intermediate virulence on seven wheat lines. RWA 6, killing nine entries, and RWA 7, killing 11 entries, both expressed an intermediate level of virulence overall, but differed in their level of virulence to 'CO03797' (Dn1), 'Yumar' (Dn4), and 'CO960293-2'. RWA 2 was the most virulent isolate, killing 14 entries, including Dn4- and Dny-containing wheat. Four wheat lines, '94M370' (Dn7), 'STARS 02RWA2414-11', CO03797, and 'CI2401', were resistant to the five isolates. The results of this screening confirm the presence of five unique Russian wheat aphid biotypes in Colorado.

  15. Genetically divergent types of the wheat leaf fungus Puccinia triticina in Ethiopia, a center of tetraploid wheat diversity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. ...

  16. A SNP genotyping array for hexaploid oat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recognizing a need in cultivated hexaploid oat (Avena sativa L.) for a reliable set of reference SNPs, we have developed a 6K BeadChip design containing 257 Infinium I and 5,486 Infinium II designs corresponding to 5,743 SNPs. Of those, 4,975 SNPs yielded successful assays after array manufacturing...

  17. Ecogeography, genetic diversity, and breeding value of wild emmer wheat (Triticum dicoccoides Korn ex Asch. & Graebn.) Thell.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wild emmer wheat (Triticum dicoccoides Körn ex Asch. & Graebn.) Thell. is the allotetraploid (2n=4x=28; genome BBAA) progenitor of cultivated wheat. It is fully compatible with the tetraploid (BBAA) durum wheat (Triticum durum), and can be crossed with the hexaploid (2n=6x=42; BBAADD) wheat (Triticu...

  18. Reproduction and Population Dynamics as Biotypic Markers of Russian Wheat Aphid Diuraphis noxia (Kurdjumov)

    PubMed Central

    Ngenya, Watson; Malinga, Joyce; Tabu, Isaiah; Masinde, Emily

    2016-01-01

    Russian wheat aphid Diuraphis noxia (Kurdjumov) is widely established in wheat-growing countries where it causes significant economic losses. The development and use of Russian wheat aphid (RWA)-resistant wheat varieties has been constrained by the variation in resident RWA populations and the evolution of virulent biotypes. An experiment was set up at the Kenya Agricultural and Livestock Research Organization (KALRO), Njoro, to characterize RWA populations based on phenotypic characteristics of reproduction, development and population dynamics. RWA populations from the regions of Eldoret, Mau Narok and Njoro were used in the study. A factorial experiment was set up in randomized complete block design replicated eleven times. A single day-old nymph was placed on a new, fully-open leaf in a 0.5 cm-diameter clear plastic straw leaf cage and observed daily for its entire lifetime. The results showed that there were variations in aphid lifespan, reproductive longevity and aphid fecundity between populations, indicating that the phenotypic markers used to determine biotypes were good enough to show distinct biotypes among populations of the RWA in Kenya. Further, the study concluded that the use of phenotypic life and reproductive markers was a valid way of characterizing biotypes of RWA worldwide. PMID:27049398

  19. Reproduction and Population Dynamics as Biotypic Markers of Russian Wheat Aphid Diuraphis noxia (Kurdjumov).

    PubMed

    Ngenya, Watson; Malinga, Joyce; Tabu, Isaiah; Masinde, Emily

    2016-04-02

    Russian wheat aphid Diuraphis noxia (Kurdjumov) is widely established in wheat-growing countries where it causes significant economic losses. The development and use of Russian wheat aphid (RWA)-resistant wheat varieties has been constrained by the variation in resident RWA populations and the evolution of virulent biotypes. An experiment was set up at the Kenya Agricultural and Livestock Research Organization (KALRO), Njoro, to characterize RWA populations based on phenotypic characteristics of reproduction, development and population dynamics. RWA populations from the regions of Eldoret, Mau Narok and Njoro were used in the study. A factorial experiment was set up in randomized complete block design replicated eleven times. A single day-old nymph was placed on a new, fully-open leaf in a 0.5 cm-diameter clear plastic straw leaf cage and observed daily for its entire lifetime. The results showed that there were variations in aphid lifespan, reproductive longevity and aphid fecundity between populations, indicating that the phenotypic markers used to determine biotypes were good enough to show distinct biotypes among populations of the RWA in Kenya. Further, the study concluded that the use of phenotypic life and reproductive markers was a valid way of characterizing biotypes of RWA worldwide.

  20. Population genetics of the wheat curl mite (Aceria tosichella Keifer) in Australia: implications for the management of wheat pathogens.

    PubMed

    Miller, A D; Umina, P A; Weeks, A R; Hoffmann, A A

    2012-04-01

    The wheat curl mite (WCM), Aceria tosichella Keifer, is a polyphagous eriophyoid mite and the primary vector of wheat streak mosaic virus (WSMV) and five other viral pathogens in cereals. Previous research using molecular markers and a series of laboratory experiments found A. tosichella in Australia to consist of two genetically distinct lineages, which have broad overlapping distributions and differ in their ability to transmit WSMV under controlled conditions. This pattern of transmission also appears to be apparent in the field, whereby a strong association between WSMV detection and a single WCM lineage has been detected. In this study, we conduct a population genetic analysis and provide information on the genetic structure of the Australian viruliferous WCM lineage. We assessed genetic differentiation of 16 WCM populations using nine microsatellite markers. Strong evidence for extensive gene flow and low genetic structuring throughout the Australian wheatbelt was evident, with an exception for Western Australian and far north Queensland populations that appear to be genetically isolated. The data also indicate genetic patterns consistent with an arrhenotokous parthenogenetic mode of reproduction. Implications of these findings are discussed with reference to the management of WCM and associated cereal pathogens in Australia and overseas.

  1. Allelic diversity associated with aridity gradient in wild emmer wheat populations.

    PubMed

    Peleg, Zvi; Saranga, Yehoshua; Krugman, Tamar; Abbo, Shahal; Nevo, Eviatar; Fahima, Tzion

    2008-01-01

    The association between allelic diversity and ecogeographical variables was studied in natural populations of wild emmer wheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell.], the tetraploid progenitor of cultivated wheat. Patterns of allelic diversity in 54 microsatellite loci were analyzed in a collection of 145 wild emmer wheat accessions representing 25 populations that were sampled across naturally occurring aridity gradient in Israel and surrounding regions. The obtained results revealed that 56% of the genetic variation resided among accessions within populations, while only 44% of the variation resided between populations. An unweighted pair-group method analysis (UPGMA) tree constructed based on the microsatellite allelic diversity divided the 25 populations into six major groups. Several groups were comprised of populations that were collected in ecologically similar but geographically remote habitats. Furthermore, genetic differentiation between populations was independent of the geographical distances. An interesting evolutionary phenomenon is highlighted by the unimodal relationship between allelic diversity and annual rainfall (r = 0.74, P < 0.0002), indicating higher allelic diversity in populations originated from habitats with intermediate environmental stress (i.e. rainfall 350-550 mm year(-1)). These results show for the first time that the 'intermediate-disturbance hypothesis', explaining biological diversity at the ecosystem level, also dominates the genetic diversity within a single species, the lowest hierarchical element of the biological diversity.

  2. Temperature stratification and insect pest populations in stored wheat with suction versus pressure aeration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-year study was conducted to compare temperature profiles in the headspace and in the bulk mass of wheat aerated through pressure aeration and suction aeration. Insect pitfall traps were used to measure naturally-occurring populations of stored product insects. Results show uniform distributi...

  3. Irrigation differentially impacts populations of indigenous antibiotic-producing Pseudomonas spp. in the rhizosphere of wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz+) and 2,4-diacetylphloroglucinol (Phl+) in the rhizosphere of wheat grown in the low precipitation zone (150 to 300 mm annually) of the...

  4. Registration of the LouAu (Louise/IWA8608077) wheat recombinant inbred line mapping population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    LouAu (Louise/IWA8608077) is a wheat (Triticum aestivum L.) recombinant inbred line population developed by the United States Department of Agriculture-Agriculture Research Service, with Oregon State and Washington State Universities, from a cross between the soft white spring cultivar 'Louise' and ...

  5. Registration of USG 3209/Jaypee Wheat Recombinant Inbred Line Mapping Population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘USG 3209’/‘Jaypee’ (Reg. No. MP-3, NSL 465777 MAP), is a soft red winter wheat (Triticum aestivum L.) recombinant inbred line (RIL) population developed by Virginia Polytechnic Institute and State University and submitted to the USDA–ARS National Small Grains Germplasm Research Facility in Aberdeen...

  6. Grazing activity and ruminal bacterial population associated with frothy bloat in steers grazing winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two grazing experiments were designed to elucidate the shifts in rumen bacterial populations (Exp. 1) and grazing activities (Exp. 2) in wheat forage diets between bloated and non-bloated steers. In Exp. 1, the bacterial DNA density was greatest for Ruminococcus flavefaciens, Streptococcus bovis, a...

  7. Utilization of deletion bins to anchor and order sequences along the wheat 7B chromosome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bread wheat (Triticum aestivum L.) has a large, complex and highly repetitive genome which is challenging to assemble into high quality pseudo-chromosomes. As part of the international effort to sequence the hexaploid bread wheat genome by the international wheat genome sequencing consortium (IWGSC)...

  8. De Novo Transcriptome Assembly and Analyses of Gene Expression during Photomorphogenesis in Diploid Wheat Triticum monococcum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triticum monococcum (2n), a close ancestor of the A-genome progenitor of cultivated hexaploid wheat, was used as a model to study components regulating photomorphogenesis in diploid wheat. Constructed were genome-wide transcriptomes of two Triticum monococcum subspecies, the wild winter wheat T. mo...

  9. Proteome Profiling of Wheat Shoots from Different Cultivars

    PubMed Central

    Vu, Lam Dai; Verstraeten, Inge; Stes, Elisabeth; Van Bel, Michiel; Coppens, Frederik; Gevaert, Kris; De Smet, Ive

    2017-01-01

    Wheat is a cereal grain and one of the world’s major food crops. Recent advances in wheat genome sequencing are by now facilitating its genomic and proteomic analyses. However, little is known about possible differences in total protein levels of hexaploid versus tetraploid wheat cultivars, and also knowledge of phosphorylated wheat proteins is still limited. Here, we performed a detailed analysis of the proteome of seedling leaves from two hexaploid wheat cultivars (Triticum aestivum L. Pavon 76 and USU-Apogee) and one tetraploid wheat (T. turgidum ssp. durum cv. Senatore Cappelli). Our shotgun proteomics data revealed that, whereas we observed some significant differences, overall a high similarity between hexaploid and tetraploid varieties with respect to protein abundance was observed. In addition, already at the seedling stage, a small set of proteins was differential between the small (USU-Apogee) and larger hexaploid wheat cultivars (Pavon 76), which could potentially act as growth predictors. Finally, the phosphosites identified in this study can be retrieved from the in-house developed plant PTM-Viewer (bioinformatics.psb.ugent.be/webtools/ptm_viewer/), making this the first searchable repository for phosphorylated wheat proteins. This paves the way for further in depth, quantitative (phospho)proteome-wide differential analyses upon a specific trigger or environmental change. PMID:28348574

  10. Acc homoeoloci and the evolution of wheat genomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We analyzed the DNA sequences of BACs from many wheat libraries containing the Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, to gain understanding of the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Mor...

  11. Absence of gene flow between diploids and hexaploids of Aster amellus at multiple spatial scales.

    PubMed

    Münzbergová, Z; Surinová, M; Castro, S

    2013-02-01

    The potential for gene exchange across ploidy levels has long been recognized, but only a few studies have explored the rate of gene flow among different cytotypes. In addition, most of the existing knowledge comes from contact zones between diploids and tetraploids. The purpose of this paper was to investigate relationships between diploid and hexaploid individuals within the Aster amellus aggregate. A. amellus is known to occur in diploid and hexaploid cytotypes in Europe, with a complex contact zone in central Europe. Patterns of genetic diversity were investigated using seven microsatellite loci at three different spatial scales: (1) in the single known mixed-ploidy population; (2) in populations at the contact zone and (3) in a wider range of populations across Europe. The results show clear separation of the cytotypes at all three spatial scales. In addition, analysis of molecular variance strongly supported a model predicting a single origin of the hexaploids, with no or very limited gene flow between the cytotypes. Some hexaploid individuals found in the mixed-ploidy population, however, fell into the diploid cluster. This could suggest recurrent polyploid formation or occasional cross-pollination between cytotypes; however, there are strong post-zygotic breeding barriers between the two cytotypes, making the latter less plausible. Overall, the results suggest that the cytotypes could represent two cryptic species. Nevertheless, their formal separation is difficult as they cannot be distinguished morphologically, occupy very similar habitat conditions and have largely overlapping distribution ranges. These results show that polyploid complexes must be treated with caution as they can hide biological diversity and can have different adaptation potentials, evolving independently.

  12. Population genetic analysis and trichothecene profiling of Fusarium graminearum from wheat in Uruguay.

    PubMed

    Pan, D; Mionetto, A; Calero, N; Reynoso, M M; Torres, A; Bettucci, L

    2016-03-11

    Fusarium graminearum sensu stricto (F. graminearum s.s.) is the major causal agent of Fusarium head blight of wheat worldwide, and contaminates grains with trichothecene mycotoxins that cause serious threats to food safety and animal health. An important aspect of managing this pathogen and reducing mycotoxin contamination of wheat is knowledge regarding its population genetics. Therefore, isolates of F. graminearum s.s. from the major wheat-growing region of Uruguay were analyzed by amplified fragment length polymorphism assays, PCR genotyping, and chemical analysis of trichothecene production. Of the 102 isolates identified as having the 15-ADON genotype via PCR genotyping, all were DON producers, but only 41 strains were also 15-ADON producers, as determined by chemical analysis. The populations were genotypically diverse but genetically similar, with significant genetic exchange occurring between them. Analysis of molecular variance indicated that most of the genetic variability resulted from differences between isolates within populations. Multilocus linkage disequilibrium analysis suggested that the isolates had a panmictic population genetic structure and that there is significant recombination occurs in F. graminearum s.s. In conclusion, tour findings provide the first detailed description of the genetic structure and trichothecene production of populations of F. graminearum s.s. from Uruguay, and expands our understanding of the agroecology of F. graminearum and of the correlation between genotypes and trichothecene chemotypes.

  13. TaGW2, a Good Reflection of Wheat Polyploidization and Evolution

    PubMed Central

    Qin, Lin; Zhao, Junjie; Li, Tian; Hou, Jian; Zhang, Xueyong; Hao, Chenyang

    2017-01-01

    Hexaploid wheat consists of three subgenomes, namely, A, B, and D. These well-characterized ancestral genomes also exist at the diploid and tetraploid levels, thereby rendering wheat as a good model species for studying polyploidization. Here, we performed intra- and inter-species comparative analyses of wheat and its relatives to dissect polymorphism and differentiation of the TaGW2 genes. Our results showed that genetic diversity of TaGW2 decreased with progression from the diploids to tetraploids and hexaploids. The strongest selection occurred in the promoter regions of TaGW2-6A and TaGW2-6B. Phylogenetic trees clearly indicated that Triticum urartu and Ae. speltoides were the donors of the A and B genomes in tetraploid and hexaploid wheats. Haplotypes detected among hexaploid genotypes traced back to the tetraploid level. Fst and π values revealed that the strongest selection on TaGW2 occurred at the tetraploid level rather than in hexaploid wheat. This infers that grain size enlargement, especially increased kernel width, mainly occurred in tetraploid genotypes. In addition, relative expression levels of TaGW2s significantly declined from the diploid level to tetraploids and hexaploids, further indicating that these genes negatively regulate kernel size. Our results also revealed that the polyploidization events possibly caused much stronger differentiation than domestication and breeding. PMID:28326096

  14. Evolution and Adaptation of Wild Emmer Wheat Populations to Biotic and Abiotic Stresses.

    PubMed

    Huang, Lin; Raats, Dina; Sela, Hanan; Klymiuk, Valentina; Lidzbarsky, Gabriel; Feng, Lihua; Krugman, Tamar; Fahima, Tzion

    2016-08-04

    The genetic bottlenecks associated with plant domestication and subsequent selection in man-made agroecosystems have limited the genetic diversity of modern crops and increased their vulnerability to environmental stresses. Wild emmer wheat, the tetraploid progenitor of domesticated wheat, distributed along a wide range of ecogeographical conditions in the Fertile Crescent, has valuable "left behind" adaptive diversity to multiple diseases and environmental stresses. The biotic and abiotic stress responses are conferred by series of genes and quantitative trait loci (QTLs) that control complex resistance pathways. The study of genetic diversity, genomic organization, expression profiles, protein structure and function of biotic and abiotic stress-resistance genes, and QTLs could shed light on the evolutionary history and adaptation mechanisms of wild emmer populations for their natural habitats. The continuous evolution and adaptation of wild emmer to the changing environment provide novel solutions that can contribute to safeguarding food for the rapidly growing human population.

  15. Population Genetic Analysis of an Eastern U.S. Wheat Powdery Mildew Population Reveals Geographic and Recent Common Ancestry with U.K. and Israeli Populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The structure of the U.S. wheat powdery mildew population (Blumeria graminis f. sp. tritici) has not been investigated, and the global evolutionary history of B. g. tritici is largely unknown. After gathering 141 single-ascoporic B. g. tritici isolates from 10 eastern U.S. locations, 34 isolates fr...

  16. Efficiently tracking selection in a multiparental population: the case of earliness in wheat.

    PubMed

    Thépot, Stéphanie; Restoux, Gwendal; Goldringer, Isabelle; Hospital, Frédéric; Gouache, David; Mackay, Ian; Enjalbert, Jérôme

    2015-02-01

    Multiparental populations are innovative tools for fine mapping large numbers of loci. Here we explored the application of a wheat Multiparent Advanced Generation Inter-Cross (MAGIC) population for QTL mapping. This population was created by 12 generations of free recombination among 60 founder lines, following modification of the mating system from strict selfing to strict outcrossing using the ms1b nuclear male sterility gene. Available parents and a subset of 380 SSD lines of the resulting MAGIC population were phenotyped for earliness and genotyped with the 9K i-Select SNP array and additional markers in candidate genes controlling heading date. We demonstrated that 12 generations of strict outcrossing rapidly and drastically reduced linkage disequilibrium to very low levels even at short map distances and also greatly reduced the population structure exhibited among the parents. We developed a Bayesian method, based on allelic frequency, to estimate the contribution of each parent in the evolved population. To detect loci under selection and estimate selective pressure, we also developed a new method comparing shifts in allelic frequency between the initial and the evolved populations due to both selection and genetic drift with expectations under drift only. This evolutionary approach allowed us to identify 26 genomic areas under selection. Using association tests between flowering time and polymorphisms, 6 of these genomic areas appeared to carry flowering time QTL, 1 of which corresponds to Ppd-D1, a major gene involved in the photoperiod sensitivity. Frequency shifts at 4 of 6 areas were consistent with earlier flowering of the evolved population relative to the initial population. The use of this new outcrossing wheat population, mixing numerous initial parental lines through multiple generations of panmixia, is discussed in terms of power to detect genes under selection and association mapping. Furthermore we provide new statistical methods for use in

  17. Influence of agro-environmental factors on fusarium infestation and population structure in wheat kernels.

    PubMed

    Rohácik, Tibor; Hudec, Kamil

    2005-01-01

    The influence of location, year and cultivar on occurrence, level of infestation and Fusarium species spectrum in winter wheat seeds were evaluated. The wheat seeds from different cultivars and localities of the Slovak Republic were used for Fusarium species evaluation during years 1999, 2000, 2002 and 2003. The significant influence of the locality on total Fusarium kernel infestation was confirmed. The total sample infestation was significantly higher in the colder and moister localities, lower infestation was in warmer and dryer ones. Cultivar "Astella" was significantly the most susceptible. The widest Fusarium species spectrum was recorded in the locations with a high level of total kernel infestation. In localities with lower infestation, the species spectrum was less numerous. F. poae was the dominant species in all locations. The species F. culmorum, F. avenaceum and Microdochium nivale were subdominant and relatively frequent in the locations with higher altitude. The frequency and density of other isolated species (F. graminearum, F. sporotrichioides, F. tricinctum, F. semitectum, F. acuminatum, F. heterosporum, F. sambucinum, F. solani, F. compactum and F. oxysporum) was trivial in all localities. The kernel infestation and Fusarium population structure in wheat grains mostly depends on microclimatic condition of the locality. Rising of rainfall rate and altitude led to an increase in the species spectrum. The wide Fusarium species spectrum is connected with the high frequency of coincident species. The species with low and medium frequency achieved low or trivial density in population structure.

  18. Ancient DNA from 8400 Year-Old Çatalhöyük Wheat: Implications for the Origin of Neolithic Agriculture

    PubMed Central

    Bilgic, Hatice; Hakki, Erdogan E.; Akkaya, Mahinur S.

    2016-01-01

    Human history was transformed with the advent of agriculture in the Fertile Crescent with wheat as one of the founding crops. Although the Fertile Crescent is renowned as the center of wheat domestication, archaeological studies have shown the crucial involvement of Çatalhöyük in this process. This site first gained attention during the 1961–65 excavations due to the recovery of primitive hexaploid wheat. However, despite the seeds being well preserved, a detailed archaeobotanical description of the samples is missing. In this article, we report on the DNA isolation, amplification and sequencing of ancient DNA of charred wheat grains from Çatalhöyük and other Turkish archaeological sites and the comparison of these wheat grains with contemporary wheat species including T. monococcum, T. dicoccum, T. dicoccoides, T. durum and T. aestivum at HMW glutenin protein loci. These ancient samples represent the oldest wheat sample sequenced to date and the first ancient wheat sample from the Middle East. Remarkably, the sequence analysis of the short DNA fragments preserved in seeds that are approximately 8400 years old showed that the Çatalhöyük wheat stock contained hexaploid wheat, which is similar to contemporary hexaploid wheat species including both naked (T. aestivum) and hulled (T. spelta) wheat. This suggests an early transitory state of hexaploid wheat agriculture from the Fertile Crescent towards Europe spanning present-day Turkey. PMID:26998604

  19. Ancient DNA from 8400 Year-Old Çatalhöyük Wheat: Implications for the Origin of Neolithic Agriculture.

    PubMed

    Bilgic, Hatice; Hakki, Erdogan E; Pandey, Anamika; Khan, Mohd Kamran; Akkaya, Mahinur S

    2016-01-01

    Human history was transformed with the advent of agriculture in the Fertile Crescent with wheat as one of the founding crops. Although the Fertile Crescent is renowned as the center of wheat domestication, archaeological studies have shown the crucial involvement of Çatalhöyük in this process. This site first gained attention during the 1961-65 excavations due to the recovery of primitive hexaploid wheat. However, despite the seeds being well preserved, a detailed archaeobotanical description of the samples is missing. In this article, we report on the DNA isolation, amplification and sequencing of ancient DNA of charred wheat grains from Çatalhöyük and other Turkish archaeological sites and the comparison of these wheat grains with contemporary wheat species including T. monococcum, T. dicoccum, T. dicoccoides, T. durum and T. aestivum at HMW glutenin protein loci. These ancient samples represent the oldest wheat sample sequenced to date and the first ancient wheat sample from the Middle East. Remarkably, the sequence analysis of the short DNA fragments preserved in seeds that are approximately 8400 years old showed that the Çatalhöyük wheat stock contained hexaploid wheat, which is similar to contemporary hexaploid wheat species including both naked (T. aestivum) and hulled (T. spelta) wheat. This suggests an early transitory state of hexaploid wheat agriculture from the Fertile Crescent towards Europe spanning present-day Turkey.

  20. Diversification of the celiac disease α-gliadin complex in wheat: a 33-mer peptide with six overlapping epitopes, evolved following polyploidization.

    PubMed

    Ozuna, Carmen V; Iehisa, Julio C M; Giménez, María J; Alvarez, Juan B; Sousa, Carolina; Barro, Francisco

    2015-06-01

    The gluten proteins from wheat, barley and rye are responsible both for celiac disease (CD) and for non-celiac gluten sensitivity, two pathologies affecting up to 6-8% of the human population worldwide. The wheat α-gliadin proteins contain three major CD immunogenic peptides: p31-43, which induces the innate immune response; the 33-mer, formed by six overlapping copies of three highly stimulatory epitopes; and an additional DQ2.5-glia-α3 epitope which partially overlaps with the 33-mer. Next-generation sequencing (NGS) and Sanger sequencing of α-gliadin genes from diploid and polyploid wheat provided six types of α-gliadins (named 1-6) with strong differences in their frequencies in diploid and polyploid wheat, and in the presence and abundance of these CD immunogenic peptides. Immunogenic variants of the p31-43 peptide were found in most of the α-gliadins. Variants of the DQ2.5-glia-α3 epitope were associated with specific types of α-gliadins. Remarkably, only type 1 α-gliadins contained 33-mer epitopes. Moreover, the full immunodominant 33-mer fragment was only present in hexaploid wheat at low abundance, probably as the result of allohexaploidization events from subtype 1.2 α-gliadins found only in Aegilops tauschii, the D-genome donor of hexaploid wheat. Type 3 α-gliadins seem to be the ancestral type as they are found in most of the α-gliadin-expressing Triticeae species. These findings are important for reducing the incidence of CD by the breeding/selection of wheat varieties with low stimulatory capacity of T cells. Moreover, advanced genome-editing techniques (TALENs, CRISPR) will be easier to implement on the small group of α-gliadins containing only immunogenic peptides.

  1. The emerging biofuel crop Camelina sativa retains a highly undifferentiated hexaploid genome structure.

    PubMed

    Kagale, Sateesh; Koh, Chushin; Nixon, John; Bollina, Venkatesh; Clarke, Wayne E; Tuteja, Reetu; Spillane, Charles; Robinson, Stephen J; Links, Matthew G; Clarke, Carling; Higgins, Erin E; Huebert, Terry; Sharpe, Andrew G; Parkin, Isobel A P

    2014-04-23

    Camelina sativa is an oilseed with desirable agronomic and oil-quality attributes for a viable industrial oil platform crop. Here we generate the first chromosome-scale high-quality reference genome sequence for C. sativa and annotated 89,418 protein-coding genes, representing a whole-genome triplication event relative to the crucifer model Arabidopsis thaliana. C. sativa represents the first crop species to be sequenced from lineage I of the Brassicaceae. The well-preserved hexaploid genome structure of C. sativa surprisingly mirrors those of economically important amphidiploid Brassica crop species from lineage II as well as wheat and cotton. The three genomes of C. sativa show no evidence of fractionation bias and limited expression-level bias, both characteristics commonly associated with polyploid evolution. The highly undifferentiated polyploid genome of C. sativa presents significant consequences for breeding and genetic manipulation of this industrial oil crop.

  2. Association analysis of historical bread wheat germplasm using additive genetic covariance of relatives and population structure.

    PubMed

    Crossa, José; Burgueño, Juan; Dreisigacker, Susanne; Vargas, Mateo; Herrera-Foessel, Sybil A; Lillemo, Morten; Singh, Ravi P; Trethowan, Richard; Warburton, Marilyn; Franco, Jorge; Reynolds, Matthew; Crouch, Jonathan H; Ortiz, Rodomiro

    2007-11-01

    Linkage disequilibrium can be used for identifying associations between traits of interest and genetic markers. This study used mapped diversity array technology (DArT) markers to find associations with resistance to stem rust, leaf rust, yellow rust, and powdery mildew, plus grain yield in five historical wheat international multienvironment trials from the International Maize and Wheat Improvement Center (CIMMYT). Two linear mixed models were used to assess marker-trait associations incorporating information on population structure and covariance between relatives. An integrated map containing 813 DArT markers and 831 other markers was constructed. Several linkage disequilibrium clusters bearing multiple host plant resistance genes were found. Most of the associated markers were found in genomic regions where previous reports had found genes or quantitative trait loci (QTL) influencing the same traits, providing an independent validation of this approach. In addition, many new chromosome regions for disease resistance and grain yield were identified in the wheat genome. Phenotyping across up to 60 environments and years allowed modeling of genotype x environment interaction, thereby making possible the identification of markers contributing to both additive and additive x additive interaction effects of traits.

  3. Physical mapping of a large plant genome using global high-information-content-fingerprinting: the distal region of the wheat ancestor Aegilops tauschii chromosome 3DS.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Physical maps employing libraries of bacterial artificial chromosome (BAC) clones are essential for comparative genomics and sequencing of large and repetitive genomes such as those of the hexaploid bread wheat. The diploid ancestor of wheat genome, Aegilops tauschii, is used as a resource for wheat...

  4. Evolution of New Disease Specificity at a Single Resistance Locus in a Crop-Weed Complex: Reconstitution of the Lr21 Gene in Wheat.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf-rust resistance gene Lr21, present in modern varieties of hexaploid wheat, originated in goatgrass Aegilops tauschii Coss., the D genome donor of wheat. The goatgrass donor was collected in Iran where it grows as a weed in wheat fields as part of the native agricultural ecosystem. In order to ...

  5. Differential gene expression in incompatible interaction between wheat and stripe rust fungus revealed by the cDNA-AFLP and comparison to compatible interaction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide. Due to special features of hexaploid wheat with large and complex genome and difficulties for transformation, and of Pst without sexual reproduction and ha...

  6. [Comparative cytogenetic analysis of hexaploid Avena L. species].

    PubMed

    Badaeva, E D; Shelukhina, O Iu; Dedkova, O S; Loskutov, I G; Pukhal'skiĭ, V A

    2011-06-01

    Using C-banding method and in situ hybridization with the 45S and 5S rRNA gene probes, six hexaploid species of the genus Avena L. with the ACD genome constitution were studied to reveal evolutionary karyotypic changes. Similarity in the C-banding patterns of chromosomal and in the patterns of distribution of the rRNA gene families suggests a common origin of all hexaploid species. Avena fatua is characterized by the broadest intraspecific variation of the karyotype; this species displays chromosomal variants typical of other hexaploid species of Avena. For instance, a translocation with the involvement of chromosome 5C marking A. occidentalis was discovered in many A. fatua accessions, whereas in other representatives of this species this chromosome is highly similar to the chromosome of A. sterilis. Only A. fatua and A. sativa show slight changes in the morphology and in the C-banding pattern of chromosome 2C. These results can be explained either by a hybrid origin of A. fatua or by the fact that this species is an intermediate evolutionary form of hexaploid oats. The 7C-17 translocation was identified in all studied accessions of wild and weedy species (A. sterilis, A. fatua, A. ludoviciana, and A. occidentalis) and in most A. sativa cultivars, but it was absent in A. byzantina and in two accessions of A. sativa. The origin and evolution of the Avena hexaploid species are discussed in context of the results.

  7. Discovery and mapping of single feature polymorphisms in wheat using affymetrix arrays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Single feature polymorphisms (SFPs) can be a rich source of markers for gene mapping and function studies. To explore the feasibility of using the Affymetrix GeneChip to discover and map SFPs in the large hexaploid wheat genome, six wheat varieties of diverse origins were analyzed for significant pr...

  8. Transcriptome profiling and expression analyses of genes critical to wheat adaptation to low temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome microarray. We compared the expressi...

  9. Rewiring the wheat reproductive system to harness heterosis for the next wave of yield improvements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bread wheat (hexaploid Triticum aestivum) provides an extraordinary ten-thousand-year story of a new species, established by early farmers, selecting for simple agronomical traits to facilitate efficient and plentiful grain harvest. The genetic changes underlying wheat domestication over thousands ...

  10. Determining Phenological Patterns Associated with the Onset of Senescence in a Wheat MAGIC Mapping Population.

    PubMed

    Camargo, Anyela V; Mott, Richard; Gardner, Keith A; Mackay, Ian J; Corke, Fiona; Doonan, John H; Kim, Jan T; Bentley, Alison R

    2016-01-01

    The appropriate timing of developmental transitions is critical for adapting many crops to their local climatic conditions. Therefore, understanding the genetic basis of different aspects of phenology could be useful in highlighting mechanisms underpinning adaptation, with implications in breeding for climate change. For bread wheat (Triticum aestivum), the transition from vegetative to reproductive growth, the start and rate of leaf senescence and the relative timing of different stages of flowering and grain filling all contribute to plant performance. In this study we screened under Smart house conditions a large, multi-founder "NIAB elite MAGIC" wheat population, to evaluate the genetic elements that influence the timing of developmental stages in European elite varieties. This panel of recombinant inbred lines was derived from eight parents that are or recently have been grown commercially in the UK and Northern Europe. We undertook a detailed temporal phenotypic analysis under Smart house conditions of the population and its parents, to try to identify known or novel Quantitative Trait Loci associated with variation in the timing of key phenological stages in senescence. This analysis resulted in the detection of QTL interactions with novel traits such the time between "half of ear emergence above flag leaf ligule" and the onset of senescence at the flag leaf as well as traits associated with plant morphology such as stem height. In addition, strong correlations between several traits and the onset of senescence of the flag leaf were identified. This work establishes the value of systematically phenotyping genetically unstructured populations to reveal the genetic architecture underlying morphological variation in commercial wheat.

  11. Determining Phenological Patterns Associated with the Onset of Senescence in a Wheat MAGIC Mapping Population

    PubMed Central

    Camargo, Anyela V.; Mott, Richard; Gardner, Keith A.; Mackay, Ian J.; Corke, Fiona; Doonan, John H.; Kim, Jan T.; Bentley, Alison R.

    2016-01-01

    The appropriate timing of developmental transitions is critical for adapting many crops to their local climatic conditions. Therefore, understanding the genetic basis of different aspects of phenology could be useful in highlighting mechanisms underpinning adaptation, with implications in breeding for climate change. For bread wheat (Triticum aestivum), the transition from vegetative to reproductive growth, the start and rate of leaf senescence and the relative timing of different stages of flowering and grain filling all contribute to plant performance. In this study we screened under Smart house conditions a large, multi-founder “NIAB elite MAGIC” wheat population, to evaluate the genetic elements that influence the timing of developmental stages in European elite varieties. This panel of recombinant inbred lines was derived from eight parents that are or recently have been grown commercially in the UK and Northern Europe. We undertook a detailed temporal phenotypic analysis under Smart house conditions of the population and its parents, to try to identify known or novel Quantitative Trait Loci associated with variation in the timing of key phenological stages in senescence. This analysis resulted in the detection of QTL interactions with novel traits such the time between “half of ear emergence above flag leaf ligule” and the onset of senescence at the flag leaf as well as traits associated with plant morphology such as stem height. In addition, strong correlations between several traits and the onset of senescence of the flag leaf were identified. This work establishes the value of systematically phenotyping genetically unstructured populations to reveal the genetic architecture underlying morphological variation in commercial wheat. PMID:27822218

  12. A Consensus Map in Cultivated Hexaploid Oat Reveals Conserved Grass Synteny with Substantial Subgenome Rearrangement.

    PubMed

    Chaffin, Ashley S; Huang, Yung-Fen; Smith, Scott; Bekele, Wubishet A; Babiker, Ebrahiem; Gnanesh, Belaghihalli N; Foresman, Bradley J; Blanchard, Steven G; Jay, Jeremy J; Reid, Robert W; Wight, Charlene P; Chao, Shiaoman; Oliver, Rebekah; Islamovic, Emir; Kolb, Frederic L; McCartney, Curt; Mitchell Fetch, Jennifer W; Beattie, Aaron D; Bjørnstad, Åsmund; Bonman, J Michael; Langdon, Tim; Howarth, Catherine J; Brouwer, Cory R; Jellen, Eric N; Klos, Kathy Esvelt; Poland, Jesse A; Hsieh, Tzung-Fu; Brown, Ryan; Jackson, Eric; Schlueter, Jessica A; Tinker, Nicholas A

    2016-07-01

    Hexaploid oat ( L., 2 = 6 = 42) is a member of the Poaceae family and has a large genome (∼12.5 Gb) containing 21 chromosome pairs from three ancestral genomes. Physical rearrangements among parental genomes have hindered the development of linkage maps in this species. The objective of this work was to develop a single high-density consensus linkage map that is representative of the majority of commonly grown oat varieties. Data from a cDNA-derived single-nucleotide polymorphism (SNP) array and genotyping-by-sequencing (GBS) were collected from the progeny of 12 biparental recombinant inbred line populations derived from 19 parents representing oat germplasm cultivated primarily in North America. Linkage groups from all mapping populations were compared to identify 21 clusters of conserved collinearity. Linkage groups within each cluster were then merged into 21 consensus chromosomes, generating a framework consensus map of 7202 markers spanning 2843 cM. An additional 9678 markers were placed on this map with a lower degree of certainty. Assignment to physical chromosomes with high confidence was made for nine chromosomes. Comparison of homeologous regions among oat chromosomes and matches to orthologous regions of rice ( L.) reveal that the hexaploid oat genome has been highly rearranged relative to its ancestral diploid genomes as a result of frequent translocations among chromosomes. Heterogeneous chromosome rearrangements among populations were also evident, probably accounting for the failure of some linkage groups to match the consensus. This work contributes to a further understanding of the organization and evolution of hexaploid grass genomes.

  13. Impact of wheat-mung bean intercropping on English grain aphid (Hemiptera: Aphididae) populations and its natural enemy.

    PubMed

    Xie, Hai-Cui; Chen, Ju-Lian; Cheng, Deng-Fa; Zhou, Hai-Bo; Sun, Jing-Rui; Liu, Yong; Francis, Frédéric

    2012-06-01

    The effects of intercropping wheat, Triticum aestivum L., with mung bean, Vigna radiate L., on the populations of English grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae), and its natural enemies were evaluated by field and laboratory experiments. The population densities of aphids and their natural enemies were evaluated in the intercropped field against different row ratio combinations of wheat-mung bean. Results showed that wheat-mung bean intercropping caused a drop in aphid densities, and the ratio 12 wheat: 4 mung bean brought about the largest drop (> 8%). In addition, the population densities of coccinellids (ladybirds) and parasitoids and the species diversity of all the natural enemies of aphid were higher in the intercropped field than in the field planted only with wheat. However, intercropping did not influence the community indices (evenness and index of dominance concentration) of the natural enemies. Y-tube olfactometer bioassays were carried out in the laboratory to test whether odor blends of host and nonhost plants affect the host selection of S. avenae. Bioassays indicated that both apterous and alate aphids significantly preferred host plant odor over odor blends of host and intercropped species. Hence, the olfactory-based host location of aphids in the field might be affected by intercropping. The intercropping experiment clearly showed that increased crop species diversity suppresses aphid population growth and preserves the population of natural enemies of aphids. Our results also provide support for the "resource concentration hypothesis" and the "enemies hypothesis".

  14. Map-based analysis of the tenacious glume gene Tg-B1 of wild emmer and its role in wheat domestication.

    PubMed

    Faris, Justin D; Zhang, Zengcui; Chao, Shiaoman

    2014-06-01

    The domestication of wheat was instrumental in spawning the civilization of humankind, and it occurred through genetic mutations that gave rise to types with non-fragile rachises, soft glumes, and free-threshing seed. Wild emmer (Triticum turgidum ssp. dicoccoides), the tetraploid AB-genome progenitor of domesticated wheat has genes that confer tenacious glumes (Tg) that underwent genetic mutations to give rise to free-threshing wheat. Here, we evaluated disomic substitution lines involving chromosomes 2A and 2B of wild emmer accessions substituted for homologous chromosomes in tetraploid and hexaploid backgrounds. The results suggested that both chromosomes 2A and 2B of wild emmer possess genes that inhibit threshability. A population of recombinant inbred lines derived from the tetraploid durum wheat variety Langdon crossed with a Langdon - T. turgidum ssp. dicoccoides accession PI 481521 chromosome 2B disomic substitution line was used to develop a genetic linkage map of 2B, evaluate the genetics of threshability, and map the gene derived from PI 481521 that inhibited threshability. A 2BS linkage map comprised of 58 markers was developed, and markers delineated the gene to a 2.3 cM interval. Comparative analysis with maps containing the tenacious glume gene Tg-D1 on chromosome arm 2 DS from Aegilops tauschii, the D genome progenitor of hexaploid wheat, revealed that the gene inhibiting threshability in wild emmer was homoeologous to Tg-D1 and therefore designated Tg-B1. Comparative analysis with rice and Brachypodium distachyon indicated a high level of divergence and poorly conserved colinearity, particularly near the Tg-B1 locus. These results provide a foundation for further studies involving Tg-B1, which, together with Tg-D1, had profound influences on wheat domestication.

  15. Chromosome-specific sequencing reveals an extensive dispensable genome component in wheat

    PubMed Central

    Liu, Miao; Stiller, Jiri; Holušová, Kateřina; Vrána, Jan; Liu, Dengcai; Doležel, Jaroslav; Liu, Chunji

    2016-01-01

    The hexaploid wheat genotype Chinese Spring (CS) has been used worldwide as the reference base for wheat genetics and genomics, and significant resources have been used by the international community to generate a reference wheat genome based on this genotype. By sequencing flow-sorted 3B chromosome from a hexaploid wheat genotype CRNIL1A and comparing the obtained sequences with those available for CS, we detected that a large number of sequences in the former were missing in the latter. If the distribution of such sequences in the hexaploid wheat genome is random, CRNILA sequences missing in CS could be as much as 159.3 Mb even if only fragments of 50 bp or longer were considered. Analysing RNA sequences available in the public domains also revealed that dispensable genes are common in hexaploid wheat. Together with those extensive intra- and interchromosomal rearrangements in CS, the existence of such dispensable genes is another factor highlighting potential issues with the use of reference genomes in various studies. Strong deviation in distributions of these dispensable sequences among genotypes with different geographical origins provided the first evidence indicating that they could be associated with adaptation in wheat. PMID:27821854

  16. Genetic Relationships, Carbendazim Sensitivity and Mycotoxin Production of the Fusarium Graminearum Populations from Maize, Wheat and Rice in Eastern China

    PubMed Central

    Qiu, Jianbo; Shi, Jianrong

    2014-01-01

    Members of the Fusarium graminearum species complex (FGSC) are important pathogens on wheat, maize, barley, and rice in China. Harvested grains are often contaminated by mycotoxins, such as the trichothecene nivalenol (NIV) and deoxynivalenol (DON) and the estrogenic mycotoxin zearalenone (ZEN), which is a big threat to humans and animals. In this study, 97 isolates were collected from maize, wheat, and rice in Jiangsu and Anhui provinces in 2013 and characterized by species- and chemotype-specific PCR. F. graminearum sensu stricto (s. str.) was predominant on maize, while most of the isolates collected from rice and wheat were identified as F. asiaticum. Fusarium isolates from three hosts varied in trichothecene chemotypes. The 3-acetyldeoxynivalenol (3ADON) chemotype predominated on wheat and rice population, while 15ADON was prevailing in the remaining isolates. Sequence analysis of the translation elongation factor 1α and trichodiene synthase indicated the accuracy of the above conclusion. Additionally, phylogenetic analysis suggested four groups with strong correlation with species, chemotype, and host. These isolates were also evaluated for their sensitivity to carbendazim and mycotoxins production. The maize population was less sensitive than the other two. The DON levels were similar in three populations, while those isolates on maize produced more ZEN. More DON was produced in carbendazim resistant strains than sensitive ones, but it seemed that carbendazim resistance had no effect on ZEN production in wheat culture. PMID:25093387

  17. Population subdivision of Fusarium graminearum from barley and wheat in the upper Midwestern United States at the turn of the century

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium graminearum, the causal agent of Fusarium head blight (FHB) in wheat and barley, is one of the most economically destructive pathogens of these grains worldwide. Recent population genetic studies of the pathogen obtained from wheat in North America supported population subdivision in part c...

  18. Natural Lactic Acid Bacteria Population and Silage Fermentation of Whole-crop Wheat

    PubMed Central

    Ni, Kuikui; Wang, Yanping; Cai, Yimin; Pang, Huili

    2015-01-01

    Winter wheat is a suitable crop to be ensiled for animal feed and China has the largest planting area of this crop in the world. During the ensiling process, lactic acid bacteria (LAB) play the most important role in the fermentation. We investigated the natural population of LAB in whole-crop wheat (WCW) and examined the quality of whole-crop wheat silage (WCWS) with and without LAB inoculants. Two Lactobacillus plantarum subsp. plantarum strains, Zhengzhou University 1 (ZZU 1) selected from corn and forage and grass 1 (FG 1) from a commercial inoculant, were used as additives. The silages inoculated with LAB strains (ZZU 1 and FG 1) were better preserved than the control, with lower pH values (3.5 and 3.6, respectively) (p<0.05) and higher contents of lactic acid (37.5 and 34.0 g/kg of fresh matter (FM), respectively) (p<0.05) than the control. Sixty LAB strains were isolated from fresh material and WCWS without any LAB inoculation. These LAB strains were divided into the following four genera and six species based on their phenotypic, biochemical and phylogenetic characteristics: Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, Lactococcus lactis subsp. lactis, Lactobacillus buchneri, and Lactobacillus plantarum subsp. plantarum. However, the prevalent LAB, which was predominantly heterofermentative (66.7%), consisted of Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, and Lactobacillus buchneri. This study revealed that most of isolated LAB strains from control WCWS were heterofermentative and could not grow well at low pH condition; the selective inoculants of Lactobacillus strains, especially ZZU 1, could improve WCWS quality significantly. PMID:26104520

  19. Genome-Wide QTL Mapping for Wheat Processing Quality Parameters in a Gaocheng 8901/Zhoumai 16 Recombinant Inbred Line Population

    PubMed Central

    Jin, Hui; Wen, Weie; Liu, Jindong; Zhai, Shengnan; Zhang, Yan; Yan, Jun; Liu, Zhiyong; Xia, Xianchun; He, Zhonghu

    2016-01-01

    Dough rheological and starch pasting properties play an important role in determining processing quality in bread wheat (Triticum aestivum L.). In the present study, a recombinant inbred line (RIL) population derived from a Gaocheng 8901/Zhoumai 16 cross grown in three environments was used to identify quantitative trait loci (QTLs) for dough rheological and starch pasting properties evaluated by Mixograph, Rapid Visco-Analyzer (RVA), and Mixolab parameters using the wheat 90 and 660 K single nucleotide polymorphism (SNP) chip assays. A high-density linkage map constructed with 46,961 polymorphic SNP markers from the wheat 90 and 660 K SNP assays spanned a total length of 4121 cM, with an average chromosome length of 196.2 cM and marker density of 0.09 cM/marker; 6596 new SNP markers were anchored to the bread wheat linkage map, with 1046 and 5550 markers from the 90 and 660 K SNP assays, respectively. Composite interval mapping identified 119 additive QTLs on 20 chromosomes except 4D; among them, 15 accounted for more than 10% of the phenotypic variation across two or three environments. Twelve QTLs for Mixograph parameters, 17 for RVA parameters and 55 for Mixolab parameters were new. Eleven QTL clusters were identified. The closely linked SNP markers can be used in marker-assisted wheat breeding in combination with the Kompetitive Allele Specific PCR (KASP) technique for improvement of processing quality in bread wheat. PMID:27486464

  20. Breeding Value of Primary Synthetic Wheat Genotypes for Grain Yield

    PubMed Central

    Jafarzadeh, Jafar; Bonnett, David; Jannink, Jean-Luc; Akdemir, Deniz; Dreisigacker, Susanne; Sorrells, Mark E.

    2016-01-01

    To introduce new genetic diversity into the bread wheat gene pool from its progenitor, Aegilops tauschii (Coss.) Schmalh, 33 primary synthetic hexaploid wheat genotypes (SYN) were crossed to 20 spring bread wheat (BW) cultivars at the International Wheat and Maize Improvement Center. Modified single seed descent was used to develop 97 populations with 50 individuals per population using first back-cross, biparental, and three-way crosses. Individuals from each cross were selected for short stature, early heading, flowering and maturity, minimal lodging, and free threshing. Yield trials were conducted under irrigated, drought, and heat-stress conditions from 2011 to 2014 in Ciudad Obregon, Mexico. Genomic estimated breeding values (GEBVs) of parents and synthetic derived lines (SDLs) were estimated using a genomic best linear unbiased prediction (GBLUP) model with markers in each trial. In each environment, there were SDLs that had higher GEBVs than their recurrent BW parent for yield. The GEBVs of BW parents for yield ranged from -0.32 in heat to 1.40 in irrigated trials. The range of the SYN parent GEBVs for yield was from -2.69 in the irrigated to 0.26 in the heat trials and were mostly negative across environments. The contribution of the SYN parents to improved grain yield of the SDLs was highest under heat stress, with an average GEBV for the top 10% of the SDLs of 0.55 while the weighted average GEBV of their corresponding recurrent BW parents was 0.26. Using the pedigree-based model, the accuracy of genomic prediction for yield was 0.42, 0.43, and 0.49 in the drought, heat and irrigated trials, respectively, while for the marker-based model these values were 0.43, 0.44, and 0.55. The SYN parents introduced novel diversity into the wheat gene pool. Higher GEBVs of progenies were due to introgression and retention of some positive alleles from SYN parents. PMID:27656893

  1. Identifying Rare FHB-Resistant Segregants in Intransigent Backcross and F2 Winter Wheat Populations

    PubMed Central

    Clark, Anthony J.; Sarti-Dvorjak, Daniela; Brown-Guedira, Gina; Dong, Yanhong; Baik, Byung-Kee; Van Sanford, David A.

    2016-01-01

    Fusarium head blight (FHB), caused mainly by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)] in the US, is one of the most destructive diseases of wheat (Triticum aestivum L. and T. durum L.). Infected grain is usually contaminated with deoxynivalenol (DON), a serious mycotoxin. The challenge in FHB resistance breeding is combining resistance with superior agronomic and quality characteristics. Exotic QTL are widely used to improve FHB resistance. Success depends on the genetic background into which the QTL are introgressed, whether through backcrossing or forward crossing; QTL expression is impossible to predict. In this study four high-yielding soft red winter wheat breeding lines with little or no scab resistance were each crossed to a donor parent (VA01W-476) with resistance alleles at two QTL: Fhb1 (chromosome 3BS) and QFhs.nau-2DL (chromosome 2DL) to generate backcross and F2 progeny. F2 individuals were genotyped and assigned to 4 groups according to presence/ absence of resistance alleles at one or both QTL. The effectiveness of these QTL in reducing FHB rating, incidence, index, severity, Fusarium-damaged kernels (FDK) and DON, in F2-derived lines was assessed over 2 years. Fhb1 showed an average reduction in DON of 17.5%, and conferred significant resistance in 3 of 4 populations. QFhs.nau-2DL reduced DON 6.7% on average and conferred significant resistance in 2 of 4 populations. The combination of Fhb1 and QFhs.nau-2DL resistance reduced DON 25.5% across all populations. Double resistant lines had significantly reduced DON compared to double susceptible lines in 3 populations. Backcross derived progeny were planted in replicated yield trials (2011 and 2012) and in a scab nursery in 2012. Several top yielding lines performed well in the scab nursery, with acceptable DON concentrations, even though the average effect of either QTL in this population was not significant. Population selection is often viewed as an “all or nothing

  2. Chromosome-anchored QTL conferring aluminum tolerance in hexaploid oat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract Aluminum (Al) toxicity is a major constraint on crop production in acid soils around the world. Hexaploid oat (Avena sativa L.) possesses signi'cant Al tolerance making it a good candidate for production in these environments. Genetic improvement for Al tolerance in oat has traditionally be...

  3. Comparative growth and development of hexaploid and tetraploid reed canarygrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reed canarygrass (Phalaris arundinacea L.) is a globally distributed forage species, a potential biofuel, and an important invasive weed. At more northern latitudes in exists as a tetraploid and at equatorial to mid-latitudes as a hexaploid, especially in Mediterranean climates. Growth and developme...

  4. Genetic structure of wild emmer wheat populations as reflected by transcribed versus anonymous SSR markers.

    PubMed

    Peleg, Zvi; Fahima, Tzion; Abbo, Shahal; Krugman, Tamar; Saranga, Yehoshua

    2008-03-01

    Simple sequence repeat (SSR) markers have become a major tool in population genetic analyses. The anonymous genomic SSRs (gSSRs) have been recently supplemented with expressed sequence tag (EST) derived SSRs (eSSRs), which represent the transcribed regions of the genome. In the present study, we used 8 populations of wild emmer wheat (Triticum turgidum subsp. dicoccoides) to compare the usefulness of the two types of SSR markers in assessing allelic diversity and population structure. gSSRs revealed significantly higher diversity than eSSRs in terms of average number of alleles (14.92 vs. 7.4, respectively), polymorphic information content (0.87 vs. 0.68, respectively), and gene diversity (He; 0.55 vs. 0.38, respectively). Despite the overall differences in the level of diversity, Mantel tests for correlations between eSSR and gSSR pairwise genetic distances were found to be significant for each population as well as for all accessions jointly (RM=0.54, p=0.01). Various genetic structure analyses (AMOVA, PCoA, STRUCTURE, unrooted UPGMA tree) revealed a better capacity of eSSRs to distinguish between populations, while gSSRs showed a higher proportion of intrapopulation (among accessions) diversity. We conclude that eSSR and gSSR markers should be employed in conjunction to obtain a high inter- and intra-specific (or inter- and intra-varietal) distinctness.

  5. End-use quality of CIMMYT-derived soft kernel durum wheat germplasm. II. Dough strenth and pan bread quality.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Durum wheat (Triticum turgidum ssp. durum) is considered unsuitable for the majority of commercial bread production because its weak gluten strength combined with flour particle size and flour starch damage after milling are not commensurate with hexaploid wheat flours. Recently a new durum cultivar...

  6. A BAC-based physical map of Brachypodium distachyon and its comparative analysis with rice and wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wheat high molecular weight (HMW)-glutenins are important seed storage proteins that determine bread-making quality in hexaploid wheat (Triticum aestivum). In this study, detailed comparative sequence analyses of large orthologous HMW-glutenin genomic regions from eight grass species, represent...

  7. Population dynamics of the fusarium head blight biocontrol agent cryptococcus flavescens OH182.9 on wheat anthers and heads

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cryptococcus flavescens OH 182.9 (NRRL Y-30216) reduces Fusarium head blight (FHB) incited by Fusarium graminearum and DON contamination of grain in greenhouse and field settings. Yet little is known about the population dynamics of OH 182.9 on wheat heads and anthers from the time of inoculating he...

  8. Triticum mosaic virus exhibits limited population variation yet shows evidence of parallel evolution after replicated serial passage in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An infectious cDNA clone of Triticum mosaic virus (TriMV) (genus Poacevirus; family Potyviridae) was used to establish three independent lineages in wheat to examine intra-host population diversity levels within protein 1 (P1) and coat protein (CP) cistrons over time. Genetic variation was assessed ...

  9. Experimental estimation of mutation rates in a wheat population with a gene genealogy approach.

    PubMed

    Raquin, Anne-Laure; Depaulis, Frantz; Lambert, Amaury; Galic, Nathalie; Brabant, Philippe; Goldringer, Isabelle

    2008-08-01

    Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 x 10(-3) per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues.

  10. RESISTANCE TO ALS-INHIBITING HERBICIDES IN WEED POPULATIONS FROM BELGIAN WHEAT FIELDS.

    PubMed

    S, Claerhout; B, De Cauwer

    2015-01-01

    In modern agriculture, most farmers rely on herbicides for weed control. The intensive use of herbicides in crops has led to the development of herbicide resistance in numerous weeds worldwide. In Belgium, farmers have encountered problems with controlling populations of Alopecurus myosuroides, Matricaria recutita, Stellaria media and Popover rhoeas in some wheat fields with the conventionally used acetolactate synthase (ALS)-inhibiting herbicides. Dose response assays were conducted in the greenhouse to test the sensitivity of these populations to the key ALS-inhibiting herbicides mesosulfuron-methyl + iodosulfuron-methyl for A. myosuroides and metsulfuron-methyl and florasulam for M. recutita, S. media and P. rhoeas. The ED₉₀- and ED₅₀-values (effective dose for resp. 90% and 50% biomass reduction) were compared with those of sensitive reference populations and the resistance index (RI) was calculated. High levels of resistance were detected forA. myosuroides (RI: 24.3) after treatment with mesosulfuron-methyl and for M. recutita (RI: 36.4 to 49.5), S. media (RI > 20) and P. rhoeas (RI: 23.6) after treatment with metsulfuron-methyl. However, the metsulfuron-methyl resistant populations of M. recutita and S. media were sufficiently controlled with florasulam at the maximum authorised field dose. This was not the case for P. rhoeas. The metsulfuron-methyl resistant P. rhoeas population were also high-level resistant against florasulam (RI: 29.5). Integrated weed management practices (crop rotation, herbicide mixing, ...) should be applied to reduce the selection pressure for resistant weeds.

  11. New QTL alleles for quality-related traits in spring wheat revealed by RIL population derived from supernumerary x non-supernumerary spikelet genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying new QTLs and alleles in exotic germplasm is paramount for further improvement of quality traits in wheat. In the present study, a RIL population developed from a cross of an elite wheat line (WCB414) and an exotic genotype with supernumerary spikelets (SS) was used to identify QTLs and n...

  12. Genome-wide mapping of spike-related and agronomic traits in a common wheat population derived from a supernumerary parent and an elite parent

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In wheat (Triticum aestivum L), exotic genotypes express a broad range of spike-related traits and could be used as a source of new genes to enrich the germplasm for wheat breeding programs. In the present study, a population of 163 recombinant inbred lines derived from a cross between an elite line...

  13. New QTL alleles for quality-related traits in spring wheat revealed by RIL population derived from supernumerary x non-supernumerary spikelet genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying new quantitative trait loci (QTLs) and alleles in exotic germplasm is paramount for further improvement of quality traits in wheat. In the present study, a population of recombinant inbred lines (RILs) developed from a cross between an elite wheat line (WCB414) and an exotic genotype wi...

  14. Mixed mating in androdioecious Mercurialis annua inferred using progeny arrays and diploid-acting microsatellite loci in a hexaploid background

    PubMed Central

    Korbecka, Grażyna; Hamilton, Alastair; Pannell, John R.

    2011-01-01

    Background and Aims The frequency at which males can be maintained with hermaphrodites in androdioecious populations is predicted to depend on the selfing rate, because self-fertilization by hermaphrodites reduces prospective siring opportunities for males. In particular, high selfing rates by hermaphrodites are expected to exclude males from a population. Here, the first estimates are provided of the mating system from two wild hexaploid populations of the androdioecious European wind-pollinated plant M. annua with contrasting male frequencies. Methods Four diploid microsatellite loci were used to genotype 19–20 progeny arrays from two populations of M. annua, one with males and one without. Mating-system parameters were estimated using the program MLTR. Key Results Both populations had similar, intermediate outcrossing rates (tm = 0·64 and 0·52 for the population with and without males, respectively). The population without males showed a lower level of correlated paternity and biparental inbreeding and higher allelic richness and gene diversity than the population with males. Conclusions The results demonstrate the utility of new diploid microsatellite loci for mating system analysis in a hexaploid plant. It would appear that androdioecious M. annua has a mixed-mating system in the wild, an uncommon finding for wind-pollinated species. This study sets a foundation for future research to assess the relative importance of the sexual system, plant-density variation and stochastic processes for the regulation of male frequencies in M. annua over space and time. PMID:21320876

  15. Population genetics of wolf spiders of fragmented habitat in the wheat belt of New South Wales.

    PubMed

    Colgan, D J; Brown, S; Major, R E; Christie, F; Gray, M R; Cassis, G

    2002-11-01

    Possible effects of habitat fragmentation on the population genetics of a species of wolf spider (Lycosidae) from remnant Callitris woodland in the wheat belt of central western New South Wales in Australia are examined. Single-strand conformational analysis of mitochondrial cytochrome oxidase (subunit 1) was used to characterize the haplotypes of 295 spiders in six blocks each of four woodland sites. DNA sequences were collected from 119 of these spiders to confirm haplotype scoring, allow phylogeny estimation and permit calculation of sequence-based statistics. Intra-block tests do not suggest widespread effects of fragmentation. Genetic diversity is high in all blocks, with 25 haplotypes being identified. Nucleotide diversity is relatively low, as all of the haplotypes are closely related. One block had a significantly low value for the Ewens/Watterson test of neutrality and one block's value was nearly significantly high. Two blocks had nearly significant values of the Harpending Raggedness Index testing for recent population bottlenecks. No other intrablock tests approach significance. Interpopulation comparisons show significant nonhomogeneity of haplotype frequencies globally and in all pairwise comparisons. Relationships between woodland blocks based on haplotype frequencies are discordant with geographical proximity. Haplotype distribution patterns suggest that population structuring existed prior to fragmentation. We develop two measures of genetic distinctiveness to identify subpopulations of interest for conserving evolutionary processes in a species' regional population. One is based on the sum of pairwise FST values and one on the spatial distribution of genetic variation. High values of the measure suggest a subpopulation might have been recently perturbed and low values that it is relatively undisturbed. The two measures identify different blocks as being of particular interest.

  16. Impact of the D genome and quantitative trait loci on quantitative traits in a spring durum by spring bread wheat cross

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desirable agronomic traits are similar for common hexaploid (6X) bread wheat (Triticum aestivum, 2n = 6x = 42, genome, AABBDD) and tetraploid (4X) durum wheat (Triticum turgidum durum, 2n = 4x = 28, genome, AABB). However, they are genetically isolated from each other due to an unequal number of ge...

  17. Fusarium head blight resistance loci in a stratified population of wheat landraces and varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To determine if Chinese and Japanese wheat landraces and varieties have unique sources of Fusarium head blight (FHB) resistance, an association mapping panel of 195 wheat accessions including both commercial varieties and landraces was genotyped with 364 genome-wide simple sequence repeat (SSR) and ...

  18. Identification of milling and baking quality QTL in multiple soft wheat mapping populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat derived food products require a range of characteristics. Identification and understanding of the genetic components controlling end-use quality of wheat is important for crop improvement. We assessed the underlying genetics controlling specific milling and baking quality parameters of soft wh...

  19. Triticum mosaic virus exhibits limited population variation yet shows evidence of parallel evolution after replicated serial passage in wheat.

    PubMed

    Bartels, Melissa; French, Roy; Graybosch, Robert A; Tatineni, Satyanarayana

    2016-05-01

    An infectious cDNA clone of Triticum mosaic virus (TriMV) (genus Poacevirus; family Potyviridae) was used to establish three independent lineages in wheat to examine intra-host population diversity levels within protein 1 (P1) and coat protein (CP) cistrons over time. Genetic variation was assessed at passages 9, 18 and 24 by single-strand conformation polymorphism, followed by nucleotide sequencing. The founding P1 region genotype was retained at high frequencies in most lineage/passage populations, while the founding CP genotype disappeared after passage 18 in two lineages. We found that rare TriMV genotypes were present only transiently and lineages followed independent evolutionary trajectories, suggesting that genetic drift dominates TriMV evolution. These results further suggest that experimental populations of TriMV exhibit lower mutant frequencies than that of Wheat streak mosaic virus (genus Tritimovirus; family Potyviridae) in wheat. Nevertheless, there was evidence for parallel evolution at a synonymous site in the TriMV CP cistron.

  20. [Population structure and niche of main scale insects in jujube orchards intercropped with wheat].

    PubMed

    Shi, Guanglu; Wang, Younian; Liu, Suqi; Miao, Zhenwang; Cao, Hui; Li, Dengke; Zhang, Teiqiang; Yu, Tongquan

    2006-07-01

    To effectively control the scale insects in jujube orchards, a field study was made on the population structure and niche of Pseudococcus comstock Kuwane, Ceroplastes japonicus Green and Quadraspidiotus perniciosus Comstock in the jujube orchards intercropped with wheat in Taigu area of Shanxi Province. The results showed that at the early development stage of jujube trees, these three kinds of scale insects mainly distributed on the southeast direction of the lower and central parts of the tree crown, and P. comstock was the dominant species, with a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects. At the mid-stage of jujube trees development, these scale insects mainly distributed on the northwest direction of the upper part of the tree crown, C. japonicus had a wider breadth of two-dimensional temporal-spatial niche than the other two scale insects, and the niche proportional similarity and interspecific competition of the three kinds of scale insects were not obvious. At the later stage of jujube trees development, there was no significant difference (P > 0.05) in the population structure of the three kinds of scale insects on the different parts and directions of tree crown, but the density of Q. perniciosus was bigger, and C. japonicus had a wider breadth of two-dimensional temporal-spatial niche. The average values of niche proportional similarity and interspecific competition of the three kinds of scale insects were smaller (P < 0.05) at the later development stage of jujube trees. Therefore, P. comstock should be controlled at the early development stage of jujube trees, all the three kinds of scale insects should be controlled selectively at the mid-stage of jujube trees development, and their overwinterings should be decreased by all means at the later development stage of jujube trees.

  1. The effect of wheat prebiotics on the gut bacterial population and iron status of iron deficient broiler chickens

    PubMed Central

    2014-01-01

    Background Currently, there is a lot of interest in improving gut health, and consequently increasing Fe absorption, by managing the colonic microbial population. This is traditionally done by the consumption of probiotics, live microbial food supplements. However, an alternative, and often very effective approach, is the consumption of food ingredients known as prebiotics. Fructans and arabinoxylans are naturally occurring non-digestible oligosaccharides in wheat that exhibit prebiotic properties and may enhance intestinal iron (Fe) absorption. The aim of this study was to assess the effect of prebiotics from wheat on Fe bioavailability in vitro (Caco-2 cells) and in vivo (broiler chickens, Gallus gallus). Methods In the current study, the effect of intra-amniotic administration of wheat samples extracts at 17 d of embryonic incubation on the Fe status and possible changes in the bacterial population in intestinal content of broiler hatchlings were investigated. A group of 144 eggs were injected with the specified solution (1 ml per egg) into the amniotic fluid. Immediately after hatch (21 d) and from each treatment group, 10 chicks were euthanized and their small intestine, liver and cecum were removed for relative mRNA abundance of intestinal Fe related transporters, relative liver ferritin amounts and bacterial analysis of cecal content, respectively. Results The in vivo results are in agreement with the in vitro observations, showing no differences in the hatchling Fe status between the treatment groups, as Fe bioavailability was not increased in vitro and no significant differences were measured in the intestinal expression of DMT1, Ferroportin and DcytB in vivo. However, there was significant variation in relative amounts of bifidobacteria and lactobacilli in the intestinal content between the treatments groups, with generally more bifidobacteria being produced with increased prebiotic content. Conclusions In this study we showed that prebiotics naturally

  2. A High-Density Genetic Map with Array-Based Markers Facilitates Structural and Quantitative Trait Locus Analyses of the Common Wheat Genome

    PubMed Central

    Iehisa, Julio Cesar Masaru; Ohno, Ryoko; Kimura, Tatsuro; Enoki, Hiroyuki; Nishimura, Satoru; Okamoto, Yuki; Nasuda, Shuhei; Takumi, Shigeo

    2014-01-01

    The large genome and allohexaploidy of common wheat have complicated construction of a high-density genetic map. Although improvements in the throughput of next-generation sequencing (NGS) technologies have made it possible to obtain a large amount of genotyping data for an entire mapping population by direct sequencing, including hexaploid wheat, a significant number of missing data points are often apparent due to the low coverage of sequencing. In the present study, a microarray-based polymorphism detection system was developed using NGS data obtained from complexity-reduced genomic DNA of two common wheat cultivars, Chinese Spring (CS) and Mironovskaya 808. After design and selection of polymorphic probes, 13,056 new markers were added to the linkage map of a recombinant inbred mapping population between CS and Mironovskaya 808. On average, 2.49 missing data points per marker were observed in the 201 recombinant inbred lines, with a maximum of 42. Around 40% of the new markers were derived from genic regions and 11% from repetitive regions. The low number of retroelements indicated that the new polymorphic markers were mainly derived from the less repetitive region of the wheat genome. Around 25% of the mapped sequences were useful for alignment with the physical map of barley. Quantitative trait locus (QTL) analyses of 14 agronomically important traits related to flowering, spikes, and seeds demonstrated that the new high-density map showed improved QTL detection, resolution, and accuracy over the original simple sequence repeat map. PMID:24972598

  3. Diversity of Fusarium species isolated from UK forage maize and the population structure of F. graminearum from maize and wheat

    PubMed Central

    2016-01-01

    Pre-harvest contamination of forage maize by mycotoxin producing Fusarium species was investigated in the UK in 2011 and 2012. A total of 15 Fusarium species were identified from a collection of 1,761 Fusarium isolates recovered from maize stalks and kernels. This study characterized the diversity of Fusarium species present in forage maize in the UK. The predominant species detected were F. graminearum (32.9%) and F. culmorum (34.1%). Along with those species; F. avenacem, F. cerealis, F. equiseti, F. langsethiae, F. napiforme, F. oxysporum, F. poae, F. proliferatum, F. scripi, F. solani, F. subglutinans, F. tricinctum and, F. verticillioides were occasionally isolated. The trichothecene genotypes for F. graminearum were determined to be 84.9% deoxynivalenol (DON) and 15.0% nivalenol (NIV) while F. culmorum isolates were determined to have 24.9% DON and 75.1% NIV genotypes. A Bayesian model-based clustering method with nine variable number of tandem repeat markers was used to evaluate the population genetic structure of 277 F. graminearum isolates from the maize and wheat in the UK. There were three genetic clusters detected which were DON in maize, NIV in maize and DON in wheat. There were high admixture probabilities for 14.1% of the isolates in the populations. In conclusion, increased maize production in the UK and the high admixture rates in a significant portion of F. graminearum populations in maize and wheat will contribute to a new pathogen population which will further complicate breeding strategies for tolerance or resistance to this pathogen in both crops. PMID:27366645

  4. Diversity of Fusarium species isolated from UK forage maize and the population structure of F. graminearum from maize and wheat.

    PubMed

    Basler, Ryan

    2016-01-01

    Pre-harvest contamination of forage maize by mycotoxin producing Fusarium species was investigated in the UK in 2011 and 2012. A total of 15 Fusarium species were identified from a collection of 1,761 Fusarium isolates recovered from maize stalks and kernels. This study characterized the diversity of Fusarium species present in forage maize in the UK. The predominant species detected were F. graminearum (32.9%) and F. culmorum (34.1%). Along with those species; F. avenacem, F. cerealis, F. equiseti, F. langsethiae, F. napiforme, F. oxysporum, F. poae, F. proliferatum, F. scripi, F. solani, F. subglutinans, F. tricinctum and, F. verticillioides were occasionally isolated. The trichothecene genotypes for F. graminearum were determined to be 84.9% deoxynivalenol (DON) and 15.0% nivalenol (NIV) while F. culmorum isolates were determined to have 24.9% DON and 75.1% NIV genotypes. A Bayesian model-based clustering method with nine variable number of tandem repeat markers was used to evaluate the population genetic structure of 277 F. graminearum isolates from the maize and wheat in the UK. There were three genetic clusters detected which were DON in maize, NIV in maize and DON in wheat. There were high admixture probabilities for 14.1% of the isolates in the populations. In conclusion, increased maize production in the UK and the high admixture rates in a significant portion of F. graminearum populations in maize and wheat will contribute to a new pathogen population which will further complicate breeding strategies for tolerance or resistance to this pathogen in both crops.

  5. Exploring the diploid wheat ancestral A genome through sequence comparison at the high-molecular-weight glutenin locus region.

    PubMed

    Dong, Lingli; Huo, Naxin; Wang, Yi; Deal, Karin; Luo, Ming-Cheng; Wang, Daowen; Anderson, Olin D; Gu, Yong Qiang

    2012-12-01

    The polyploid nature of hexaploid wheat (T. aestivum, AABBDD) often represents a great challenge in various aspects of research including genetic mapping, map-based cloning of important genes, and sequencing and accurately assembly of its genome. To explore the utility of ancestral diploid species of polyploid wheat, sequence variation of T. urartu (A(u)A(u)) was analyzed by comparing its 277-kb large genomic region carrying the important Glu-1 locus with the homologous regions from the A genomes of the diploid T. monococcum (A(m)A(m)), tetraploid T. turgidum (AABB), and hexaploid T. aestivum (AABBDD). Our results revealed that in addition to a high degree of the gene collinearity, nested retroelement structures were also considerably conserved among the A(u) genome and the A genomes in polyploid wheats, suggesting that the majority of the repetitive sequences in the A genomes of polyploid wheats originated from the diploid A(u) genome. The difference in the compared region between A(u) and A is mainly caused by four differential TE insertion and two deletion events between these genomes. The estimated divergence time of A genomes calculated on nucleotide substitution rate in both shared TEs and collinear genes further supports the closer evolutionary relationship of A to A(u) than to A(m). The structure conservation in the repetitive regions promoted us to develop repeat junction markers based on the A(u) sequence for mapping the A genome in hexaploid wheat. Eighty percent of these repeat junction markers were successfully mapped to the corresponding region in hexaploid wheat, suggesting that T. urartu could serve as a useful resource for developing molecular markers for genetic and breeding studies in hexaploid wheat.

  6. The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

    PubMed

    Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

    2016-12-22

    The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat.

  7. The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

    PubMed

    Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

    2016-09-29

    The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in seedlings under standard growth conditions. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or upregulation of senescence gene markers was apparent in these seedlings suggesting senescence is not required for Lr34 resistance. Several abiotic stress response genes were upregulated in these seedling in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Photoperiod and light intensity had significant effects on Lr34 phenotypes. These data demonstrate that expression of a highly durable, broad spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. This article is protected by copyright. All rights reserved.

  8. Aeration management for stored hard red winter wheat: simulated impact on rusty grain beetle (Coleoptera: Cucujidae) populations.

    PubMed

    Arthur, F H; Flinn, P W

    2000-08-01

    Simulation studies were conducted to determine temperature accumulations below defined thresholds and to show the impact of controlled aeration on populations of the rusty grain beetle, Cryptolestes ferrigineus (Stephens), a major secondary pest of stored wheat, Triticum aestivum (L.). Recorded data from weather stations in Texas, Oklahoma, Kansas, eastern New Mexico, and eastern Colorado (356 total) were used to determine hours of temperature accumulation below 23.9 degrees C in June and July, 15.6 degrees C in September and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m3/s/m3 (0.1 cubic ft3/min/bu), which requires 120 h of temperatures below the specified threshold to complete an aeration cycle, summer cooling at 23.9 degrees C in bulk-stored wheat could be completed throughout the hard red winter wheat zone except for extreme southern Texas. An early-autumn cooling cycle at 15.6 degrees C could not be completed throughout most of Texas and Oklahoma before the end of September. The late-autumn cooling cycle could be completed in all states except Texas by the end of November. Five geographic regions were delineated and the times required for completion of the summer, early-autumn, and late-autumn cooling cycles within each region were estimated. Population growth of the rusty grain beetle was modeled for San Antonio, TX; Abilene, TX; Tulsa, OK; Topeka KS; and Goodland, KS, by predicting the numbers of adults in the top, outer middle, outer periphery, and the center of the bin during a 1-yr storage season. Populations of C. ferrugineus in San Antonio and Austin were predicted to exceed the Federal Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during the winter, and increase the following spring. In Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the top and outer middle of the bin, whereas populations in

  9. Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

    PubMed Central

    Winberg, Anna; West, Christina E; Strinnholm, Åsa; Nordström, Lisbeth; Hedman, Linnea; Rönmark, Eva

    2015-01-01

    Objectives Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren. Methods In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges. Results In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%). Conclusions There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy. PMID:26134827

  10. Characterization and expression patterns of small RNAs in synthesized Brassica hexaploids.

    PubMed

    Shen, Yanyue; Zhao, Qin; Zou, Jun; Wang, Wenliang; Gao, Yi; Meng, Jinling; Wang, Jianbo

    2014-06-01

    Polyploidy has played an important role in promoting plant evolution through genomic merging and doubling. We used high-throughput sequencing to compare miRNA expression profiles between Brassica hexaploid and its parents. A total of 613, 784 and 742 known miRNAs were identified in Brassica rapa, Brassica carinata, and Brassica hexaploid, respectively. We detected 618 miRNAs were differentially expressed (log(2)Ratio ≥ 1, P ≤ 0.05) between Brassica hexaploid and its parents, and 425 miRNAs were non-additively expressed in Brassica hexaploid, which suggest a trend of non-additive miRNA regulation following hybridization and polyploidization. Remarkably, majority of the non-additively expressed miRNAs in the Brassica hexaploid are repressed, and there was a bias toward repression of B. rapa miRNAs, which is consistent with the progenitor-biased gene repression in the synthetic allopolyploids. In addition, we identified 653 novel mature miRNAs in Brassica hexaploid and its parents. Finally, we found that almost all the non-additive accumulation of siRNA clusters exhibited a low-parent pattern in Brassica hexaploid. Non-additive small RNA regulation is involved in a range of biological pathways, probably providing a driving force for variation and adaptation in allopolyploids.

  11. Single nucleotide polymorphism genotyping in polyploid wheat with the Illumina GoldenGate assay.

    PubMed

    Akhunov, Eduard; Nicolet, Charles; Dvorak, Jan

    2009-08-01

    Single nucleotide polymorphisms (SNPs) are indispensable in such applications as association mapping and construction of high-density genetic maps. These applications usually require genotyping of thousands of SNPs in a large number of individuals. Although a number of SNP genotyping assays are available, most of them are designed for SNP genotyping in diploid individuals. Here, we demonstrate that the Illumina GoldenGate assay could be used for SNP genotyping of homozygous tetraploid and hexaploid wheat lines. Genotyping reactions could be carried out directly on genomic DNA without the necessity of preliminary PCR amplification. A total of 53 tetraploid and 38 hexaploid homozygous wheat lines were genotyped at 96 SNP loci. The genotyping error rate estimated after removal of low-quality data was 0 and 1% for tetraploid and hexaploid wheat, respectively. Developed SNP genotyping assays were shown to be useful for genotyping wheat cultivars. This study demonstrated that the GoldenGate assay is a very efficient tool for high-throughput genotyping of polyploid wheat, opening new possibilities for the analysis of genetic variation in wheat and dissection of genetic basis of complex traits using association mapping approach.

  12. Effect of mechanical weeding on wild chamomile (Matricaria chamomilla L.) populations in winter wheat crop (Triticum aestivum L.).

    PubMed

    Jaunard, D; Bizoux, J P; Monty, A; Henriet, F; De Proft, M; Vancutsem, F; Mahy, G; Bodson, B

    2012-01-01

    Currently, economic, agronomic and environmental concerns lead to reduce the use of herbicides. Mechanical weeding can help to reach this objective. Dynamics and biology of wild chamomile (Matricaria chamomilla L.) populations were assessed as well as dynamic of winter wheat (Triticum aestivum L.) for four level of application of a weeder-harrow (0, 1, 2, 3 treatment(s)). After each treatment, an effect of mechanical weeding on wild chamomile density was observed. Density of wild chamomile decreased significantly with intensification of mechanical weeding. A third treatment allowed eliminating late emerged plants.

  13. Composition of the Fusarium graminearum species complex populations in wheat cropping environments in Southern Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Fusarium graminearum species complex (FGSC) comprises several toxigenic species that cause Fusarium head blight (FHB) in wheat. In this study, high number (n=671 isolates) of pathogenic isolates (isolated from infected spikes) was obtained from a 3-year large-scale survey (2009-2011) conducted o...

  14. Identifying rare FHB-resistant transgressive segregants in intransigent backcross and F2 winter wheat populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB), caused mainly by Fusarium graminearum Schwabe [telomorph: Gibberella zeae Schwein.(Petch)] in the US, is one of the most destructive diseases of wheat (Triticum aestivum L. and T. durum L.). FHB-infected grain is usually contaminated with deoxynivalenol (DON) a mycotoxin ...

  15. Population Dynamics of the Wheat Pest, Hessian fly, in the Southeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hessian fly, Mayetiola destructor (Say), is a wheat crop pest in the United States creating millions of dollars of crop losses each year. The primary means of controlling this insect pest is through the use of resistant cultivars. Over the years, this practice has led to Hessian flies containing g...

  16. Improvement of baking quality traits through a diverse soft winter wheat population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding baking quality improvements into soft winter wheat (SWW) entails crossing lines based on quality traits, assessing new lines, and repeating several times as little is known about the genetics of these traits. Previous research on SWW baking quality focused on quantitative trait locus and ge...

  17. Establishing an efficient way to utilize the drought resistance germplasm population in wheat.

    PubMed

    Wang, Jiancheng; Guan, Yajing; Wang, Yang; Zhu, Liwei; Wang, Qitian; Hu, Qijuan; Hu, Jin

    2013-01-01

    Drought resistance breeding provides a hopeful way to improve yield and quality of wheat in arid and semiarid regions. Constructing core collection is an efficient way to evaluate and utilize drought-resistant germplasm resources in wheat. In the present research, 1,683 wheat varieties were divided into five germplasm groups (high resistant, HR; resistant, R; moderate resistant, MR; susceptible, S; and high susceptible, HS). The least distance stepwise sampling (LDSS) method was adopted to select core accessions. Six commonly used genetic distances (Euclidean distance, Euclid; Standardized Euclidean distance, Seuclid; Mahalanobis distance, Mahal; Manhattan distance, Manhat; Cosine distance, Cosine; and Correlation distance, Correlation) were used to assess genetic distances among accessions. Unweighted pair-group average (UPGMA) method was used to perform hierarchical cluster analysis. Coincidence rate of range (CR) and variable rate of coefficient of variation (VR) were adopted to evaluate the representativeness of the core collection. A method for selecting the ideal constructing strategy was suggested in the present research. A wheat core collection for the drought resistance breeding programs was constructed by the strategy selected in the present research. The principal component analysis showed that the genetic diversity was well preserved in that core collection.

  18. Quantification of genetic relationships among A genomes of wheats.

    PubMed

    Brandolini, A; Vaccino, P; Boggini, G; Ozkan, H; Kilian, B; Salamini, F

    2006-04-01

    The genetic relationships of A genomes of Triticum urartu (Au) and Triticum monococcum (Am) in polyploid wheats are explored and quantified by AFLP fingerprinting. Forty-one accessions of A-genome diploid wheats, 3 of AG-genome wheats, 19 of AB-genome wheats, 15 of ABD-genome wheats, and 1 of the D-genome donor Ae. tauschii have been analysed. Based on 7 AFLP primer combinations, 423 bands were identified as potentially A genome specific. The bands were reduced to 239 by eliminating those present in autoradiograms of Ae. tauschii, bands interpreted as common to all wheat genomes. Neighbour-joining analysis separates T. urartu from T. monococcum. Triticum urartu has the closest relationship to polyploid wheats. Triticum turgidum subsp. dicoccum and T. turgidum subsp. durum lines are included in tightly linked clusters. The hexaploid spelts occupy positions in the phylogenetic tree intermediate between bread wheats and T. turgidum. The AG-genome accessions cluster in a position quite distant from both diploid and other polyploid wheats. The estimates of similarity between A genomes of diploid and polyploid wheats indicate that, compared with Am, Au has around 20% higher similarity to the genomes of polyploid wheats. Triticum timo pheevii AG genome is molecularly equidistant from those of Au and Am wheats.

  19. Effect of microbial inoculants on the indigenous actinobacterial endophyte population in the roots of wheat as determined by terminal restriction fragment length polymorphism.

    PubMed

    Conn, Vanessa M; Franco, Christopher M M

    2004-11-01

    The effect of single actinobacterial endophyte seed inoculants and a mixed microbial soil inoculant on the indigenous endophytic actinobacterial population in wheat roots was investigated by using the molecular technique terminal restriction fragment length polymorphism (T-RFLP). Wheat was cultivated either from seeds coated with the spores of single pure actinobacterial endophytes of Microbispora sp. strain EN2, Streptomyces sp. strain EN27, and Nocardioides albus EN46 or from untreated seeds sown in soil with and without a commercial mixed microbial soil inoculant. The endophytic actinobacterial population within the roots of 6-week-old wheat plants was assessed by T-RFLP. Colonization of the wheat roots by the inoculated actinobacterial endophytes was detected by T-RFLP, as were 28 to 42 indigenous actinobacterial genera present in the inoculated and uninoculated plants. The presence of the commercial mixed inoculant in the soil reduced the endophytic actinobacterial diversity from 40 genera to 21 genera and reduced the detectable root colonization by approximately half. The results indicate that the addition of a nonadapted microbial inoculum to the soil disrupted the natural actinobacterial endophyte population, reducing diversity and colonization levels. This was in contrast to the addition of a single actinobacterial endophyte to the wheat plant, where the increase in colonization level could be confirmed even though the indigenous endophyte population was not adversely affected.

  20. Pentaploid Wheat Hybrids: Applications, Characterisation, and Challenges

    PubMed Central

    Padmanaban, Sriram; Zhang, Peng; Hare, Ray A.; Sutherland, Mark W.; Martin, Anke

    2017-01-01

    Interspecific hybridisation between hexaploid and tetraploid wheat species leads to the development of F1 pentaploid hybrids with unique chromosomal constitutions. Pentaploid hybrids derived from bread wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum spp. durum Desf.) crosses can improve the genetic background of either parent by transferring traits of interest. The genetic variability derived from bread and durum wheat and transferred into pentaploid hybrids has the potential to improve disease resistance, abiotic tolerance, and grain quality, and to enhance agronomic characters. Nonetheless, pentaploid wheat hybrids have not been fully exploited in breeding programs aimed at improving crops. There are several potential barriers for efficient pentaploid wheat production, such as low pollen compatibility, poor seed set, failed seedling establishment, and frequent sterility in F1 hybrids. However, most of the barriers can be overcome by careful selection of the parental genotypes and by employing the higher ploidy level genotype as the maternal parent. In this review, we summarize the current research on pentaploid wheat hybrids and analyze the advantages and pitfalls of current methods used to assess pentaploid-derived lines. Furthermore, we discuss current and potential applications in commercial breeding programs and future directions for research into pentaploid wheat. PMID:28367153

  1. Evolution of polyploid triticum wheats under cultivation: the role of domestication, natural hybridization and allopolyploid speciation in their diversification.

    PubMed

    Matsuoka, Yoshihiro

    2011-05-01

    The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as a group of discrete evolutionary processes that separately proceeded at the tetraploid and hexaploid levels. This standpoint underscores the important role of natural hybridization in the reticulate diversification of the tetraploid-hexaploid Triticum wheat complex and highlights critical, but underappreciated, issues that concern the allopolyploid speciation of common wheat.

  2. The Genetic Control of Grain Protein Content under Variable Nitrogen Supply in an Australian Wheat Mapping Population

    PubMed Central

    Mahjourimajd, Saba; Taylor, Julian; Rengel, Zed; Khabaz-Saberi, Hossein; Kuchel, Haydn; Okamoto, Mamoru

    2016-01-01

    Genetic variation has been observed in both protein concentration in wheat grain and total protein content (protein yield). Here we describe the genetic analysis of variation for grain protein in response to nitrogen (N) supply and locate significant genomic regions controlling grain protein components in a spring wheat population. In total, six N use efficiency (NUE) field trials were carried out for the target traits in a sub-population of doubled haploid lines derived from a cross between two Australian varieties, RAC875 and Kukri, in Southern and Western Australia from 2011 to 2013. Twenty-four putative Quantitative Trait Loci (QTL) for protein-related traits were identified at high and low N supply and ten QTL were identified for the response to N for the traits studied. These loci accounted for a significant proportion of the overall effect of N supply. Several of the regions were co-localised with grain yield QTL and are promising targets for further investigation and selection in breeding programs. PMID:27438012

  3. A multiparental cross population for mapping QTL for agronomic traits in durum wheat (Triticum turgidum ssp. durum).

    PubMed

    Milner, Sara Giulia; Maccaferri, Marco; Huang, Bevan Emma; Mantovani, Paola; Massi, Andrea; Frascaroli, Elisabetta; Tuberosa, Roberto; Salvi, Silvio

    2016-02-01

    Multiparental cross designs for mapping quantitative trait loci (QTL) provide an efficient alternative to biparental populations because of their broader genetic basis and potentially higher mapping resolution. We describe the development and deployment of a recombinant inbred line (RIL) population in durum wheat (Triticum turgidum ssp. durum) obtained by crossing four elite cultivars. A linkage map spanning 2664 cM and including 7594 single nucleotide polymorphisms (SNPs) was produced by genotyping 338 RILs. QTL analysis was carried out by both interval mapping on founder haplotype probabilities and SNP bi-allelic tests for heading date and maturity date, plant height and grain yield from four field experiments. Sixteen QTL were identified across environments and detection methods, including two yield QTL on chromosomes 2BL and 7AS, with the former mapped independently from the photoperiod response gene Ppd-B1, while the latter overlapped with the vernalization locus VRN-A3. Additionally, 21 QTL with environment-specific effects were found. Our results indicated a prevalence of environment-specific QTL with relatively small effect on the control of grain yield. For all traits, functionally different QTL alleles in terms of direction and size of genetic effect were distributed among parents. We showed that QTL results based on founder haplotypes closely matched functional alleles at known heading date loci. Despite the four founders, only 2.1 different functional haplotypes were estimated per QTL, on average. This durum wheat population provides a mapping resource for detailed genetic dissection of agronomic traits in an elite background typical of breeding programmes.

  4. QTLs Associated with Agronomic Traits in the Cutler × AC Barrie Spring Wheat Mapping Population Using Single Nucleotide Polymorphic Markers

    PubMed Central

    Perez-Lara, Enid; Semagn, Kassa; Chen, Hua; Iqbal, Muhammad; N’Diaye, Amidou; Kamran, Atif; Navabi, Alireza; Pozniak, Curtis; Spaner, Dean

    2016-01-01

    We recently reported three earliness per se quantitative trait loci (QTL) associated with flowering and maturity in a recombinant inbred lines (RILs) population derived from a cross between the spring wheat (Triticum aestivum L.) cultivars ‘Cutler’ and ‘AC Barrie’ using 488 microsatellite and diversity arrays technology (DArT) markers. Here, we present QTLs associated with flowering time, maturity, plant height, and grain yield using high density single nucleotide polymorphic (SNP) markers in the same population. A mapping population of 158 RILs and the two parents were evaluated at five environments for flowering, maturity, plant height and grain yield under field conditions, at two greenhouse environments for flowering, and genotyped with a subset of 1809 SNPs out of the 90K SNP array and 2 functional markers (Ppd-D1 and Rht-D1). Using composite interval mapping on the combined phenotype data across all environments, we identified a total of 19 QTLs associated with flowering time in greenhouse (5), and field (6) conditions, maturity (5), grain yield (2) and plant height (1). We mapped these QTLs on 8 chromosomes and they individually explained between 6.3 and 37.8% of the phenotypic variation. Four of the 19 QTLs were associated with multiple traits, including a QTL on 2D associated with flowering, maturity and grain yield; two QTLs on 4A and 7A associated with flowering and maturity, and another QTL on 4D associated with maturity and plant height. However, only the QTLs on both 2D and 4D had major effects, and they mapped adjacent to well-known photoperiod response Ppd-D1 and height reducing Rht-D1 genes, respectively. The QTL on 2D reduced flowering and maturity time up to 5 days with a yield penalty of 436 kg ha-1, while the QTL on 4D reduced plant height by 13 cm, but increased maturity by 2 days. The high density SNPs allowed us to map eight moderate effect, two major effect, and nine minor effect QTLs that were not identified in our previous study

  5. Genetic characterization of North American populations of the wheat curl mite (Aceria tosichella) and dry bulb mite (Aceria tulipae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious d...

  6. Variation between Ethiopian and North American barley varieties (Hordeum vulgare) in response to Russian wheat aphid (Diuraphis noxia) populations.

    PubMed

    Araya, Alemu; Belay, Tesfay; Hussein, Temam

    2014-03-15

    The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), causes severe damage to barley, Hordeum vulgare L. (Poales: Poaceae), in the highlands of Ethiopia. Little information is available on the control of this pest in Ethiopia. An experiment aimed at evaluating the resistance of barley varieties from the USA to D. noxia populations and determining biotypic variation between Ethiopian and North American D. noxia populations was conducted. The D. noxia-resistant barley varieties Burton and RWA-1758 from the USA, the resistant barley line 3296-15 from Ethiopia, and a local Ethiopian susceptible variety were included in a randomized design in a greenhouse under natural light conditions. There were highly significant differences (P < 0.001) in the mean D. noxia population, leaf chlorosis, leaf rolling, plant stunting, number of tillers per plant, and the percentage of infested tillers per plant between the resistant and susceptible varieties. The aphid population per tiller was lower on the resistant barley plants than on the susceptible plants. Severe plant damage was observed on the local barley variety, while the least damage was observed on Burton, followed by RWA-1758. Burton and RWA-1758 were therefore highly resistant and moderately resistant, respectively, to the northern Ethiopian D. noxia populations, indicating similarities in biotypes between the United States and northern Ethiopian D. noxia populations. The damage to variety 3296-15 was greater than to Burton and RWA-1758. Leaf chlorosis scores and leaf rolling scores for variety 3296-15 upon treatment with the north Ethiopian D. noxia population indicate likely biotypic variation between D. noxia populations of northern and central Ethiopia.

  7. Wheat Allergy

    MedlinePlus

    ... Wheat (bran, durum, germ, gluten, grass, malt, sprouts, starch) Wheat bran hydrolysate Wheat germ oil Wheat grass ... in the following: Glucose syrup Surimi Soy sauce Starch (gelatinized starch, modified starch, modified food starch, vegetable ...

  8. Effects of plant tannins supplementation on animal response and in vivo ruminal bacterial populations associated with bloat in heifers grazing wheat forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research was conducted to determine the effects of sources of tannins on in vitro ruminal gas and foam production, in vivo ruminal bacterial populations, bloat dynamics and ADG of heifers grazing wheat forage. Two experiments were conducted to 1) enumerate the effect of tannins supplementation on bi...

  9. Chromosomes 3B and 4D are associated with several milling and baking quality traits in a soft white spring wheat (Triticum aestivum L.) population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat is marketed based on end-use quality characteristics and better knowledge of the underlying genetics of specific quality parameters is essential to enhance the breeding process. A set of 188 recombinant inbred lines from a ‘Louise’ by ‘Penawawa’ mapping population was grown in two crop years a...

  10. Inheritance of dense spike in diploid wheat and Aegilops squarrosa.

    PubMed

    Goncharov, N P; Kondratenko, E Ya; Kawahara, T

    2002-01-01

    The individuals of diploid wheat Triticum boeoticum, T. monococcum and T. sinskajae and goatgrass Aegilops squarrosa were picked out with screening the dense spike characteristics. The dense-spike accessions were discovered in diploid wheat (T. sinskajae) and Ae. squarrosa. Inheritance of the dense spike was studied. The trait was found to be controlled by a recessive gene in T. sinskajae and by an incomplete dominant gene in Ae. squarrosa. The dosage effect of dominant gene C was detected in interspecific pentaploid F1 hybrid plants T. compactum x T. palmovae (2n =35, A(u)A(b)BDD genome). The spike of pentaploid hybrid was not so dense as compared to hexaploid wheat T. compactum. This is the first report showing similarity of the expression of dominant gene C on D genome of the hexaploid wheat to that of dense spike gene in Ae. squarrosa. The existence of dense-spike accessions of Ae. squarrosa allows us to hypothesize that the origin of T. compactum is independent from that of common wheat.

  11. Validation of a 1DL earliness per se (eps) flowering QTL in bread wheat (Triticum aestivum).

    PubMed

    Zikhali, Meluleki; Leverington-Waite, Michelle; Fish, Lesley; Simmonds, James; Orford, Simon; Wingen, Luzie U; Goram, Richard; Gosman, Nick; Bentley, Alison; Griffiths, Simon

    2014-01-01

    Vernalization, photoperiod and the relatively poorly defined earliness per se (eps) genes regulate flowering in plants. We report here the validation of a major eps quantitative trait locus (QTL) located on wheat 1DL using near isogenic lines (NILs). We used four independent pairs of NILs derived from a cross between Spark and Rialto winter wheat varieties, grown in both the field and controlled environments. NILs carrying the Spark allele, defined by QTL flanking markers Xgdm111 and Xbarc62, consistently flowered 3-5 days earlier when fully vernalized relative to those with the Rialto. The effect was independent of photoperiod under field conditions, short days (10-h light), long days (16-h light) and very long days (20-h light). These results validate our original QTL identified using doubled haploid (DH) populations. This QTL represents variation maintained in elite north-western European winter wheat germplasm. The two DH lines used to develop the NILs, SR9 and SR23 enabled us to define the location of the 1DL QTL downstream of marker Xgdm111. SR9 has the Spark 1DL arm while SR23 has a recombinant 1DL arm with the Spark allele from Xgdm111 to the distal end. Our work suggests that marker assisted selection of eps effects is feasible and useful even before the genes are cloned. This means eps genes can be defined and positionally cloned in the same way as the photoperiod and vernalization genes have been. This validation study is a first step towards fine mapping and eventually cloning the gene directly in hexaploid wheat.

  12. Fast and Efficient Screening for Wheat Loss-of-Gene Mutants Using Multiplexed Melt Curve Analyses.

    PubMed

    Mieog, Jos C; Ral, Jean-Philippe F

    2016-01-01

    This study describes a new approach in the screening for loss-of-gene mutants in Heavy Ion Bombardment (HIB) mutant populations of genetically complex organisms such as hexaploid bread wheat using multiplexed single-color (SYBR Green) melt curve analyses. The assay was set up for three target genes to test its validity and applicability. For each gene, three genome-specific primer pairs (one for each genome) with distinct melt curves were developed and multiplexed. This allowed screening for "single null mutants" (plants with the target gene deleted in one of the three genomes) for all three genomes in a single reaction. The first two genes (α-Amylase 3 and Epsilon Cyclase) were used to test the approach as HIB null lines for all three genomes were already available for these. The third assay was successfully applied to identify new single null lines of the target gene α-Amylase 2 in an in-house HIB wheat collection. The use of SYBR Green greatly reduced the time and/or cost investment compared to other techniques and the approach proved highly suitable for high-throughput applications.

  13. Detection of QTLs for heading time and photoperiod response in wheat using a doubled-haploid population.

    PubMed

    Sourdille, P; Snape, J W; Cadalen, T; Charmet, G; Nakata, N; Bernard, S; Bernard, M

    2000-06-01

    The genetic basis of heading time in wheat (Triticum aestivum L.) was investigated through the study of flowering under normal autumn sown field conditions as well as photoperiod responses under a controlled environment. Quantitative trait loci (QTLs) for these traits were mapped in a doubled-haploid (DH) population derived from a cross between the wheat cultivars 'Courtot' and 'Chinese Spring'. A molecular marker linkage map of this cross that was previously constructed based on 187 DH lines and 380 markers was used for QTL mapping. The genome was well covered (85%) except for chromosomes 1D and 4D, and a set of anchor loci regularly spaced over the genome (one marker each 15.5 cM) was chosen for marker regression analysis. The presence of a QTL was declared at a significance threshold of alpha = 0.005. The population was grown under field conditions in Clermont-Ferrand, France during two years (1994-1995), in Norwich, U.K. over one year (1998), and also under controlled environments in Norwich. For each trait, between 2 and 4 QTLs were identified with individual effects ranging between 6.3% and 44.4% of the total phenotypic variation. Two QTLs were detected that simultaneously affected heading time and photoperiod response. For heading time, these two QTLs were detected in more than one year. One QTL located on chromosome arm 2BS near the locus Xfbb121-2B, co-segregated with the gene Ppd-B1 known to be involved in photoperiod response. This chromosome region explained a large part of the variation (23.4-44.4% depending on the years or the traits). Another region located on chromosome arm 7BS between the loci Xfbb324-7B and Xfbb53-7B also had a strong effect (7.3-15.3%). This region may correspond to a QTL for earliness per se.

  14. Fine mapping and genetic association analysis of Net2, the causative D-genome locus of low temperature-induced hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii.

    PubMed

    Sakaguchi, Kouhei; Nishijima, Ryo; Iehisa, Julio Cesar Masaru; Takumi, Shigeo

    2016-10-01

    Hybrid necrosis has been observed in many interspecific hybrids from crosses between tetraploid wheat and the wheat D-genome donor Aegilops tauschii. Type II necrosis is a kind of hybrid incompatibility that is specifically characterized by low-temperature induction and growth suppression. Two complementary genes, Net1 on the AB genome and Net2 on the D genome, putatively control type II necrosis in ABD triploids and synthetic hexaploid wheat. Toward map-based cloning of Net2, a fine map around the Net2 region on 2DS was constructed in this study. Using the draft genome sequence of Ae. tauschii and the physical map of the barley genome, the Net2 locus was mapped within a 0.6 cM interval between two closely linked markers. Although local chromosomal rearrangements were observed in the Net2-corresponding region between the barley/Brachypodium and Ae. tauschii genomes, the two closely linked markers were significantly associated with type II necrosis in Ae. tauschii. These results suggest that these markers will aid efficient selection of Net2 non-carrier individuals from the Ae. tauschii population and intraspecific progeny, and could help with introgression of agriculturally important genes from Ae. tauschii to common wheat.

  15. Resistance to Multiple Soil-Borne Pathogens of the Pacific Northwest, USA Is Colocated in a Wheat Recombinant Inbred Line Population

    PubMed Central

    Thompson, Alison L.; Mahoney, Aaron K.; Smiley, Richard W.; Paulitz, Timothy C.; Hulbert, Scot; Garland-Campbell, Kim

    2017-01-01

    Soil-borne pathogens of the Pacific Northwest decrease yields in both spring and winter wheat. Pathogens of economic importance include Fusarium culmorum, Pratylenchus neglectus, P. thornei, and Rhizoctonia solani AG8. Few options are available to growers to manage these pathogens and reduce yield loss, therefore the focus for breeding programs is on developing resistant wheat cultivars. A recombinant inbred line population, LouAu (MP-7, NSL 511036), was developed to identify quantitative trait loci (QTL) associated with resistance to P. neglectus and P. thornei. This same population was later suspected to be resistant to F. culmorum and R. solani AG8. This study confirms partial resistance to F. culmorum and R. solani AG8 is present in this population. Six major and 16 speculative QTL were identified across seven measured traits. Four of the six major QTL were found within the same genomic region of the 5A wheat chromosome suggesting shared gene(s) contribute to the resistance. These QTL will be useful in breeding programs looking to incorporate resistance to soil-borne pathogens in wheat cultivars. PMID:28159864

  16. Consumption of pesticide-treated wheat seed by a rural population in Malawi

    PubMed Central

    Schier, Joshua G.; Sejvar, James J.; Lutterloh, Emily; Likaka, Andrew; Katsoudas, Eugenia; Karaseva, Yelena D.; Barr, Beth Tippett; Redwood, Yanique; Monroe, Stephan

    2015-01-01

    An outbreak of typhoid fever in rural Malawi triggered an investigation by the Malawi Ministry of Health and the Centers for Disease Control and Prevention in July 2009. During the investigation, villagers were directly consuming washed, donated, pesticide-treated wheat seed meant for planting. The objective of this study was to evaluate the potential for pesticide exposure and health risk in the outbreak community. A sample of unwashed (1430 g) and washed (759 g) wheat seed donated for planting, but which would have been directly consumed, was tested for 365 pesticides. Results were compared with each other (percentage change), the US Environmental Protection Agency’s (EPA) health guidance values and estimated daily exposures were compared with their Reference dose (RfD). Unwashed and washed seed samples contained, respectively: carboxin, 244 and 57 p.p.m.; pirimiphos methyl, 8.18 and 8.56 p.p.m.; total permethrin, 3.62 and 3.27 p.p.m.; and carbaryl, 0.057 and 0.025 p.p.m.. Percentage change calculations (unwashed to washed) were as follows: carboxin, −76.6%; pirimiphos methyl, +4.6%; total permethrin, −9.7%; and carbaryl −56.1%. Only carboxin and total permethrin concentration among washed seed samples exceeded US EPA health guidance values (285 × and seven times, respectively). Adult estimated exposure scenarios (1 kg seed) exceeded the RfD for carboxin (8 ×) and pirimiphos methyl (12 ×). Adult villagers weighing 70 kg would have to consume 0.123, 0.082, 1.06, and 280 kg of washed seed daily to exceed the RfD for carboxin, pirimiphos methyl, permethrins, and carbaryl, respectively. Carboxin, pirimiphos methyl, permethrins, and carbaryl were detected in both unwashed and washed samples of seed. Carboxin, total permethrin, and carbaryl concentration were partially reduced by washing. Health risks from chronic exposure to carboxin and pirimiphos methyl in these amounts are unclear. The extent of this practice among food insecure communities receiving

  17. A step change in the transfer of interspecific variation into wheat from Amblyopyrum muticum.

    PubMed

    King, Julie; Grewal, Surbhi; Yang, Cai-Yun; Hubbart, Stella; Scholefield, Duncan; Ashling, Stephen; Edwards, Keith J; Allen, Alexandra M; Burridge, Amanda; Bloor, Claire; Davassi, Alessandro; da Silva, Glacy J; Chalmers, Ken; King, Ian P

    2017-02-01

    Despite some notable successes, only a fraction of the genetic variation available in wild relatives has been utilized to produce superior wheat varieties. This is as a direct result of the lack of availability of suitable high-throughput technologies to detect wheat/wild relative introgressions when they occur. Here, we report on the use of a new SNP array to detect wheat/wild relative introgressions in backcross progenies derived from interspecific hexaploid wheat/Ambylopyrum muticum F1 hybrids. The array enabled the detection and characterization of 218 genomewide wheat/Am. muticum introgressions, that is a significant step change in the generation and detection of introgressions compared to previous work in the field. Furthermore, the frequency of introgressions detected was sufficiently high to enable the construction of seven linkage groups of the Am. muticum genome, thus enabling the syntenic relationship between the wild relative and hexaploid wheat to be determined. The importance of the genetic variation from Am. muticum introduced into wheat for the development of superior varieties is discussed.

  18. Reconstruction of the synthetic W9784 x Opata85 wheat reference population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reference populations are a valuable resource in genetics studies of crop species for determining marker order, marker selection, trait mapping, construction of large-insert libraries, cross-referencing marker platforms, and genome sequencing. Useful reference populations can be propagated indefinit...

  19. QTLs associated with agronomic traits in the Attila × CDC Go spring wheat population evaluated under conventional management

    PubMed Central

    Zou, Jun; Iqbal, Muhammad; Chen, Hua; Asif, Mohammad; N’Diaye, Amidou; Navabi, Alireza; Perez-Lara, Enid; Pozniak, Curtis; Yang, Rong-Cai; Randhawa, Harpinder; Spaner, Dean

    2017-01-01

    Recently, we investigated the effect of the wheat 90K single nucleotide polymorphic (SNP) array and three gene-specific (Ppd-D1, Vrn-A1 and Rht-B1) markers on quantitative trait loci (QTL) detection in a recombinant inbred lines (RILs) population derived from a cross between two spring wheat (Triticum aestivum L.) cultivars, ‘Attila’ and ‘CDC Go’, and evaluated for eight agronomic traits at three environments under organic management. The objectives of the present study were to investigate the effect of conventional management on QTL detection in the same mapping population using the same set of markers as the organic management and compare the results with organic management. Here, we evaluated 167 RILs for number of tillers (tillering), flowering time, maturity, plant height, test weight (grain volume weight), 1000 kernel weight, grain yield, and grain protein content at seven conventionally managed environments from 2008 to 2014. Using inclusive composite interval mapping (ICIM) on phenotypic data averaged across seven environments and a subset of 1203 informative markers (1200 SNPs and 3 gene specific markers), we identified a total of 14 QTLs associated with flowering time (1), maturity (2), plant height (1), grain yield (1), test weight (2), kernel weight (4), tillering (1) and grain protein content (2). Each QTL individually explained from 6.1 to 18.4% of the phenotypic variance. Overall, the QTLs associated with each trait explained from 9.7 to 35.4% of the phenotypic and from 22.1 to 90.8% of the genetic variance. Three chromosomal regions on chromosomes 2D (61–66 cM), 4B (80–82 cM) and 5A (296–297 cM) harbored clusters of QTLs associated with two to three traits. The coincidental region on chromosome 5A harbored QTL clusters for both flowering and maturity time, and mapped about 2 cM proximal to the Vrn-A1 gene, which was in high linkage disequilibrium (0.70 ≤ r2 ≤ 0.75) with SNP markers that mapped within the QTL confidence interval

  20. QTLs associated with agronomic traits in the Attila × CDC Go spring wheat population evaluated under conventional management.

    PubMed

    Zou, Jun; Semagn, Kassa; Iqbal, Muhammad; Chen, Hua; Asif, Mohammad; N'Diaye, Amidou; Navabi, Alireza; Perez-Lara, Enid; Pozniak, Curtis; Yang, Rong-Cai; Randhawa, Harpinder; Spaner, Dean

    2017-01-01

    Recently, we investigated the effect of the wheat 90K single nucleotide polymorphic (SNP) array and three gene-specific (Ppd-D1, Vrn-A1 and Rht-B1) markers on quantitative trait loci (QTL) detection in a recombinant inbred lines (RILs) population derived from a cross between two spring wheat (Triticum aestivum L.) cultivars, 'Attila' and 'CDC Go', and evaluated for eight agronomic traits at three environments under organic management. The objectives of the present study were to investigate the effect of conventional management on QTL detection in the same mapping population using the same set of markers as the organic management and compare the results with organic management. Here, we evaluated 167 RILs for number of tillers (tillering), flowering time, maturity, plant height, test weight (grain volume weight), 1000 kernel weight, grain yield, and grain protein content at seven conventionally managed environments from 2008 to 2014. Using inclusive composite interval mapping (ICIM) on phenotypic data averaged across seven environments and a subset of 1203 informative markers (1200 SNPs and 3 gene specific markers), we identified a total of 14 QTLs associated with flowering time (1), maturity (2), plant height (1), grain yield (1), test weight (2), kernel weight (4), tillering (1) and grain protein content (2). Each QTL individually explained from 6.1 to 18.4% of the phenotypic variance. Overall, the QTLs associated with each trait explained from 9.7 to 35.4% of the phenotypic and from 22.1 to 90.8% of the genetic variance. Three chromosomal regions on chromosomes 2D (61-66 cM), 4B (80-82 cM) and 5A (296-297 cM) harbored clusters of QTLs associated with two to three traits. The coincidental region on chromosome 5A harbored QTL clusters for both flowering and maturity time, and mapped about 2 cM proximal to the Vrn-A1 gene, which was in high linkage disequilibrium (0.70 ≤ r2 ≤ 0.75) with SNP markers that mapped within the QTL confidence interval. Six of the 14

  1. Identifying quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in two spring wheat populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium crown rot (FCR), caused by F. pseudograminearum and F. culmorum, reduces wheat yields in the Pacific Northwest (PNW) of the U.S. by as much as 35%. Currently there is no consistent durable resistance to FCR in PNW wheat cultivars. Significant QTL for crown rot resistance have been documente...

  2. SNP Discovery and Chromosome Anchoring Provide the First Physically-Anchored Hexaploid Oat Map and Reveal Synteny with Model Species

    PubMed Central

    Chao, Shiaoman; Jellen, Eric N.; Carson, Martin L.; Rines, Howard W.; Obert, Donald E.; Lutz, Joseph D.; Shackelford, Irene; Korol, Abraham B.; Wight, Charlene P.; Gardner, Kyle M.; Hattori, Jiro; Beattie, Aaron D.; Bjørnstad, Åsmund; Bonman, J. Michael; Jannink, Jean-Luc; Sorrells, Mark E.; Brown-Guedira, Gina L.; Mitchell Fetch, Jennifer W.; Harrison, Stephen A.; Howarth, Catherine J.; Ibrahim, Amir; Kolb, Frederic L.; McMullen, Michael S.; Murphy, J. Paul; Ohm, Herbert W.; Rossnagel, Brian G.; Yan, Weikai; Miclaus, Kelci J.; Hiller, Jordan; Maughan, Peter J.; Redman Hulse, Rachel R.; Anderson, Joseph M.; Islamovic, Emir

    2013-01-01

    A physically anchored consensus map is foundational to modern genomics research; however, construction of such a map in oat (Avena sativa L., 2n = 6x = 42) has been hindered by the size and complexity of the genome, the scarcity of robust molecular markers, and the lack of aneuploid stocks. Resources developed in this study include a modified SNP discovery method for complex genomes, a diverse set of oat SNP markers, and a novel chromosome-deficient SNP anchoring strategy. These resources were applied to build the first complete, physically-anchored consensus map of hexaploid oat. Approximately 11,000 high-confidence in silico SNPs were discovered based on nine million inter-varietal sequence reads of genomic and cDNA origin. GoldenGate genotyping of 3,072 SNP assays yielded 1,311 robust markers, of which 985 were mapped in 390 recombinant-inbred lines from six bi-parental mapping populations ranging in size from 49 to 97 progeny. The consensus map included 985 SNPs and 68 previously-published markers, resolving 21 linkage groups with a total map distance of 1,838.8 cM. Consensus linkage groups were assigned to 21 chromosomes using SNP deletion analysis of chromosome-deficient monosomic hybrid stocks. Alignments with sequenced genomes of rice and Brachypodium provide evidence for extensive conservation of genomic regions, and renewed encouragement for orthology-based genomic discovery in this important hexaploid species. These results also provide a framework for high-resolution genetic analysis in oat, and a model for marker development and map construction in other species with complex genomes and limited resources. PMID:23533580

  3. Starch waxiness in hexaploid wheat (Triticum aestivum L.) by NIR reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch, the primary energy storage component of plants, consists of two large macromolecules, amylose and amylopectin. Each molecule is composed of long chains of alpha-D-glucopyranosyl units, with branching present in amylopectin and absent in amylose. The relative abundance of these two molecules ...

  4. Synthesis of trigeneric hybrids of hexaploid wheat with diploid wheatgrasses: Specificity of chromosome pairing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wild grasses in the tribe Triticeae are excellent sources of genes for superior traits, including resistance to various diseases. Diploid wheatgrasses – Lophopyrum elongatum (Host) Á. Löve (2n = 2x = 14; EE genome) and Thinopyrum bessarabicum (Savul. & Rayss) Á. Löve (2n = 2x = 14; JJ genome) – are...

  5. Development of a D genome specific marker resource for diploid and hexaploid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mapping and map-based cloning of genes that control agriculturally and economically important traits remain great challenges for plants with complex highly repetitive genomes such as those of the grass tribe, Triticeae. Mapping limitations in the Triticeae are primarily due to low frequencies of po...

  6. O-Glucosyltransferase activities toward phenolic natural products and xenobiotics in wheat and herbicide-resistant and herbicide-susceptible black-grass (Alopecurus myosuroides).

    PubMed

    Brazier, Melissa; Cole, David J; Edwards, Robert

    2002-01-01

    Herbicide safeners manipulate herbicide selectivity by enhancing the activities of detoxifying enzymes, such as glutathione transferases (GSTs) and cytochrome P450 mono-oxygenases (CYPs) in cereal crops. As part of a study examining the importance of O-glucosyltransferases (OGTs) in pesticide metabolism in hexaploid bread wheat (Triticum aestivum L.), seedlings were grown in the presence of dichlormid, a safener used in maize and cloquintocet mexyl, a wheat safener. The efficacy of the treatments was confirmed by monitoring changes in the abundance of phi and tau class GSTs. OGT activities in the root and shoot tissue were assayed using phenolics of natural and xenobiotic origin to determine if they were enhanced by safeners. Cloquintocet mexyl selectively increased OGT activities toward xenobiotics (4-nitrophenol and 2,4,5-trichlorophenol) and flavonoids, (quercetin, luteolin, genistein and coumestrol) in both the roots and shoots. However, OGT activity towards simple phenols and phenylpropanoids was not enhanced by cloquintocet mexyl. Dichlormid was a much weaker enhancer of OGT activity, with the same subset of OGT activities increased as determined with cloquintocet mexyl, but with the effect being largely restricted to the roots. OGT activities were also determined in black-grass (Alopecurus myosuroides L.), an agronomically important weed in wheat. Two populations of black-grass differing in their sensitivity to herbicides were analysed. The population Peldon, which is resistant to multiple classes of herbicides due in part to the elevated expression of CYPs and GSTs active in herbicide detoxification, contained higher OGT activities than herbicide sensitive black-grass. Unlike wheat, treatment with cloquintocet mexyl or dichlormid, had no effect on OGT activities in either black-grass population.

  7. A pseudo-response regulator is misexpressed in the photoperiod insensitive Ppd-D1a mutant of wheat (Triticum aestivum L.).

    PubMed

    Beales, James; Turner, Adrian; Griffiths, Simon; Snape, John W; Laurie, David A

    2007-09-01

    Ppd-D1 on chromosome 2D is the major photoperiod response locus in hexaploid wheat (Triticum aestivum). A semi-dominant mutation widely used in the "green revolution" converts wheat from a long day (LD) to a photoperiod insensitive (day neutral) plant, providing adaptation to a broad range of environments. Comparative mapping shows Ppd-D1 to be colinear with the Ppd-H1 gene of barley (Hordeum vulgare) which is a member of the pseudo-response regulator (PRR) gene family. To investigate the relationship between wheat and barley photoperiod genes we isolated homologues of Ppd-H1 from a 'Chinese Spring' wheat BAC library and compared them to sequences from other wheat varieties with known Ppd alleles. Varieties with the photoperiod insensitive Ppd-D1a allele which causes early flowering in short (SD) or LDs had a 2 kb deletion upstream of the coding region. This was associated with misexpression of the 2D PRR gene and expression of the key floral regulator FT in SDs, showing that photoperiod insensitivity is due to activation of a known photoperiod pathway irrespective of day length. Five Ppd-D1 alleles were found but only the 2 kb deletion was associated with photoperiod insensitivity. Photoperiod insensitivity can also be conferred by mutation at a homoeologous locus on chromosome 2B (Ppd-B1). No candidate mutation was found in the 2B PRR gene but polymorphism within the 2B PRR gene cosegregated with the Ppd-B1 locus in a doubled haploid population, suggesting that insensitivity on 2B is due to a mutation outside the sequenced region or to a closely linked gene.

  8. Searching for novel sources of field resistance to Ug99 and Ethiopian stem rust races in durum wheat via association mapping.

    PubMed

    Letta, Tesfaye; Maccaferri, Marco; Badebo, Ayele; Ammar, Karim; Ricci, Andrea; Crossa, Jose; Tuberosa, Roberto

    2013-05-01

    Puccinia graminis f. sp. tritici, the causative agent of stem rust in wheat, is a devastating disease of durum wheat. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few of them have remained effective against Ug99 (TTKSK race) and other durum-specific Ethiopian races. An association mapping (AM) approach based on 183 diverse durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four field-evaluation seasons and artificial inoculation with Ug99 and a mixture of durum-specific races. The panel was profiled with simple sequence repeat, Diversity Arrays Technology and sequence-tagged site markers (1,253 in total). The resistance turned out to be oligogenic, with twelve QTL-tagging markers that were significant (P < 0.05) across three or four seasons. R (2) values ranged from 1.1 to 11.3 %.Twenty-four additional single-marker/QTL regions were found to be significant over two seasons. The AM results confirmed the role of Sr13, previously described in bi-parental mapping studies, and the role of chromosome regions putatively harbouring Sr9, Sr14, Sr17 and Sr28. Three minor QTLs were coincident with those reported in hexaploid wheat and five overlapped with those recently reported in the Sebatel × Kristal durum mapping population. Thirteen single-marker/QTL regions were located in chromosome regions where no Sr genes/QTLs have been previously reported. The allelic variation identified in this study is readily available and can be exploited for marker-assisted selection, thus providing additional opportunities for a more durable stem rust resistance under field conditions.

  9. Population-Specific Patterns of Linkage Disequilibrium and SNP Variation in Spring and Winter Polyploid Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Single nucleotide polymorphisms (SNPs) are ideally suited for the construction of high-resolution genetic maps, studying population evolutionary history and performing genome-wide association mapping experiments. Here we used a genome-wide set of 1536 SNPs to study linkage disequilibrium (LD) and po...

  10. Evolution of the Oat Genetic Road Map: From Tetraploid to Hexaploid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of a genetic linkage map for hexaploid oat (Avena sativa L. 2n = 6 x = 42) that defines all 21 chromosomes has been hindered due to the lack of oat-based markers and the size and complexity of the oat genome. Recent efforts in oat DArT, SSR, and SNP marker development should improve...

  11. Population structure within lineages of Wheat streak mosaic virus derived from a common founding event exhibits stochastic variation inconsistent with the deterministic quasi-species model

    SciTech Connect

    French, Roy; Stenger, Drake C. . E-mail: dstenger@unlnotes.unl.edu

    2005-12-20

    Structure of Wheat streak mosaic virus (WSMV) populations derived from a common founding event and subjected to serial passage at high multiplicity of infection (MOI) was evaluated. The founding population was generated by limiting dilution inoculation. Lineages of known pedigree were sampled at passage 9 (two populations) and at passage 15, with (three populations) or without mixing (four populations) of lineages at passage 10. Polymorphism within each population was assessed by sequencing 17-21 clones containing a 1371 nt region (WSMV-Sidney 81 nts 8001-9371) encompassing the entire coat protein cistron and flanking regions. Mutation frequency averaged {approx}5.0 x 10{sup -4}/nt across all populations and ranged from 2.4 to 11.6 x 10{sup -4}/nt within populations, but did not consistently increase or decrease with the number of passages removed from the founding population. Shared substitutions (19 nonsynonymous, 10 synonymous, and 3 noncoding) occurred at 32 sites among 44 haplotypes. Only four substitutions became fixed (frequency = 100%) within a population and nearly one third (10/32) never achieved a frequency of 10% or greater in any sampled population. Shared substitutions were randomly distributed with respect to genome position, with transitions outnumbering transversions 5.4:1 and a clear bias for A to G and U to C substitutions. Haplotype composition of each population was unique with complexity of each population varying unpredictably, in that the number and frequency of haplotypes within a lineage were not correlated with number of passages removed from the founding population or whether the population was derived from a single or mixed lineage. The simplest explanation is that plant virus lineages, even those propagated at high MOI, are subject to frequent, narrow genetic bottlenecks during systemic movement that result in low effective population size and stochastic changes in population structure upon serial passage.

  12. Genetic and comparative genomics mapping reveals that a powdery mildew resistance gene Ml3D232 originating from wild emmer co-segregates with an NBS-LRR analog in common wheat (Triticum aestivum L.).

    PubMed

    Zhang, Hongtao; Guan, Haiying; Li, Jingting; Zhu, Jie; Xie, Chaojie; Zhou, Yilin; Duan, Xiayu; Yang, Tsomin; Sun, Qixin; Liu, Zhiyong

    2010-11-01

    Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most important wheat diseases worldwide and breeding for resistance using diversified disease resistance genes is the most promising approach to prevent outbreaks of powdery mildew. A powdery mildew resistance gene, originating from wild emmer wheat (Triticum turgidum var. dicoccoides) accessions collected from Israel, has been transferred into the hexaploid wheat line 3D232 through crossing and backcrossing. Inoculation results with 21 B. graminis f. sp. tritici races indicated that 3D232 is resistant to all of the powdery mildew isolates tested. Genetic analyses of 3D232 using an F(2) segregating population and F(3) families indicated that a single dominant gene, Ml3D232, confers resistance in the host seedling stage. By applying molecular markers and bulked segregant analysis (BSA), we have identified polymorphic simple sequence repeats (SSR), expressed sequence tags (EST) and derived sequence tagged site (STS) markers to determine that the Ml3D232 is located on chromosome 5BL bin 0.59-0.76. Comparative genetic analyses using mapped EST markers and genome sequences of rice and Brachypodium established co-linearity of the Ml3D232 genomic region with a 1.4 Mb genomic region on Brachypodium distachyon chromosome 4, and a 1.2 Mb contig located on the Oryza sativa chromosome 9. Our comparative approach enabled us to develop new EST-STS markers and to delimit the genomic region carrying Ml3D232 to a 0.8 cM segment that is collinear with a 558 kb region on B. distachyon. Eight EST markers, including an NBS-LRR analog, co-segregated with Ml3D232 to provide a target site for fine genetic mapping, chromosome landing and map-based cloning of the powdery mildew resistance gene. This newly developed common wheat germplasm provides broad-spectrum resistance to powdery mildew and a valuable resource for wheat breeding programs.

  13. Wheat Genotypes With Combined Resistance to Wheat Curl Mite, Wheat Streak Mosaic Virus, Wheat Mosaic Virus, and Triticum Mosaic Virus.

    PubMed

    Chuang, Wen-Po; Rojas, Lina Maria Aguirre; Khalaf, Luaay Kahtan; Zhang, Guorong; Fritz, Allan K; Whitfield, Anna E; Smith, C Michael

    2017-01-13

    The wheat curl mite, Aceria tosichella Keifer, (WCM) is a global pest of bread wheat that reduces yields significantly. In addition, WCM carries Wheat streak mosaic virus (WSMV, family Potyviridae, genus Tritimovirus), the most significant wheat virus in North America; High Plains wheat mosaic virus (HPWMoV, genus Emaravirus, formerly High plains virus); and Triticum mosaic virus (TriMV, family Potyviridae, genus Poacevirus). Viruses carried by WCM have reduced wheat yields throughout the U.S. Great Plains for >50 yr, with average yield losses of 2-3% and occasional yield losses of 7-10%. Acaricides are ineffective against WCM, and delayed planting of winter wheat is not feasible. Five wheat breeding lines containing Cmc4, a WCM resistance gene from Aegilops tauschii, and Wsm2, a WSMV resistance gene from wheat germplasm CO960293-2 were selected from the breeding process and assessed for phenotypic reaction to WCM feeding, population increase, and the degree of WSMV, HPWMoV, and TriMV infection. Experiments determined that all five lines are resistant to WCM biotype 1 feeding and population increase, and that two breeding lines contain resistance to WSMV, HPWMoV, and TriMV infection as well. These WCM-, WSMV-, HPWMoV-, and TriMV-resistant genotypes can be used improve management of wheat yield losses from WCM-virus complexes.

  14. Analysis of wheat SAGE tags reveals evidence for widespread antisense transcription

    PubMed Central

    Poole, Rebecca L; Barker, Gary LA; Werner, Kay; Biggi, Gaia F; Coghill, Jane; Gibbings, J George; Berry, Simon; Dunwell, Jim M; Edwards, Keith J

    2008-01-01

    Background Serial Analysis of Gene Expression (SAGE) is a powerful tool for genome-wide transcription studies. Unlike microarrays, it has the ability to detect novel forms of RNA such as alternatively spliced and antisense transcripts, without the need for prior knowledge of their existence. One limitation of using SAGE on an organism with a complex genome and lacking detailed sequence information, such as the hexaploid bread wheat Triticum aestivum, is accurate annotation of the tags generated. Without accurate annotation it is impossible to fully understand the dynamic processes involved in such complex polyploid organisms. Hence we have developed and utilised novel procedures to characterise, in detail, SAGE tags generated from the whole grain transcriptome of hexaploid wheat. Results Examination of 71,930 Long SAGE tags generated from six libraries derived from two wheat genotypes grown under two different conditions suggested that SAGE is a reliable and reproducible technique for use in studying the hexaploid wheat transcriptome. However, our results also showed that in poorly annotated and/or poorly sequenced genomes, such as hexaploid wheat, considerably more information can be extracted from SAGE data by carrying out a systematic analysis of both perfect and "fuzzy" (partially matched) tags. This detailed analysis of the SAGE data shows first that while there is evidence of alternative polyadenylation this appears to occur exclusively within the 3' untranslated regions. Secondly, we found no strong evidence for widespread alternative splicing in the developing wheat grain transcriptome. However, analysis of our SAGE data shows that antisense transcripts are probably widespread within the transcriptome and appear to be derived from numerous locations within the genome. Examination of antisense transcripts showing sequence similarity to the Puroindoline a and Puroindoline b genes suggests that such antisense transcripts might have a role in the regulation of

  15. Mapping and QTL analysis of drought tolerance in a spring wheat population using AFLP and DArt markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water availability is commonly the most limiting factor to crop production. This study was conducted to map quantitative trait loci (QTL) involved in drought tolerance in wheat (Triticum aestivum L.) to enable their use for marker assisted selection (MAS) in breeding. Using amplified fragment leng...

  16. Optimizing Training Population Size and Genotyping Strategy for Genomic Prediction Using Association Study Results and Pedigree Information. A Case of Study in Advanced Wheat Breeding Lines

    PubMed Central

    Jahoor, Ahmed; Orabi, Jihad; Andersen, Jeppe R.; Janss, Luc L.; Jensen, Just

    2017-01-01

    Wheat breeding programs generate a large amount of variation which cannot be completely explored because of limited phenotyping throughput. Genomic prediction (GP) has been proposed as a new tool which provides breeding values estimations without the need of phenotyping all the material produced but only a subset of it named training population (TP). However, genotyping of all the accessions under analysis is needed and, therefore, optimizing TP dimension and genotyping strategy is pivotal to implement GP in commercial breeding schemes. Here, we explored the optimum TP size and we integrated pedigree records and genome wide association studies (GWAS) results to optimize the genotyping strategy. A total of 988 advanced wheat breeding lines were genotyped with the Illumina 15K SNPs wheat chip and phenotyped across several years and locations for yield, lodging, and starch content. Cross-validation using the largest possible TP size and all the SNPs available after editing (~11k), yielded predictive abilities (rGP) ranging between 0.5–0.6. In order to explore the Training population size, rGP were computed using progressively smaller TP. These exercises showed that TP of around 700 lines were enough to yield the highest observed rGP. Moreover, rGP were calculated by randomly reducing the SNPs number. This showed that around 1K markers were enough to reach the highest observed rGP. GWAS was used to identify markers associated with the traits analyzed. A GWAS-based selection of SNPs resulted in increased rGP when compared with random selection and few hundreds SNPs were sufficient to obtain the highest observed rGP. For each of these scenarios, advantages of adding the pedigree information were shown. Our results indicate that moderate TP sizes were enough to yield high rGP and that pedigree information and GWAS results can be used to greatly optimize the genotyping strategy. PMID:28081208

  17. Identification of novel quantitative trait loci for days to ear emergence and flag leaf glaucousness in a bread wheat (Triticum aestivum L.) population adapted to southern Australian conditions.

    PubMed

    Bennett, Dion; Izanloo, Ali; Edwards, James; Kuchel, Haydn; Chalmers, Ken; Tester, Mark; Reynolds, Matthew; Schnurbusch, Thorsten; Langridge, Peter

    2012-03-01

    In southern Australia, where the climate is predominantly Mediterranean, achieving the correct flowering time in bread wheat minimizes the impact of in-season cyclical and terminal drought. Flag leaf glaucousness has been hypothesized as an important component of drought tolerance but its value and genetic basis in locally adapted germplasm is unknown. From a cross between Kukri and RAC875, a doubled-haploid (DH) population was developed. A genetic linkage map consisting of 456 DArT and SSR markers was used to detect QTL affecting time to ear emergence and Zadoks growth score in seven field experiments. While ear emergence time was similar between the parents, there was significant transgressive segregation in the population. This was the result of segregation for the previously characterized Ppd-D1a and Ppd-B1 photoperiod responsive alleles. QTL of smaller effect were also detected on chromosomes 1A, 4A, 4B, 5A, 5B, 7A and 7B. A novel QTL for flag leaf glaucousness of large, repeatable effect was detected in six field experiments, on chromosome 3A (QW.aww-3A) and accounted for up to 52 percent of genetic variance for this trait. QW.aww-3A was validated under glasshouse conditions in a recombinant inbred line population from the same cross. The genetic basis of time to ear emergence in this population will aid breeders' understanding of phenological adaptation to the local environment. Novel loci identified for flag leaf glaucousness and the wide phenotypic variation within the DH population offers considerable scope to investigate the impact and value of this trait for bread wheat production in southern Australia.

  18. Genome-wide quantitative trait locus mapping identifies multiple major loci for brittle rachis and threshability in Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao).

    PubMed

    Jiang, Yun-Feng; Lan, Xiu-Jin; Luo, Wei; Kong, Xing-Chen; Qi, Peng-Fei; Wang, Ji-Rui; Wei, Yu-Ming; Jiang, Qian-Tao; Liu, Ya-Xi; Peng, Yuan-Ying; Chen, Guo-Yue; Dai, Shou-Fen; Zheng, You-Liang

    2014-01-01

    Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) is a semi-wild hexaploid wheat resource that is only naturally distributed in the Qinghai-Tibet Plateau. Brittle rachis and hard threshing are two important characters of Tibetan semi-wild wheat. A whole-genome linkage map of T. aestivum ssp. tibetanum was constructed using a recombinant inbred line population (Q1028×ZM9023) with 186 lines, 564 diversity array technology markers, and 117 simple sequence repeat markers. Phenotypic data on brittle rachis and threshability, as two quantitative traits, were evaluated on the basis of the number of average spike rachis fragments per spike and percent threshability in 2012 and 2013, respectively. Quantitative trait locus (QTL) mapping performed using inclusive composite interval mapping analysis clearly identified four QTLs for brittle rachis and three QTLs for threshability. However, three loci on 2DS, 2DL, and 5AL showed pleiotropism for brittle rachis and threshability; they respectively explained 5.3%, 18.6%, and 18.6% of phenotypic variation for brittle rachis and 17.4%, 13.2%, and 35.2% of phenotypic variation for threshability. A locus on 3DS showed an independent effect on brittle rachis, which explained 38.7% of the phenotypic variation. The loci on 2DS and 3DS probably represented the effect of Tg and Br1, respectively. The locus on 5AL was in very close proximity to the Q gene, but was different from the predicted q in Tibetan semi-wild wheat. To our knowledge, the locus on 2DL has never been reported in common wheat but was prominent in T. aestivum ssp. tibetanum accession Q1028. It remarkably interacted with the locus on 5AL to affect brittle rachis. Several major loci for brittle rachis and threshability were identified in Tibetan semi-wild wheat, improving the understanding of these two characters and suggesting the occurrence of special evolution in Tibetan semi-wild wheat.

  19. In search of tetraploid wheat accessions reduced in celiac disease-related gluten epitopes.

    PubMed

    van den Broeck, Hetty; Hongbing, Chen; Lacaze, Xavier; Dusautoir, Jean-Claude; Gilissen, Ludovicus; Smulders, Marinus; van der Meer, Ingrid

    2010-11-01

    Tetraploid wheat (durum wheat) is mainly used for the preparation of pasta. As a result of breeding, thousands of tetraploid wheat varieties exist, but also tetraploid landraces are still maintained and used for local food preparations. Gluten proteins present in wheat can induce celiac disease, a T-cell mediated auto-immune disorder, in genetically predisposed individuals after ingestion. Compared to hexaploid wheat, tetraploid wheat might be reduced in T-cell stimulatory epitopes that cause celiac disease because of the absence of the D-genome. We tested gluten protein extracts from 103 tetraploid wheat accessions (obtained from the Dutch CGN genebank and from the French INRA collection) including landraces, old, modern, and domesticated accessions of various tetraploid species and subspecies from many geographic origins. Those accessions were typed for their level of T-cell stimulatory epitopes by immunoblotting with monoclonal antibodies against the α-gliadin epitopes Glia-α9 and Glia-α20. In the first selection, we found 8 CGN and 6 INRA accessions with reduced epitope staining. Fourteen of the 57 CGN accessions turned out to be mixed with hexaploid wheat, and 5 out of the 8 selected CGN accessions were mixtures of two or more different gluten protein chemotypes. Based on single seed analysis, lines from two CGN accessions and one INRA accession were obtained with significantly reduced levels of Glia-α9 and Glia-α20 epitopes. These lines will be further tested for industrial quality and may contribute to the development of safer foods for celiac patients.

  20. On-farm dynamic management of genetic diversity: the impact of seed diffusions and seed saving practices on a population-variety of bread wheat.

    PubMed

    Thomas, Mathieu; Demeulenaere, Elise; Dawson, Julie C; Khan, Abdul Rehman; Galic, Nathalie; Jouanne-Pin, Sophie; Remoue, Carine; Bonneuil, Christophe; Goldringer, Isabelle

    2012-12-01

    Since the domestication of crop species, humans have derived specific varieties for particular uses and shaped the genetic diversity of these varieties. Here, using an interdisciplinary approach combining ethnobotany and population genetics, we document the within-variety genetic structure of a population-variety of bread wheat (Triticum aestivum L.) in relation to farmers' practices to decipher their contribution to crop species evolution. Using 19 microsatellites markers, we conducted two complementary graph theory-based methods to analyze population structure and gene flow among 19 sub-populations of a single population-variety [Rouge de Bordeaux (RDB)]. The ethnobotany approach allowed us to determine the RDB history including diffusion and reproduction events. We found that the complex genetic structure among the RDB sub-populations is highly consistent with the structure of the seed diffusion and reproduction network drawn based on the ethnobotanical study. This structure highlighted the key role of the farmer-led seed diffusion through founder effects, selection and genetic drift because of human practices. An important result is that the genetic diversity conserved on farm is complementary to that found in the genebank indicating that both systems are required for a more efficient crop diversity conservation.

  1. On-farm dynamic management of genetic diversity: the impact of seed diffusions and seed saving practices on a population-variety of bread wheat

    PubMed Central

    Thomas, Mathieu; Demeulenaere, Elise; Dawson, Julie C; Khan, Abdul Rehman; Galic, Nathalie; Jouanne-Pin, Sophie; Remoue, Carine; Bonneuil, Christophe; Goldringer, Isabelle

    2012-01-01

    Since the domestication of crop species, humans have derived specific varieties for particular uses and shaped the genetic diversity of these varieties. Here, using an interdisciplinary approach combining ethnobotany and population genetics, we document the within-variety genetic structure of a population-variety of bread wheat (Triticum aestivum L.) in relation to farmers’ practices to decipher their contribution to crop species evolution. Using 19 microsatellites markers, we conducted two complementary graph theory-based methods to analyze population structure and gene flow among 19 sub-populations of a single population-variety [Rouge de Bordeaux (RDB)]. The ethnobotany approach allowed us to determine the RDB history including diffusion and reproduction events. We found that the complex genetic structure among the RDB sub-populations is highly consistent with the structure of the seed diffusion and reproduction network drawn based on the ethnobotanical study. This structure highlighted the key role of the farmer-led seed diffusion through founder effects, selection and genetic drift because of human practices. An important result is that the genetic diversity conserved on farm is complementary to that found in the genebank indicating that both systems are required for a more efficient crop diversity conservation. PMID:23346224

  2. Photoperiod insensitive Ppd-A1a mutations in tetraploid wheat (Triticum durum Desf.).

    PubMed

    Wilhelm, Edward P; Turner, Adrian S; Laurie, David A

    2009-01-01

    Variation in photoperiod response plays an important role in adapting crops to agricultural environments. In hexaploid wheat, mutations conferring photoperiod insensitivity (flowering after a similar time in short or long days) have been mapped on the 2B (Ppd-B1) and 2D (Ppd-D1) chromosomes in colinear positions to the 2H Ppd-H1 gene of barley. No A genome mutation is known. On the D genome, photoperiod insensitivity is likely to be caused by deletion of a regulatory region that causes misexpression of a member of the pseudo-response regulator (PRR) gene family and activation of the photoperiod pathway irrespective of day length. Photoperiod insensitivity in tetraploid (durum) wheat is less characterized. We compared pairs of near-isogenic lines that differ in photoperiod response and showed that photoperiod insensitivity is associated with two independent deletions of the A genome PRR gene that cause altered expression. This is associated with induction of the floral regulator FT. The A genome deletions and the previously described D genome deletion of hexaploid wheat remove a common region, suggesting a shared mechanism for photoperiod insensitivity. The identification of the A genome mutations will allow characterization of durum wheat germplasm and the construction of genotypes with novel combinations of photoperiod insensitive alleles.

  3. Structural and functional partitioning of bread wheat chromosome 3B.

    PubMed

    Choulet, Frédéric; Alberti, Adriana; Theil, Sébastien; Glover, Natasha; Barbe, Valérie; Daron, Josquin; Pingault, Lise; Sourdille, Pierre; Couloux, Arnaud; Paux, Etienne; Leroy, Philippe; Mangenot, Sophie; Guilhot, Nicolas; Le Gouis, Jacques; Balfourier, Francois; Alaux, Michael; Jamilloux, Véronique; Poulain, Julie; Durand, Céline; Bellec, Arnaud; Gaspin, Christine; Safar, Jan; Dolezel, Jaroslav; Rogers, Jane; Vandepoele, Klaas; Aury, Jean-Marc; Mayer, Klaus; Berges, Hélène; Quesneville, Hadi; Wincker, Patrick; Feuillet, Catherine

    2014-07-18

    We produced a reference sequence of the 1-gigabase chromosome 3B of hexaploid bread wheat. By sequencing 8452 bacterial artificial chromosomes in pools, we assembled a sequence of 774 megabases carrying 5326 protein-coding genes, 1938 pseudogenes, and 85% of transposable elements. The distribution of structural and functional features along the chromosome revealed partitioning correlated with meiotic recombination. Comparative analyses indicated high wheat-specific inter- and intrachromosomal gene duplication activities that are potential sources of variability for adaption. In addition to providing a better understanding of the organization, function, and evolution of a large and polyploid genome, the availability of a high-quality sequence anchored to genetic maps will accelerate the identification of genes underlying important agronomic traits.

  4. Registration of Common Wheat Germplasm with Mutations in SBEII Genes Conferring Increased Grain Amylose and Resistant Starch Content

    PubMed Central

    Schönhofen, André; Hazard, Brittany; Zhang, Xiaoqin; Dubcovsky, Jorge

    2016-01-01

    Starch present in the endosperm of common wheat (Triticum aestivum L.) grains is an important source of carbohydrates worldwide. Starches with a greater proportion of amylose have increased levels of resistant starch, a dietary fiber that can provide human health benefits. Induced mutations in STARCH BRANCHING ENZYME II (SBEII) genes in wheat are associated with increased amylose and resistant starch. Ethyl methane sulfonate mutations in SBEIIa and SBEIIb paralogs were combined in the hexaploid wheat cultivar Lassik. Four mutant combinations were generated: SBEIIa/b-AB (Reg. No. GP-997, PI 675644); SBEIIa/b-A, SBEIIa-D (Reg. No. GP-998, PI 675645); SBEIIa/b-B, SBEIIa-D (Reg. No. GP-999, PI 675646); and SBEIIa/b-AB, SBEIIa-D (Reg. No. GP-1000, PI 675647). The SBEII mutant lines were compared with a wild-type control in a greenhouse and field experiment. The quintuple mutant line (SBEIIa/b-AB, SBEIIa-D) presented significant increases in both amylose (51% greenhouse; 63% field) and resistant starch (947% greenhouse; 1057% field) relative to the control. A decrease in total starch content (7.8%) was observed in the field experiment. The quintuple mutant also differed in starch viscosity parameters. Registration of the hexaploid wheat SBEII-mutant lines by University of California, Davis can help expedite the development of common wheat cultivars with increased amylose and resistant starch content. PMID:27818720

  5. Relationship between Russian wheat aphid abundance and edaphic and topographic characteristics of wheat fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study explores the spatial relationship between Russian wheat aphid population density and variation in edaphic or topographic factors within wheat fields. Multiple regression analysis was applied to data collected from six wheat fields located in three States, Colorado, Wyoming, and Nebraska....

  6. Simultaneous selection for yield-related traits and susceptibility to Fusarium head blight in spring wheat RIL population

    PubMed Central

    Wiśniewska, Halina; Surma, Maria; Krystkowiak, Karolina; Adamski, Tadeusz; Kuczyńska, Anetta; Ogrodowicz, Piotr; Mikołajczak, Krzysztof; Belter, Jolanta; Majka, Maciej; Kaczmarek, Zygmunt; Krajewski, Paweł; Sawikowska, Aneta; Lenc, Leszek; Baturo-Cieśniewska, Anna; Łukanowski, Aleksander; Góral, Tomasz; Sadowski, Czesław

    2016-01-01

    Fusarium head blight (FHB), caused by the fungal plant pathogen Fusarium, is a fungal disease that occurs in wheat and can cause significant yield and grain quality losses. The present paper examines variation in the resistance of spring wheat lines derived from a cross between Zebra and Saar cultivars. Experiments covering 198 lines and parental cultivars were conducted in three years, in which inoculation with Fusarium culmorum was applied. Resistance levels were estimated by scoring disease symptoms on kernels. In spite of a similar reaction of parents to F. culmorum infection, significant differentiation between lines was found in all the analyzed traits. Seven molecular markers selected as linked to FHB resistance QTLs gave polymorphic products for Zebra and Saar: Xgwm566, Xgwm46, Xgwm389, Xgwm533, Xgwm156, Xwmc238, and Xgwm341. Markers Xgwm389 and Xgwm533 were associated with the rate of Fusarium-damaged kernels (FDK) as well as with kernel weight per spike and thousand kernel weight in control plants. Zebra allele of marker Xwmc238 increased kernel weight per spike and thousand kernel weight both in control and infected plants, whereas Zebra allele of marker Xgwm566 reduced the percentage of FDK and simultaneously reduced the thousand kernel weight in control and infected plants. PMID:27162499

  7. Simultaneous selection for yield-related traits and susceptibility to Fusarium head blight in spring wheat RIL population.

    PubMed

    Wiśniewska, Halina; Surma, Maria; Krystkowiak, Karolina; Adamski, Tadeusz; Kuczyńska, Anetta; Ogrodowicz, Piotr; Mikołajczak, Krzysztof; Belter, Jolanta; Majka, Maciej; Kaczmarek, Zygmunt; Krajewski, Paweł; Sawikowska, Aneta; Lenc, Leszek; Baturo-Cieśniewska, Anna; Łukanowski, Aleksander; Góral, Tomasz; Sadowski, Czesław

    2016-03-01

    Fusarium head blight (FHB), caused by the fungal plant pathogen Fusarium, is a fungal disease that occurs in wheat and can cause significant yield and grain quality losses. The present paper examines variation in the resistance of spring wheat lines derived from a cross between Zebra and Saar cultivars. Experiments covering 198 lines and parental cultivars were conducted in three years, in which inoculation with Fusarium culmorum was applied. Resistance levels were estimated by scoring disease symptoms on kernels. In spite of a similar reaction of parents to F. culmorum infection, significant differentiation between lines was found in all the analyzed traits. Seven molecular markers selected as linked to FHB resistance QTLs gave polymorphic products for Zebra and Saar: Xgwm566, Xgwm46, Xgwm389, Xgwm533, Xgwm156, Xwmc238, and Xgwm341. Markers Xgwm389 and Xgwm533 were associated with the rate of Fusarium-damaged kernels (FDK) as well as with kernel weight per spike and thousand kernel weight in control plants. Zebra allele of marker Xwmc238 increased kernel weight per spike and thousand kernel weight both in control and infected plants, whereas Zebra allele of marker Xgwm566 reduced the percentage of FDK and simultaneously reduced the thousand kernel weight in control and infected plants.

  8. Genomics as the key to unlocking the polyploid potential of wheat.

    PubMed

    Borrill, Philippa; Adamski, Nikolai; Uauy, Cristobal

    2015-12-01

    Polyploidy has played a central role in plant genome evolution and in the formation of new species such as tetraploid pasta wheat and hexaploid bread wheat. Until recently, the high sequence conservation between homoeologous genes, together with the large genome size of polyploid wheat, had hindered genomic analyses in this important crop species. In the past 5 yr, however, the advent of next-generation sequencing has radically changed the wheat genomics landscape. Here, we review a series of advances in genomic resources and tools for functional genomics that are shifting the paradigm of what is possible in wheat molecular genetics and breeding. We discuss how understanding the relationship between homoeologues can inform approaches to modulate the response of quantitative traits in polyploid wheat; we also argue that functional redundancy has 'locked up' a wide range of phenotypic variation in wheat. We explore how genomics provides key tools to inform targeted manipulation of multiple homoeologues, thereby allowing researchers and plant breeders to unlock the full polyploid potential of wheat.

  9. Transcriptome de novo assembly from next-generation sequencing and comparative analyses in the hexaploid salt marsh species Spartina maritima and Spartina alterniflora (Poaceae)

    PubMed Central

    Ferreira de Carvalho, J; Poulain, J; Da Silva, C; Wincker, P; Michon-Coudouel, S; Dheilly, A; Naquin, D; Boutte, J; Salmon, A; Ainouche, M

    2013-01-01

    Spartina species have a critical ecological role in salt marshes and represent an excellent system to investigate recurrent polyploid speciation. Using the 454 GS-FLX pyrosequencer, we assembled and annotated the first reference transcriptome (from roots and leaves) for two related hexaploid Spartina species that hybridize in Western Europe, the East American invasive Spartina alterniflora and the Euro-African S. maritima. The de novo read assembly generated 38 478 consensus sequences and 99% found an annotation using Poaceae databases, representing a total of 16 753 non-redundant genes. Spartina expressed sequence tags were mapped onto the Sorghum bicolor genome, where they were distributed among the subtelomeric arms of the 10 S. bicolor chromosomes, with high gene density correlation. Normalization of the complementary DNA library improved the number of annotated genes. Ecologically relevant genes were identified among GO biological function categories in salt and heavy metal stress response, C4 photosynthesis and in lignin and cellulose metabolism. Expression of some of these genes had been found to be altered by hybridization and genome duplication in a previous microarray-based study in Spartina. As these species are hexaploid, up to three duplicated homoeologs may be expected per locus. When analyzing sequence polymorphism at four different loci in S. maritima and S. alterniflora, we found up to four haplotypes per locus, suggesting the presence of two expressed homoeologous sequences with one or two allelic variants each. This reference transcriptome will allow analysis of specific Spartina genes of ecological or evolutionary interest, estimation of homoeologous gene expression variation using RNA-seq and further gene expression evolution analyses in natural populations. PMID:23149455

  10. Registration of Warhorse wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Warhorse' (Reg. No. CV-1096, PI 670157) hard red winter (HRW) wheat (Triticum aestivum L.) was developed and released by the Montana Agricultural Experiment Station in September 2013. Warhorse is of unknown pedigree, derived from a composite of three topcrosses made to the same F1 population in 200...

  11. Wheat Newsletter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review was written for readers of the Annual Wheat Newsletter, Volume 53. It summarizes activities on wheat research during 2006 at the U.S. Grain Marketing Research Laboratory (USGMRL). The article includes technical abstracts of research accomplishments from the Grain Quality and Structure ...

  12. Eat Wheat!

    ERIC Educational Resources Information Center

    Idaho Wheat Commission, Boise.

    This pamphlet contains puzzles, games, and a recipe designed to teach elementary school pupils about wheat. It includes word games based on the U.S. Department of Agriculture Food Guide Pyramid and on foods made from wheat. The Food Guide Pyramid can be cut out of the pamphlet and assembled as a three-dimensional information source and food guide.…

  13. Population dynamics and metabolite target analysis of lactic acid bacteria during laboratory fermentations of wheat and spelt sourdoughs.

    PubMed

    Van der Meulen, Roel; Scheirlinck, Ilse; Van Schoor, Ann; Huys, Geert; Vancanneyt, Marc; Vandamme, Peter; De Vuyst, Luc

    2007-08-01

    Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem.

  14. Transcriptome-scale homoeolog-specific transcript assemblies of bread wheat

    PubMed Central

    2012-01-01

    Background Bread wheat is one of the world’s most important food crops and considerable efforts have been made to develop genomic resources for this species. This includes an on-going project by the International Wheat Genome Sequencing Consortium to assemble its large and complex genome, which is hexaploid and contains three closely related ‘homoeologous’ copies for each chromosome. This multi-national effort avoids the complications polyploidy entails for correct assembly of the genome by sequencing flow-sorted chromosome arms one at a time. Here we report on an alternate approach, a direct homoeolog-specific assembly of the expressed portion of the genome, the transcriptome. Results After assessment of the ability of various assemblers to generate homoeolog-specific assemblies, we employed a two-stage assembly process to produce a high-quality assembly of the transcriptome of hexaploid wheat from Roche-454 and Illumina GAIIx paired-end sequence reads. The assembly process made use of a rapid partitioning of expressed sequences into homoeologous clusters, followed by a parallel high-fidelity assembly of each cluster on a 1150-processor compute cloud. We assessed assembly quality through comparison to known wheat gene sequences and found that in ca. 98.5% of cases the assembly was sufficiently accurate for homoeologous triplets to be cleanly separated into either two or three separate contigs. Comparison to publicly available transcript collections suggests that the assembly covers ~75-80% of the complete transcriptome. Conclusions This work therefore describes the first homoeolog-specific sequence assembly of the wheat transcriptome and provides a reference transcriptome for future wheat research. Furthermore, our assembly methodology is transferable to other polyploid organisms. PMID:22989011

  15. Virus-induced gene silencing of WRKY53 and an inducible phenylalanine ammonia-lyase in wheat reduces aphid resistance.

    PubMed

    Van Eck, Leon; Schultz, Thia; Leach, Jan E; Scofield, Steven R; Peairs, Frank B; Botha, Anna-Maria; Lapitan, Nora L V

    2010-12-01

    Although several wheat genes differentially expressed during the Russian wheat aphid resistance response have recently been identified, their requirement for and specific role in resistance remain unclear. Progress in wheat-aphid interaction research is hampered by inadequate collections of mutant germplasm and difficulty in transforming hexaploid wheat. Virus-induced gene silencing (VIGS) technology is emerging as a viable reverse genetics approach in cereal crops. However, the potential of VIGS for determining aphid defence gene function in wheat has not been evaluated. We report on the use of recombinant barley stripe mosaic virus (BSMV) to target and silence a WRKY53 transcription factor and an inducible phenylalanine ammonia-lyase (PAL) gene, both predicted to contribute to aphid defence in a genetically resistant wheat line. After inoculating resistant wheat with the VIGS constructs, transcript abundance was reduced to levels similar to that observed in susceptible wheat. Notably, the level of PAL expression was also suppressed by the WKRY53 construct, suggesting that these genes operate in the same defence response network. Both knockdowns exhibited a susceptible phenotype upon aphid infestation, and aphids feeding on silenced plants exhibited a significant increase in fitness compared to aphids feeding on control plants. Altered plant phenotype and changes in aphid behaviour after silencing imply that WKRY53 and PAL play key roles in generating a successful resistance response. This study is the first report on the successful use of VIGS to investigate genes involved in wheat-insect interactions.

  16. A consensus map in cultivated hexaploid oat reveals conserved grass synteny with substantial sub-genome rearrangement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hexaploid oat (Avena sativa, 2n = 6x = 42) is a member of the Poaceae family with a very large genome (~13 Gb) containing 21 chromosome pairs: seven from each of two similar ancestral diploids (A and D) and seven from a more diverged ancestral diploid (C). Physical rearrangements among ancestral oat...

  17. Additive-dominance genetic model analyses for late-maturity alpha-amylase activity in a bread wheat factorial crossing population.

    PubMed

    Rasul, Golam; Glover, Karl D; Krishnan, Padmanaban G; Wu, Jixiang; Berzonsky, William A; Ibrahim, Amir M H

    2015-12-01

    Elevated level of late maturity α-amylase activity (LMAA) can result in low falling number scores, reduced grain quality, and downgrade of wheat (Triticum aestivum L.) class. A mating population was developed by crossing parents with different levels of LMAA. The F2 and F3 hybrids and their parents were evaluated for LMAA, and data were analyzed using the R software package 'qgtools' integrated with an additive-dominance genetic model and a mixed linear model approach. Simulated results showed high testing powers for additive and additive × environment variances, and comparatively low powers for dominance and dominance × environment variances. All variance components and their proportions to the phenotypic variance for the parents and hybrids were significant except for the dominance × environment variance. The estimated narrow-sense heritability and broad-sense heritability for LMAA were 14 and 54%, respectively. High significant negative additive effects for parents suggest that spring wheat cultivars 'Lancer' and 'Chester' can serve as good general combiners, and that 'Kinsman' and 'Seri-82' had negative specific combining ability in some hybrids despite of their own significant positive additive effects, suggesting they can be used as parents to reduce LMAA levels. Seri-82 showed very good general combining ability effect when used as a male parent, indicating the importance of reciprocal effects. High significant negative dominance effects and high-parent heterosis for hybrids demonstrated that the specific hybrid combinations; Chester × Kinsman, 'Lerma52' × Lancer, Lerma52 × 'LoSprout' and 'Janz' × Seri-82 could be generated to produce cultivars with significantly reduced LMAA level.

  18. Recurrent deletions of puroindoline genes at the grain hardness locus in four independent lineages of polyploid wheat.

    PubMed

    Li, Wanlong; Huang, Li; Gill, Bikram S

    2008-01-01

    Polyploidy is known to induce numerous genetic and epigenetic changes but little is known about their physiological bases. In wheat, grain texture is mainly determined by the Hardness (Ha) locus consisting of genes Puroindoline a (Pina) and b (Pinb). These genes are conserved in diploid progenitors but were deleted from the A and B genomes of tetraploid Triticum turgidum (AB). We now report the recurrent deletions of Pina-Pinb in other lineages of polyploid wheat. We analyzed the Ha haplotype structure in 90 diploid and 300 polyploid accessions of Triticum and Aegilops spp. Pin genes were conserved in all diploid species and deletion haplotypes were detected in all polyploid Triticum and most of the polyploid Aegilops spp. Two Pina-Pinb deletion haplotypes were found in hexaploid wheat (Triticum aestivum; ABD). Pina and Pinb were eliminated from the G genome, but maintained in the A genome of tetraploid Triticum timopheevii (AG). Subsequently, Pina and Pinb were deleted from the A genome but retained in the A(m) genome of hexaploid Triticum zhukovskyi (A(m)AG). Comparison of deletion breakpoints demonstrated that the Pina-Pinb deletion occurred independently and recurrently in the four polyploid wheat species. The implications of Pina-Pinb deletions for polyploid-driven evolution of gene and genome and its possible physiological significance are discussed.

  19. Origin, Migration Routes and Worldwide Population Genetic Structure of the Wheat Yellow Rust Pathogen Puccinia striiformis f.sp. tritici

    PubMed Central

    Ali, Sajid; Gladieux, Pierre; Leconte, Marc; Gautier, Angélique; Justesen, Annemarie F.; Hovmøller, Mogens S.; Enjalbert, Jérôme; de Vallavieille-Pope, Claude

    2014-01-01

    Analyses of large-scale population structure of pathogens enable the identification of migration patterns, diversity reservoirs or longevity of populations, the understanding of current evolutionary trajectories and the anticipation of future ones. This is particularly important for long-distance migrating fungal pathogens such as Puccinia striiformis f.sp. tritici (PST), capable of rapid spread to new regions and crop varieties. Although a range of recent PST invasions at continental scales are well documented, the worldwide population structure and the center of origin of the pathogen were still unknown. In this study, we used multilocus microsatellite genotyping to infer worldwide population structure of PST and the origin of new invasions based on 409 isolates representative of distribution of the fungus on six continents. Bayesian and multivariate clustering methods partitioned the set of multilocus genotypes into six distinct genetic groups associated with their geographical origin. Analyses of linkage disequilibrium and genotypic diversity indicated a strong regional heterogeneity in levels of recombination, with clear signatures of recombination in the Himalayan (Nepal and Pakistan) and near-Himalayan regions (China) and a predominant clonal population structure in other regions. The higher genotypic diversity, recombinant population structure and high sexual reproduction ability in the Himalayan and neighboring regions suggests this area as the putative center of origin of PST. We used clustering methods and approximate Bayesian computation (ABC) to compare different competing scenarios describing ancestral relationship among ancestral populations and more recently founded populations. Our analyses confirmed the Middle East-East Africa as the most likely source of newly spreading, high-temperature-adapted strains; Europe as the source of South American, North American and Australian populations; and Mediterranean-Central Asian populations as the origin of

  20. Genetic control of seed proteins in wheat.

    PubMed

    Dhaliwal, H S

    1977-09-01

    Electrophoretic profiles of crude protein extracts from seed of F1 hybrids and reciprocal crosses among diploid, tetraploid and hexaploid wheats were compared with those of their respective parental species. The electrophoretic patterns within each of three pairs of reciprocal crosses, T.boeoticum X T.urartu, T.monococcun X T. urartu and T.dicoccum X T. araraticum, were different from one another but were identical with those of their respective maternal parents. Protein bands characteristic of the paternal parents were missing in F1 hybrid seed suggesting that the major seed proteins in wheat were presumably regulated by genotype of the maternal parent rather than by the seed genotype. However, in another three pairs of reciprocal crosses, T.boeoticum X T. durum, T.dicoccum X T.aestivum and T. zhukovskyi x T. aestivum, protein bands attributable to the paternal parents were present in the F1 hybrid seeds indicating that the seed proteins were not always exclusively regulated by the maternal genotype. The expression of paternal genomes is presumably determined by dosage and genetic affinity of the maternal and paternal genomes in the hybrid endosperm. The maternal regulation of seed protein content is probably accomplished through the maternal control over seed size. The seed protein quality may, however, depend upon the extent of expression of the paternal genome.

  1. WheatGenome.info: an integrated database and portal for wheat genome information.

    PubMed

    Lai, Kaitao; Berkman, Paul J; Lorenc, Michal Tadeusz; Duran, Chris; Smits, Lars; Manoli, Sahana; Stiller, Jiri; Edwards, David

    2012-02-01

    Bread wheat (Triticum aestivum) is one of the most important crop plants, globally providing staple food for a large proportion of the human population. However, improvement of this crop has been limited due to its large and complex genome. Advances in genomics are supporting wheat crop improvement. We provide a variety of web-based systems hosting wheat genome and genomic data to support wheat research and crop improvement. WheatGenome.info is an integrated database resource which includes multiple web-based applications. These include a GBrowse2-based wheat genome viewer with BLAST search portal, TAGdb for searching wheat second-generation genome sequence data, wheat autoSNPdb, links to wheat genetic maps using CMap and CMap3D, and a wheat genome Wiki to allow interaction between diverse wheat genome sequencing activities. This system includes links to a variety of wheat genome resources hosted at other research organizations. This integrated database aims to accelerate wheat genome research and is freely accessible via the web interface at http://www.wheatgenome.info/.

  2. Spatial and Host-Related Variation in Prevalence and Population Density of Wheat Curl Mite (Aceria tosichella) Cryptic Genotypes in Agricultural Landscapes

    PubMed Central

    Lewandowski, Mariusz; Rector, Brian G.; Szydło, Wiktoria

    2017-01-01

    The wheat curl mite (WCM), Aceria tosichella Keifer, is a major pest of cereals worldwide that also comprises a complex of at least 16 genetic lineages with divergent physiological traits, including host associations and specificity. The goal of this study was to test the extent to which host-plant species and landscape spatial variation influence WCM presence and population density across the entire area of Poland (>311,000 km2). Three important findings arose from the results of the study. (1) The majority of WCM lineages analyzed exhibited variation in patterns of prevalence and/or population density on both spatial and host-associated scales. (2) Areas of occurrence and local abundance were delineated for specific WCM lineages and it was determined that the most pestiferous lineages are much less widespread than was expected, suggesting relatively recent introductions into Poland and the potential for further spread. (3) The 16 WCM lineages under study assorted within four discrete host assemblages, within which similar host preferences and host infestation patterns were detected. Of these four groups, one consists of lineages associated with cereals. In addition to improving basic ecological knowledge of a widespread arthropod herbivore, the results of this research identify high-risk areas for the presence of the most pestiferous WCM lineages in the study area (viz. the entirety of Poland). They also provide insight into the evolution of pest species of domesticated crops and facilitate testing of fundamental hypotheses about the ecological factors that shape this pest community. PMID:28099506

  3. The iSelect 9 K SNP analysis revealed polyploidization induced revolutionary changes and intense human selection causing strong haplotype blocks in wheat

    PubMed Central

    Hao, Chenyang; Wang, Yuquan; Chao, Shiaoman; Li, Tian; Liu, Hongxia; Wang, Lanfen; Zhang, Xueyong

    2017-01-01

    A Chinese wheat mini core collection was genotyped using the wheat 9 K iSelect SNP array. Total 2420 and 2396 polymorphic SNPs were detected on the A and the B genome chromosomes, which formed 878 haplotype blocks. There were more blocks in the B genome, but the average block size was significantly (P < 0.05) smaller than those in the A genome. Intense selection (domestication and breeding) had a stronger effect on the A than on the B genome chromosomes. Based on the genetic pedigrees, many blocks can be traced back to a well-known Strampelli cross, which was made one century ago. Furthermore, polyploidization of wheat (both tetraploidization and hexaploidization) induced revolutionary changes in both the A and the B genomes, with a greater increase of gene diversity compared to their diploid ancestors. Modern breeding has dramatically increased diversity in the gene coding regions, though obvious blocks were formed on most of the chromosomes in both tetraploid and hexaploid wheats. Tag-SNP markers identified in this study can be used for marker assisted selection using haplotype blocks as a wheat breeding strategy. This strategy can also be employed to facilitate genome selection in other self-pollinating crop species. PMID:28134278

  4. Wheat: The Whole Story.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Education, Oklahoma City.

    This publication presents information on wheat. Wheat was originally a wild grass and not native to the United States. Wheat was not planted there until 1777 (and then only as a hobby crop). Wheat is grown on more acres than any other grain in this country. Soft wheats are grown east of the Mississippi River, and hard wheats are grown west of the…

  5. Structural organization of the barley D-hordein locus in comparison with its orthologous regions of wheat genomes.

    PubMed

    Gu, Yong Qiang; Anderson, Olin D; Londeorë, Cynthia F; Kong, Xiuying; Chibbar, Ravindra N; Lazo, Gerard R

    2003-12-01

    D hordein, a prolamin storage protein of barley endosperms, is highly homologous to the high molecular weight (HWM) glutenin subunits, which are the major determinants of bread-making quality in wheat flour. In hexaploid wheat (AABBDD), each genome contains two paralogous copies of HMW-glutenin genes that encode the x- and y-type HMW-glutenin subunits. Previously, we reported the sequence analysis of a 102-kb genomic region that contains the HMW-glutenin locus of the D genome from Aegilops tauschii, the donor of the D genome of hexaploid wheat. Here, we present the sequence analysis of a 120-kb D-hordein region of the barley genome, a more distantly related member of the Triticeae grass tribe. Comparative sequence analysis revealed that gene content and order are generally conserved. Genes included in both of these orthologous regions are arranged in the following order: a Xa21-like receptor kinase, an endosperm globulin, an HMW prolamin, and a serine (threonine) protein kinase. However, in the wheat D genome, a region containing both the globulin and HMW-glutenin gene was duplicated, indicating that this duplication event occurred after the separation of the wheat and barley genomes. The intergenic regions are divergent with regard to the sequence and structural organization. It was found that different types of retroelements are responsible for the intergenic structure divergence in the wheat and barley genomes. In the barley region, we identified 16 long terminal repeat (LTR) retrotransposons in three distinct nested clusters. These retroelements account for 63% of the contig sequence. In addition, barley D hordein was compared with wheat HMW glutenins in terms of cysteine residue conservation and repeat domain organization.

  6. Accelerated Senescence and Enhanced Disease Resistance in Hybrid Chlorosis Lines Derived from Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii

    PubMed Central

    Tosa, Yukio; Yoshida, Kentaro; Park, Pyoyun; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions. PMID:25806790

  7. A Catalog of Regulatory Sequences for Trait Gene for the Genome Editing of Wheat

    PubMed Central

    Makai, Szabolcs; Tamás, László; Juhász, Angéla

    2016-01-01

    Wheat has been cultivated for 10000 years and ever since the origin of hexaploid wheat it has been exempt from natural selection. Instead, it was under the constant selective pressure of human agriculture from harvest to sowing during every year, producing a vast array of varieties. Wheat has been adopted globally, accumulating variation for genes involved in yield traits, environmental adaptation and resistance. However, one small but important part of the wheat genome has hardly changed: the regulatory regions of both the x- and y-type high molecular weight glutenin subunit (HMW-GS) genes, which are alone responsible for approximately 12% of the grain protein content. The phylogeny of the HMW-GS regulatory regions of the Triticeae demonstrates that a genetic bottleneck may have led to its decreased diversity during domestication and the subsequent cultivation. It has also highlighted the fact that the wild relatives of wheat may offer an unexploited genetic resource for the regulatory region of these genes. Significant research efforts have been made in the public sector and by international agencies, using wild crosses to exploit the available genetic variation, and as a result synthetic hexaploids are now being utilized by a number of breeding companies. However, a newly emerging tool of genome editing provides significantly improved efficiency in exploiting the natural variation in HMW-GS genes and incorporating this into elite cultivars and breeding lines. Recent advancement in the understanding of the regulation of these genes underlines the needs for an overview of the regulatory elements for genome editing purposes. PMID:27766102

  8. A Catalog of Regulatory Sequences for Trait Gene for the Genome Editing of Wheat.

    PubMed

    Makai, Szabolcs; Tamás, László; Juhász, Angéla

    2016-01-01

    Wheat has been cultivated for 10000 years and ever since the origin of hexaploid wheat it has been exempt from natural selection. Instead, it was under the constant selective pressure of human agriculture from harvest to sowing during every year, producing a vast array of varieties. Wheat has been adopted globally, accumulating variation for genes involved in yield traits, environmental adaptation and resistance. However, one small but important part of the wheat genome has hardly changed: the regulatory regions of both the x- and y-type high molecular weight glutenin subunit (HMW-GS) genes, which are alone responsible for approximately 12% of the grain protein content. The phylogeny of the HMW-GS regulatory regions of the Triticeae demonstrates that a genetic bottleneck may have led to its decreased diversity during domestication and the subsequent cultivation. It has also highlighted the fact that the wild relatives of wheat may offer an unexploited genetic resource for the regulatory region of these genes. Significant research efforts have been made in the public sector and by international agencies, using wild crosses to exploit the available genetic variation, and as a result synthetic hexaploids are now being utilized by a number of breeding companies. However, a newly emerging tool of genome editing provides significantly improved efficiency in exploiting the natural variation in HMW-GS genes and incorporating this into elite cultivars and breeding lines. Recent advancement in the understanding of the regulation of these genes underlines the needs for an overview of the regulatory elements for genome editing purposes.

  9. The effect of wheat prebiotics on the gut bacterial population and iron status of iron deficient broiler chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years, there is a lot of interest in improving the intestinal health, and consequently increasing minerals as iron absorption, by managing the intestinal microbial population. This is traditionally done by the consumption of probiotics, which are live microbial food supplements. However, a...

  10. Efficient and transgene-free genome editing in wheat through transient expression of CRISPR/Cas9 DNA or RNA

    PubMed Central

    Zhang, Yi; Liang, Zhen; Zong, Yuan; Wang, Yanpeng; Liu, Jinxing; Chen, Kunling; Qiu, Jin-Long; Gao, Caixia

    2016-01-01

    Editing plant genomes is technically challenging in hard-to-transform plants and usually involves transgenic intermediates, which causes regulatory concerns. Here we report two simple and efficient genome-editing methods in which plants are regenerated from callus cells transiently expressing CRISPR/Cas9 introduced as DNA or RNA. This transient expression-based genome-editing system is highly efficient and specific for producing transgene-free and homozygous wheat mutants in the T0 generation. We demonstrate our protocol to edit genes in hexaploid bread wheat and tetraploid durum wheat, and show that we are able to generate mutants with no detectable transgenes. Our methods may be applicable to other plant species, thus offering the potential to accelerate basic and applied plant genome-engineering research. PMID:27558837

  11. Small RNAs, DNA methylation and transposable elements in wheat

    PubMed Central

    2010-01-01

    Background More than 80% of the wheat genome is composed of transposable elements (TEs). Since active TEs can move to different locations and potentially impose a significant mutational load, their expression is suppressed in the genome via small non-coding RNAs (sRNAs). sRNAs guide silencing of TEs at the transcriptional (mainly 24-nt sRNAs) and post-transcriptional (mainly 21-nt sRNAs) levels. In this study, we report the distribution of these two types of sRNAs among the different classes of wheat TEs, the regions targeted within the TEs, and their impact on the methylation patterns of the targeted regions. Results We constructed an sRNA library from hexaploid wheat and developed a database that included our library and three other publicly available sRNA libraries from wheat. For five completely-sequenced wheat BAC contigs, most perfectly matching sRNAs represented TE sequences, suggesting that a large fraction of the wheat sRNAs originated from TEs. An analysis of all wheat TEs present in the Triticeae Repeat Sequence database showed that sRNA abundance was correlated with the estimated number of TEs within each class. Most of the sRNAs perfectly matching miniature inverted repeat transposable elements (MITEs) belonged to the 21-nt class and were mainly targeted to the terminal inverted repeats (TIRs). In contrast, most of the sRNAs matching class I and class II TEs belonged to the 24-nt class and were mainly targeted to the long terminal repeats (LTRs) in the class I TEs and to the terminal repeats in CACTA transposons. An analysis of the mutation frequency in potentially methylated sites revealed a three-fold increase in TE mutation frequency relative to intron and untranslated genic regions. This increase is consistent with wheat TEs being preferentially methylated, likely by sRNA targeting. Conclusions Our study examines the wheat epigenome in relation to known TEs. sRNA-directed transcriptional and post-transcriptional silencing plays important roles in

  12. Exploiting the Repetitive Fraction of the Wheat Genome for High-Throughput Single-Nucleotide Polymorphism Discovery and Genotyping.

    PubMed

    Cubizolles, Nelly; Rey, Elodie; Choulet, Frédéric; Rimbert, Hélène; Laugier, Christel; Balfourier, François; Bordes, Jacques; Poncet, Charles; Jack, Peter; James, Chris; Gielen, Jan; Argillier, Odile; Jaubertie, Jean-Pierre; Auzanneau, Jérôme; Rohde, Antje; Ouwerkerk, Pieter B F; Korzun, Viktor; Kollers, Sonja; Guerreiro, Laurent; Hourcade, Delphine; Robert, Olivier; Devaux, Pierre; Mastrangelo, Anna-Maria; Feuillet, Catherine; Sourdille, Pierre; Paux, Etienne

    2016-03-01

    Transposable elements (TEs) account for more than 80% of the wheat genome. Although they represent a major obstacle for genomic studies, TEs are also a source of polymorphism and consequently of molecular markers such as insertion site-based polymorphism (ISBP) markers. Insertion site-based polymorphisms have been found to be a great source of genome-specific single-nucleotide polymorphism (SNPs) in the hexaploid wheat ( L.) genome. Here, we report on the development of a high-throughput SNP discovery approach based on sequence capture of ISBP markers. By applying this approach to the reference sequence of chromosome 3B from hexaploid wheat, we designed 39,077 SNPs that are evenly distributed along the chromosome. We demonstrate that these SNPs can be efficiently scored with the KASPar (Kompetitive allele-specific polymerase chain reaction) genotyping technology. Finally, through genetic diversity and genome-wide association studies, we also demonstrate that ISBP-derived SNPs can be used in marker-assisted breeding programs.

  13. Discovery, evaluation and distribution of haplotypes and new alleles of the Photoperiod-A1 gene in wheat.

    PubMed

    Muterko, Alexandr; Kalendar, Ruslan; Cockram, James; Balashova, Irina

    2015-05-01

    Photoperiod response in wheat is determined to a large extent by the homoeologous series of Photoperiod 1 (Ppd1) genes. In this study, Ppd-A1 genomic sequences from the 5' UTR and promoter region were analysed in 104 accessions of six tetraploid wheat species (Triticum dicoccoides, T. dicoccum, T. turgidum, T. polonicum, T. carthlicum, T. durum) and 102 accessions of six hexaploid wheat species (T. aestivum, T. compactum, T. sphaerococcum, T. spelta, T. macha, T. vavilovii). This data was supplemented with in silico analysis of publicly available sequences from 46 to 193 accessions of diploid and tetraploid wheat, respectively. Analysis of a region of the Ppd-A1 promoter identified thirteen haplotypes, which were divided in two haplogroups. Distribution of the Ppd-A1 haplogroups and haplotypes in wheat species, and their geographical distributions were analysed. Polymerase chain reaction combined with a heteroduplex mobility assay was subsequently used to efficiently discriminate between Ppd-A1 alleles, allowing identification of the Ppd-A1b haplotypes and haplogroups. The causes of anomalous migration of Ppd-A1 heteroduplexes in gels were found to be the localization of mismatches relative to the center of fragment, the cumulative effect of neighbouring polymorphic sites, and the location of mismatches within A/T-tracts. Analysis of the Ppd-A1 5' UTR in hexaploid wheat revealed a novel mutation within the "photoperiod critical" region in a subset of T. compactum accessions. This putative photoperiod insensitive allele (designated Ppd-A1a.4) includes a 684 bp deletion which spans region in common with deletions previously identified in other photoperiod insensitive Ppd1 alleles.

  14. The evolution of polyploid wheats: identification of the A genome donor species.

    PubMed

    Dvorák, J; Terlizzi, P; Zhang, H B; Resta, P

    1993-02-01

    Cytogenetic work has shown that the tetraploid wheats, Triticum turgidum and T. timopheevii, and the hexaploid wheat T. aestivum have one pair of A genomes, whereas hexaploid T. zhukovskyi has two. Variation in 16 repeated nucleotide sequences was used to identify sources of the A genomes. The A genomes of T. turgidum, T. timopheevii, and T. aestivum were shown to be contributed by T. urartu. Little divergence in the repeated nucleotide sequences was detected in the A genomes of these species from the genome of T. urartu. In T. zhukovskyi one A genome was contributed by T. urartu and the other was contributed by T. monococcum. It is concluded that T. zhukovskyi originated from hybridization of T. timopheevii with T. monococcum. The repeated nucleotide sequence profiles in the A genomes of T. zhukovskyi showed reduced correspondence with those in the genomes of both ancestral species, T. urartu and T. monococcum. This differentiation is attributed to heterogenetic chromosome pairing and segregation among chromosomes of the two A genomes in T. zhukovskyi.

  15. Recurrent Deletions of Puroindoline Genes at the Grain Hardness Locus in Four Independent Lineages of Polyploid Wheat1[W][OA

    PubMed Central

    Li, Wanlong; Huang, Li; Gill, Bikram S.

    2008-01-01

    Polyploidy is known to induce numerous genetic and epigenetic changes but little is known about their physiological bases. In wheat, grain texture is mainly determined by the Hardness (Ha) locus consisting of genes Puroindoline a (Pina) and b (Pinb). These genes are conserved in diploid progenitors but were deleted from the A and B genomes of tetraploid Triticum turgidum (AB). We now report the recurrent deletions of Pina-Pinb in other lineages of polyploid wheat. We analyzed the Ha haplotype structure in 90 diploid and 300 polyploid accessions of Triticum and Aegilops spp. Pin genes were conserved in all diploid species and deletion haplotypes were detected in all polyploid Triticum and most of the polyploid Aegilops spp. Two Pina-Pinb deletion haplotypes were found in hexaploid wheat (Triticum aestivum; ABD). Pina and Pinb were eliminated from the G genome, but maintained in the A genome of tetraploid Triticum timopheevii (AG). Subsequently, Pina and Pinb were deleted from the A genome but retained in the Am genome of hexaploid Triticum zhukovskyi (AmAG). Comparison of deletion breakpoints demonstrated that the Pina-Pinb deletion occurred independently and recurrently in the four polyploid wheat species. The implications of Pina-Pinb deletions for polyploid-driven evolution of gene and genome and its possible physiological significance are discussed. PMID:18024553

  16. Wheat Mitochondria

    PubMed Central

    Raison, John K.; Chapman, Elza A.; White, P. Y.

    1977-01-01

    Mitochondrial oxidative activity and membrane lipid structure of two wheat (Triticum aestivum L.) cultivars were measured as a function of temperature. The Arrhenius activation energy for the oxidation of both succinate and α-ketoglutarate was constant over the temperature range of 3 to 27 C. The activation energy for succinate-cytochrome c oxidoreductase activity was also constant over the same temperature range. The concentration of mitochondria in the reaction, the degree of initial inhibition of state 3 respiration, and the time after isolation of mitochondria were each shown to be capable of causing a disproportionate decrease in the rate of oxidation at low temperatures which resulted in an apparent increase in the activation energy of oxidative activity. Using three spin-labeling techniques, wheat membrane lipids were shown to undergo phase changes at about 0 C and 30 C. It is concluded that the membrane lipids of wheat, a chillingresistant plant, undergo a phase transition similar to the transition observed in the membrane lipids of chilling-sensitive plants. For wheat, however, the transition is initiated at a lower temperature and extends over a wider temperature range. PMID:16659906

  17. Waxy genes from spelt wheat: new alleles for modern wheat breeding and new phylogenetic inferences about the origin of this species

    PubMed Central

    Guzmán, Carlos; Caballero, Leonor; Martín, Luis M.; Alvarez, Juan B.

    2012-01-01

    Background and Aims Waxy proteins are responsible for amylose synthesis in wheat seeds, being encoded by three waxy genes (Wx-A1, Wx-B1 and Wx-D1) in hexaploid wheat. In addition to their role in starch quality, waxy loci have been used to study the phylogeny of wheat. The origin of European spelt (Triticum aestivum ssp. spelta) is not clear. This study compared waxy gene sequences of a Spanish spelt collection with their homologous genes in emmer (T. turgidum ssp. dicoccum), durum (T. turgidum ssp. durum) and common wheat (T. aestivum ssp. aestivum), together with other Asian and European spelt that could be used to determine the origin of European spelt. Methods waxy genes were amplified and sequenced. Geneious Pro software, DNAsp and MEGA5 were used for sequence, nucleotide diversity and phylogenetic analysis, respectively. Key Results Three, four and three new alleles were described for the Wx-A1, Wx-B1 and Wx-D1 loci, respectively. Spelt accessions were classified into two groups based on the variation in Wx-B1, which suggests that there were two different origins for the emmer wheat that has been found to be part of the spelt genetic make-up. One of these groups was only detected in Iberian material. No differences were found between the rest of the European spelt and the Asiatic spelt, which suggested that the Iberian material had a different origin from the other spelt sources. Conclusions The results suggested that the waxy gene variability present in wheat is undervalued. The evaluation of this variability has permitted the detection of ten new waxy alleles that could affect starch quality and thus could be used in modern wheat breeding. In addition, two different classes of Wx-B1 were detected that could be used for evaluating the phylogenetic relationships and the origins of different types of wheat. PMID:22984164

  18. Allelic variation at the VRN-1 promoter region in polyploid wheat.

    PubMed

    Yan, L; Helguera, M; Kato, K; Fukuyama, S; Sherman, J; Dubcovsky, J

    2004-11-01

    Vernalization, the requirement of a long exposure to low temperatures to induce flowering, is an essential adaptation of plants to cold winters. We have shown recently that the vernalization gene VRN-1 from diploid wheat Triticum monococcum is the meristem identity gene APETALA1, and that deletions in its promoter were associated with spring growth habit. In this study, we characterized the allelic variation at the VRN-1 promoter region in polyploid wheat. The Vrn-A1a allele has a duplication including the promoter region. Each copy has similar foldback elements inserted at the same location and is flanked by identical host direct duplications (HDD). This allele was found in more than half of the hexaploid varieties but not among the tetraploid lines analyzed here. The Vrn-A1b allele has two mutations in the HDD region and a 20-bp deletion in the 5' UTR compared with the winter allele. The Vrn-A1b allele was found in both tetraploid and hexaploid accessions but at a relatively low frequency. Among the tetraploid wheat accessions, we found two additional alleles with 32 bp and 54 bp deletions that included the HDD region. We found no size polymorphisms in the promoter region among the winter wheat varieties. The dominant Vrn-A1 allele from two spring varieties from Afghanistan and Egypt ( Vrn-A1c allele) and all the dominant Vrn-B1 and Vrn-D1 alleles included in this study showed no differences from their respective recessive alleles in promoter sequences. Based on these results, we concluded that the VRN-1 genes should have additional regulatory sites outside the promoter region studied here.

  19. The tae-miR408-Mediated Control of TaTOC1 Genes Transcription Is Required for the Regulation of Heading Time in Wheat1[OPEN

    PubMed Central

    Zhao, Xiang Yu; Hong, Po; Chen, Xiang Bin; Ye, Xing Guo; Pan, Yan You; Wang, Jian

    2016-01-01

    Timing of flowering is not only an interesting topic in developmental biology, but it also plays a significant role in agriculture for its effects on the maturation time of seed. The hexaploid wheat (Triticum aestivum) is one of the most important crop species whose flowering time, i.e. heading time, greatly influences yield. However, it remains unclear whether and how microRNAs regulate heading time in it. In our current study, we identified the tae-miR408 in wheat and its targets in vivo, including Triticum aestivum TIMING OF CAB EXPRESSION-A1 (TaTOC-A1), TaTOC-B1, and TaTOC-D1. The tae-miR408 levels were reciprocal to those of TaTOC1s under long-day and short-day conditions. Wheat plants with a knockdown of TaTOC1s via RNA interference and overexpression of tae-miR408 showed early-heading phenotype. Furthermore, TaTOC1s expression was down-regulated by the tae-miR408 in the hexaploid wheat. In addition, other important agronomic traits in wheat, such as plant height and flag leaf angle, were regulated by both tae-miR408 and TaTOC1s. Thus, our results suggested that the tae-miR408 functions in the wheat heading time by mediating TaTOC1s expression, and the study provides important new information on the mechanism underlying heading time regulation in wheat. PMID:26768600

  20. Morphological features and physicochemical properties of waxy wheat starch.

    PubMed

    Zhang, Huanxin; Zhang, Wei; Xu, Chunzhong; Zhou, Xing

    2013-11-01

    Morphological features, granule composition, and physicochemical properties of waxy wheat starch were compared with those of normal wheat starch. The morphologies and granule populations were found to be similar for the two starches. However, waxy wheat starch contained a smaller proportion of B-type granules, had a larger average granule diameter, and a higher degree of crystallinity than normal wheat starch, as measured by particle size analysis and differential scanning calorimetry. These differences resulted in a higher gelatinization temperature, transition enthalpy, peak viscosity, breakdown, swelling power, lower peak viscosity temperature and final viscosity in waxy wheat starch. These points suggest that waxy wheat starch should have greater resistance to retrogradation during cooling and higher water-holding capacity under dry conditions. Highlighting the differences in physicochemical properties of waxy and normal wheat starches should help point toward effective applications of waxy wheat starch in the food industry.

  1. A chromosome bin map of 2148 expressed sequence tag loci of wheat homoeologous group 7.

    PubMed

    Hossain, K G; Kalavacharla, V; Lazo, G R; Hegstad, J; Wentz, M J; Kianian, P M A; Simons, K; Gehlhar, S; Rust, J L; Syamala, R R; Obeori, K; Bhamidimarri, S; Karunadharma, P; Chao, S; Anderson, O D; Qi, L L; Echalier, B; Gill, B S; Linkiewicz, A M; Ratnasiri, A; Dubcovsky, J; Akhunov, E D; Dvorák, J; Miftahudin; Ross, K; Gustafson, J P; Radhawa, H S; Dilbirligi, M; Gill, K S; Peng, J H; Lapitan, N L V; Greene, R A; Bermudez-Kandianis, C E; Sorrells, M E; Feril, O; Pathan, M S; Nguyen, H T; Gonzalez-Hernandez, J L; Conley, E J; Anderson, J A; Choi, D W; Fenton, D; Close, T J; McGuire, P E; Qualset, C O; Kianian, S F

    2004-10-01

    The objectives of this study were to develop a high-density chromosome bin map of homoeologous group 7 in hexaploid wheat (Triticum aestivum L.), to identify gene distribution in these chromosomes, and to perform comparative studies of wheat with rice and barley. We mapped 2148 loci from 919 EST clones onto group 7 chromosomes of wheat. In the majority of cases the numbers of loci were significantly lower in the centromeric regions and tended to increase in the distal regions. The level of duplicated loci in this group was 24% with most of these loci being localized toward the distal regions. One hundred nineteen EST probes that hybridized to three fragments and mapped to the three group 7 chromosomes were designated landmark probes and were used to construct a consensus homoeologous group 7 map. An additional 49 probes that mapped to 7AS, 7DS, and the ancestral translocated segment involving 7BS also were designated landmarks. Landmark probe orders and comparative maps of wheat, rice, and barley were produced on the basis of corresponding rice BAC/PAC and genetic markers that mapped on chromosomes 6 and 8 of rice. Identification of landmark ESTs and development of consensus maps may provide a framework of conserved coding regions predating the evolution of wheat genomes.

  2. A Wheat Cinnamyl Alcohol Dehydrogenase TaCAD12 Contributes to Host Resistance to the Sharp Eyespot Disease.

    PubMed

    Rong, Wei; Luo, Meiying; Shan, Tianlei; Wei, Xuening; Du, Lipu; Xu, Huijun; Zhang, Zengyan

    2016-01-01

    Sharp eyespot, caused mainly by the necrotrophic fungus Rhizoctonia cerealis, is a destructive disease in hexaploid wheat (Triticum aestivum L.). In Arabidopsis, certain cinnamyl alcohol dehydrogenases (CADs) have been implicated in monolignol biosynthesis and in defense response to bacterial pathogen infection. However, little is known about CADs in wheat defense responses to necrotrophic or soil-borne pathogens. In this study, we isolate a wheat CAD gene TaCAD12 in response to R. cerealis infection through microarray-based comparative transcriptomics, and study the enzyme activity and defense role of TaCAD12 in wheat. The transcriptional levels of TaCAD12 in sharp eyespot-resistant wheat lines were significantly higher compared with those in susceptible wheat lines. The sequence and phylogenetic analyses revealed that TaCAD12 belongs to IV group in CAD family. The biochemical assay proved that TaCAD12 protein is an authentic CAD enzyme and possesses catalytic efficiencies toward both coniferyl aldehyde and sinapyl aldehyde. Knock-down of TaCAD12 transcript significantly repressed resistance of the gene-silenced wheat plants to sharp eyespot caused by R. cerealis, whereas TaCAD12 overexpression markedly enhanced resistance of the transgenic wheat lines to sharp eyespot. Furthermore, certain defense genes (Defensin, PR10, PR17c, and Chitinase1) and monolignol biosynthesis-related genes (TaCAD1, TaCCR, and TaCOMT1) were up-regulated in the TaCAD12-overexpressing wheat plants but down-regulated in TaCAD12-silencing plants. These results suggest that TaCAD12 positively contributes to resistance against sharp eyespot through regulation of the expression of certain defense genes and monolignol biosynthesis-related genes in wheat.

  3. A Wheat Cinnamyl Alcohol Dehydrogenase TaCAD12 Contributes to Host Resistance to the Sharp Eyespot Disease

    PubMed Central

    Rong, Wei; Luo, Meiying; Shan, Tianlei; Wei, Xuening; Du, Lipu; Xu, Huijun; Zhang, Zengyan

    2016-01-01

    Sharp eyespot, caused mainly by the necrotrophic fungus Rhizoctonia cerealis, is a destructive disease in hexaploid wheat (Triticum aestivum L.). In Arabidopsis, certain cinnamyl alcohol dehydrogenases (CADs) have been implicated in monolignol biosynthesis and in defense response to bacterial pathogen infection. However, little is known about CADs in wheat defense responses to necrotrophic or soil-borne pathogens. In this study, we isolate a wheat CAD gene TaCAD12 in response to R. cerealis infection through microarray-based comparative transcriptomics, and study the enzyme activity and defense role of TaCAD12 in wheat. The transcriptional levels of TaCAD12 in sharp eyespot-resistant wheat lines were significantly higher compared with those in susceptible wheat lines. The sequence and phylogenetic analyses revealed that TaCAD12 belongs to IV group in CAD family. The biochemical assay proved that TaCAD12 protein is an authentic CAD enzyme and possesses catalytic efficiencies toward both coniferyl aldehyde and sinapyl aldehyde. Knock-down of TaCAD12 transcript significantly repressed resistance of the gene-silenced wheat plants to sharp eyespot caused by R. cerealis, whereas TaCAD12 overexpression markedly enhanced resistance of the transgenic wheat lines to sharp eyespot. Furthermore, certain defense genes (Defensin, PR10, PR17c, and Chitinase1) and monolignol biosynthesis-related genes (TaCAD1, TaCCR, and TaCOMT1) were up-regulated in the TaCAD12-overexpressing wheat plants but down-regulated in TaCAD12-silencing plants. These results suggest that TaCAD12 positively contributes to resistance against sharp eyespot through regulation of the expression of certain defense genes and monolignol biosynthesis-related genes in wheat. PMID:27899932

  4. Systematic Investigation of FLOWERING LOCUS T-Like Poaceae Gene Families Identifies the Short-Day Expressed Flowering Pathway Gene, TaFT3 in Wheat (Triticum aestivum L.)

    PubMed Central

    Halliwell, Joanna; Borrill, Philippa; Gordon, Anna; Kowalczyk, Radoslaw; Pagano, Marina L.; Saccomanno, Benedetta; Bentley, Alison R.; Uauy, Cristobal; Cockram, James

    2016-01-01

    To date, a small number of major flowering time loci have been identified in the related Triticeae crops, bread wheat (Triticum aestivum), durum wheat (T. durum), and barley (Hordeum vulgare). Natural genetic variants at these loci result in major phenotypic changes which have adapted crops to the novel environments encountered during the spread of agriculture. The polyploid nature of bread and durum wheat means that major flowering time loci in which recessive alleles confer adaptive advantage in related diploid species have not been readily identified. One such example is the PPD-H2 flowering time locus encoded by FLOWERING LOCUS T 3 (HvFT3) in the diploid crop barley, for which recessive mutant alleles confer delayed flowering under short day (SD) photoperiods. In autumn-sown barley, such alleles aid the repression of flowering over the winter, which help prevent the development of cold-sensitive floral organs until the onset of inductive long day (LD) photoperiods the following spring. While the identification of orthologous loci in wheat could provide breeders with alternative mechanisms to fine tune flowering time, systematic identification of wheat orthologs of HvFT3 has not been reported. Here, we characterize the FT gene families in six Poaceae species, identifying novel members in all taxa investigated, as well as FT3 homoeologs from the A, B and D genomes of hexaploid (TaFT3) and tetraploid wheat. Sequence analysis shows TaFT3 homoeologs display high similarity to the HvFT3 coding region (95–96%) and predicted protein (96–97%), with conservation of intron/exon structure across the five cereal species investigated. Genetic mapping and comparative analyses in hexaploid and tetraploid wheat find TaFT3 homoeologs map to the long arms of the group 1 chromosomes, collinear to HvFT3 in barley and FT3 orthologs in rice, foxtail millet and brachypodium. Genome-specific expression analyses show FT3 homoeologs in tetraploid and hexaploid wheat are upregulated

  5. QTL mapping of adult plant resistance to Ug99 stem rust in the spring wheat population RB07/MN06113-8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emergence and spread of the Ug99 race group of the stem rust pathogen in the past decade has exposed the vulnerability of wheat to this disease. Discovery of novel and effective sources of resistance is vital to reduce losses. The experimental breeding line MN06113-8 and cultivar RB07 developed ...

  6. Spatial and host-associated variation in prevalence and population density of wheat curl mite (Aceria tosichella) cryptic genotypes in agricultural landscapes.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wheat curl mite (WCM), Aceria tosichella Keifer, is a major pest of cereals worldwide that also comprises a complex of at least 16 genetic lineages with divergent physiological traits, including host preference and specificity. The goal of this study was to test the extent to which host-plant sp...

  7. Identification of genes bordering breakpoints of the pericentric inversions on 2B, 4B, and 5A in bread wheat (Triticum aestivum L.).

    PubMed

    Ma, Jian; Gao, Shang; Stiller, Jiri; Jiang, Qian-Tao; Lan, Xiu-Jin; Liu, Ya-Xi; Pu, Zhi-En; Wang, Jirui; Wei, Yuming; Zheng, You-Liang

    2015-08-01

    Chromosome translocation is an important driving force in shaping genomes during evolution. Detailed knowledge of chromosome translocations in a given species and its close relatives should increase the efficiency and precision of chromosome engineering in crop improvement. To identify genes flanking the breakpoints of translocations and inversions as a step toward identifying breakpoints in bread wheat, we systematically analysed genes in the Brachypodium genome against wheat survey sequences and bin-mapped ESTs (expressed sequence tags) derived from the hexaploid wheat genotype 'Chinese Spring'. In addition to those well-known translocations between group 4, 5, and 7 chromosomes, this analysis identified genes flanking the three pericentric inversions on chromosomes 2B, 4B, and 5A. However, numerous chromosomal rearrangements reported in early studies could not be confirmed. The genes flanking the breakpoints reported in this study are valuable for isolating these breakpoints.

  8. Genome-Wide Linkage Mapping of QTL for Adult-Plant Resistance to Stripe Rust in a Chinese Wheat Population Linmai 2 × Zhong 892

    PubMed Central

    Liu, Jindong; He, Zhonghu; Wu, Ling; Bai, Bin; Wen, Weie; Xie, Chaojie; Xia, Xianchun

    2015-01-01

    Stripe rust is one of the most devastating diseases of wheat (Triticum aestivum) worldwide. Adult-plant resistance (APR) is an efficient approach to provide long-term protection of wheat from the disease. The Chinese winter wheat cultivar Zhong 892 has a moderate level of APR to stripe rust in the field. To determine the inheritance of the APR resistance in this cultivar, 273 F6 recombinant inbred lines (RILs) were developed from a cross between Linmai 2 and Zhong 892. The RILs were evaluated for maximum disease severity (MDS) in two sites during the 2011–2012, 2012–2013 and 2013–2014 cropping seasons, providing data for five environments. Illumina 90k SNP (single nucleotide polymorphism) chips were used to genotype the RILs and their parents. Composite interval mapping (CIM) detected eight QTL, namely QYr.caas-2AL, QYr.caas-2BL.3, QYr.caas-3AS, QYr.caas-3BS, QYr.caas-5DL, QYr.caas-6AL, QYr.caas-7AL and QYr.caas-7DS.1, respectively. All except QYr.caas-2BL.3 resistance alleles were contributed by Zhong 892. QYr.caas-3AS and QYr.caas-3BS conferred stable resistance to stripe rust in all environments, explaining 6.2–17.4% and 5.0–11.5% of the phenotypic variances, respectively. The genome scan of SNP sequences tightly linked to QTL for APR against annotated proteins in wheat and related cereals genomes identified two candidate genes (autophagy-related gene and disease resistance gene RGA1), significantly associated with stripe rust resistance. These QTL and their closely linked SNP markers, in combination with kompetitive allele specific PCR (KASP) technology, are potentially useful for improving stripe rust resistances in wheat breeding. PMID:26714310

  9. Spring Wheat Breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common wheat, known as bread wheat, is one of major crops for human food consumption. It is further classified into spring and winter wheat based on the distinct growing seasons. Spring wheat is grown worldwide and usually planted in the spring and harvested in late summer or early fall. In this c...

  10. Genes encoding plastid acetyl-CoA carboxylase and 3-phosphoglycerate kinase of the Triticum/Aegilops complex and the evolutionary history of polyploid wheat

    PubMed Central

    Huang, Shaoxing; Sirikhachornkit, Anchalee; Su, Xiujuan; Faris, Justin; Gill, Bikram; Haselkorn, Robert; Gornicki, Piotr

    2002-01-01

    The classic wheat evolutionary history is one of adaptive radiation of the diploid Triticum/Aegilops species (A, S, D), genome convergence and divergence of the tetraploid (Triticum turgidum AABB, and Triticum timopheevii AAGG) and hexaploid (Triticum aestivum, AABBDD) species. We analyzed Acc-1 (plastid acetyl-CoA carboxylase) and Pgk-1 (plastid 3-phosphoglycerate kinase) genes to determine phylogenetic relationships among Triticum and Aegilops species of the wheat lineage and to establish the timeline of wheat evolution based on gene sequence comparisons. Triticum urartu was confirmed as the A genome donor of tetraploid and hexaploid wheat. The A genome of polyploid wheat diverged from T. urartu less than half a million years ago (MYA), indicating a relatively recent origin of polyploid wheat. The D genome sequences of T. aestivum and Aegilops tauschii are identical, confirming that T. aestivum arose from hybridization of T. turgidum and Ae. tauschii only 8,000 years ago. The diploid Triticum and Aegilops progenitors of the A, B, D, G, and S genomes all radiated 2.5–4.5 MYA. Our data suggest that the Acc-1 and Pgk-1 loci have different histories in different lineages, indicating genome mosaicity and significant intraspecific differentiation. Some loci of the S genome of Aegilops speltoides and the G genome of T. timophevii are closely related, suggesting the same origin of some parts of their genomes. None of the Aegilops genomes analyzed is a close relative of the B genome, so the diploid progenitor of the B genome remains unknown. PMID:12060759

  11. Wheat acetyl-coenzyme A carboxylase: cDNA and protein structure.

    PubMed Central

    Gornicki, P; Podkowinski, J; Scappino, L A; DiMaio, J; Ward, E; Haselkorn, R

    1994-01-01

    cDNA fragments encoding part of wheat (Triticum aestivum) acetyl-CoA carboxylase (ACC; EC 6.4.1.2) were cloned by PCR using primers based on the alignment of several biotin-dependent carboxylases. A set of overlapping clones encoding the entire wheat ACC was then isolated by using these fragments as probes. The cDNA sequence contains a 2257-amino acid reading frame encoding a 251-kDa polypeptide. The amino acid sequence of the most highly conserved domain, corresponding to the biotin carboxylases of prokaryotes, is 52-55% identical to ACC of yeast, rat, and diatom. Identity with the available C-terminal amino acid sequence of maize ACC is 66%. The biotin attachment site has the typical eukaryotic EVMKM sequence. The cDNA does not encode an obvious chloroplast targeting sequence. Various cDNA fragments hybridize in Northern blots to a 7.9-kb mRNA. Southern analysis with cDNA probes revealed multiple hybridizing fragments in hexaploid wheat DNA. Some of the wheat cDNA probes also hybridize with ACC-specific DNA from other plants, indicating significant conservation among plant ACCs. Images PMID:7913745

  12. [Alleles at storage protein loci in Triticum spelta L. accessions and their occurrence in related wheats].

    PubMed

    Kozub, N A; Boguslavskiĭ, R L; Sozinov, I A; Tverdokhleb, E V; Ksinias, I N; Blium, Ia B; Sozinov, A A

    2014-01-01

    Variation at eight storage protein loci was analyzed in the collection of T. spelta accessions from the National Centre of Plant Genetic Resources of Ukraine, most of which are European spelts. The analysis allowed identification of seven alleles at the Gli-B1 locus, five alleles at the Gli-A1 and Glu-B1 loci, three alleles at the Gli-A3 locus, two at the Gli-D1, Gli-B5, Glu-A1, and Glu-D1 loci. The majority of alleles are encountered among common wheat cultivars, only five alleles were specific for spelts. The high frequency of the alleles Gli-B1hs* and h encoding the 45-type gamma-gliadin in European spelts and durum wheat cultivars, as well as the occurrence of these alleles in T. dicoccum, in particular, in accessions from Switzerland and Germany, supports von Büren's hypothesis that European spelt resulted from hybridization between a tetraploid wheat with the 45-type y-gliadin and a hexaploid wheat. Analysis of genetic distances based on the genotypes at eight storage protein loci permitted differentiation of the Asian spelt accession from European spelts.

  13. Effect of beta-cyclodextrin on pasting properties of wheat starch.

    PubMed

    Li, W D; Huang, J C; Corke, H

    2000-06-01

    Changes of viscosity characteristics of genetically diverse hexaploid wheat starches during pasting in water, 1% NaCl solution, or at pH 4 or pH 10 were studied using a Rapid Visco-Analyzer. Peak viscosity (PV), hot paste viscosity (HPV) and cool paste viscosity (CPV) of all the wheat starches was little affected in pH 4 and pH 10 treatments. In 1% NaCl, all starches showed substantial increases in all three parameters relative to pasting in water. The use of 1% beta-cyclodextrin (beta-CD) (cycloheptaamylose) solution increased PV of high-swelling starches, but generally slightly decreased that of low swelling starches in all treatment conditions. HPV was always reduced by addition of 1% beta-CD, but CPV was increased in most treatments for Anza and Yecora Rojo (low swelling), but decreased for Klasic (high swelling). Bacterial alpha-amylase was added to starch or flour. The effect of beta-CD was shown to be independent of alpha-amylase inhibition in wheat starch, but beta-CD strongly inhibited alpha-amylase in wheat flour.

  14. NAD-dependent aromatic alcohol dehydrogenase in wheats (Triticum L.) and goatgrasses (Aegilops L.): evolutionary genetics.

    PubMed

    Jaaska, V

    1984-04-01

    Evolutionary electrophoretic variation of a NAD-specific aromatic alcohol dehydrogenase, AADH-E, in wheat and goatgrass species is described and discussed in comparison with a NAD-specific alcohol dehydrogenase (ADH-A) and a NADP-dependent AADH-B studied previously. Cultivated tetraploid emmer wheats (T. turgidum s. l.) and hexaploid bread wheats (T. aestivum s. l.) are all fixed for a heterozygous triplet, E(0.58)/E(0.64). The slowest isoenzyme, E(0.58), is controlled by a homoeoallelic gene on the chromosome arm 6AL of T. aestivum cv. 'Chinese Spring' and is inherent in all diploid wheats, T. monococcum s. Str., T. boeoticum s. l. and T. urartu. The fastest isoenzyme, E(0.64), is presumably controlled by the B- and D-genome homoeoalleles of the bread wheat and is the commonest alloenzyme of diploid goat-grasses, including Ae. speltaides and Ae. tauschii. The tetraploid T. timopheevii s. str. has a particular heterozygous triplet E(0.56)/E(0.71), whereas the hexaploid T. zhukovskyi exhibited polymorphism with electromorphs characteristic of T. timopheevii and T. monococcum. Wild tetraploid wheats, T. dicoccoides and T. araraticum, showed partially homologous intraspecific variation of AADH-E with heterozygous triplets E(0.58)/E(0.64) (the commonest), E(0.58)/E(0.71), E(0.45)/E(0.58), E(0.48)/E(0.58) and E(0.56)/E(0.58) recorded. Polyploid goatgrasses of the D-genome group, excepting Ae. cylindrica, are fixed for the common triplet E(0.58)/E(0.64). Ae. cylindrica and polyploid goatgrasses of the C(u)-genome group, excepting Ae. kotschyi, are homozygous for E(0.64). Ae. kotschyi is exceptional, showing fixed heterozygosity for both AADH-E and ADH-A with unique triplets E(0.56)/E(0.64) and A(0.49)/A(0.56).

  15. Adverse Effects of Wheat Gluten.

    PubMed

    Koning, Frits

    2015-01-01

    Man began to consume cereals approximately 10,000 years ago when hunter-gatherers settled in the fertile golden crescent in the Middle East. Gluten has been an integral part of the Western type of diet ever since, and wheat consumption is also common in the Middle East, parts of India and China as well as Australia and Africa. In fact, the food supply in the world heavily depends on the availability of cereal-based food products, with wheat being one of the largest crops in the world. Part of this is due to the unique properties of wheat gluten, which has a high nutritional value and is crucial for the preparation of high-quality dough. In the last 10 years, however, wheat and gluten have received much negative attention. Many believe that it is inherently bad for our health and try to avoid consumption of gluten-containing cereals; a gluten-low lifestyle so to speak. This is fueled by a series of popular publications like Wheat Belly; Lose the Wheat, Lose the Weight, and Find Your Path Back to Health. However, in reality, there is only one condition where gluten is definitively the culprit: celiac disease (CD), affecting approximately 1% of the population in the Western world. Here, I describe the complexity of the cereals from which gluten is derived, the special properties of gluten which make it so widely used in the food industry, the basis for its toxicity in CD patients and the potential for the development of safe gluten and alternatives to the gluten-free diet.

  16. Dwarfing Genes Rht-B1b and Rht-D1b Are Associated with Both Type I FHB Susceptibility and Low Anther Extrusion in Two Bread Wheat Populations

    PubMed Central

    He, Xinyao; Singh, Pawan K.; Dreisigacker, Susanne; Singh, Sukhwinder; Lillemo, Morten; Duveiller, Etienne

    2016-01-01

    It has been well documented that dwarfing genes Rht-B1b and Rht-D1b are associated with Type I susceptibility to Fusarium head blight (FHB) in wheat; but the underlying mechanism has not been well delineated. Anther extrusion (AE) has also been related to Type I resistance for initial FHB infection, where high AE renders FHB resistance. In this study, two doubled haploid populations were used to investigate the impact of the two dwarfing genes on FHB resistance and AE, and to elucidate the role of AE in Rht-mediated FHB susceptibility. Both populations were derived by crossing the FHB susceptible cultivar ‘Ocoroni F86’ (Rht-B1a/Rht-D1b) with an FHB resistant variety (Rht-B1b/Rht-D1a), which was ‘TRAP#1/BOW//Taigu derivative’ in one population (the TO population) and ‘Ivan/Soru#2’ in the other (the IO population). Field experiments were carried out from 2010 to 2012 in El Batán, Mexico, where spray inoculation was adopted and FHB index, plant height (PH), and AE were evaluated, with the latter two traits showing always significantly negative correlations with FHB severity. The populations were genotyped with the DArTseq GBS platform, the two dwarfing genes and a few SSRs for QTL analysis, and the results indicated that Rht-B1b and Rht-D1b collectively accounted for 0–41% of FHB susceptibility and 13–23% of reduced AE. It was also observed that three out of the four AE QTL in the TO population and four out of the five AE QTL in the IO population were associated with FHB resistance. Collectively, our results demonstrated the effects of Rht-B1b and Rht-D1b on Type I FHB susceptibility and reducing AE, and proposed that their impacts on Type I FHB susceptibility may partly be explained by their effects on reducing AE. The implication of the relationship between the two dwarfing genes and AE for hybrid wheat breeding was also discussed. PMID:27606928

  17. Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry

    PubMed Central

    Schalk, Kathrin; Lang, Christina; Wieser, Herbert; Koehler, Peter; Scherf, Katharina Anne

    2017-01-01

    Coeliac disease (CD) is triggered by the ingestion of gluten proteins from wheat, rye, and barley. The 33-mer peptide from α2-gliadin has frequently been described as the most important CD-immunogenic sequence within gluten. However, from more than 890 published amino acid sequences of α-gliadins, only 19 sequences contain the 33-mer. In order to make a precise assessment of the importance of the 33-mer, it is necessary to elucidate which wheat species and cultivars contain the peptide and at which concentrations. This paper presents the development of a stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry to quantitate the 33-mer in flours of 23 hexaploid modern and 15 old common (bread) wheat as well as two spelt cultivars. All flours contained the 33-mer peptide at levels ranging from 91–603 μg/g flour. In contrast, the 33-mer was absent (wheat, emmer, einkorn), most likely because of the absence of the D-genome, which encodes α2-gliadins. Due to the presence of the 33-mer in all common wheat and spelt flours analysed here, the special focus in the literature on this most immunodominant peptide seems to be justified. PMID:28327674

  18. Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry.

    PubMed

    Schalk, Kathrin; Lang, Christina; Wieser, Herbert; Koehler, Peter; Scherf, Katharina Anne

    2017-03-22

    Coeliac disease (CD) is triggered by the ingestion of gluten proteins from wheat, rye, and barley. The 33-mer peptide from α2-gliadin has frequently been described as the most important CD-immunogenic sequence within gluten. However, from more than 890 published amino acid sequences of α-gliadins, only 19 sequences contain the 33-mer. In order to make a precise assessment of the importance of the 33-mer, it is necessary to elucidate which wheat species and cultivars contain the peptide and at which concentrations. This paper presents the development of a stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry to quantitate the 33-mer in flours of 23 hexaploid modern and 15 old common (bread) wheat as well as two spelt cultivars. All flours contained the 33-mer peptide at levels ranging from 91-603 μg/g flour. In contrast, the 33-mer was absent (wheat, emmer, einkorn), most likely because of the absence of the D-genome, which encodes α2-gliadins. Due to the presence of the 33-mer in all common wheat and spelt flours analysed here, the special focus in the literature on this most immunodominant peptide seems to be justified.

  19. Earliness per se QTLs and their interaction with the photoperiod insensitive allele Ppd-D1a in the Cutler × AC Barrie spring wheat population.

    PubMed

    Kamran, A; Iqbal, M; Navabi, A; Randhawa, H; Pozniak, C; Spaner, D

    2013-08-01

    Earliness per se regulates flowering time independent of environmental signals and helps to fine tune the time of flowering and maturity. In this study, we aimed to map earliness per se quantitative trait loci (QTLs) affecting days to flowering and maturity in a population developed by crossing two spring wheat cultivars, Cutler and AC Barrie. The population of 177 recombinant inbred lines (RILs) was genotyped for a total of 488 SSR and DArT polymorphic markers on all 21 chromosomes. Three QTLs of earliness per se affecting days to flowering and maturity were mapped on chromosomes 1B (QEps.dms-1B1 and QEps.dms-1B2) and 5B (QEps.dms-5B1), in individual environments and when all the environments were combined. A QTL affecting flowering time (QFlt.dms-4A1) was identified on chromosome 4A. Two grain yield QTLs were mapped on chromosome 5B, while one QTL was mapped on chromosome 1D. The population segregated for the photoperiod insensitive gene, Ppd-D1a, and it induced earlier flowering by 0.69 days and maturity by 1.28 days. The photoperiod insensitive allele Ppd-D1a interacted in an additive fashion with QTLs for flowering and maturity times. The earliness per se QTL QFlt.dms-5B.1 inducing earlier flowering could help to elongate grain filling duration for higher grain yield. Hence, chromosome 5B possesses promising genomic regions that may be introgressed for higher grain yield with earlier maturity through marker-assisted selection in bread wheat.

  20. Changes in the Russian Wheat Aphid (Hemiptera: Aphididae) Biotype Complex in South Africa.

    PubMed

    Jankielsohn, Astrid

    2016-04-01

    Russian wheat aphid Diuraphis noxia (Kurdjumov) has spread from its native area in central Asia to all the major wheat-producing countries in the world to become an international wheat pest. Because the Russian wheat aphid is a serious threat to the wheat industry in South Africa, it is important to investigate the key factors involved in the distribution of Russian wheat aphid biotypes and in the changes of the Russian wheat aphid biotype complex in South Africa. There are currently four known Russian wheat aphid biotypes occurring in South Africa. Russian wheat aphid samples were collected from 2011 to 2014 during the wheat-growing season in spring and summer and these samples were screened to determine the biotype status. RWASA1 occurred predominantly in the Western Cape, while RWASA2 and RWASA3 occurred predominantly in the Eastern Free State. Following the first record of RWASA4 in 2011, this biotype was restricted to the Eastern Free State. The surveys suggest that the Russian wheat aphid bioype complex was more diverse in the Eastern Free State than in the other wheat production areas. There was also a shift in Russian wheat aphid biotype composition over time. The Russian wheat aphid biotype complex is dynamic, influenced by environmental factors such as host plants, altitude, and climate, and it can change and diversify over time causing fluctuation in populations over sites and years. This dynamic nature of the Russian wheat aphid will continue to challenge the development of Russian wheat aphid-resistant wheat cultivars in South Africa, and the continued monitoring of the biotypic and genetic structure, to determine genetic relatedness and variation in different biotypes, of Russian wheat aphid populations is important for protecting wheat.

  1. TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.

    PubMed

    Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

    2013-08-01

    Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat.

  2. TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice

    PubMed Central

    Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Lan, Xiujin; Mao, Long

    2013-01-01

    Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat. PMID:23918959

  3. Solid-stemmed wheat does not affect overwintering mortality of the wheat stem sawfly, Cephus cinctus.

    PubMed

    Cárcamo, Héctor A; Beres, Brian L; Herle, Carolyn E; McLean, Hugh; McGinne, Sean

    2011-01-01

    The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America. Host plant resistance in the form of solid-stemmed wheat cultivars is the main control strategy for C. cinctus. This study investigated the effect of novel and traditional solid wheat hosts on the overwintering mortality and cold-hardiness of C. cinctus. Field conditions from 2003-2005 showed that overwintering mortality in various wheat cultivars averaged 8% and was not related to the type of wheat cultivar. Similarly, supercooling points (-22° C) were not influenced by wheat host type. C. cintus are cold-hardy; up to 80% survive 10 days at -20° C and 10% survive 40 days. Its overwintering microhabitat near the crown area of the plant is well insulated for temperatures above -10° C and remains ~ 20° C above ambient minima. These data suggest that winter mortality is a minor factor in the population dynamics of wheat stem sawfly, and despite clear detrimental effects on larval weight and adult fitness, solid-stemmed cultivars do not reduce the ability of larvae to survive winters.

  4. Proteomics of Wheat Flour

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat is a major food crop grown on more than 215 million hectares of land throughout the world. Wheat flour provides an important source of protein for human nutrition and is used as a principal ingredient in a wide range of food products, largely because wheat flour, when mixed with water, has un...

  5. Population.

    ERIC Educational Resources Information Center

    King, Pat; Landahl, John

    This pamphlet has been prepared in response to a new problem, a rapidly increasing population, and a new need, population education. It is designed to help teachers provide their students with some basic population concepts with stress placed on the elements of decision making. In the first section of the pamphlet, some of the basic concepts of…

  6. [Population].

    PubMed

    1979-01-01

    Data on the population of Venezuela between 1975 and 1977 are presented in descriptive tables and graphs. Information is included on the employed population according to category, sex, and type of economic activity, and by sex, age, and area on the employment rate and the total, the economically active, and the unemployed population.

  7. Genome-wide analysis of complex wheat gliadins, the dominant carriers of celiac disease epitopes.

    PubMed

    Wang, Da-Wei; Li, Da; Wang, Junjun; Zhao, Yue; Wang, Zhaojun; Yue, Guidong; Liu, Xin; Qin, Huanju; Zhang, Kunpu; Dong, Lingli; Wang, Daowen

    2017-03-16

    Gliadins, specified by six compound chromosomal loci (Gli-A1/B1/D1 and Gli-A2/B2/D2) in hexaploid bread wheat, are the dominant carriers of celiac disease (CD) epitopes. Because of their complexity, genome-wide characterization of gliadins is a strong challenge. Here, we approached this challenge by combining transcriptomic, proteomic and bioinformatic investigations. Through third-generation RNA sequencing, full-length transcripts were identified for 52 gliadin genes in the bread wheat cultivar Xiaoyan 81. Of them, 42 were active and predicted to encode 25 α-, 11 γ-, one δ- and five ω-gliadins. Comparative proteomic analysis between Xiaoyan 81 and six newly-developed mutants each lacking one Gli locus indicated the accumulation of 38 gliadins in the mature grains. A novel group of α-gliadins (the CSTT group) was recognized to contain very few or no CD epitopes. The δ-gliadins identified here or previously did not carry CD epitopes. Finally, the mutant lacking Gli-D2 showed significant reductions in the most celiac-toxic α-gliadins and derivative CD epitopes. The insights and resources generated here should aid further studies on gliadin functions in CD and the breeding of healthier wheat.

  8. Genome-wide analysis of complex wheat gliadins, the dominant carriers of celiac disease epitopes

    PubMed Central

    Wang, Da-Wei; Li, Da; Wang, Junjun; Zhao, Yue; Wang, Zhaojun; Yue, Guidong; Liu, Xin; Qin, Huanju; Zhang, Kunpu; Dong, Lingli; Wang, Daowen

    2017-01-01

    Gliadins, specified by six compound chromosomal loci (Gli-A1/B1/D1 and Gli-A2/B2/D2) in hexaploid bread wheat, are the dominant carriers of celiac disease (CD) epitopes. Because of their complexity, genome-wide characterization of gliadins is a strong challenge. Here, we approached this challenge by combining transcriptomic, proteomic and bioinformatic investigations. Through third-generation RNA sequencing, full-length transcripts were identified for 52 gliadin genes in the bread wheat cultivar Xiaoyan 81. Of them, 42 were active and predicted to encode 25 α-, 11 γ-, one δ- and five ω-gliadins. Comparative proteomic analysis between Xiaoyan 81 and six newly-developed mutants each lacking one Gli locus indicated the accumulation of 38 gliadins in the mature grains. A novel group of α-gliadins (the CSTT group) was recognized to contain very few or no CD epitopes. The δ-gliadins identified here or previously did not carry CD epitopes. Finally, the mutant lacking Gli-D2 showed significant reductions in the most celiac-toxic α-gliadins and derivative CD epitopes. The insights and resources generated here should aid further studies on gliadin functions in CD and the breeding of healthier wheat. PMID:28300172

  9. Population.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

  10. EST mining for structure and expression of genes in the region of the wheat high-molecular-weight glutenin loci.

    PubMed

    Anderson, O D

    2009-08-01

    An in-depth analysis was carried out with expressed sequence tags (ESTs) for genes in and near the HMW-GS loci. Considerations for using ESTs are discussed, including the occurrence of chimeric and aberrant HMW-GS ESTs. Complete gene sequences demonstrated the feasibility of constructing accurate full-length coding regions from EST assemblies and found, or supported, errors in several previously reported HMW-GS gene sequences. New complete HMW-GS gene sequences are reported for the cultivars Chinese Spring and Glenlea. The Ay subunit gene, which is considered null in cultivated wheats, was shown to transcribe in at least two germplasms. Analyses support the conclusion that of the five known genes within this genomic region, the two HMW-GS genes and the globulin gene are highly expressed. The other two genes, encoding a receptor kinase and a protein kinase, have one and no identifiable wheat EST, respectively, although ESTs are found for the orthologous genes in barley. The ESTs of all five genes within the HMW-GS region are either definitely associated with the endosperm or possibly originate from imbibed seed, suggesting the four distinct gene classes in this region are part of a seed or endosperm chromatin domain. EST resources were also used to determine relative abundance of ESTs for all classes of wheat prolamines and indicated differential levels of expression both among germplasms and among the three genomes of hexaploid wheats.

  11. Induced mutations in the starch branching enzyme II (SBEII) genes increase amylose and resistant starch content in durum wheat

    PubMed Central

    Hazard, Brittany; Zhang, Xiaoqin; Colasuonno, Pasqualina; Uauy, Cristobal; Beckles, Diane M.; Dubcovsky, Jorge

    2016-01-01

    Starch is the largest component of the wheat (Triticum aestivum L.) grain and consists of approximately 70-80% amylopectin and 20-30% amylose. Amylopectin is a highly-branched, readily digested polysaccharide, whereas amylose has few branches and forms complexes that resist digestion and mimic dietary fiber (resistant starch). Down-regulation of the starch branching enzyme II (SBEII) gene by RNA interference (RNAi) was previously shown to increase amylose content in both hexaploid and tetraploid wheat. We generated ethyl methane sulphonate (EMS) mutants for the SBEIIa-A and SBEIIa-B homoeologs in the tetraploid durum wheat variety Kronos (T. turgidum ssp. durum L.). Single-gene mutants showed non-significant increases in amylose and resistant starch content, but a double mutant combining a SBEIIa-A knock-out mutation with a SBEIIa-B splice-site mutation showed a 22% increase in amylose content (P<0.0001) and a 115% increase in resistant starch content (P<0.0001). In addition, we obtained mutants for the A and B genome copies of the paralogous SBEIIb gene, mapped them 1-2 cM from SBEIIa, and generated double SBEIIa-SBEIIb mutants to study the effect of the SBEIIb gene in the absence of SBEIIa. These mutants are available to those interested in increasing amylose content and resistant starch in durum wheat. PMID:26924849

  12. Characterization of FLOWERING LOCUS T1 (FT1) gene in Brachypodium and wheat.

    PubMed

    Lv, Bo; Nitcher, Rebecca; Han, Xiuli; Wang, Shuyun; Ni, Fei; Li, Kun; Pearce, Stephen; Wu, Jiajie; Dubcovsky, Jorge; Fu, Daolin

    2014-01-01

    The phase transition from vegetative to reproductive growth is a critical event in the life cycle of flowering plants. FLOWERING LOCUS T (FT) plays a central role in the regulation of this transition by integrating signals from multiple flowering pathways in the leaves and transmitting them to the shoot apical meristem. In this study, we characterized FT homologs in the temperate grasses Brachypodium distachyon and polyploid wheat using transgenic and mutant approaches. Downregulation of FT1 by RNAi was associated with a significant downregulation of the FT-like genes FT2 and FT4 in Brachypodium and FT2 and FT5 in wheat. In a transgenic wheat line carrying a highly-expressed FT1 allele, FT2 and FT3 were upregulated under both long and short days. Overexpression of FT1 caused extremely early flowering during shoot regeneration in both Brachypodium and hexaploid wheat, and resulted in insufficient vegetative tissue to support the production of viable seeds. Downregulation of FT1 transcripts by RNA interference (RNAi) resulted in non-flowering Brachypodium plants and late flowering plants (2-4 weeks delay) in wheat. A similar delay in heading time was observed in tetraploid wheat plants carrying mutations for both FT-A1 and FT-B1. Plants homozygous only for mutations in FT-B1 flowered later than plants homozygous only for mutations in FT-A1, which corresponded with higher transcript levels of FT-B1 relative to FT-A1 in the early stages of development. Taken together, our data indicate that FT1 plays a critical role in the regulation of flowering in Brachypodium and wheat, and that this role is associated with the simultaneous regulation of other FT-like genes. The differential effects of mutations in FT-A1 and FT-B1 on wheat heading time suggest that different allelic combinations of FT1 homoeologs could be used to adjust wheat heading time to improve adaptation to changing environments.

  13. How diverse a farmer-managed wheat landrace can be?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenotypic variation in phenological, quantitative and qualitative traits was assessed in geographically-isolated, farmer-managed wheat landrace populations grown under subsistence farming conditions. Several multivariate, genetic diversity and sequential equation modeling procedures were used to bu...

  14. A large-scale introgression of genomic components of Brassica rapa into B. napus by the bridge of hexaploid derived from hybridization between B. napus and B. oleracea.

    PubMed

    Li, Qinfei; Mei, Jiaqin; Zhang, Yongjing; Li, Jiana; Ge, Xianhong; Li, Zaiyun; Qian, Wei

    2013-08-01

    Brassica rapa (AA) has been used to widen the genetic basis of B. napus (AACC), which is a new but important oilseed crop worldwide. In the present study, we have proposed a strategy to develop new type B. napus carrying genomic components of B. rapa by crossing B. rapa with hexaploid (AACCCC) derived from B. napus and B. oleracea (CC). The hexaploid exhibited large flowers and high frequency of normal chromosome segregation, resulting in good seed set (average of 4.48 and 12.53 seeds per pod by self and open pollination, respectively) and high pollen fertility (average of 87.05 %). It was easy to develop new type B. napus by crossing the hexaploid with 142 lines of B. rapa from three ecotype groups, with the average crossability of 9.24 seeds per pod. The genetic variation of new type B. napus was diverse from that of current B. napus, especially in the A subgenome, revealed by genome-specific simple sequence repeat markers. Our data suggest that the strategy proposed here is a large-scale and highly efficient method to introgress genomic components of B. rapa into B. napus.

  15. Evolution of New Disease Specificity at a Simple Resistance Locus in a Crop–Weed Complex: Reconstitution of the Lr21 Gene in Wheat

    PubMed Central

    Huang, Li; Brooks, Steven; Li, Wanlong; Fellers, John; Nelson, James C.; Gill, Bikram

    2009-01-01

    The wheat leaf-rust resistance gene Lr21 was first identified in an Iranian accession of goatgrass, Aegilops tauschii Coss., the D-genome donor of hexaploid bread wheat, and was introgressed into modern wheat cultivars by breeding. To elucidate the origin of the gene, we analyzed sequences of Lr21 and lr21 alleles from 24 wheat cultivars and 25 accessions of Ae. tauschii collected along the Caspian Sea in Iran and Azerbaijan. Three basic nonfunctional lr21 haplotypes, H1, H2, and H3, were identified. Lr21 was found to be a chimera of H1 and H2, which were found only in wheat. We attempted to reconstitute a functional Lr21 allele by crossing the cultivars Fielder (H1) and Wichita (H2). Rust inoculation of 5876 F2 progeny revealed a single resistant plant that proved to carry the H1H2 haplotype, a result attributed to intragenic recombination. These findings reflect how plants balance the penalty and the necessity of a resistance gene and suggest that plants can reuse “dead” alleles to generate new disease-resistance specificity, leading to a “death–recycle” model of plant-resistance gene evolution at simple loci. We suggest that selection pressure in crop–weed complexes contributes to this process. PMID:19364806

  16. Genome-Wide Analysis of Stowaway-Like MITEs in Wheat Reveals High Sequence Conservation, Gene Association, and Genomic Diversification1[C][W

    PubMed Central

    Yaakov, Beery; Ben-David, Smadar; Kashkush, Khalil

    2013-01-01

    The diversity and evolution of wheat (Triticum-Aegilops group) genomes is determined, in part, by the activity of transposable elements that constitute a large fraction of the genome (up to 90%). In this study, we retrieved sequences from publicly available wheat databases, including a 454-pyrosequencing database, and analyzed 18,217 insertions of 18 Stowaway-like miniature inverted-repeat transposable element (MITE) families previously characterized in wheat that together account for approximately 1.3 Mb of sequence. All 18 families showed high conservation in length, sequence, and target site preference. Furthermore, approximately 55% of the elements were inserted in transcribed regions, into or near known wheat genes. Notably, we observed significant correlation between the mean length of the MITEs and their copy number. In addition, the genomic composition of nine MITE families was studied by real-time quantitative polymerase chain reaction analysis in 40 accessions of Triticum spp. and Aegilops spp., including diploids, tetraploids, and hexaploids. The quantitative polymerase chain reaction data showed massive and significant intraspecific and interspecific variation as well as genome-specific proliferation and nonadditive quantities in the polyploids. We also observed significant differences in the methylation status of the insertion sites among MITE families. Our data thus suggest a possible role for MITEs in generating genome diversification and in the establishment of nascent polyploid species in wheat. PMID:23104862

  17. Osmotic regulation of 10 wheat (Triticum aestivum L.) genotypes at soil water deficits.

    PubMed

    Hongbo, Shao; Zongsuo, Liang; Mingan, Shao

    2006-02-01

    Drought is a worldwide problem, seriously influencing plant (crop) productivity. Wheat is a stable food for 35% of the world population, moreover about 60% of land area on the globe belongs to arid and semi-arid zone. Wheat drought resistance is a multi-gene-controlling quantitative character and wheat final production in field is realized mainly by physiological regulation under the condition of multi-environmental factor interaction. Exploring drought resistance physiological mechanisms for different wheat genotypes is of importance to finding new drought resistance gene resources and conventional breeding and the basis for wheat drought resistance biotechnological breeding and platform. Osmotic adjustment regulation is the main component for physiological machinery of wheat drought resistance. By pot-cultivating experiments, investigation of osmotic adjustment comparison for 10 wheat genotypes at soil water deficits (75% FC, 55% FC, 45% FC, respectively), was conducted. The main results were as followed: (1) K(+) content in 10 wheat genotypes at three levels of soil water stress and at the same soil water deficit was very different. Five of these 10 wheat genotypes had higher K K(+) content under the condition of 75% FC. (2) Five of these 10 wheat genotypes possessed greater soluble sugar content at 55% FC soil water level. (3) Proline (Pro) content in five wheat genotypes was higher at 75% FC. (4) Five of these 10 wheat genotypes had lower malondialdehyde (MDA) content at 45% FC at seedling stage. Osmotic adjustment of wheat different genotypes was discussed in terms of different content of osmotic solutes.

  18. WheatGenome.info: A Resource for Wheat Genomics Resource.

    PubMed

    Lai, Kaitao

    2016-01-01

    An integrated database with a variety of Web-based systems named WheatGenome.info hosting wheat genome and genomic data has been developed to support wheat research and crop improvement. The resource includes multiple Web-based applications, which are implemented as a variety of Web-based systems. These include a GBrowse2-based wheat genome viewer with BLAST search portal, TAGdb for searching wheat second generation genome sequence data, wheat autoSNPdb, links to wheat genetic maps using CMap and CMap3D, and a wheat genome Wiki to allow interaction between diverse wheat genome sequencing activities. This portal provides links to a variety of wheat genome resources hosted at other research organizations. This integrated database aims to accelerate wheat genome research and is freely accessible via the web interface at http://www.wheatgenome.info/ .

  19. Genotyping-by-sequencing to re-map QTL for type II Fusarium head blight and leaf rust resistance in a wheat-tall wheatgrass introgression recombinant inbred population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium graminaerum (Fusarium head blight; FHB) and Puccinia recondita Roberge ex Desmaz. f. sp. tritici Eriks. & E. Henn (leaf rust; LR) are two major fungal pathogens threatening the wheat crop; consequently identifying resistance genes from various sources is always of importance to wheat breede...

  20. Do we need to worry about eating wheat?

    PubMed

    Shewry, P R; Hey, S J

    2016-03-01

    Wheat is a staple food throughout the temperate world and an important source of nutrients for many millions of people. However, the last few years have seen increasing concerns about adverse effects of wheat on health, particularly in North America and Europe, with the increasing adoption of wheat-free or gluten-free diets. This relates to two concerns: that wheat products are disproportionally responsible for increases in obesity and type 2 diabetes and that wheat gluten proteins cause a range of adverse reactions, including allergies, coeliac disease and 'non-coeliac gluten sensitivity'. The first concern has been refuted in previous publications, and we therefore focus on the second here. Current evidence indicates that allergy to ingested wheat and coeliac disease (and related intolerances) each occur in up to 1% of the population. The extent to which their prevalence has increased is difficult to quantify due to improved diagnosis and increased awareness. However, neither appears to be increasing disproportionally when compared with other immunologically mediated adverse reactions to food. Other adverse reactions to wheat are more difficult to define as their mechanisms are not understood and they are therefore difficult to diagnose. In particular, 'non-coeliac wheat sensitivity' has been reported to occur in 6% or more of the population in the US. However, the application of more rigorous diagnostic criteria is likely to give substantially lower estimates of prevalence. It is therefore unlikely that the health of more than a small proportion of the population will be improved by eliminating wheat or gluten from the diet. In fact, the opposite may occur as wheat is an important source of protein, B vitamins, minerals and bioactive components.

  1. Investigating the role of respiration in plant salinity tolerance by analyzing mitochondrial proteomes from wheat and a salinity-tolerant Amphiploid (wheat × Lophopyrum elongatum).

    PubMed

    Jacoby, Richard P; Millar, A Harvey; Taylor, Nicolas L

    2013-11-01

    The effect of salinity on mitochondrial properties was investigated by comparing the reference wheat variety Chinese Spring (CS) to a salt-tolerant amphiploid (AMP). The octoploid AMP genotype was previously generated by combining hexaploid bread wheat (CS) with the diploid wild wheatgrass adapted to salt marshes, Lophopyrum elongatum. Here we used a combination of physiological, biochemical, and proteomic analyses to explore the mitochondrial and respiratory response to salinity in these two genotypes. The AMP showed greater growth tolerance to salinity treatments and altered respiration rate in both roots and shoots. A proteomic workflow of 2D-DIGE and MALDI TOF/TOF mass spectrometry was used to compare the protein composition of isolated mitochondrial samples from roots and shoots of both genotypes, following control or salt treatment. A large set of mitochondrial proteins were identified as responsive to salinity in both genotypes, notably enzymes involved in detoxification of reactive oxygen species. Genotypic differences in mitochondrial composition were also identified, with AMP exhibiting a higher abundance of manganese superoxide dismutase, serine hydroxymethyltransferase, aconitase, malate dehydrogenase, and β-cyanoalanine synthase compared to CS. We present peptide fragmentation spectra derived from some of these AMP-specific protein spots, which could serve as biomarkers to track superior protein variants.

  2. Effects of herbicide applications in wheat fields

    PubMed Central

    Varshney, Sugandha; Hayat, Shamshul; Alyemeni, Mohammed Nasser; Ahmad, Aqil

    2012-01-01

    The present review encompasses the physiological and yield constraints of herbicide applications with special reference to wheat productivity. Post-independence lagging of Indian agriculture to feed its population led to haphazard use of chemical pesticides and weedicides which deteriorated the productivity pay-off particularly of wheat and rice. Past some decades witnessed the potential use of certain phytohormones in augmenting abiotic stress to get rid of yield gap and productivity constraints. We summed up with reviewing the potential role of these natural regulators in overcoming above mentioned drawbacks to substitute or to integrate these chemicals with the use of plant hormones. PMID:22516826

  3. Registration of 'Ripper' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Ripper’ (Reg. No. CV-1016, PI 644222) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2006 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado S...

  4. Wheat: Science and Trade

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Up-to-date textbooks are needed to educate the agricultural scientists of tomorrow. This manuscript comprises one chapter in such a textbook, “Wheat: Science and Trade”, and covers the subject of wheat genetic engineering. The chapter begins with a summary of key discussion elements and ends with a...

  5. Registration of 'Antero' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ’Antero’ (Reg. No. CV-XXXX, PI 667743) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2012 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State Univ...

  6. Registration of 'Byrd' wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Byrd' (PI 664257) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released August, 2011, through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State University (CSU), USDA-ARS ...

  7. Agrometeorology and Wheat Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter wheat phenology varies among shoots on the plant to main stems on plants within a plot to locations across a landscape. Most often phenological measurements have focused on small treatment plots under presumably similar soils and topography. Many models exist to predict wheat phenology for sm...

  8. Markers linked to wheat stem rust resistance gene Sr11 effective to Puccinia graminis f. sp. tritici race TKTTF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat stem rust caused by Puccinia graminis f. sp. tritici can cause severe yield losses on susceptible wheat varieties and cultivars. Although stem rust can be controlled by the use of genetic resistance, population dynamics of P. graminis f. sp. tritici can frequently lead to defeat of wheat stem ...

  9. Fine-Mapping the Wheat Snn1 Locus Conferring Sensitivity to the Parastagonospora nodorum Necrotrophic Effector SnTox1 Using an Eight Founder Multiparent Advanced Generation Inter-Cross Population.

    PubMed

    Cockram, James; Scuderi, Alice; Barber, Toby; Furuki, Eiko; Gardner, Keith A; Gosman, Nick; Kowalczyk, Radoslaw; Phan, Huyen P; Rose, Gemma A; Tan, Kar-Chun; Oliver, Richard P; Mackay, Ian J

    2015-09-28

    The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the world's most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum produces necrotrophic protein effectors that mediate host cell death, providing nutrients for continuation of the infection process. The recent discovery of pathogen effectors has revolutionized disease resistance breeding for necrotrophic diseases in crop species, allowing often complex genetic resistance mechanisms to be broken down into constituent parts. To date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox1, to screen 642 progeny from an eight-parent multiparent advanced generation inter-cross (i.e., MAGIC) population, genotyped with a 90,000-feature single-nucleotide polymorphism array. The MAGIC founders showed a range of sensitivity to SnTox1, with transgressive segregation evident in the progeny. SnTox1 sensitivity showed high heritability, with quantitative trait locus analyses fine-mapping the Snn1 locus to the short arm of chromosome 1B. In addition, a previously undescribed SnTox1 sensitivity locus was identified on the long arm of chromosome 5A, termed here QSnn.niab-5A.1. The peak single-nucleotide polymorphism for the Snn1 locus was converted to the KASP genotyping platform, providing breeders and researchers a simple and cheap diagnostic marker for allelic state at Snn1.

  10. Fine-Mapping the Wheat Snn1 Locus Conferring Sensitivity to the Parastagonospora nodorum Necrotrophic Effector SnTox1 Using an Eight Founder Multiparent Advanced Generation Inter-Cross Population

    PubMed Central

    Cockram, James; Scuderi, Alice; Barber, Toby; Furuki, Eiko; Gardner, Keith A.; Gosman, Nick; Kowalczyk, Radoslaw; Phan, Huyen P.; Rose, Gemma A.; Tan, Kar-Chun; Oliver, Richard P.; Mackay, Ian J.

    2015-01-01

    The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the world’s most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum produces necrotrophic protein effectors that mediate host cell death, providing nutrients for continuation of the infection process. The recent discovery of pathogen effectors has revolutionized disease resistance breeding for necrotrophic diseases in crop species, allowing often complex genetic resistance mechanisms to be broken down into constituent parts. To date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox1, to screen 642 progeny from an eight-parent multiparent advanced generation inter-cross (i.e., MAGIC) population, genotyped with a 90,000-feature single-nucleotide polymorphism array. The MAGIC founders showed a range of sensitivity to SnTox1, with transgressive segregation evident in the progeny. SnTox1 sensitivity showed high heritability, with quantitative trait locus analyses fine-mapping the Snn1 locus to the short arm of chromosome 1B. In addition, a previously undescribed SnTox1 sensitivity locus was identified on the long arm of chromosome 5A, termed here QSnn.niab-5A.1. The peak single-nucleotide polymorphism for the Snn1 locus was converted to the KASP genotyping platform, providing breeders and researchers a simple and cheap diagnostic marker for allelic state at Snn1. PMID:26416667

  11. Effects of combined thiamethoxam and diatomaceous earth on mortality and progeny production of four Pakistani populations of Rhyzopertha dominica (Coleoptera: Bostrychidae) on wheat, rice and maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioassays were conducted to evaluate the effects of combining thiamethoxam at 0.25, 0.5 and 0.75 mg/kg with the diatomaceous earth (DE) formulation, SilicoSec, at the rate of 100 mg/kg against four diverse populations of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) th...

  12. Similarities of omega gliadins from Triticum urartu to those encoded on chromosome 1A of hexaploid wheat and evidence for their post-translational processing.

    PubMed

    DuPont, F M; Vensel, W; Encarnacao, T; Chan, R; Kasarda, D D

    2004-05-01

    The omega-gliadins encoded on chromosome 1 of the A genome were purified from Triticum aestivum L. (2n=6 x=42, AABBDD) cv. Butte86, nullisomic 1D-tetrasomic 1A of cv. Chinese Spring (CS N1DT1A), and the diploid T. urartu (2n=2 x=14, AA ). Reverse-phase high-performance liquid chromatography combined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis of gliadin extracts from CS nullisomic-tetrasomic (NT) lines confirmed the assignment to chromosome 1A. The purified omega-gliadins were characterized by mass spectrometry and N-terminal sequencing. The 1A-encoded omega-gliadins were smaller than 1B- or 1D-encoded omega-gliadins. The N-terminal amino acid sequences for 1A omega-gliadin mature peptides were nearly identical to those for the T. urartu omega-gliadins and were more similar to 1D omega-gliadin sequences than to sequences for T. monococum omega-gliadins, barley C-hordeins, or rye omega-secalins. They diverged greatly from the N-terminal sequences for the 1B omega-gliadins. The data suggest that T. urartu is the A-genome donor, and that post-translational cleavage by an asparaginyl endoprotease produces those omega-gliadins with N-terminal sequences beginning with KEL.

  13. A spider population in flux: selection and abandonment of artificial web-sites and the importance of intraspecific interactions in Lephthyphantes tenuis (Araneae: Linyphiidae) in wheat.

    PubMed

    Samu, Ferenc; Sunderland, Keith D; Topping, Chris J; Fenlon, John S

    1996-04-01

    Lepthyphantes tenuis, a small sheet-webbuilding linyphiid spider is one of the most abundant spider species of cereal fields in Europe. In the present study we examined the process of web-site selection and web-site tenacity by adult females of this species in a winter wheat field. Spiders were selective in their choice of web-site. Different immigration rates into various manipulated web-sites, in field and laboratory, suggested that structural support and suitable micro-climate (high humidity) are the most important factors in the selection. Small holes dug in the ground were the most favoured web-sites. Web-site occupation was influenced by the presence of other conspecific spiders. Territorial contests occurred between spiders attempting to occupy the same web, these almost invariably led to the take-over of the web when the intruder was heavier. Interference, but also a certain level of tolerance, between spiders within the same web-site but in different webs was suggested by direct and indirect evidence. Many holes supported two or even three spiders in vertically stratified webs. Leaving probability of marked spiders was significantly higher in multiply occupied holes than in holes with a single web. Comparison with the results of a no-interference stochastic model showed that multiple occupancy in nature is less frequent than predicted by the model. There was further evidence for weak extra-web-interference between spiders in that multiple occupancy was even less frequent and overall occupancy was lower in web-sites which were packed close to each other. However, a level of tolerance for crowding is shown by the fact that closely packed hole colonies supported a spider density 13 times higher than in natural web-sites in the field. A marking experiment was carried out to gain information on web-site tenacity (i.e. the length of time a spider spends in a web-site) and abandonment. The average duration of tenacity was less than 2 days. A random loss function

  14. A novel wheat bZIP transcription factor, TabZIP60, confers multiple abiotic stress tolerances in transgenic Arabidopsis.

    PubMed

    Zhang, Lina; Zhang, Lichao; Xia, Chuan; Zhao, Guangyao; Liu, Ji; Jia, Jizeng; Kong, Xiuying

    2015-04-01

    The basic region/leucine zipper (bZIP) transcription factors (TFs) play vital roles in the response to abiotic stress. However, little is known about the function of bZIP genes in wheat abiotic stress. In this study, we report the isolation and functional characterization of the TabZIP60 gene. Three homologous genome sequences of TabZIP60 were isolated from hexaploid wheat and mapped to the wheat homoeologous group 6. A subcellular localization analysis indicated that TabZIP60 is a nuclear-localized protein that activates transcription. Furthermore, TabZIP60 gene transcripts were strongly induced by polyethylene glycol, salt, cold and exogenous abscisic acid (ABA) treatments. Further analysis showed that the overexpression of TabZIP60 in Arabidopsis resulted in significantly improved tolerances to drought, salt, freezing stresses and increased plant sensitivity to ABA in seedling growth. Meanwhile, the TabZIP60 was capable of binding ABA-responsive cis-elements that are present in promoters of many known ABA-responsive genes. A subsequent analysis showed that the overexpression of TabZIP60 led to enhanced expression levels of some stress-responsive genes and changes in several physiological parameters. Taken together, these results suggest that TabZIP60 enhances multiple abiotic stresses through the ABA signaling pathway and that modifications of its expression may improve multiple stress tolerances in crop plants.

  15. Dynamics of tandem repetitive Afa-family sequences in Triticeae, wheat-related species.

    PubMed

    Nagaki, K; Tsujimoto, H; Sasakuma, T

    1998-08-01

    The Afa-family sequences in wheat-related species, Triticeae, are tandem repetitive sequences of 340 bp. All the analyzed Triticeae species carried the sequences in their genomes, though the copy numbers varied about 100-fold among the species. The nucleotide fragments amplified by PCR were cloned and sequenced, and their behavior in the evolution of Triticeae was analyzed by the neighbor-joining (NJ) method. The sequences in genomes with many copies of this family clustered at independent branches of the phylogenic tree, whereas the sequences in genomes with a few copies did not. This may suggest that Afa-family sequences had amplified several times in the evolution of Triticeae, each using a limited number of different master copies. In addition, the sequences of the A and B genomes of hexaploid common wheat indicated that the Afa-family sequences had not evolved in a concerted manner between the genomes. Furthermore, the sequences of each chromosome of the D genome of this species indicated that the sequences had amplified on all over the D-genome chromosomes in a short period.

  16. Metabolite Profiling of a Diverse Collection of Wheat Lines Using Ultraperformance Liquid Chromatography Coupled with Time-of-Flight Mass Spectrometry

    PubMed Central

    Wolfe, Pamela; Byrne, Patrick F.; Thompson, Henry J.

    2012-01-01

    Genetic differences among major types of wheat are well characterized; however, little is known about how these distinctions affect the small molecule profile of the wheat seed. Ethanol/water (65% v/v) extracts of seed from 45 wheat lines representing 3 genetically distinct classes, tetraploid durum (Triticum turgidum subspecies durum) (DW) and hexaploid hard and soft bread wheat (T. aestivum subspecies aestivum) (BW) were subjected to ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS). Discriminant analyses distinguished DW from BW with 100% accuracy due to differences in expression of nonpolar and polar ions, with differences attributed to sterol lipids/fatty acids and phospholipids/glycerolipids, respectively. Hard versus soft BW was distinguished with 100% accuracy by polar ions, with differences attributed to heterocyclic amines and polyketides versus phospholipid ions, respectively. This work provides a foundation for identification of metabolite profiles associated with desirable agronomic and human health traits and for assessing how environmental factors impact these characteristics. PMID:22957002

  17. The Wheat GT Factor TaGT2L1D Negatively Regulates Drought Tolerance and Plant Development

    PubMed Central

    Zheng, Xin; Liu, Haipei; Ji, Hongtao; Wang, Youning; Dong, Baodi; Qiao, Yunzhou; Liu, Mengyu; Li, Xia

    2016-01-01

    GT factors are trihelix transcription factors that specifically regulate plant development and stress responses. Recently, several GT factors have been characterized in different plant species; however, little is known about the role of GT factors in wheat. Here, we show that TaGT2L1A, TaGT2L1B, and TaGT2L1D are highly homologous in hexaploid wheat, and are localized to wheat chromosomes 2A, 2B, and 2D, respectively. These TaGT2L1 genes encode proteins containing two SANT domains and one central helix. All three homologs were ubiquitously expressed during wheat development and were responsive to osmotic stress. Functional analyses demonstrated that TaGT2L1D acts as a transcriptional repressor; it was able to suppress the expression of AtSDD1 in Arabidopsis by binding directly to the GT3 box in its promoter that negatively regulates drought tolerance. TaGT2L1D overexpression markedly increased the number of stomata and reduced drought tolerance in gtl1-3 plants. Notably, ectopic expression of TaGT2L1D also affected floral organ development and overall plant growth. These results demonstrate that TaGT2L1 is an ortholog of AtGTL1, and that it plays an evolutionarily conserved role in drought resistance by fine tuning stomatal density in wheat. Our data also highlight the role of TaGT2L1 in plant growth and development. PMID:27245096

  18. Argentina wheat yield model

    NASA Technical Reports Server (NTRS)

    Callis, S. L.; Sakamoto, C.

    1984-01-01

    Five models based on multiple regression were developed to estimate wheat yields for the five wheat growing provinces of Argentina. Meteorological data sets were obtained for each province by averaging data for stations within each province. Predictor variables for the models were derived from monthly total precipitation, average monthly mean temperature, and average monthly maximum temperature. Buenos Aires was the only province for which a trend variable was included because of increasing trend in yield due to technology from 1950 to 1963.

  19. 21 CFR 184.1322 - Wheat gluten.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Wheat gluten. 184.1322 Section 184.1322 Food and....1322 Wheat gluten. (a) Wheat gluten (CAS Reg. No. 8002-80-0) is the principal protein component of wheat and consists mainly of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour...

  20. Wheat for Kids! [and] Teacher's Guide.

    ERIC Educational Resources Information Center

    Idaho Wheat Commission, Boise.

    "Wheat for Kids" contains information at the elementary school level about: the structure of the wheat kernel; varieties of wheat and their uses; growing wheat; making wheat dough; the U.S. Department of Agriculture Food Guide Pyramid and nutrition; Idaho's part of the international wheat market; recipes; and word games based on the…

  1. A high-density, SNP-based consensus map of tetraploid wheat as a bridge to integrate durum and bread wheat genomics and breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consensus linkage maps are important tools in crop genomics. We have assembled a high-density tetraploid wheat consensus map by integrating 13 datasets from independent biparental populations involving durum wheat cultivars (Triticum turgidum ssp. durum), cultivated emmer (T. turgidum ssp. dicoccum...

  2. Wheat streak mosaic virus resistance in eight wheat germplasm lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat Streak Mosaic Virus (WSMV) disease is an important disease in wheat. Use of resistant cultivars is the most effective approach to reduce the yield losses caused by the disease. To identify new sources of resistance to WSMV, eight resistant wheat lines that were selected based on the results fr...

  3. New Uses for Wheat and Modified Wheat Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hard wheat from the Great Plains historically has been used as a source of flour for the production of leavened bakery products. However, potentially applications of wheat in both new markets and new products has necessitated the need to develop wheats with novel processing attributes. The most lo...

  4. Wheat Quality Council, Hard Spring Wheat Technical Committee, 2014 Crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eleven experimental lines of hard spring wheat were grown at up to five locations in 2014 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Wheat samples were submitted through the Wheat Quality Council and processed and milled at the USDA-ARS Hard Red Spr...

  5. Distribution and diversity of Russian wheat aphid (Hemiptera: Aphididae) biotypes in South Africa and Lesotho.

    PubMed

    Jankielsohn, Astrid

    2011-10-01

    Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) was recorded for the first time in South Africa in 1978. In 2005, a second biotype, RWASA2, emerged, and here we report on the emergence of yet another biotype, found for the first time in 2009. The discovery of new Russian wheat aphid biotypes is a significant challenge to the wheat, Triticum aestivum L., industry in South Africa. Russian wheat aphid resistance in wheat, that offered wheat producers a long-term solution to Russian wheat aphid control, may no longer be effective in areas where the new biotypes occur. It is therefore critical to determine the diversity and extent of distribution of biotypes in South Africa to successfully deploy Russian wheat aphid resistance in wheat. Screening of 96 Russian wheat aphid clones resulted in identification of three Russian wheat aphid biotypes. Infestations of RWASA1 caused susceptible damage symptoms only in wheat entries containing the Dn3 gene. Infestations of RWASA2 caused susceptible damage symptoms in wheat entries containing Dn1, Dn2, Dn3, and Dn9 resistant genes. Based on the damage-rating scores for the seven resistance sources, a new biotype, which caused damage rating scores different from those for RWASA1 and RWASA2, was evident among the Russian wheat aphid populations tested. This new biotype is virulent to the same resistance sources as RWASA2 (Dn1, Dn2, Dn3, and Dn9), but it also has added virulence to Dn4, whereas RWASA2 is avirulent to this resistance source.

  6. Short, natural, and extended photoperiod response in BC2F4 lines of bread wheat with different photoperiod-1 (Ppd-1) alleles.

    PubMed

    Bentley, A R; Horsnell, R; Werner, C P; Turner, A S; Rose, G A; Bedard, C; Howell, P; Wilhelm, E P; Mackay, I J; Howells, R M; Greenland, A; Laurie, D A; Gosman, N

    2013-04-01

    Flowering is a critical period in the life cycle of flowering plant species, resulting in an irreversible commitment of significant resources. Wheat is photoperiod sensitive, flowering only when daylength surpasses a critical length; however, photoperiod insensitivity (PI) has been selected by plant breeders for >40 years to enhance yield in certain environments. Control of flowering time has been greatly facilitated by the development of molecular markers for the Photoperiod-1 (Ppd-1) homeoloci, on the group 2 chromosomes. In the current study, an allelic series of BC2F4 lines in the winter wheat cultivars 'Robigus' and 'Alchemy' was developed to elucidate the influence on flowering of eight gene variants from the B- and D-genomes of bread wheat and the A-genome of durum wheat. Allele effects were tested in short, natural, and extended photoperiods in the field and controlled environments. Across genetic background and treatment, the D-genome PI allele, Ppd-D1a, had a more potent effect on reducing flowering time than Ppd-B1a. However, there was significant donor allele effect for both Ppd-D1a and Ppd-B1a, suggesting the presence of linked modifier genes and/or additional sources of latent sensitivity. Development of Ppd-A1a BC2F4 lines derived from synthetic hexaploid wheat provided an opportunity to compare directly the flowering time effect of the A-genome allele from durum with the B- and D-genome variants from bread wheat for the first time. Analyses indicated that the reducing effect of Ppd-A1a is comparable with that of Ppd-D1a, confirming it as a useful alternative source of PI.

  7. Wheat-based foods and non celiac gluten/wheat sensitivity: Is drastic processing the main key issue?

    PubMed

    Fardet, Anthony

    2015-12-01

    While gluten and wheat must be absolutely avoided in coeliac disease and allergy, respectively, nutritional recommendations are largely more confused about non-coeliac wheat/gluten sensitivity (NCWGS). Today, some even recommend avoiding all cereal-based foods. In this paper, the increased NCWGS prevalence is hypothesized to parallel the use of more and more drastic processes applied to the original wheat grain. First, a parallel between gluten-related disorders and wheat processing and consumption evolution is briefly proposed. Notably, increased use of exogenous vital gluten is considered. Drastic processing in wheat technology are mainly grain fractionation and refining followed by recombination and salt, sugars and fats addition, being able to render ultra-processed cereal-based foods more prone to trigger chronic low-grade inflammation. Concerning bread, intensive kneading and the choice of wheat varieties with high baking quality may have rendered gluten less digestible, moving digestion from pancreatic to intestinal proteases. The hypothesis of a gluten resistant fraction reaching colon and interacting with microflora is also considered in relation with increased inflammation. Besides, wheat flour refining removes fiber co-passenger which have potential anti-inflammatory property able to protect digestive epithelium. Finally, some research tracks are proposed, notably the comparison of NCWGS prevalence in populations consuming ultra-versus minimally-processed cereal-based foods.

  8. Evaluation of broiler performance when fed Roundup-Ready wheat (event MON 71800), control, and commercial wheat varieties.

    PubMed

    Kan, C A; Hartnell, G F

    2004-08-01

    We evaluated the nutritional value of broiler diets containing approximately 40% wheat grain from Roundup Ready wheat (MON 71800), its similar nontransgenic control (MON 71900), or reference commercial wheat varieties. The feeding trial lasted 40 d, and each treatment consisted of 10 replicates of 1-d-old Ross 308 broilers (5 pens of males and 5 pens of females). Each pen contained 12 birds, and at d 13 birds were randomly removed until 9 birds remained. Body weight and feed intake were measured on pen basis at 40 d. At d 41, four broilers per pen were slaughtered. The carcasses were dissected, and cut-up yields were determined. Dry matter, protein, and fat contents of breast meat were determined. The data were analyzed by an ANOVA procedure. The BW and feed conversion at d 40 averaged 2,450 g and 1.52, respectively. There were no significant treatment x sex interactions, except for evisceration yield with significant differences (P < 0.05) in yield between birds fed 2 commercial wheat varieties. Data for final BW, feed conversion, carcass yield, and breast meat were not statistically different (P < 0.05) between broilers fed MON 71800 or MON 71900 or the population of birds fed commercial wheat varieties, except a lower carcass yield at d 41 for birds fed the nontransgenic control wheat. Thus MON 71800 was nutritionally equivalent to nongenetically modified wheat varieties when fed to broilers.

  9. Pollination biology of the hexaploid self-compatible species Turnera velutina (Passifloraceae).

    PubMed

    Sosenski, P; Ramos, S E; Domínguez, C A; Boege, K; Fornoni, J

    2017-03-01

    The evolution of monomorphisms from heterostylous ancestors has been related to the presence of homostyly and the loss of self-incompatibility, allowing the occurrence of selfing, which could be advantageous under pollinator limitation. However, flowers of some monomorphic species show herkogamy, attraction and rewarding traits that presumably favour cross-pollination and/or a mixed mating system. This study evaluated the contributions of pollinators, breeding system and floral traits to the reproduction of Turnera velutina, a herkogamous monomorphic species. Floral visitors and frequency of visits were recorded, controlled hand cross-pollinations were conducted under greenhouse and natural conditions, and individual variation in floral traits was characterised to determine their contribution to seed production. Apis mellifera was the most frequent floral visitor. Flowers presented approach herkogamy, high variation in nectar features, and a positive correlation of floral length with nectar volume and sugar concentration. Seed production did not differ between manual self- and cross-pollinations, controls or open cross-pollinations, but autonomous self-pollination produced, on average, 82.74% fewer seeds than the other forms, irrespective of the level of herkogamy. Differences in seed production among autonomous self-pollination and other treatments showed that T. velutina flowers depend on insect pollination for reproduction, and that approach herkogamy drastically reduced seed production in the absence of pollen vectors. The lack of differences in seed production from manual cross- and self-pollinations suggests the possible presence of a mixed mating system in the studied population. Overall, this species was possibly derived from a distylous ancestor but appears fully capable of outcrossing despite being monomorphic.

  10. Thermoformed wheat gluten biopolymers.

    PubMed

    Pallos, Ferenc M; Robertson, George H; Pavlath, Attila E; Orts, William J

    2006-01-25

    The quantity of available wheat gluten exceeds the current food use markets. Thermoforming is an alternative technical means for transforming wheat gluten. Thermoforming was applied here to wheat gluten under chemically reductive conditions to form pliable, translucent sheets. A wide variety of conditions, i.e., temperature, reducing agents, plasticizers and additives were tested to obtain a range of elastic properties in the thermoformed sheets. These properties were compared to those of commercially available polymers, such as polypropylene. Elasticity of the gluten formulations were indexed by Young's modulus and were in the range measured for commercial products when tested in the 30-70% relative humidity range. Removal of the gliadin subfraction of gluten yielded polymers with higher Young's modulus since this component acts as a polymer-chain terminator. At relative humidity less than 30% all whole gluten-based sheets were brittle, while above 70% they were highly elastic.

  11. Chromosome arm-specific BAC end sequences permit comparative analysis of homoeologous chromosomes and genomes of polyploid wheat

    PubMed Central

    2012-01-01

    Background Bread wheat, one of the world’s staple food crops, has the largest, highly repetitive and polyploid genome among the cereal crops. The wheat genome holds the key to crop genetic improvement against challenges such as climate change, environmental degradation, and water scarcity. To unravel the complex wheat genome, the International Wheat Genome Sequencing Consortium (IWGSC) is pursuing a chromosome- and chromosome arm-based approach to physical mapping and sequencing. Here we report on the use of a BAC library made from flow-sorted telosomic chromosome 3A short arm (t3AS) for marker development and analysis of sequence composition and comparative evolution of homoeologous genomes of hexaploid wheat. Results The end-sequencing of 9,984 random BACs from a chromosome arm 3AS-specific library (TaaCsp3AShA) generated 11,014,359 bp of high quality sequence from 17,591 BAC-ends with an average length of 626 bp. The sequence represents 3.2% of t3AS with an average DNA sequence read every 19 kb. Overall, 79% of the sequence consisted of repetitive elements, 1.38% as coding regions (estimated 2,850 genes) and another 19% of unknown origin. Comparative sequence analysis suggested that 70-77% of the genes present in both 3A and 3B were syntenic with model species. Among the transposable elements, gypsy/sabrina (12.4%) was the most abundant repeat and was significantly more frequent in 3A compared to homoeologous chromosome 3B. Twenty novel repetitive sequences were also identified using de novo repeat identification. BESs were screened to identify simple sequence repeats (SSR) and transposable element junctions. A total of 1,057 SSRs were identified with a density of one per 10.4 kb, and 7,928 junctions between transposable elements (TE) and other sequences were identified with a density of one per 1.39 kb. With the objective of enhancing the marker density of chromosome 3AS, oligonucleotide primers were successfully designed from 758 SSRs and 695

  12. Virulence characterization of international collections of the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat stripe rust (yellow rust, Yr), caused by Puccinia striiformis f. sp. tritici (Pst), is an economically important disease of wheat worldwide. Virulence information of Pst populations is important to implement effective disease control with resistant cultivars. A total of 235 Pst isolates from...

  13. Resistance to Ug99 stem rust in six bread wheat cultivars maps to chromosome 6DS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 80% of wheat area worldwide is currently grown to varieties that are susceptible to the Ug99 race group of the stem rust fungus. Wheat lines Niini, Tinkio, Coni, Pfunye, Blouk and Ripper were resistant to Ug99 at the seedling and adult plant stages. We mapped stem rust resistance in populations...

  14. Biolistics Transformation of Wheat

    NASA Astrophysics Data System (ADS)

    Sparks, Caroline A.; Jones, Huw D.

    We present a complete, step-by-step guide to the production of transformed wheat plants using a particle bombardment device to deliver plasmid DNA into immature embryos and the regeneration of transgenic plants via somatic embryogenesis. Currently, this is the most commonly used method for transforming wheat and it offers some advantages. However, it will be interesting to see whether this position is challenged as facile methods are developed for delivering DNA by Agrobacterium tumefaciens or by the production of transformants via a germ-line process (see other chapters in this book).

  15. Molecular and Morpho-Agronomical Characterization of Root Architecture at Seedling and Reproductive Stages for Drought Tolerance in Wheat

    PubMed Central

    Vinod; Naik, Bhojaraja K.; Chand, Suresh; Deshmukh, Rupesh; Mallick, Niharika; Singh, Sanjay; Singh, Nagendra Kumar; Tomar, S. M. S.

    2016-01-01

    Water availability is a major limiting factor for wheat (Triticum aestivum L.) production in rain-fed agricultural systems worldwide. Root architecture is important for water and nutrition acquisition for all crops, including wheat. A set of 158 diverse wheat genotypes of Australian (72) and Indian (86) origin were studied for morpho-agronomical traits in field under irrigated and drought stress conditions during 2010–11 and 2011-12.Out of these 31 Indian wheat genotypes comprising 28 hexaploid (Triticum aestivum L.) and 3 tetraploid (T. durum) were characterized for root traits at reproductive stage in polyvinyl chloride (PVC) pipes. Roots of drought tolerant genotypes grew upto137cm (C306) as compared to sensitive one of 63cm with a mean value of 94.8cm. Root architecture traits of four drought tolerant (C306, HW2004, HD2888 and NI5439) and drought sensitive (HD2877, HD2012, HD2851 and MACS2496) genotypes were also observed at 6 and 9 days old seedling stage. The genotypes did not show any significant variation for root traits except for longer coleoptiles and shoot and higher absorptive surface area in drought tolerant genotypes. The visible evaluation of root images using WinRhizo Tron root scanner of drought tolerant genotype HW2004 indicated compact root system with longer depth while drought sensitive genotype HD2877 exhibited higher horizontal root spread and less depth at reproductive stage. Thirty SSR markers were used to study genetic variation which ranged from 0.12 to 0.77 with an average value of 0.57. The genotypes were categorized into three subgroups as highly tolerant, sensitive, moderately sensitive and tolerant as intermediate group based on UPGMA cluster, STRUCTURE and principal coordinate analyses. The genotypic clustering was positively correlated to grouping based on root and morpho-agronomical traits. The genetic variability identified in current study demonstrated these traits can be used to improve drought tolerance and association

  16. Characterization of ω-secalin genes from rye, triticale, and a wheat 1BL/1RS translocation line.

    PubMed

    Jiang, Q-T; Wei, Y-M; Andre, L; Lu, Z-X; Pu, Z-E; Peng, Y-Y; Zheng, Y-L

    2010-01-01

    Sixty-two DNA sequences for the coding regions of omega-secalin (ω-secalin) genes have been characterized from rye (Secale cereale L.), hexaploid and octoploid triticale (× Triticosecale Wittmack), and wheat (Triticum aestivum L.) 1BL/1RS translocation line. Only 19 out of the 62 ω-secalin gene sequences were full-length open reading frames (ORFs), which can be expressed into functional proteins. The other 43 DNA sequences were pseudogenes, as their ORFs were interrupted by one or a few stop codons or frameshift mutations. The 19 ω-secalin genes have a typical primary structure, which is different from wheat gliadins. There was no cysteine residue in ω-secalin proteins, and the potential celiac disease (CD) toxic epitope (PQQP) was identified to appear frequently in the repetitive domains. The ω-secalin genes from various cereal species shared high homology in their gene sequences. The ω-secalin gene family has involved fewer variations after the integration of the rye R chromosome or whole genome into the wheat or triticale genome. The higher Ka/Ks ratio (i.e. non-synonymous to synonymous substitutions per site) in ω-secalin pseudogenes than in ω-secalin ORFs indicate that the pseudogenes may be subject to a reduced selection pressure. Based on the conserved sequences of ω-secalin genes, it will be possible to manipulate the expression of this gene family in rye, triticale, or wheat 1BL/1RS translocation lines, to reduce its negative effects on grain quality.

  17. Organic Wheat Farming Improves Grain Zinc Concentration.

    PubMed

    Helfenstein, Julian; Müller, Isabel; Grüter, Roman; Bhullar, Gurbir; Mandloi, Lokendra; Papritz, Andreas; Siegrist, Michael; Schulin, Rainer; Frossard, Emmanuel

    2016-01-01

    Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms.

  18. Organic Wheat Farming Improves Grain Zinc Concentration

    PubMed Central

    Helfenstein, Julian; Müller, Isabel; Grüter, Roman; Bhullar, Gurbir; Mandloi, Lokendra; Papritz, Andreas; Siegrist, Michael; Schulin, Rainer; Frossard, Emmanuel

    2016-01-01

    Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms. PMID:27537548

  19. 21 CFR 184.1322 - Wheat gluten.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Wheat gluten. 184.1322 Section 184.1322 Food and... Substances Affirmed as GRAS § 184.1322 Wheat gluten. (a) Wheat gluten (CAS Reg. No. 8002-80-0) is the principal protein component of wheat and consists mainly of gliadin and glutenin. Wheat gluten is...

  20. 21 CFR 184.1322 - Wheat gluten.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Wheat gluten. 184.1322 Section 184.1322 Food and... Substances Affirmed as GRAS § 184.1322 Wheat gluten. (a) Wheat gluten (CAS Reg. No. 8002-80-0) is the principal protein component of wheat and consists mainly of gliadin and glutenin. Wheat gluten is...

  1. 21 CFR 184.1322 - Wheat gluten.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Wheat gluten. 184.1322 Section 184.1322 Food and... Substances Affirmed as GRAS § 184.1322 Wheat gluten. (a) Wheat gluten (CAS Reg. No. 8002-80-0) is the principal protein component of wheat and consists mainly of gliadin and glutenin. Wheat gluten is...

  2. 21 CFR 184.1322 - Wheat gluten.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Wheat gluten. 184.1322 Section 184.1322 Food and... Substances Affirmed as GRAS § 184.1322 Wheat gluten. (a) Wheat gluten (CAS Reg. No. 8002-80-0) is the principal protein component of wheat and consists mainly of gliadin and glutenin. Wheat gluten is...

  3. 21 CFR 137.190 - Cracked wheat.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Cracked wheat. 137.190 Section 137.190 Food and... Related Products § 137.190 Cracked wheat. Cracked wheat is the food prepared by so cracking or cutting... such wheat, other than moisture, remain unaltered. Cracked wheat contains not more than 15 percent...

  4. 21 CFR 137.190 - Cracked wheat.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Cracked wheat. 137.190 Section 137.190 Food and... Related Products § 137.190 Cracked wheat. Cracked wheat is the food prepared by so cracking or cutting... such wheat, other than moisture, remain unaltered. Cracked wheat contains not more than 15 percent...

  5. Development of isohomoeoallelic lines within the wheat cv. Courtot for high molecular weight glutenin subunits: transfer of the Glu-D1 locus to chromosome 1A.

    PubMed

    Dumur, J; Branlard, G; Tanguy, A-M; Dardevet, M; Coriton, O; Huteau, V; Lemoine, J; Jahier, Joseph

    2009-08-01

    Wheat quality depends on protein composition and grain protein content. High molecular weight glutenin subunits (HMW-GS) play an important role in determining the viscoelastic properties of gluten. In an attempt to improve the bread-making quality of hexaploid wheat by elaborating novel HMW-GS combinations, a fragment of wheat chromosome 1D containing the Glu-D1 locus encoding the Dx2+Dy12 subunits was translocated to the long arm of chromosome 1A using the ph1b mutation. The partially isohomoeoallelic line selected was characterized using cytogenetical and molecular approaches to assess the amount of chromatin introgressed in the translocated 1A chromosome. Triple-target genomic in situ hybridization indicated that the translocated 1A chromosome had a terminal 1D segment representing 25% of the length of the recombinant long arm. The translocation was also identified on the long arm using molecular markers, and its length was estimated with a minimum of 91 cM. Proteome analysis was performed on total endosperm proteins. Out of the 152 major spots detected, 9 spots were up-regulated and 4 spots were down-regulated. Most of these proteins were identified as alpha-, beta-, gamma-gliadins assigned to the chromosomes of homoeologous groups 1 and 6. Quantitative variations in the HMW-GS were only observed in subunit Dy12 in response to duplication of the Glu-D1 locus.

  6. Registration of Colter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Colter’ (Reg. No. CV-1099, PI 670156) hard red winter wheat (Triticum aestivum L.) was developed and released by the Montana Agricultural Experiment Stations in September 2013. Colter was derived from the cross MT9982*2/BZ9W96-895. MT9982 is a sib selection of 'Yellowstone', and BZ9W96-895 is an unr...

  7. Registration of "Merl" Wheat.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Merl’ (Reg. No. CV- , PI 658598) soft red winter (SRW) wheat (Triticum aestivum L.)developed and tested as VA03W-412 by the Virginia Agricultural Experiment Station was released in March 2009. Merl was derived from the three-way cross ‘Roane’ / Pioneer Brand ‘2643’ // ‘38158’ (PI 619052). Merl is a...

  8. Registration of Camelot Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Camelot ' (PI 653832) hard red winter wheat (Triticum aestivum L.) was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in 2008. In addition to researchers at the releasing institutions, USDA-ARS researchers at Manhattan, KS, and St. Paul, MN, ...

  9. Wheat - Aegilops introgressions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aegilops is the most closely related genus to Triticum in the tribe Triticeae. Aegilops speltoides Tausch (B genome donor) and Ae. tauschii Coss. (D genome donor) contributed two of the three genomes present in common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD genomes). The Aegilops genus c...

  10. Registration of 'Otto' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistance to strawbreaker foot rot (caused by Oculimacula yallundae Crous & W. Gams and O. acuformis Crous & W. Gams) and to stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici Eriks.) are important traits for winter wheat cultivars produced in the Pacifi Northwest region of the Uni...

  11. Registration of 'Cowboy' wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Cowboy' (Reg. No. CV-1095, PI 668564) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released cooperatively by Colorado State University (CSU) and the University of Wyoming (UWYO) in August 2011. In addition to researchers at CSU and U...

  12. Registration of 'Tiger' wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Tiger’ hard white winter wheat (Triticum aestivum L.) was developed at Research Center-Hays, Kansas State University and released by Kansas Agricultural Experiment Station in 2010. Tiger was selected from a three-way cross KS98H245/’Trego’//KS98HW518 made in 1999 at Hays, KS. The objective of this ...

  13. Wheat allergy: diagnosis and management.

    PubMed

    Cianferoni, Antonella

    2016-01-01

    Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker's asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to

  14. Wheat allergy: diagnosis and management

    PubMed Central

    Cianferoni, Antonella

    2016-01-01

    Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to

  15. Genetic analysis of wheat domestication and evolution under domestication.

    PubMed

    Peleg, Zvi; Fahima, Tzion; Korol, Abraham B; Abbo, Shahal; Saranga, Yehoshua

    2011-10-01

    Wheat is undoubtedly one of the world's major food sources since the dawn of Near Eastern agriculture and up to the present day. Morphological, physiological, and genetic modifications involved in domestication and subsequent evolution under domestication were investigated in a tetraploid recombinant inbred line population, derived from a cross between durum wheat and its immediate progenitor wild emmer wheat. Experimental data were used to test previous assumptions regarding a protracted domestication process. The brittle rachis (Br) spike, thought to be a primary characteristic of domestication, was mapped to chromosome 2A as a single gene, suggesting, in light of previously reported Br loci (homoeologous group 3), a complex genetic model involved in spike brittleness. Twenty-seven quantitative trait loci (QTLs) conferring threshability and yield components (kernel size and number of kernels per spike) were mapped. The large number of QTLs detected in this and other studies suggests that following domestication, wheat evolutionary processes involved many genomic changes. The Br gene did not show either genetic (co-localization with QTLs) or phenotypic association with threshability or yield components, suggesting independence of the respective loci. It is argued here that changes in spike threshability and agronomic traits (e.g. yield and its components) are the outcome of plant evolution under domestication, rather than the result of a protracted domestication process. Revealing the genomic basis of wheat domestication and evolution under domestication, and clarifying their inter-relationships, will improve our understanding of wheat biology and contribute to further crop improvement.

  16. Haplotype Detection from Next-Generation Sequencing in High-Ploidy-Level Species: 45S rDNA Gene Copies in the Hexaploid Spartina maritima

    PubMed Central

    Boutte, Julien; Aliaga, Benoît; Lima, Oscar; Ferreira de Carvalho, Julie; Ainouche, Abdelkader; Macas, Jiri; Rousseau-Gueutin, Mathieu; Coriton, Olivier; Ainouche, Malika; Salmon, Armel

    2015-01-01

    Gene and whole-genome duplications are widespread in plant nuclear genomes, resulting in sequence heterogeneity. Identification of duplicated genes may be particularly challenging in highly redundant genomes, especially when there are no diploid parents as a reference. Here, we developed a pipeline to detect the different copies in the ribosomal RNA gene family in the hexaploid grass Spartina maritima from next-generation sequencing (Roche-454) reads. The heterogeneity of the different domains of the highly repeated 45S unit was explored by identifying single nucleotide polymorphisms (SNPs) and assembling reads based on shared polymorphisms. SNPs were validated using comparisons with Illumina sequence data sets and by cloning and Sanger (re)sequencing. Using this approach, 29 validated polymorphisms and 11 validated haplotypes were reported (out of 34 and 20, respectively, that were initially predicted by our program). The rDNA domains of S. maritima have similar lengths as those found in other Poaceae, apart from the 5′-ETS, which is approximately two-times longer in S. maritima. Sequence homogeneity was encountered in coding regions and both internal transcribed spacers (ITS), whereas high intragenomic variability was detected in the intergenic spacer (IGS) and the external transcribed spacer (ETS). Molecular cytogenetic analysis by fluorescent in situ hybridization (FISH) revealed the presence of one pair of 45S rDNA signals on the chromosomes of S. maritima instead of three expected pairs for a hexaploid genome, indicating loss of duplicated homeologous loci through the diploidization process. The procedure developed here may be used at any ploidy level and using different sequencing technologies. PMID:26530424

  17. Cancer mortality in four northern wheat-producing states.

    PubMed Central

    Schreinemachers, D M

    2000-01-01

    Chlorophenoxy herbicides are used both in cereal grain agriculture and in nonagricultural settings such as right-of-ways, lawns, and parks. Minnesota, North Dakota, South Dakota, and Montana grow most of the spring and durum wheat produced in the United States. More than 90% of spring and durum wheat is treated with chlorophenoxy herbicides, in contrast to treatment of approximately 30% of winter wheat. In this ecologic study I used wheat acreage as a surrogate for exposure to chlorophenoxy herbicides. I investigated the association of chlorophenoxy herbicides with cancer mortality during 1980-1989 for selected counties based on level of agriculture ([greater and equal to] 20%) and rural population ([greater and equal to] 50%). Age-standardized cancer mortality rates were determined for grouped counties based on tertiles of wheat acreage per county or for individual counties for frequently occurring cancers. The cancer sites that showed positive trends of increasing cancer mortality with increasing wheat acreage were esophagus, stomach, rectum, pancreas, larynx, prostate, kidney and ureter, brain, thyroid, bone, and all cancers (men) and oral cavity and tongue, esophagus, stomach, liver and gall bladder and bile ducts, pancreas, cervix, ovary, bladder, and other urinary organs, and all cancers (women). Rare cancers in men and women and cancers in boys and girls were studied by comparing counties above and below the median of wheat acreage per county. There was increased mortality for cancer of the nose and eye in both men and women, brain and leukemia in both boys and girls, and all cancers in boys. These results suggest an association between cancer mortality and wheat acreage in counties of these four states. PMID:11017893

  18. Gene flow between wheat and wild relatives: empirical evidence from Aegilops geniculata, Ae. neglecta and Ae. triuncialis

    PubMed Central

    Arrigo, Nils; Guadagnuolo, Roberto; Lappe, Sylvain; Pasche, Sophie; Parisod, Christian; Felber, François

    2011-01-01

    Gene flow between domesticated species and their wild relatives is receiving growing attention. This study addressed introgression between wheat and natural populations of its wild relatives (Aegilops species). The sampling included 472 individuals, collected from 32 Mediterranean populations of three widespread Aegilops species (Aegilops geniculata, Ae. neglecta and Ae. triuncialis) and compared wheat field borders to areas isolated from agriculture. Individuals were characterized with amplified fragment length polymorphism fingerprinting, analysed through two computational approaches (i.e. Bayesian estimations of admixture and fuzzy clustering), and sequences marking wheat-specific insertions of transposable elements. With this combined approach, we detected substantial gene flow between wheat and Aegilops species. Specifically, Ae. neglecta and Ae. triuncialis showed significantly more admixed individuals close to wheat fields than in locations isolated from agriculture. In contrast, little evidence of gene flow was found in Ae. geniculata. Our results indicated that reproductive barriers have been regularly bypassed during the long history of sympatry between wheat and Aegilops. PMID:25568015

  19. Tetraploid Wheat Landraces in the Mediterranean Basin: Taxonomy, Evolution and Genetic Diversity

    PubMed Central

    Oliveira, Hugo R.; Campana, Michael G.; Jones, Huw; Hunt, Harriet V.; Leigh, Fiona; Redhouse, David I.; Lister, Diane L.; Jones, Martin K.

    2012-01-01

    The geographic distribution of genetic diversity and the population structure of tetraploid wheat landraces in the Mediterranean basin has received relatively little attention. This is complicated by the lack of consensus concerning the taxonomy of tetraploid wheats and by unresolved questions regarding the domestication and spread of naked wheats. These knowledge gaps hinder crop diversity conservation efforts and plant breeding programmes. We investigated genetic diversity and population structure in tetraploid wheats (wild emmer, emmer, rivet and durum) using nuclear and chloroplast simple sequence repeats, functional variations and insertion site-based polymorphisms. Emmer and wild emmer constitute a genetically distinct population from durum and rivet, the latter seeming to share a common gene pool. Our population structure and genetic diversity data suggest a dynamic history of introduction and extinction of genotypes in the Mediterranean fields. PMID:22615891

  20. Wheat yield forecasts using LANDSAT data

    NASA Technical Reports Server (NTRS)

    Colwell, J. E.; Rice, D. P.; Nalepka, R. F.

    1977-01-01

    Several considerations of winter wheat yield prediction using LANDSAT data were discussed. In addition, a simple technique which permits direct early season forecasts of wheat production was described.

  1. Genomic prediction in CIMMYT maize and wheat breeding programs

    PubMed Central

    Crossa, J; Pérez, P; Hickey, J; Burgueño, J; Ornella, L; Cerón-Rojas, J; Zhang, X; Dreisigacker, S; Babu, R; Li, Y; Bonnett, D; Mathews, K

    2014-01-01

    Genomic selection (GS) has been implemented in animal and plant species, and is regarded as a useful tool for accelerating genetic gains. Varying levels of genomic prediction accuracy have been obtained in plants, depending on the prediction problem assessed and on several other factors, such as trait heritability, the relationship between the individuals to be predicted and those used to train the models for prediction, number of markers, sample size and genotype × environment interaction (GE). The main objective of this article is to describe the results of genomic prediction in International Maize and Wheat Improvement Center's (CIMMYT's) maize and wheat breeding programs, from the initial assessment of the predictive ability of different models using pedigree and marker information to the present, when methods for implementing GS in practical global maize and wheat breeding programs are being studied and investigated. Results show that pedigree (population structure) accounts for a sizeable proportion of the prediction accuracy when a global population is the prediction problem to be assessed. However, when the prediction uses unrelated populations to train the prediction equations, prediction accuracy becomes negligible. When genomic prediction includes modeling GE, an increase in prediction accuracy can be achieved by borrowing information from correlated environments. Several questions on how to incorporate GS into CIMMYT's maize and wheat programs remain unanswered and subject to further investigation, for example, prediction within and between related bi-parental crosses. Further research on the quantification of breeding value components for GS in plant breeding populations is required. PMID:23572121

  2. Pratylenchus thornei Associated with Reduced Wheat Yield in Oregon

    PubMed Central

    Smiley, Richard W.; Whittaker, Ruth G.; Gourlie, Jennifer A.; Easley, Sandra A.

    2005-01-01

    Pratylenchus thornei reaches high population densities in non-irrigated annual cropping systems in low-rainfall regions of the Pacific Northwest. Two spring wheat varieties with different levels of tolerance and susceptibility to P. thornei were treated or not treated with aldicarb in three experiments. Grain yield was inversely correlated (P < 0.05) with pre-plant populations of P. thornei in soil and with P. thornei density in mature roots. As population of P. thornei increased, yield of the moderately tolerant/moderately susceptible variety Krichauff was generally more stable than for the intolerant/susceptible variety Machete. The reproductive factor (Pf/Pi) was generally lower (P < 0.05) for Krichauff than Machete. Aldicarb improved wheat yield (P < 0.05) in highly infested fields by an average of 67% for Krichauff and 113% for Machete. Aldicarb increased (P < 0.05) numbers of headed tillers, plant height, and grain test weight and kernel weight, and reduced (P < 0.05) the density of P. thornei in mature wheat roots, variability in height of heads, and leaf canopy temperature. Aldicarb did not improve yield in a soil with a low population of P. thornei. This is the first report that P. thornei causes economic damage to wheat in the Pacific Northwest. PMID:19262842

  3. Effect of storage and insect infestation on the mineral and vitamin contents of wheat grain and flour.

    PubMed

    Keskin, S; Ozkaya, H

    2013-04-01

    The objective of this study was to evaluate how storage and Sitophilus granarius L. infestation affects mineral and vitamin (thiamin and riboflavin) contents of wheat grain and flour obtained from the wheat. Wheat samples were infested with nonsexed S. granarius at a rate of two adults per kilogram, and stored for 6 mo at 30 +/- 1 degrees C and 70 +/- 5% relative humidity. Every 30 d, samples of wheat were collected and evaluated for insect population, mineral, thiamin, and riboflavin contents. Flour milled from these wheat samples was also evaluated for mineral, thiamin, and riboflavin contents. None of the analyses performed on the uninfested wheat and flour samples showed any noticeable change during the storage period. The insect population of the infested wheat samples increased during the storage period. The ratio of the mineral contents to dry matter significantly increased in the infested wheat and flour samples during the infestation period, whereas thiamin and riboflavin contents considerably decreased. The feeding habits of S. granarius and the distribution of minerals and vitamins in the wheat grain caused the changes observed in the levels of these compounds. The effects of infestation were greatest in the latter stages, during which the insect population increased greatly.

  4. Trends in wheat-flour fortification with folic acid and iron--worldwide, 2004 and 2007.

    PubMed

    2008-01-11

    Consumption of adequate amounts of folic acid by women before pregnancy and during early pregnancy decreases their risk for having a pregnancy affected by neural tube defects (NTDs), the most common preventable type of birth defects worldwide. Consumption of iron ameliorates iron deficiency, the most prevalent nutritional deficiency in the world, affecting approximately 2 billion persons. Although certain populations consume substantial amounts of rice and corn, worldwide, the consumption of wheat flour is greater than that of any other cereal grain. Fortification of wheat flour is an effective, simple, and inexpensive strategy for supplying folic acid, iron, and other vitamins and minerals to large segments of the world population. To assess the global change from 2004 to 2007 in 1) the percentage of wheat flour being fortified with folic acid and iron; 2) the total number of persons overall and women in particular with access to fortified wheat flour; and 3) the total number of newborns whose mothers had access to fortified wheat flour during pregnancy, CDC analyzed data from the Flour Fortification Initiative (FFI). This report summarizes the results of that assessment, which indicated that the worldwide percentage of wheat-flour fortification increased from 18% in 2004 to 27% in 2007. The estimated number of persons with access to fortified wheat flour increased by approximately 540 million, and the annual number of newborns whose mothers had access to fortified wheat flour during pregnancy increased by approximately 14 million. Nonetheless, approximately two thirds of the world population lacks access to fortified wheat flour. Programs should continue to expand coverage of wheat-flour fortification as a strategy to increase folic acid and iron consumption.

  5. Whole-Genome Mapping of Agronomic and Metabolic Traits to Identify Novel Quantitative Trait Loci in Bread Wheat Grown in a Water-Limited Environment1[W][OA

    PubMed Central

    Hill, Camilla B.; Taylor, Julian D.; Edwards, James; Mather, Diane; Bacic, Antony; Langridge, Peter; Roessner, Ute

    2013-01-01

    Drought is a major environmental constraint responsible for grain yield losses of bread wheat (Triticum aestivum) in many parts of the world. Progress in breeding to improve complex multigene traits, such as drought stress tolerance, has been limited by high sensitivity to environmental factors, low trait heritability, and the complexity and size of the hexaploid wheat genome. In order to obtain further insight into genetic factors that affect yield under drought, we measured the abundance of 205 metabolites in flag leaf tissue sampled from plants of 179 cv Excalibur/Kukri F1-derived doubled haploid lines of wheat grown in a field experiment that experienced terminal drought stress. Additionally, data on 29 agronomic traits that had been assessed in the same field experiment were used. A linear mixed model was used to partition and account for nongenetic and genetic sources of variation, and quantitative trait locus analysis was used to estimate the genomic positions and effects of individual quantitative trait loci. Comparison of the agronomic and metabolic trait variation uncovered novel correlations between some agronomic traits and the levels of certain primary metabolites, including metabolites with either positive or negative associations with plant maturity-related or grain yield-related traits. Our analyses demonstrate that specific regions of the wheat genome that affect agronomic traits also have distinct effects on specific combinations of metabolites. This approach proved valuable for identifying novel biomarkers for the performance of wheat under drought and could facilitate the identification of candidate genes involved in drought-related responses in bread wheat. PMID:23660834

  6. Registration of 'Bill Brown' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Bill Brown’ (Reg. No. CV-133, PI 653260) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2007 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorad...

  7. Registration of 'Bill Brown' wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Bill Brown’ (Reg. No. CV-133, PI 653260) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2007 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorad...

  8. Registration of 'Thunder CL' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Thunder CL' (Reg. No. CV- , PI XXXXXX) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2008 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State Uni...

  9. Registration of 'LCS Wizard' wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to develop widely adapted hard winter wheat (Triticum aestivum L.) varieties to meet the needs of mills, bakeries, and consumers in the eastern and Great Plains regions of the United States. ‘LCS Wizard’ (Reg. No. CV-1111, PI 669574), a hard red winter (HRW) wheat,...

  10. Registration of 'Rollag' spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) (caused primarily by Fusarium graminearum Schwabe) is a disease that annually threatens wheat (Triticum aestivum L.) grown in the northern plains of the United States. Resistance to this disease is a high priority trait in the University of Minnesota’s spring wheat breedi...

  11. Wheat landraces: A mini review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers developed and utilized diverse wheat landraces to meet the complexity of a multitude of spatio-temporal, agro-ecological systems and to provide reliable sustenance and a sustainable food source to local communities. The genetic structure of wheat landraces is an evolutionary approach to surv...

  12. Incidence of Wheat streak mosaic virus, Triticum mosaic virus, and Wheat mosaic virus in wheat curl mites recovered from maturing winter wheat spikes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat curl mites (WCM; Aceria tosichella) transmit Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and Wheat mosaic virus (WMoV) to wheat (Triticum aestivum L.) in the Great Plains region of the United States. These viruses can be detected in single, double, or triple combinations i...

  13. Allelic variation in developmental genes and effects on winter wheat heading date in the U.S. Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heading date in wheat (Triticum aestivum L.) and other small grain cereals is affected by the vernalization and photoperiod pathways. The reduced-height loci also have an effect on growth and development. Heading date was evaluated in a population of 299 hard winter wheat entries representative of t...

  14. Genome-wide genetic dissection of supernumerary spikelet and related traits in common wheat (Triticum aestivum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In wheat (Triticum aestivum L), exotic genotypes express a broad range of spike-related traits and could be used as a source of new genes to enrich the germplasm for wheat breeding programs. In the present study, a population of 163 recombinant inbred lines derived from a cross between an elite line...

  15. Quantifying Russian wheat aphid pest intensity across the Great Plains.

    PubMed

    Merrill, Scott C; Peairs, Frank B

    2012-12-01

    Wheat, the most important cereal crop in the Northern Hemisphere, is at-risk for an approximate 10% reduction in worldwide production because of animal pests. The potential economic impact of cereal crop pests has resulted in substantial research efforts into the understanding of pest agroecosystems and development of pest management strategy. Management strategy is informed frequently by models that describe the population dynamics of important crop pests and because of the economic impact of these pests, many models have been developed. Yet, limited effort has ensued to compare and contrast models for their strategic applicability and quality. One of the most damaging pests of wheat in North America is the Russian wheat aphid, Diuraphis noxia (Kurdjumov). Eighteen D. noxia population dynamic models were developed from the literature to describe pest intensity. The strongest models quantified the negative effects of fall and spring precipitation on aphid intensity, and the positive effects associated with alternate food source availability. Population dynamic models were transformed into spatially explicit models and combined to form a spatially explicit, model-averaged result. Our findings were used to delineate pest intensity on winter wheat across much of the Great Plains and will help improve D. noxia management strategy.

  16. Tracking wheat rust on a continental scale.

    PubMed

    Kolmer, James A

    2005-08-01

    The rusts of wheat are important fungal plant pathogens that can be disseminated thousands of kilometers across continents and oceans by wind. Rusts are obligate parasites that interact with resistance genes in wheat in a gene-for-gene manner. New races of rust develop by mutation and selection for virulence against rust resistance genes in wheat. In recent years, new races of wheat leaf rust, wheat stripe rust, and wheat stem rust have been introduced into wheat production areas in different continents. These introductions have complicated efforts to develop wheat cultivars with durable rust resistance and have reduced the number of effective rust-resistance genes that are available for use. The migration patterns of wheat rusts are characterized by identifying their virulence against important rust resistance genes in wheat and by the use of molecular markers.

  17. The expression of CBF genes at Fr-2 locus is associated with the level of frost tolerance in Bulgarian winter wheat cultivars.

    PubMed

    Todorovska, Elena Georgieva; Kolev, Stanislav; Christov, Nikolai Kirilov; Balint, Andras; Kocsy, Gabor; Vágújfalvi, Attila; Galiba, Gabor

    2014-05-04

    The regulation of the majority of cold-regulated genes in plants is mediated by CBF (C-repeat binding factors) transcription factor family. Natural differences in frost tolerance (FT) of wheat have been mapped to the Fr-2 (Frost Resistance-2) locus on chromosome group 5 and are associated with variation in threshold induction temperatures and/or transcript levels of CBF genes. This study used real-time reverse-transcription polymerase chain reaction (qRT-PCR) to compare the relative expression levels of four T. aestivum CBF genes (TaCBF15.2, TaCBFA19, TaCBFA2 and TaCBFD21) in crown tissue of two Bulgarian hexaploid winter wheat cultivars (Milena and Russalka) with distinct levels of low-temperature (LT) tolerance but same vernalization requirement, and the spring cultivar Chinese Spring. The transcription profiles of the selected TaCBF genes showed that they are induced by cold treatment at 2 °C. Analysis of transcript abundance revealed that the four TaCBF genes were expressed at higher levels in the frost tolerant Milena than in the susceptible Russalka. Largest differences (fivefold and fourfold) in expression levels between both winter cultivars were observed in two of the analysed genes, TaCBF15.2 and TaCBFA19, respectively. The higher steady-state expression levels of TaCBF genes before the onset of the LT treatment in Milena, combined with stronger induction by cold treatment, suggest that these molecular responses to LT are associated with superior FT development capacity. The results expand our understanding of the molecular mechanisms underlying LT acclimation in Bulgarian wheat and can be used for development of functional markers for improvement of FT wheat-breeding programmes.

  18. Plant-Parasitic Nematodes Associated with Reduced Wheat Yield in Oregon: Heterodera avenae.

    PubMed

    Smiley, Richard W; Whittaker, Ruth G; Gourlie, Jennifer A; Easley, Sandra A; Ingham, Russell E

    2005-09-01

    Heterodera avenae is widely distributed in the western United States, where most wheat is grown in non-irrigated winter wheat/summer fallow rotations in low rainfall regions. Economic and social pressures have motivated growers to pursue a transition from winter wheat/summer fallow rotation to no-till annual spring cereals. Annual cereals are also planted in some irrigated fields. The impact of H. avenae on spring wheat yield in the Pacific Northwest had been observed but not quantified. Spring wheat was planted with or without aldicarb to examine relationships between H. avenae and yield under dryland and irrigated conditions in moderately infested fields. Spring wheat yields were negatively correlated (P < 0.05) with initial populations of H. avenae. Aldicarb application improved spring wheat yield as much as 24%. The infective juvenile stage of H. avenae reached a peak density during mid-spring. Yield of irrigated annual winter wheat was also negatively correlated with initial density of H. avenae. Research priorities necessary to develop control strategies include a description of the pathotype, identification of sources for genetic resistance, and integrated practices designed to manage multiple yield-reducing pests.

  19. Plant-Parasitic Nematodes Associated with Reduced Wheat Yield in Oregon: Heterodera avenae.

    PubMed Central

    Smiley, Richard W.; Whittaker, Ruth G.; Gourlie, Jennifer A.; Easley, Sandra A.; Ingham, Russell E.

    2005-01-01

    Heterodera avenae is widely distributed in the western United States, where most wheat is grown in non-irrigated winter wheat/summer fallow rotations in low rainfall regions. Economic and social pressures have motivated growers to pursue a transition from winter wheat/summer fallow rotation to no-till annual spring cereals. Annual cereals are also planted in some irrigated fields. The impact of H. avenae on spring wheat yield in the Pacific Northwest had been observed but not quantified. Spring wheat was planted with or without aldicarb to examine relationships between H. avenae and yield under dryland and irrigated conditions in moderately infested fields. Spring wheat yields were negatively correlated (P < 0.05) with initial populations of H. avenae. Aldicarb application improved spring wheat yield as much as 24%. The infective juvenile stage of H. avenae reached a peak density during mid-spring. Yield of irrigated annual winter wheat was also negatively correlated with initial density of H. avenae. Research priorities necessary to develop control strategies include a description of the pathotype, identification of sources for genetic resistance, and integrated practices designed to manage multiple yield-reducing pests. PMID:19262877

  20. Drought Tolerance in Wheat

    PubMed Central

    Prodhan, Zakaria Hossain; Faruq, Golam

    2013-01-01

    Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress. PMID:24319376

  1. Comparison of the chromosomes of Triticum timopheevi with related wheats using the techniques of C-banding and in situ hybridization.

    PubMed

    Hutchinson, J; Miller, T E; Jahier, J; Shepherd, K W

    1982-03-01

    The chromosomes of the tetraploid wheats Triticum timopheevi (Genome AAGG) and T. araraticum (Genome AAGG) were C-banded at mitosis. The identity of the banded and unbanded chromosomes was then established by firstly making comparisons with the hexaploid species T. zhukovskyi which has the genome formula AAAAGG. Secondly, the meiotic pairing in F1 hybrids between T. timopheevi and diploid wheats was examined by means of C-banding. The results showed that the banded chromosomes belonged to the G genome, while the unbanded chromosomes belonged to the A genome. Only one of the two pairs of satellited chromosomes had strong heterochromatic bands. The relationship between the genomes of T. timopheevi and T. dicoccum (Genome AABB) was then assessed at meiosis in hybrids between these species, using the techniques of C-banding and in situ hybridisation of a cloned ribosomal RNA gene probe. It was concluded that there were differences both in the amount and distribution of heterochromatin and also translocation differences between the species.

  2. Using multi-spectral imagery to detect and map stress induced by Russian wheat aphid

    NASA Astrophysics Data System (ADS)

    Backoulou, Georges Ferdinand

    Scope and Method of Study. The rationale of this study was to assess the stress in wheat field induced by the Russian wheat aphid using multispectral imagery. The study was conducted to (a) determine the relationship between RWA and edaphic and topographic factors; (b) identify and quantify the spatial pattern of RWA infestation within wheat fields; (c) differentiate the stress induced by RWA from other stress causing factors. Data used for the analysis included RWA population density from the wheat field in, Texas, Colorado, Wyoming, and Nebraska, Digital Elevation Model from the Unites States Geological Survey (USGS), soil data from the Soil Survey Geographic database (SSURGO), and multispectral imagery acquired in the panhandle of Oklahoma. Findings and Conclusions. The study revealed that the population density of the Russian wheat aphid was related to topographic and edaphic factors. Slope and sand were predictor variables that were positively related to the density of RWA at the field level. The study has also demonstrated that stress induced by the RWA has a specific spatial pattern that can be distinguished from other stress causing factors using a combination of landscape metrics and topographic and edaphic characteristics of wheat fields. Further field-based studies using multispectral imagery and spatial pattern analysis are suggested. The suggestions require acquiring biweekly multispectral imagery and collecting RWA, topographic and edaphic data at the sampling points during the phonological growth development of wheat plants. This is an approach that may pretend to have great potential for site specific technique for the integrated pest management.

  3. Studies on the nutraceuticals composition of wheat derived oils wheat bran oil and wheat germ oil.

    PubMed

    Kumar, G Suresh; Krishna, A G Gopala

    2015-02-01

    Fat-soluble nutraceuticals of cereals are known for number of disease preventive activities. Hence wheat bran oil (WBO) and wheat germ oil (WGO) were extracted from wheat bran and germ which yielded 3.35 % and 7.35 % of oil, containing polyunsaturated fatty acids (PUFA) (64 %, 61.2 %) respectively. Both oils contained tocopherols and carotenoids, which were higher in wheat germ oil (273 mg/100 g, 12.23 mg/100 g) than wheat bran oil (190 mg/100 g, 2.21 mg/100 g). Steryl ferulates were also present in both the oils, but their content was eight-fold higher in WBO than in WGO. Three major steryl ferulates identified by HPLC were campesteryl ferulate and sitostenyl ferulate, campestanyl ferulate and β-sitosteryl ferulate as in γ-oryzanol and another ferulate, viz., sitostanyl ferulate. A strong IC50 value of 7.5 mg/mL and 21.6 mg/mL DPPH free radicals scavenging for wheat germ oil for wheat bran oil was observed. NMR ((13)C and (1)H) profile explored the evidence of distribution of antioxidant molecules in the unsaponifiable matter of wheat derived oil. Since oils rich in PUFA and minor components are required for the normal physiological activities, blending such oils with other edible oils of the diet in wheat growing countries like India may be useful to provide health benefits.

  4. Shortcomings in wheat yield predictions

    NASA Astrophysics Data System (ADS)

    Semenov, Mikhail A.; Mitchell, Rowan A. C.; Whitmore, Andrew P.; Hawkesford, Malcolm J.; Parry, Martin A. J.; Shewry, Peter R.

    2012-06-01

    Predictions of a 40-140% increase in wheat yield by 2050, reported in the UK Climate Change Risk Assessment, are based on a simplistic approach that ignores key factors affecting yields and hence are seriously misleading.

  5. An Efficient Approach for the Development of Locus Specific Primers in Bread Wheat (Triticum aestivum L.) and Its Application to Re-Sequencing of Genes Involved in Frost Tolerance.

    PubMed

    Babben, Steve; Perovic, Dragan; Koch, Michael; Ordon, Frank

    2015-01-01

    Recent declines in costs accelerated sequencing of many species with large genomes, including hexaploid wheat (Triticum aestivum L.). Although the draft sequence of bread wheat is known, it is still one of the major challenges to developlocus specific primers suitable to be used in marker assisted selection procedures, due to the high homology of the three genomes. In this study we describe an efficient approach for the development of locus specific primers comprising four steps, i.e. (i) identification of genomic and coding sequences (CDS) of candidate genes, (ii) intron- and exon-structure reconstruction, (iii) identification of wheat A, B and D sub-genome sequences and primer development based on sequence differences between the three sub-genomes, and (iv); testing of primers for functionality, correct size and localisation. This approach was applied to single, low and high copy genes involved in frost tolerance in wheat. In summary for 27 of these genes for which sequences were derived from Triticum aestivum, Triticum monococcum and Hordeum vulgare, a set of 119 primer pairs was developed and after testing on Nulli-tetrasomic (NT) lines, a set of 65 primer pairs (54.6%), corresponding to 19 candidate genes, turned out to be specific. Out of these a set of 35 fragments was selected for validation via Sanger's amplicon re-sequencing. All fragments, with the exception of one, could be assigned to the original reference sequence. The approach presented here showed a much higher specificity in primer development in comparison to techniques used so far in bread wheat and can be applied to other polyploid species with a known draft sequence.

  6. Genetic evidence for differential selection of grain and embryo weight during wheat evolution under domestication

    PubMed Central

    Golan, Guy; Oksenberg, Adi; Peleg, Zvi

    2015-01-01

    Wheat is one of the Neolithic founder crops domesticated ~10 500 years ago. Following the domestication episode, its evolution under domestication has resulted in various genetic modifications. Grain weight, embryo weight, and the interaction between those factors were examined among domesticated durum wheat and its direct progenitor, wild emmer wheat. Experimental data show that grain weight has increased over the course of wheat evolution without any parallel change in embryo weight, resulting in a significantly reduced (30%) embryo weight/grain weight ratio in domesticated wheat. The genetic factors associated with these modifications were further investigated using a population of recombinant inbred substitution lines that segregated for chromosome 2A. A cluster of loci affecting grain weight and shape was identified on the long arm of chromosome 2AL. Interestingly, a novel locus controlling embryo weight was mapped on chromosome 2AS, on which the wild emmer allele promotes heavier embryos and greater seedling vigour. To the best of our knowledge, this is the first report of a QTL for embryo weight in wheat. The results suggest a differential selection of grain and embryo weight during the evolution of domesticated wheat. It is argued that conscious selection by early farmers favouring larger grains and smaller embryos appears to have resulted in a significant change in endosperm weight/embryo weight ratio in the domesticated wheat. Exposing the genetic factors associated with endosperm and embryo size improves our understanding of the evolutionary dynamics of wheat under domestication and is likely to be useful for future wheat-breeding efforts. PMID:26019253

  7. Estimating climate change, CO2 and technology development effects on wheat yield in northeast Iran.

    PubMed

    Bannayan, M; Mansoori, H; Rezaei, E Eyshi

    2014-04-01

    Wheat is the main food for the majority of Iran's population. Precise estimation of wheat yield change in future is essential for any possible revision of management strategies. The main objective of this study was to evaluate the effects of climate change, CO2 concentration, technology development and their integrated effects on wheat production under future climate change. This study was performed under two scenarios of the IPCC Special Report on Emission Scenarios (SRES): regional economic (A2) and global environmental (B1). Crop production was projected for three future time periods (2020, 2050 and 2080) in comparison with a baseline year (2005) for Khorasan province located in the northeast of Iran. Four study locations in the study area included Mashhad, Birjand, Bojnourd and Sabzevar. The effect of technology development was calculated by fitting a regression equation between the observed wheat yields against historical years considering yield potential increase and yield gap reduction as technology development. Yield relative increase per unit change of CO2 concentration (1 ppm(-1)) was considered 0.05 % and was used to implement the effect of elevated CO2. The HadCM3 general circulation model along with the CSM-CERES-Wheat crop model were used to project climate change effects on wheat crop yield. Our results illustrate that, among all the factors considered, technology development provided the highest impact on wheat yield change. Highest wheat yield increase across all locations and time periods was obtained under the A2 scenario. Among study locations, Mashhad showed the highest change in wheat yield. Yield change compared to baseline ranged from -28 % to 56 % when the integration of all factors was considered across all locations. It seems that achieving higher yield of wheat in future may be expected in northeast Iran assuming stable improvements in production technology.

  8. Genetic evidence for differential selection of grain and embryo weight during wheat evolution under domestication.

    PubMed

    Golan, Guy; Oksenberg, Adi; Peleg, Zvi

    2015-09-01

    Wheat is one of the Neolithic founder crops domesticated ~10 500 years ago. Following the domestication episode, its evolution under domestication has resulted in various genetic modifications. Grain weight, embryo weight, and the interaction between those factors were examined among domesticated durum wheat and its direct progenitor, wild emmer wheat. Experimental data show that grain weight has increased over the course of wheat evolution without any parallel change in embryo weight, resulting in a significantly reduced (30%) embryo weight/grain weight ratio in domesticated wheat. The genetic factors associated with these modifications were further investigated using a population of recombinant inbred substitution lines that segregated for chromosome 2A. A cluster of loci affecting grain weight and shape was identified on the long arm of chromosome 2AL. Interestingly, a novel locus controlling embryo weight was mapped on chromosome 2AS, on which the wild emmer allele promotes heavier embryos and greater seedling vigour. To the best of our knowledge, this is the first report of a QTL for embryo weight in wheat. The results suggest a differential selection of grain and embryo weight during the evolution of domesticated wheat. It is argued that conscious selection by early farmers favouring larger grains and smaller embryos appears to have resulted in a significant change in endosperm weight/embryo weight ratio in the domesticated wheat. Exposing the genetic factors associated with endosperm and embryo size improves our understanding of the evolutionary dynamics of wheat under domestication and is likely to be useful for future wheat-breeding efforts.

  9. 19 CFR 19.32 - Wheat manipulation; reconditioning.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Wheat manipulation; reconditioning. 19.32 Section... Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing, blending, or commingling of imported wheat and domestic wheat, or of imported wheat of different classes and grades, as...

  10. 19 CFR 19.32 - Wheat manipulation; reconditioning.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Wheat manipulation; reconditioning. 19.32 Section... Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing, blending, or commingling of imported wheat and domestic wheat, or of imported wheat of different classes and grades, as...

  11. 19 CFR 19.32 - Wheat manipulation; reconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Wheat manipulation; reconditioning. 19.32 Section... Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing, blending, or commingling of imported wheat and domestic wheat, or of imported wheat of different classes and grades, as...

  12. 19 CFR 19.32 - Wheat manipulation; reconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Wheat manipulation; reconditioning. 19.32 Section... Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing, blending, or commingling of imported wheat and domestic wheat, or of imported wheat of different classes and grades, as...

  13. Dough Rheology and Wet Milling of Hard Waxy Wheat Flours

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To realize the full potential of waxy wheat (Triticum aestivum L.), wet milling of waxy wheat flour to produce gluten and waxy wheat starch was investigated. Flours of six advanced lines of waxy hard wheats, one normal hard wheat (‘Karl 92’), and one partial waxy wheat (‘Trego’) were fractionated by...

  14. A Genetic Framework for Grain Size and Shape Variation in Wheat[C][W

    PubMed Central

    Gegas, Vasilis C.; Nazari, Aida; Griffiths, Simon; Simmonds, James; Fish, Lesley; Orford, Simon; Sayers, Liz; Doonan, John H.; Snape, John W.

    2010-01-01

    Grain morphology in wheat (Triticum aestivum) has been selected and manipulated even in very early agrarian societies and remains a major breeding target. We undertook a large-scale quantitative analysis to determine the genetic basis of the phenotypic diversity in wheat grain morphology. A high-throughput method was used to capture grain size and shape variation in multiple mapping populations, elite varieties, and a broad collection of ancestral wheat species. This analysis reveals that grain size and shape are largely independent traits in both primitive wheat and in modern varieties. This phenotypic structure was retained across the mapping populations studied, suggesting that these traits are under the control of a limited number of discrete genetic components. We identified the underlying genes as quantitative trait loci that are distinct for grain size and shape and are largely shared between the different mapping populations. Moreover, our results show a significant reduction of phenotypic variation in grain shape in the modern germplasm pool compared with the ancestral wheat species, probably as a result of a relatively recent bottleneck. Therefore, this study provides the genetic underpinnings of an emerging phenotypic model where wheat domestication has transformed a long thin primitive grain to a wider and shorter modern grain. PMID:20363770

  15. Linkage disequilibrium and genome-wide association mapping in tetraploid wheat (Triticum turgidum L.).

    PubMed

    Laidò, Giovanni; Marone, Daniela; Russo, Maria A; Colecchia, Salvatore A; Mastrangelo, Anna M; De Vita, Pasquale; Papa, Roberto

    2014-01-01

    Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker-trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker-trait associations.

  16. Linkage Disequilibrium and Genome-Wide Association Mapping in Tetraploid Wheat (Triticum turgidum L.)

    PubMed Central

    Laidò, Giovanni; Marone, Daniela; Russo, Maria A.; Colecchia, Salvatore A.; Mastrangelo, Anna M.; De Vita, Pasquale; Papa, Roberto

    2014-01-01

    Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker–trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker–trait associations. PMID:24759998

  17. Cadmium minimization in wheat: A critical review.

    PubMed

    Rizwan, Muhammad; Ali, Shafaqat; Abbas, Tahir; Zia-Ur-Rehman, Muhammad; Hannan, Fakhir; Keller, Catherine; Al-Wabel, Mohammad I; Ok, Yong Sik

    2016-08-01

    Cadmium (Cd) accumulation in wheat (Triticum aestivum L.) and its subsequent transfer to food chain is a major environmental issue worldwide. Understanding wheat response to Cd stress and its management for aiming to reduce Cd uptake and accumulation in wheat may help to improve wheat growth and grain quality. This paper reviewed the toxic effects, tolerance mechanisms, and management of Cd stress in wheat. It was concluded that Cd decreased germination, growth, mineral nutrients, photosynthesis and grain yield of wheat and plant response to Cd toxicity varies with cultivars, growth conditions and duration of stress applied. Cadmium caused oxidative stress and genotoxicity in wheat plants. Stimulation of antioxidant defense system, osmoregulation, ion homeostasis and over production of signalling molecules are important adaptive strategies of wheat under Cd stress. Exogenous application of plant growth regulators, inorganic amendments, proper fertilization, silicon, and organic, manures and biochar, amendments are commonly used for the reduction of Cd uptake in wheat. Selection of low Cd-accumulating wheat cultivars, crop rotation, soil type, and exogenous application of microbes are among the other agronomic practices successfully employed in reducing Cd uptake by wheat. These management practices could enhance wheat tolerance to Cd stress and reduce the transfer of Cd to the food chain. However, their long-term sustainability in reducing Cd uptake by wheat needs further assessment.

  18. Distribution of Wheat Germ Agglutinin in Young Wheat Plants 12

    PubMed Central

    Mishkind, Michael; Keegstra, Kenneth; Palevitz, Barry A.

    1980-01-01

    A liquid phase, competition-binding radioimmunoassay for wheat germ agglutinin, with a detection limit of 10 nanograms, was developed in order to determine the distribution of this lectin in young wheat plants. Affinity columns for wheat germ agglutinin removed all antigenically detectable activity from crude extracts of wheat tissue; thus, the antigenic cross-reactivity detected by the assay possesses sugar-binding specificity similar to the wheat germ-derived lectin. The amount of lectin per dry grain is approximately 1 microgram, all associated with the embryo. At 34 days of growth, the level of lectin per plant was reduced by about 50%, with approximately one-third in the roots and two-thirds in the shoot. The data also indicate that actively growing regions of the plant (the bases of the leaves and rapidly growing adventitious roots) contain the highest levels of lectin. Half of the lectin associated with the roots could be solubilized by washing intact roots in buffer containing oligomers of N-acetylglucosamine, whereas the remainder is liberated only upon homogenization of the tissue. Images PMID:16661559

  19. Comparison of statistical models for analyzing wheat yield time series.

    PubMed

    Michel, Lucie; Makowski, David

    2013-01-01

    The world's population is predicted to exceed nine billion by 2050 and there is increasing concern about the capability of agriculture to feed such a large population. Foresight studies on food security are frequently based on crop yield trends estimated from yield time series provided by national and regional statistical agencies. Various types of statistical models have been proposed for the analysis of yield time series, but the predictive performances of these models have not yet been evaluated in detail. In this study, we present eight statistical models for analyzing yield time series and compare their ability to predict wheat yield at the national and regional scales, using data provided by the Food and Agriculture Organization of the United Nations and by the French Ministry of Agriculture. The Holt-Winters and dynamic linear models performed equally well, giving the most accurate predictions of wheat yield. However, dynamic linear models have two advantages over Holt-Winters models: they can be used to reconstruct past yield trends retrospectively and to analyze uncertainty. The results obtained with dynamic linear models indicated a stagnation of wheat yields in many countries, but the estimated rate of increase of wheat yield remained above 0.06 t ha⁻¹ year⁻¹ in several countries in Europe, Asia, Africa and America, and the estimated values were highly uncertain for several major wheat producing countries. The rate of yield increase differed considerably between French regions, suggesting that efforts to identify the main causes of yield stagnation should focus on a subnational scale.

  20. Comparison of Statistical Models for Analyzing Wheat Yield Time Series

    PubMed Central

    Michel, Lucie; Makowski, David

    2013-01-01

    The world's population is predicted to exceed nine billion by 2050 and there is increasing concern about the capability of agriculture to feed such a large population. Foresight studies on food security are frequently based on crop yield trends estimated from yield time series provided by national and regional statistical agencies. Various types of statistical models have been proposed for the analysis of yield time series, but the predictive performances of these models have not yet been evaluated in detail. In this study, we present eight statistical models for analyzing yield time series and compare their ability to predict wheat yield at the national and regional scales, using data provided by the Food and Agriculture Organization of the United Nations and by the French Ministry of Agriculture. The Holt-Winters and dynamic linear models performed equally well, giving the most accurate predictions of wheat yield. However, dynamic linear models have two advantages over Holt-Winters models: they can be used to reconstruct past yield trends retrospectively and to analyze uncertainty. The results obtained with dynamic linear models indicated a stagnation of wheat yields in many countries, but the estimated rate of increase of wheat yield remained above 0.06 t ha−1 year−1 in several countries in Europe, Asia, Africa and America, and the estimated values were highly uncertain for several major wheat producing countries. The rate of yield increase differed considerably between French regions, suggesting that efforts to identify the main causes of yield stagnation should focus on a subnational scale. PMID:24205280

  1. Shifts of microbial communities of wheat (Triticum aestivum L.) cultivation in a closed artificial ecosystem.

    PubMed

    Qin, Youcai; Fu, Yuming; Dong, Chen; Jia, Nannan; Liu, Hong

    2016-05-01

    The microbial communities of plant ecosystems are in relation to plant growing environment, but the alteration in biodiversity of rhizosphere and phyllosphere microbial communities in closed and controlled environments is unknown. The purpose of this study is to analyze the change regularity of microbial communities with wheat plants dependent-cultivated in a closed artificial ecosystem. The microbial community structures in closed-environment treatment plants were investigated by a culture-dependent approach, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), and Illumina Miseq high-throughput sequencing. The results indicated that the number of microbes decreased along with time, and the magnitude of bacteria, fungi, and actinomycetes were 10(7)-10(8), 10(5), and 10(3)-10(4) CFU/g (dry weight), respectively. The analysis of PCR-DGGE and Illumina Miseq revealed that the wheat leaf surface and near-root substrate had different microbial communities at different periods of wheat ecosystem development and showed that the relative highest diversity of microbial communities appeared at late and middle periods of the plant ecosystem, respectively. The results also indicated that the wheat leaf and substrate had different microbial community compositions, and the wheat substrate had higher richness of microbial community than the leaf. Flavobacterium, Pseudomonas, Paenibacillus, Enterobacter, Penicillium, Rhodotorula, Acremonium, and Alternaria were dominant in the wheat leaf samples, and Pedobacter, Flavobacterium, Halomonas, Marinobacter, Salinimicrobium, Lysobacter, Pseudomonas, Halobacillus, Xanthomonas, Acremonium, Monographella, and Penicillium were dominant populations in the wheat near-root substrate samples.

  2. Climate change induced rainfall patterns affect wheat productivity and agroecosystem functioning dependent on soil types

    NASA Astrophysics Data System (ADS)

    Tabi Tataw, James; Baier, Fabian; Krottenthaler, Florian; Pachler, Bernadette; Schwaiger, Elisabeth; Whylidal, Stefan; Formayer, Herbert; Hösch, Johannes; Baumgarten, Andreas; Zaller, Johann G.

    2014-05-01

    Wheat is a crop of global importance supplying more than half of the world's population with carbohydrates. We examined, whether climate change induced rainfall patterns towards less frequent but heavier events alter wheat agroecosystem productivity and functioning under three different soil types. Therefore, in a full-factorial experiment Triticum aestivum L. was cultivated in 3 m2 lysimeter plots containing the soil types sandy calcaric phaeozem, gleyic phaeozem or calcic chernozem. Prognosticated rainfall patterns based on regionalised climate change model calculations were compared with current long-term rainfall patterns; each treatment combination was replicated three times. Future rainfall patterns significantly reduced wheat growth and yield, reduced the leaf area index, accelerated crop development, reduced arbuscular mycorrhizal fungi colonisation of roots, increased weed density and the stable carbon isotope signature (δ13C) of both old and young wheat leaves. Different soil types affected wheat growth and yield, ecosystem root production as well as weed abundance and biomass. The interaction between climate and soil type was significant only for the harvest index. Our results suggest that even slight changes in rainfall patterns can significantly affect the functioning of wheat agroecosystems. These rainfall effects seemed to be little influenced by soil types suggesting more general impacts of climate change across different soil types. Wheat production under future conditions will likely become more challenging as further concurrent climate change factors become prevalent.

  3. Effect of Wheat Flour Packaging Materials on Infestation by Lasioderma serricorne (F.).

    PubMed

    Lü, Jianhua; Ma, Dan

    2015-05-01

    The ability of the cigarette beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), to infest wheat flour under packaged and unpackaged conditions was investigated in the laboratory at 27 ± 2°C and 75% ± 5% relative humidity. Five common packaging materials, namely, vacuum plastic bags, kraft paper bags, nonwoven cloth bags, aluminum foil bags, and woven plastic bags, were investigated. Adults and eggs of L. serricorne were released on different packaged wheat flour or on unpackaged wheat flour, and infestation levels (number of live adults and larvae) were determined after 45 days. When adults were released on wheat flour, the infestation degree varied depending on the package materials. The highest infestation was observed in refined wheat flour packaged in nonwoven cloth bags. With wheat flour packaged in kraft paper bags exposed to adults or eggs, there was no insect infestation or insect infestation was negligible (mean population, <1.3). With wheat flour packaged in aluminum foil bags and vacuum plastic bags exposed to adults or eggs, there was no insect infestation. Damage to the packaging materials along the folds or edges was found in nonwoven cloth bags and woven plastic bags. Therefore, both aluminum foil and plastic bags had the greatest resistance to package invasion by L. serricorne.

  4. Trichothecene genotypes of Fusarium graminearum from wheat in Uruguay.

    PubMed

    Pan, Dinorah; Calero, Natalia; Mionetto, Ana; Bettucci, Lina

    2013-03-01

    Gibberella zeae (Schwein.) Petch (anamorph F. graminearum Schwabe) is the primary causal agent of FHB of wheat in Uruguay. In the last decade, F. graminearum has produced destructive epidemics on wheat in Uruguay, causing yield losses and price discounts due to reduced seed quality. Strains of F. graminearum clade usually express one of three strain-specific profiles of trichothecene metabolites: nivalenol and its acetylated derivatives (NIV chemotype), deoxynivalenol and 3-acetyldeoxynivalenol (3-AcDON chemotype), or deoxynivalenol and 15-acetyldeoxynivalenol (15-AcDON chemotype). A multiplex PCR assay of Tri3, Tri5, and Tri7 was used to determine the trichothecene genotype of 111 strains of F. graminearum collected during 2003 and 2009 growing seasons from fields located in the major wheat production area of Uruguay. The result showed that all except one of the isolates were of DON genotype, with the remainder of NIV genotype in years 2003 and 2009. All strains with the DON genotype were also of the 15-AcDON genotype in 2003 and nearly all (45/50) in 2009. No DON/3-AcDON genotypes were found in either growing season. No potential shifts in the populations were found in the trichothecene genotypes between 2003 and the 2009 epidemic FHB harvest seasons. This study provides the first data on trichothecene genotypes of F. graminearum strains isolated from wheat in Uruguay and add to the current regional knowledge of trichothecene genotypes.

  5. Technological properties of bakers' yeasts in durum wheat semolina dough.

    PubMed

    Giannone, Virgilio; Longo, Chiara; Damigella, Arcangelo; Raspagliesi, Domenico; Spina, Alfio; Palumbo, Massimo

    2010-04-01

    Properties of 13 Saccharomyces cerevisiae strains isolated from different sources (traditional sourdoughs, industrial baking yeasts etc.) were studied in dough produced with durum wheat (Sicilian semolina, variety Mongibello). Durum wheat semolina and durum wheat flour are products prepared from grain of durum wheat (Triticum durum Desf.) by grinding or milling processes in which the bran and germ are essentially removed and the remainder is comminuted to a suitable degree of fineness. Acidification and leavening properties of the dough were evaluated. Strains isolated from traditional sourdoughs (DSM PST18864, DSM PST18865 and DSM PST18866) showed higher leavening power, valuable after the first and second hours of fermentation, than commercial baking yeasts. In particular the strain DSM PST 18865 has also been successfully tested in bakery companies for the improvement of production processes. Baking and staling tests were carried out on five yeast strains to evaluate their fermentation ability directly and their resistance to the staling process. Amplified fragment length polymorphism (fAFLP) was used to investigate genetic variations in the yeast strains. This study showed an appreciable biodiversity in the microbial populations of both wild and commercial yeast strains.

  6. Stress-induced changes in wheat grain composition and quality.

    PubMed

    Ashraf, M

    2014-01-01

    Abiotic stresses such as drought, salinity, waterlogging, and high temperature cause a myriad of changes in the metabolism of plants, and there is a lot of overlap in these changes in plants in response to different stresses such as drought and salinity. These stress-induced metabolic changes cause impaired crop growth thereby resulting in poor yield. The metabolic changes taking place in several plant species due to a particular abiotic stress have been revealed from the whole plant to the molecular level by researchers, but most studies have focused on organs such as leaf, stem, and root. Information on such stress-induced changes in seed or grains is infrequent in the literature. From the information that is available, it is now evident that abiotic stress can induce considerable changes in the composition and quality of cereal grains including those of wheat, the premier staple food crop in the world. Thus, the present review discusses how far different types of stresses, mainly salinity, drought, high temperature, and waterlogging, can alter the wheat grain composition and quality. By fully uncovering the stress-induced changes in the nutritional values of wheat grains it would be possible to establish whether balanced supplies of essential nutrients are available to the human population from the wheat crop grown on stress-affected areas.

  7. Growing Wheat. People on the Farm.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

    This booklet, one in a series about life on modern farms, describes the daily life of the Don Riffel family, wheat farmers in Kansas. Beginning with early morning, the booklet traces the family's activities through a typical harvesting day in July, while explaining how a wheat farm is run. The booklet also briefly describes the wheat growing…

  8. Hard Spring Wheat Technical Committee 2016 Crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven experimental lines of hard spring wheat were grown at up to five locations in 2016 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Wheat samples were submitted through the Wheat Quality Council and processed and milled at the USDA-ARS Hard Red Spri...

  9. Sequence diversity of wheat mosaic virus isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High Plains disease of wheat and maize emerged in the United States in 1993 and its distribution has expanded in subsequent years. Wheat mosaic virus (WMoV), transmitted by eriophyid wheat curl mites (Aceria tosichella) is the causal agent of disease. WMoV and other members of the genus Emaravirus...

  10. Registration of 'UI Stone' spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soft white spring wheat (Triticum aestivumL.) is an important wheat class being used in domestic and international markets, especially in Idaho and Pacific Northwest (PNW). The objective of this study was to develop a SWS wheat cultivar with high grain yield, desirable end-use quality, and resistanc...

  11. The value of wheat landraces (Editorial)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whether man was domesticated by wheat, or wheat was domesticated by man is but two faces of the same coin; both incidents marked a turning point in human history and led to the emergence of human civilization in the Fertile Crescent of the Old World. The complex history of wheat domestication from i...

  12. Characterization of polyploid wheat genomic diversity using a high-density 90,000 single nucleotide polymorphism array.

    PubMed

    Wang, Shichen; Wong, Debbie; Forrest, Kerrie; Allen, Alexandra; Chao, Shiaoman; Huang, Bevan E; Maccaferri, Marco; Salvi, Silvio; Milner, Sara G; Cattivelli, Luigi; Mastrangelo, Anna M; Whan, Alex; Stephen, Stuart; Barker, Gary; Wieseke, Ralf; Plieske, Joerg; Lillemo, Morten; Mather, Diane; Appels, Rudi; Dolferus, Rudy; Brown-Guedira, Gina; Korol, Abraham; Akhunova, Alina R; Feuillet, Catherine; Salse, Jerome; Morgante, Michele; Pozniak, Curtis; Luo, Ming-Cheng; Dvorak, Jan; Morell, Matthew; Dubcovsky, Jorge; Ganal, Martin; Tuberosa, Roberto; Lawley, Cindy; Mikoulitch, Ivan; Cavanagh, Colin; Edwards, Keith J; Hayden, Matthew; Akhunov, Eduard

    2014-08-01

    High-density single nucleotide polymorphism (SNP) genotyping arrays are a powerful tool for studying genomic patterns of diversity, inferring ancestral relationships between individuals in populations and studying marker-trait associations in mapping experiments. We developed a genotyping array including about 90,000 gene-associated SNPs and used it to characterize genetic variation in allohexaploid and allotetraploid wheat populations. The array includes a significant fraction of common genome-wide distributed SNPs that are represented in populations of diverse geographical origin. We used density-based spatial clustering algorithms to enable high-throughput genotype calling in complex data sets obtained for polyploid wheat. We show that these model-free clustering algorithms provide accurate genotype calling in the presence of multiple clusters including clusters with low signal intensity resulting from significant sequence divergence at the target SNP site or gene deletions. Assays that detect low-intensity clusters can provide insight into the distribution of presence-absence variation (PAV) in wheat populations. A total of 46 977 SNPs from the wheat 90K array were genetically mapped using a combination of eight mapping populations. The developed array and cluster identification algorithms provide an opportunity to infer detailed haplotype structure in polyploid wheat and will serve as an invaluable resource for diversity studies and investigating the genetic basis of trait variation in wheat.

  13. Characterization of polyploid wheat genomic diversity using a high-density 90 000 single nucleotide polymorphism array

    PubMed Central

    Wang, Shichen; Wong, Debbie; Forrest, Kerrie; Allen, Alexandra; Chao, Shiaoman; Huang, Bevan E; Maccaferri, Marco; Salvi, Silvio; Milner, Sara G; Cattivelli, Luigi; Mastrangelo, Anna M; Whan, Alex; Stephen, Stuart; Barker, Gary; Wieseke, Ralf; Plieske, Joerg; International Wheat Genome Sequencing Consortium; Lillemo, Morten; Mather, Diane; Appels, Rudi; Dolferus, Rudy; Brown-Guedira, Gina; Korol, Abraham; Akhunova, Alina R; Feuillet, Catherine; Salse, Jerome; Morgante, Michele; Pozniak, Curtis; Luo, Ming-Cheng; Dvorak, Jan; Morell, Matthew; Dubcovsky, Jorge; Ganal, Martin; Tuberosa, Roberto; Lawley, Cindy; Mikoulitch, Ivan; Cavanagh, Colin; Edwards, Keith J; Hayden, Matthew; Akhunov, Eduard

    2014-01-01

    High-density single nucleotide polymorphism (SNP) genotyping arrays are a powerful tool for studying genomic patterns of diversity, inferring ancestral relationships between individuals in populations and studying marker–trait associations in mapping experiments. We developed a genotyping array including about 90 000 gene-associated SNPs and used it to characterize genetic variation in allohexaploid and allotetraploid wheat populations. The array includes a significant fraction of common genome-wide distributed SNPs that are represented in populations of diverse geographical origin. We used density-based spatial clustering algorithms to enable high-throughput genotype calling in complex data sets obtained for polyploid wheat. We show that these model-free clustering algorithms provide accurate genotype calling in the presence of multiple clusters including clusters with low signal intensity resulting from significant sequence divergence at the target SNP site or gene deletions. Assays that detect low-intensity clusters can provide insight into the distribution of presence–absence variation (PAV) in wheat populations. A total of 46 977 SNPs from the wheat 90K array were genetically mapped using a combination of eight mapping populations. The developed array and cluster identification algorithms provide an opportunity to infer detailed haplotype structure in polyploid wheat and will serve as an invaluable resource for diversity studies and investigating the genetic basis of trait variation in wheat. PMID:24646323

  14. Dissection of genetic factors underlying wheat kernel shape and size in an elite x nonadapted cross using a high density SNP linkage map

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat kernel shape and size has been under selection since early domestication. Kernel morphology is a major consideration in wheat breeding, as it impacts grain yield and quality. A population of 160 recombinant inbred lines (RIL), developed using an elite (ND 705) and a nonadapted genotype (PI 414...

  15. Biofortification of wheat grain with iron and zinc: integrating novel genomic resources and knowledge from model crops

    PubMed Central

    Borrill, Philippa; Connorton, James M.; Balk, Janneke; Miller, Anthony J.; Sanders, Dale; Uauy, Cristobal

    2014-01-01

    Wheat, like many other staple cereals, contains low levels of the essential micronutrients iron and zinc. Up to two billion people worldwide suffer from iron and zinc deficiencies, particularly in regions with predominantly cereal-based diets. Although wheat flour is commonly fortified during processing, an attractive and more sustainable solution is biofortification, which requires developing new varieties of wheat with inherently higher iron and zinc content in their grains. Until now most studies aimed at increasing iron and zinc content in wheat grains have focused on discovering natural variation in progenitor or related species. However, recent developments in genomics and transformation have led to a step change in targeted research on wheat at a molecular level. We discuss promising approaches to improve iron and zinc content in wheat using knowledge gained in model grasses. We explore how the latest resources developed in wheat, including sequenced genomes and mutant populations, can be exploited for biofortification. We also highlight the key research and practical challenges that remain in improving iron and zinc content in wheat. PMID:24600464

  16. Biofortification of wheat grain with iron and zinc: integrating novel genomic resources and knowledge from model crops.

    PubMed

    Borrill, Philippa; Connorton, James M; Balk, Janneke; Miller, Anthony J; Sanders, Dale; Uauy, Cristobal

    2014-01-01

    Wheat, like many other staple cereals, contains low levels of the essential micronutrients iron and zinc. Up to two billion people worldwide suffer from iron and zinc deficiencies, particularly in regions with predominantly cereal-based diets. Although wheat flour is commonly fortified during processing, an attractive and more sustainable solution is biofortification, which requires developing new varieties of wheat with inherently higher iron and zinc content in their grains. Until now most studies aimed at increasing iron and zinc content in wheat grains have focused on discovering natural variation in progenitor or related species. However, recent developments in genomics and transformation have led to a step change in targeted research on wheat at a molecular level. We discuss promising approaches to improve iron and zinc content in wheat using knowledge gained in model grasses. We explore how the latest resources developed in wheat, including sequenced genomes and mutant populations, can be exploited for biofortification. We also highlight the key research and practical challenges that remain in improving iron and zinc content in wheat.

  17. 21 CFR 139.138 - Whole wheat macaroni products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Whole wheat macaroni products. 139.138 Section 139... and Noodle Products § 139.138 Whole wheat macaroni products. (a) Whole wheat macaroni products are the...)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as...

  18. 21 CFR 139.138 - Whole wheat macaroni products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Whole wheat macaroni products. 139.138 Section 139... and Noodle Products § 139.138 Whole wheat macaroni products. (a) Whole wheat macaroni products are the...)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as...

  19. 21 CFR 139.138 - Whole wheat macaroni products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Whole wheat macaroni products. 139.138 Section 139... and Noodle Products § 139.138 Whole wheat macaroni products. (a) Whole wheat macaroni products are the...)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as...

  20. 21 CFR 139.138 - Whole wheat macaroni products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Whole wheat macaroni products. 139.138 Section 139... and Noodle Products § 139.138 Whole wheat macaroni products. (a) Whole wheat macaroni products are the...)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as...

  1. 21 CFR 139.138 - Whole wheat macaroni products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Whole wheat macaroni products. 139.138 Section 139... and Noodle Products § 139.138 Whole wheat macaroni products. (a) Whole wheat macaroni products are the...)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as...

  2. Wheat Rusts in the United States in 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2007 90% of wheat stem rust races were QFC and 10% were RCRS Both races are relatively avirulent to wheat cultiars grown in the U.S. Wheat stem rust occurred in scattered locations on research plots of susceptible wheat cultivars in 2007, and did not cause yield loss. Wheat leaf rust was widespr...

  3. Diseases Which Challenge Global Wheat Production - The Cereal Rusts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rusts of wheat are common and widespread diseases in the US and throughout the world. Wheat rusts have been important throughout the history of wheat cultivation and are currently important diseases that are responsible for regularly occurring yield losses in wheat. The wheat rust fungi are obli...

  4. Lysine fortification of wheat flour improves selected indices of the nutritional status of predominantly cereal-eating families in Pakistan.

    PubMed

    Hussain, Tajammal; Abbas, Shaid; Khan, Mushtaq A; Scrimshaw, Nevin S

    2004-06-01

    Wheat provides more than 50% of the protein and calorie intake of the population of Pakistan. Legumes and animal protein that could complement the amino acid pattern of wheat, in which lysine is the first limiting amino acid for utilization of protein, are not affordable by members of lower socioeconomic groups in developing countries. The purpose of the study was to determine whether lysine fortification of wheat flour would have a positive impact on populations consuming a predominantly wheat-based diet. A double-blind study was carried out for three months on the outskirts of Peshawar, Pakistan. Forty families received wheat flour fortified with lysine, and 40 families received wheat flour without lysine. Wheat provided 59% of the protein for men, 65% for women, and 58% for children. The weight and height of the children in both groups increased during the study, but the increase was significantly greater in the lysine group. Hemoglobin increased significantly in the women receiving lysine-fortified flour. Transferrin levels increased significantly in men, women, and children in the lysine group as compared with those in the control group. Prealbumin increased significantly in adults receiving additional lysine but decreased in children. Men, women, and children in the lysine-supplemented families had significant increases in CD4, CD8, and complement C3 as compared with controls. These results indicate that lysine fortification of wheat flour can significantly improve sensitive indicators of nutritional status in a population consuming a diet in which 58% to 65% of the protein, depending on age and sex, is supplied by wheat.

  5. Registration of 'Clara CL' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Clara CL’ hard white winter wheat (Triticum aestivum L.) was developed at the Agricultural Research Center-Hays, Kansas State University and released by the Kansas Agricultural Experiment Station in 2011. Clara CL carries one Clearfield gene and has the tolerance to imazamox herbicide. Clara CL wa...

  6. Registration of Vision 45 Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Vision 45’ (Reg. No. CV-1110, PI 667642), is a hard red winter (HRW) wheat (Triticum aestivum L.) cultivar that was developed and tested as VA07HRW-45 and released by the Virginia Agricultural Experiment Station in 2012. Vision 45 was derived from the cross ‘Provinciale’/‘Vision 10’ using a modifie...

  7. Reinforcement Effect of Alkali-Hydrolyzed Wheat Gluten and Shear-Degraded Wheat Starch in Carboxylated Styrene-Butadiene Composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat gluten (WG) and wheat starch (WS) are the protein and carbohydrate obtained from wheat flours. Wheat gluten is not water soluble or dispersible due to its hydrophobic nature. To prepare wheat gluten dispersions, an alkali hydrolysis reaction was carried out to produce a stable aqueous disper...

  8. A laboratory-based comparison of a molluscicide and an alternative food source (red clover) as means of reducing slug damage to winter wheat.

    PubMed

    Brooks, Andrew S; Wilcox, Andrew; Cook, Richard T; Crook, Mitchell J

    2005-07-01

    Slugs are major pests of many crops in the UK, including winter wheat, yet current methods of control are often unreliable. This study investigates the potential use of red clover, as an alternative food source, to reduce the amount of damage caused to winter wheat by the field slug, Deroceras reticulatum (Müller). Two laboratory-based studies, each conducted over a 7-day period, investigated the effects of red clover seedlings and commercial metaldehyde pellets on damage to winter wheat seeds and seedlings. The results indicate that metaldehyde applications, in the form of commercially available pellets, resulted in significantly greater protection to wheat seeds compared with red clover, whereas metaldehyde and red clover were equally as effective in reducing damage to wheat seedlings. A further laboratory experiment investigated the effect of two slug population densities (48 and 16 adults m(-2)) and high and low red clover seed rates (125% and 75% of a standard rate) on damage to wheat seeds. Results showed that, at the highest slug population density, red clover sown at 125% of the standard rate gave 99% protection to wheat seeds, compared with the 75% seed rate which gave 55%. At the lower slug population density, both seed rates of red clover resulted in similar levels of protection. Implications for the potential use of red clover as an alternative food source for reducing damage to winter wheat in field conditions are discussed.

  9. Elite Haplotypes of a Protein Kinase Gene TaSnRK2.3 Associated with Important Agronomic Traits in Common Wheat

    PubMed Central

    Miao, Lili; Mao, Xinguo; Wang, Jingyi; Liu, Zicheng; Zhang, Bin; Li, Weiyu; Chang, Xiaoping; Reynolds, Matthew; Wang, Zhenhua; Jing, Ruilian

    2017-01-01

    Plant-specific protein kinase SnRK2s play crucial roles in response to various environmental stimuli. TaSnRK2.3, a SnRK2 member, was involved in the response to multiple abiotic stresses in wheat. To facilitate the use of TaSnRK2.3 in wheat breeding, the three genomic sequences of TaSnRK2.3, originating from the A, B, and D genomes of hexaploid wheat, were obtained. Sequence polymorphism assays showing 4 and 10 variations were detected at TaSnRK2.3-1A and at TaSnRK2.3-1B, respectively, yet no variation was identified at TaSnRK2.3-1D. Three haplotypes for A genome, and two main haplotypes for B genome of TaSnRK2.3 were identified in 32 genotypes. Functional markers (2.3AM1, 2.3AM2, 2.3BM1, 2.3BM2) were successfully developed to distinguish different haplotypes. Association analysis was performed with the general linear model in TASSEL 2.1. The results showed that both TaSnRK2.3-1A and TaSnRK2.3-1B were significantly associated with plant height (PH), length of peduncle and penultimate node, as well as 1,000-grain weight (TGW) under different environments. Additionally, TaSnRK2.3-1B was significantly associated with stem water-soluble carbohydrates at flowering and mid-grain filling stages. Hap-1A-1 had higher TGW and lower PH; Hap-1B-1 had higher TGW and stem water-soluble carbohydrates, as well as lower PH, thus the two haplotypes were considered as elite haplotypes. Geographic distribution and allelic frequencies indicated that the two preferred haplotypes Hap-1A-1 and Hap-1B-1 were positively selected in the process of Chinese wheat breeding. These results could be valuable for genetic improvement and germplasm enhancement using molecular marker assisted selection in wheat breeding.

  10. Genome-wide exploration of metal tolerance protein (MTP) genes in common wheat (Triticum aestivum): insights into metal homeostasis and biofortification.

    PubMed

    Vatansever, Recep; Filiz, Ertugrul; Eroglu, Seckin

    2017-04-01

    Metal transport process in plants is a determinant of quality and quantity of the harvest. Although it is among the most important of staple crops, knowledge about genes that encode for membrane-bound metal transporters is scarce in wheat. Metal tolerance proteins (MTPs) are involved in trace metal homeostasis at the sub-cellular level, usually by providing metal efflux out of the cytosol. Here, by using various bioinformatics approaches, genes that encode for MTPs in the hexaploid wheat genome (Triticum aestivum, abbreviated as Ta) were identified and characterized. Based on the comparison with known rice MTPs, the wheat genome contained 20 MTP sequences; named as TaMTP1-8A, B and D. All TaMTPs contained a cation diffusion facilitator (CDF) family domain and most members harbored a zinc transporter dimerization domain. Based on motif, phylogeny and alignment analysis, A, B and D genomes of TaMTP3-7 sequences demonstrated higher homology compared to TaMTP1, 2 and 8. With reference to their rice orthologs, TaMTP1s and TaMTP8s belonged to Zn-CDFs, TaMTP2s to Fe/Zn-CDFs and TaMTP3-7s to Mn-CDFs. Upstream regions of TaMTP genes included diverse cis-regulatory motifs, indicating regulation by developmental stage, tissue type and stresses. A scan of the coding sequences of 20 TaMTPs against published miRNAs predicted a total of 14 potential miRNAs, mainly targeting the members of most diverged groups. Expression analysis showed that several TaMTPs were temporally and spatially regulated during the developmental time-course. In grains, MTPs were preferentially expressed in the aleurone layer, which is known as a reservoir for high concentrations of iron and zinc. The work identified and characterized metal tolerance proteins in common wheat and revealed a potential involvement of MTPs in providing a sink for trace element storage in wheat grains.

  11. Contribution of Crop Models to Adaptation in Wheat.

    PubMed

    Chenu, Karine; Porter, John Roy; Martre, Pierre; Basso, Bruno; Chapman, Scott Cameron; Ewert, Frank; Bindi, Marco; Asseng, Senthold

    2017-04-04

    With world population growing quickly, agriculture needs to produce more with fewer inputs while being environmentally friendly. In a context of changing environments, crop models are useful tools to simulate crop yields. Wheat (Triticum spp.) crop models have been evolving since the 1960s to translate processes related to crop growth and development into mathematical equations. These have been used over decades for agronomic purposes, and have more recently incorporated advances in the modeling of environmental footprints, biotic constraints, trait and gene effects, climate change impact, and the upscaling of global change impacts. This review outlines the potential and limitations of modern wheat crop models in assisting agronomists, breeders, and policymakers to address the current and future challenges facing agriculture.

  12. Characterizing Croatian Wheat Germplasm Diversity and Structure in a European Context by DArT Markers.

    PubMed

    Novoselović, Dario; Bentley, Alison R; Šimek, Ruđer; Dvojković, Krešimir; Sorrells, Mark E; Gosman, Nicolas; Horsnell, Richard; Drezner, Georg; Šatović, Zlatko

    2016-01-01

    Narrowing the genetic base available for future genetic progress is a major concern to plant breeders. In order to avoid this, strategies to characterize and protect genetic diversity in regional breeding pools are required. In this study, 89 winter wheat cultivars released in Croatia between 1936 and 2006 were genotyped using 1,229 DArT (diversity array technology) markers to assess the diversity and population structure. In order to place Croatian breeding pool (CBP) in a European context, Croatian wheat cultivars were compared to 523 European cultivars from seven countries using a total of 166 common DArT markers. The results show higher genetic diversity in the wheat breeding pool from Central Europe (CE) as compared to that from Northern and Western European (NWE) countries. The most of the genetic diversity was attributable to the differences among cultivars within countries. When the geographical criterion (CE vs. NWE) was applied, highly significant difference between regions was obtained that accounted for 16.19% of the total variance, revealing that the CBP represents genetic variation not currently captured in elite European wheat. The current study emphasizes the important contribution made by plant breeders to maintaining wheat genetic diversity and suggests that regional breeding is essential to the maintenance of this diversity. The usefulness of open-access wheat datasets is also highlighted.

  13. Genetic structure of Tribolium castaneum (Coleptera: Tenebrionidae) populations in mills

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The red flour beetle, Tribolium castaneum, is primarily found associated with human structures such as wheat and rice mills, which are spatially isolated resource patches with apparently limited immigration that could produce genetically structured populations. We investigated genetic diversity and...

  14. Remote sensing to detect the movement of wheat curl mites through the spatial spread of virus symptoms, and identification of thrips as predators of wheat curl mites

    NASA Astrophysics Data System (ADS)

    Stilwell, Abby R.

    The wheat curl mite (WCM), Aceria tosichella Keifer, transmits three viruses to winter wheat: wheat streak mosaic virus, High Plains virus, and Triticum mosaic virus. This virus complex causes yellowing of the foliage and stunting of plants. WCMs disperse by wind, and an increased understanding of mite movement and subsequent virus spread is necessary in determining the risk of serious virus infections in winter wheat. These risk parameters will help growers make better decisions regarding WCM management. The objectives of this study were to evaluate the capabilities of remote sensing to identify virus infected plants and to establish the potential of using remote sensing to track virus spread and consequently, mite movement. Although the WCM is small and very hard to track, the viruses it vectors produce symptoms that can be detected with remote sensing. Field plots of simulated volunteer wheat were established between 2006 and 2009, infested with WCMs, and spread mites and virus into adjacent winter wheat. The virus gradients created by WCM movement allowed for the measurement of mite movement potential with both proximal and aerial remote sensing instruments. The ability to detect WCM-vectored viruses with remote sensing was investigated by comparing vegetation indices calculated from proximal remote sensing data to ground truth data obtained in the field. Of the ten vegetation indices tested, the red edge position (REP) index had the best relationship with ground truth data. The spatial spread of virus from WCM source plots was modeled with cokriging. Virus symptoms predicted by cokriging occurred in an oval pattern displaced to the southeast. Data from the spatial spread in small plots of this study were used to estimate the potential sphere of influence for volunteer wheat fields. The impact of thrips on WCM populations was investigated by a series of greenhouse, field, and observational studies. WCM populations in winter wheat increased more slowly when

  15. Incorporating Yearly Derived Winter Wheat Maps Into Winter Wheat Yield Forecasting Model

    NASA Technical Reports Server (NTRS)

    Skakun, S.; Franch, B.; Roger, J.-C.; Vermote, E.; Becker-Reshef, I.; Justice, C.; Santamaría-Artigas, A.

    2016-01-01

    Wheat is one of the most important cereal crops in the world. Timely and accurate forecast of wheat yield and production at global scale is vital in implementing food security policy. Becker-Reshef et al. (2010) developed a generalized empirical model for forecasting winter wheat production using remote sensing data and official statistics. This model was implemented using static wheat maps. In this paper, we analyze the impact of incorporating yearly wheat masks into the forecasting model. We propose a new approach of producing in season winter wheat maps exploiting satellite data and official statistics on crop area only. Validation on independent data showed that the proposed approach reached 6% to 23% of omission error and 10% to 16% of commission error when mapping winter wheat 2-3 months before harvest. In general, we found a limited impact of using yearly winter wheat masks over a static mask for the study regions.

  16. No significant difference in antigenicity or tissue transglutaminase substrate specificity of Irish and US wheat gliadins.

    PubMed

    Keaveny, A P; Offner, G D; Bootle, E; Nunes, D P

    2000-04-01

    The prevalence of clinical celiac disease has been shown to vary both across time and between genetically similar populations. Differences in wheat antigenicity and transglutaminase substrate properties are a possible explanation for these differences. This study assessed the antigenicity and transglutaminase substrate specificities of gliadins from regions of high and low celiac disease prevalence. Gliadin was extracted from three commercial US wheat sources and two Irish sources. SDS-PAGE and western blotting revealed minor, but significant variations in the gliadin extracts. However, ELISA showed no difference in the antigenicity of these gliadins. Transglutaminase pretreatment of gliadin resulted in no significant change in gliadin antigenicity and kinetic studies showed that the Kms of the various gliadins were very similar. Purified IgA and IgG had no effect on transglutaminase activity. In summary, minor variations in wheat gliadins are unlikely to explain the observed differences in disease expression across genetically similar populations.

  17. Study of wheat protein based materials

    NASA Astrophysics Data System (ADS)

    Ye, Peng

    Wheat gluten is a naturally occurring protein polymer. It is produced in abundance by the agricultural industry, is biodegradable and very inexpensive (less than $0.50/lb). It has unique viscoelastic properties, which makes it a promising alternative to synthetic plastics. The unplasticized wheat gluten is, however, brittle. Plasticizers such as glycerol are commonly used to give flexibility to the articles made of wheat gluten but with the penalty of greatly reduced stiffness. Former work showed that the brittleness of wheat gluten can also be improved by modifying it with a tri-thiol additive with no penalty of reduced stiffness. However, the cost of the customer designed tri-thiol additive was very high and it was unlikely to make a cost effective material from such an expensive additive. Here we designed a new, inexpensive thiol additive called SHPVA. It was synthesized from polyvinyl alcohol (PVA) through a simple esterification reaction. The mechanical data of the molded wheat gluten/SHPVA material indicated that wheat gluten was toughened by SHPVA. As a control, the wheat gluten/PVA material showed no improvement compared with wheat gluten itself. Several techniques have been used to characterize this novel protein/polymer blend. Differential scanning calorimetric (DSC) study showed two phases in both wheat gluten/PVA and wheat gluten/SHPVA material. However, scanning electron microscope (SEM) pictures indicated that PVA was macroscopically separated from wheat gluten, while wheat gluten/SHPVA had a homogeneous look. The phase image from the atomic force microscope (AFM) gave interesting contrast based on the difference in the mechanical properties of these two phases. The biodegradation behavior of these protein/polymer blends was examined in soil. SHPVA was not degraded in the time period of the experiment. Wheat gluten/SHPVA degraded slower than wheat gluten. We also developed some other interesting material systems based on wheat gluten, including the

  18. The Microgeographical Patterns of Morphological and Molecular Variation of a Mixed Ploidy Population in the Species Complex Actinidia chinensis

    PubMed Central

    Liu, Yifei; Li, Dawei; Yan, Ling; Huang, Hongwen

    2015-01-01

    Polyploidy and hybridization are thought to have significant impacts on both the evolution and diversification of the genus Actinidia, but the structure and patterns of morphology and molecular diversity relating to ploidy variation of wild Actinidia plants remain much less understood. Here, we examine the distribution of morphological variation and ploidy levels along geographic and environmental variables of a large mixed-ploidy population of the A. chinensis species complex. We then characterize the extent of both genetic and epigenetic diversity and differentiation exhibited between individuals of different ploidy levels. Our results showed that while there are three ploidy levels in this population, hexaploids were constituted the majority (70.3%). Individuals with different ploidy levels were microgeographically structured in relation to elevation and extent of niche disturbance. The morphological characters examined revealed clear difference between diploids and hexaploids, however tetraploids exhibited intermediate forms. Both genetic and epigenetic diversity were high but the differentiation among cytotypes was weak, suggesting extensive gene flow and/or shared ancestral variation occurred in this population even across ploidy levels. Epigenetic variation was clearly correlated with changes in altitudes, a trend of continuous genetic variation and gradual increase of epigenomic heterogeneities of individuals was also observed. Our results show that complex interactions between the locally microgeographical environment, ploidy and gene flow impact A. chinensis genetic and epigenetic variation. We posit that an increase in ploidy does not broaden the species habitat range, but rather permits A. chinensis adaptation to specific niches. PMID:25658107

  19. Recognition of wheat varieties by image analysis

    NASA Astrophysics Data System (ADS)

    Yang, Hongwei; Zhou, Zhanming; Zhao, Renyong; Wang, Bingxi

    2003-09-01

    The objective of this paper is to develop a rapid, objective, and easy method for recognizing wheat varieties, which is important for breeding, milling and marketing. The method can be used in place of the existing procedures to remove subjectivity from wheat variety recognition. In contrast to previous work, most of which has focused on wheat morphological characteristics, the features utilized in this paper are based mainly on kernel color. Varietal classification is performed by using Support Vector Machines (SVMs) method. More than 96% correct recognition rates are achieved with bulk samples involving 16 varieties representing a wide range of wheat varieties, wheat class, and kernel types. The proportion of single wheat kernels correctly recognized ranges from 87% to 93%. The results were encouraging since the method proposed here can be easily conducted in routine inspection.

  20. Wheat yield dynamics: a structural econometric analysis.

    PubMed

    Sahin, Afsin; Akdi, Yilmaz; Arslan, Fahrettin

    2007-10-15

    In this study we initially have tried to explore the wheat situation in Turkey, which has a small-open economy and in the member countries of European Union (EU). We have observed that increasing the wheat yield is fundamental to obtain comparative advantage among countries by depressing domestic prices. Also the changing structure of supporting schemes in Turkey makes it necessary to increase its wheat yield level. For this purpose, we have used available data to determine the dynamics of wheat yield by Ordinary Least Square Regression methods. In order to find out whether there is a linear relationship among these series we have checked each series whether they are integrated at the same order or not. Consequently, we have pointed out that fertilizer usage and precipitation level are substantial inputs for producing high wheat yield. Furthermore, in respect for our model, fertilizer usage affects wheat yield more than precipitation level.

  1. Cyclical parthenogenetic reproduction in the Russian wheat aphid (Hemiptera: Aphididae) in the United States: sexual reproduction and its outcome on biotypic diversity.

    PubMed

    Puterka, G J; Hammon, R W; Burd, J D; Peairs, F B; Randolph, T L; Cooper, W R

    2012-06-01

    In 1986, the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), became an invasive species of United States. Nearly 20 yr later, new biotypes appeared that were capable of overcoming most sources of resistance and became a renewed threat to wheat, Triticum aestivum L., production. Cyclical (CP) and obligate (OP) parthenogenesis enables aphids to both adapt to changing environments and exploit host resources. We documented these forms of reproduction for Russian wheat aphid in wheat and wild grasses in the Central Great Plains and Rocky Mountain regions during falls 2004-2009. Colonies from sample sites also were held under unheated greenhouse conditions and observed for the presence of sexual morphs and eggs through the winter. Russian wheat aphid populations were mainly OP and attempted to overwinter as adults, regardless of region sampled. A few populations contained oviparae but no males (gynocyclic) and were not specific to any particular region. Observation of the Russian wheat aphid colonies under greenhouse conditions failed to produce males or eggs. In spring 2007, CP was confirmed in a small population of Russian wheat aphid that eclosed from eggs (fundatricies) on wild grasses and wheat near Dove Creek, CO, in the Colorado Plateau region where other aphid species undergo CP. Lineages from ninety-three fundatricies were screened against 16 resistant and susceptible cereal entries to determine their biotypic classification. A high degree of biotypic diversity (41.4%) was detected in this population. Although CP was a rare in Russian wheat aphid populations, genetic recombination during the sexual cycle creates new biotypes and can have significant effects on population genetics.

  2. Evaluation and reselection of wheat resistance to Russian wheat aphid biotype 2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Russian wheat aphid (RWA, Diuraphis noxia, Mordvilko) biotype 2 (RWA2) is virulent to most known RWA resistance genes and severely threatens wheat production in the hard winter wheat area of the US western Great Plains. We determined RWA2 reactions of 386 cultivars from China, 227 advanced breeding...

  3. Resistance to Wheat streak mosaic virus identified in synthetic wheat lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) is a significant pathogen in wheat that causes economic loss each year. WSMV is typically controlled using cultural practices such as the removal of volunteer wheat. Genetic resistance is limited. Until recently, no varieties have been available with major resista...

  4. Effects of protein in wheat flour on retrogradation of wheat starch.

    PubMed

    Xijun, Lian; Junjie, Guo; Danli, Wang; Lin, Li; Jiaran, Zhu

    2014-08-01

    Albumins, globulins, gliadins, and glutenins were isolated from wheat flour and the effects of those proteins on retrogradation of wheat starch were investigated. The results showed that only glutenins retarded retrogradation of wheat starch and other 3 proteins promoted it. The results of IR spectra proved that no S-S linkage formed during retrogradation of wheat starch blended with wheat proteins. Combination of wheat starch and globulins or gliadins through glucosidic bonds hindered the hydrolysis of wheat starch by α-amylase. The melting peak temperatures of retrograded wheat starch attached to different proteins were 128.46, 126.14, 132.03, 121.65, and 134.84 °C for the control with no protein, albumins, glutenins, globulins, gliadins groups, respectively, and there was no second melting temperature for albumins group. Interaction of wheat proteins and starch in retrograded wheat starch greatly decreased the endothermic enthalpy (△H) of retrograded wheat starch. Retrograded wheat starch bound to gliadins might be a new kind of resistant starch based on glycosidic bond between starch and protein.

  5. Binary mixtures of waxy wheat and conventional wheat as measured by nir reflectance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waxy wheat contains very low concentration (generally <2%) of amylose in endosperm starch, in contrast to conventional wheat whose starch is typically 20% amylose, with the balance being the branched macromolecule, amylopectin. With the release of a commercial hard winter waxy wheat cultivar in the ...

  6. Physiological responses of hard red winter wheat to infection by wheat streak mosaic virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat streak mosaic virus (WSMV) causes significant yield loss in hard red winter wheat in the U.S. Southern High Plains. Despite the prevalence of this pathogen, little is known about the physiological response of wheat to WSMV infection. A 2-year study was initiated to (i) investigate the effect o...

  7. Safeguarding world wheat and barley production against Russian wheat aphid: An international pre-breeding initiative

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Russian wheat aphid (RWA), Diuraphis noxia, is one of the most damaging insect pests of wheat and barley throughout the World. This aphid, although is not yet present in Australia, is extremely damaging with up to 70% yield loses in wheat and barley producing lands, causing significant financia...

  8. Immunocytochemical localization of wheat germ agglutinin in wheat

    PubMed Central

    1982-01-01

    Immunocytological techniques were developed to localize the plant lectin, wheat germ agglutinin (WGA), in the tissues and cells of wheat plants. In a previous study we demonstrated with a radioimmunoassay that the lectin is present in wheat embryos and adult plants both in the roots and at the base of the stem. We have now found, using rhodamine, peroxidase, and ferritin-labeled secondary antibodies, that WGA is located in cells and tissues that establish direct contact with the soil during germination and growth of the plant In the embryo, WGA is found in the surface layer of the radicle, the first adventitious roots, the coleoptile, and the scutellum. Although found throughout the coleorhiza and epiblast, it is at its highest levels within the cells at the surface of these organs. In adult plants, WGA is located only in the caps and tips of adventitious roots. Reaction product for WGA was not visualized in embryonic or adult leaves or in other tissues of adult plants. At the subcellular level, WGA is located at the periphery of protein bodies, within electron-translucent regions of the cytoplasm, and at the cell wall-protoplast interface. Since WGA is found at potential infection sites and is known to have fungicidal properties, it may function in the defense against fungal pathogens. PMID:7045136

  9. LACIE: Wheat yield models for the USSR

    NASA Technical Reports Server (NTRS)

    Sakamoto, C. M.; Leduc, S. K.

    1977-01-01

    A quantitative model determining the relationship between weather conditions and wheat yield in the U.S.S.R. was studied to provide early reliable forecasts on the size of the U.S.S.R. wheat harvest. Separate models are developed for spring wheat and for winter. Differences in yield potential and responses to stress conditions and cultural improvements necessitate models for each class.

  10. Description of durum wheat linkage map and comparative sequence analysis of wheat mapped DArT markers with rice and Brachypodium genomes

    PubMed Central

    2013-01-01

    Background The importance of wheat to the world economy, together with progresses in high-throughput next-generation DNA sequencing, have accelerated initiatives of genetic research for wheat improvement. The availability of high density linkage maps is crucial to identify genotype-phenotype associations, but also for anchoring BAC contigs to genetic maps, a strategy followed for sequencing the wheat genome. Results Here we report a genetic linkage map in a durum wheat segregating population and the study of mapped DArT markers. The linkage map consists of 126 gSSR, 31 EST-SSR and 351 DArT markers distributed in 24 linkage groups for a total length of 1,272 cM. Through bioinformatic approaches we have analysed 327 DArT clones to reveal their redundancy, syntenic and functional aspects. The DNA sequences of 174 DArT markers were assembled into a non-redundant set of 60 marker clusters. This explained the generation of clusters in very small chromosome regions across genomes. Of these DArT markers, 61 showed highly significant (Expectation < E-10) BLAST similarity to gene sequences in public databases of model species such as Brachypodium and rice. Based on sequence alignments, the analysis revealed a mosaic gene conservation, with 54 and 72 genes present in rice and Brachypodium species, respectively. Conclusions In the present manuscript we provide a detailed DArT markers characterization and the basis for future efforts in durum wheat map comparing. PMID:24304553

  11. Aspergillus section Flavi and aflatoxins in Algerian wheat and derived products.

    PubMed

    Riba, Amar; Bouras, Noureddine; Mokrane, Salim; Mathieu, Florence; Lebrihi, Ahmed; Sabaou, Nasserdine

    2010-10-01

    Wheat and its derivatives are a very important staple food for North African populations. The aim of this study was to analyze populations of Aspergillus section Flavi from local wheat based on aflatoxins (AFs), cyclopiazonic acid (CPA) and sclerotia production, and also to evaluate AFs-contaminated wheat collected from two different climatic regions in Algeria. A total of 108 samples of wheat were collected during the following phases: pre-harvest, storage in silos and after processing. The results revealed that among the Aspergillus species isolated, those belonging to section Flavi were predominant. Of the 150 strains of Aspergillus section Flavi isolated, 144 were identified as Aspergillus flavus and 6 as Aspergillus tamarii. We showed that 72% and 10% of the A. flavus strains produced AFs and CPA, respectively. Among the 150 strains tested, 60 produced amounts of AFB1 ranging from 12.1 to 234.6 microg/g of CYA medium. Also, we showed that most strains produced large sclerotia. AFB1was detected by HPLC in 56.6% of the wheat samples and derived products (flour, semolina and bran) with contamination levels ranging from 0.13 to 37.42 microg/kg.

  12. Recent trends and perspectives of molecular markers against fungal diseases in wheat

    PubMed Central

    Goutam, Umesh; Kukreja, Sarvjeet; Yadav, Rakesh; Salaria, Neha; Thakur, Kajal; Goyal, Aakash K.

    2015-01-01

    Wheat accounts for 19% of the total production of major cereal crops in the world. In view of ever increasing population and demand for global food production, there is an imperative need of 40–60% increase in wheat production to meet the requirement of developing world in coming 40 years. However, both biotic and abiotic stresses are major hurdles for attaining the goal. Among the most important diseases in wheat, fungal diseases pose serious threat for widening the gap between actual and attainable yield. Fungal disease management, mainly, depends on the pathogen detection, genetic and pathological variability in population, development of resistant cultivars and deployment of effective resistant genes in different epidemiological regions. Wheat protection and breeding of resistant cultivars using conventional methods are time-consuming, intricate and slow processes. Molecular markers offer an excellent alternative in development of improved disease resistant cultivars that would lead to increase in crop yield. They are employed for tagging the important disease resistance genes and provide valuable assistance in increasing selection efficiency for valuable traits via marker assisted selection (MAS). Plant breeding strategies with known molecular markers for resistance and functional genomics enable a breeder for developing resistant cultivars of wheat against different fungal diseases. PMID:26379639

  13. Iturin levels on wheat spikes linked to biological control of Fusarium head blight by Bacillus amyloliquefaciens.

    PubMed

    Crane, J M; Gibson, D M; Vaughan, R H; Bergstrom, G C

    2013-02-01

    The TrigoCor strain of Bacillus amyloliquefaciens provides consistent control against Fusarium head blight of wheat in controlled settings but there is a lack of disease and deoxynivalenol suppression in field settings. Since production of antifungal compounds is thought to be the main mode of action of TrigoCor control, we quantified levels of a key family of antifungal metabolites, iturins, as well as monitored Bacillus populations on wheat spikes over 14 days post-application in both the greenhouse and the field. We found that initial iturin levels on spikes in the greenhouse were three times greater than on spikes in the field, but that by 3 days post-application, iturin levels were equivalent and very low in both settings. We also determined that iturins declined rapidly over a 3-day post-application period on wheat spikes in both environments, despite the presence of significant Bacillus populations. Greenhouse trials and antibiosis tests indicated that the lower iturin levels on wheat spikes in the field could be a major factor limiting disease control in field settings. Future efforts to improve Bacillus disease control on wheat spikes and in the phyllosphere of various plants should focus on maintaining higher levels of iturins over critical infection periods.

  14. Proteomic analysis of wheat flour allergens.

    PubMed

    Akagawa, Mitsugu; Handoyo, Tri; Ishii, Takeshi; Kumazawa, Shigenori; Morita, Naofumi; Suyama, Kyozo

    2007-08-22

    Wheat can cause severe IgE-mediated systematic reactions, but knowledge on relevant wheat allergens at the molecular level is scanty. The aim of the present study was to achieve a more detailed and comprehensive characterization of the wheat allergens involved in food allergy to wheat using proteomic strategies, referred to as "allergenomics". Whole flour proteins were separated by two-dimensional gel electrophoresis with isoelectric focusing and lithium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, IgE-binding proteins were detected by immunoblotting with sera of patients with a food allergy to wheat. After tryptic digestion, the peptides of IgE-binding proteins were analyzed by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. In this study, we identified four previously reported wheat allergens or their sequentially homologous proteins [serpin, alpha-amylase inhibitor, gamma-gliadin, and low molecular weight (LMW) glutenin] by a database search. As a result of the high resolution of two-dimensional gel electrophoresis, nine subunits of LMW glutenins were identified as the most predominant IgE-binding antigens. The two-dimensional allergen map can be beneficial in many ways. It could be used, for example, for precise diagnosis of wheat-allergic patients and assessment of wheat allergens in food. Additionally, we compared allergenomics to conventional biochemical methods and evaluated the usefulness of a proteomic strategy for identifying putative allergens to wheat allergy.

  15. [Effect of rye chromosomes on features of androgenesis in wheat-rye substituted lines of Triticum aestivum L. sort Saratovskaya 29/Secale cerale L. sort Onokhoiskaia and Triticale].

    PubMed

    Dobrovolskaia, O B; Pershina, L A; Kravtsova, L A; Silkova, O G; Shchapova, A I

    2001-05-01

    The characteristic features of androgenesis in six wheat-rye substitution lines Triticum aestivum L. (cv. Saratovskaya 29)/Secale cereale L. (cv. Onokhoiskaya) and triticale (2n = 56) using anther culture at different concentrations of 2,4-D in the growth medium were studied. Under variable cultivation conditions, the significant effect of genotypic diversity on the variability of such androgenesis parameters as the frequency of productive anthers, the frequency of embryoid formation, and the frequency of total regenerated plantlets, was shown. It was demonstrated that chromosomes 1R, 3R, and 7R stimulated the formation of androgenous embryoids, while chromosome 5R produced an opposite effect. In triticale and substitution lines, the regeneration ability of androgenous embryoids induced by elevated 2,4-D concentrations was inhibited. Chromosome 1R of the Onokhoiskaya cultivar was suggested to contain genes suppressing regeneration of green plantlets, while chromosome 3R, conversely, stimulated their formation. Chromosomes 1R, 2R, 3R, and 7R of the Onokhoiskaya cultivar did not inhibit the spontaneous formation of androgenous hexaploids in the substitution lines.

  16. The case of the missing wheat

    NASA Astrophysics Data System (ADS)

    Lobell, David B.

    2012-06-01

    In Lewis Carroll's Through the Looking Glass, Alice finds herself running as fast as she can but not moving anywhere. The Red Queen explains to her 'Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that.' Such is the situation in global agriculture. Global demand for agricultural products continues to rise as population grows and people get richer. As they get richer, people have fewer babies but eat more. And they use a lot more energy, which is increasingly derived from agricultural products. Crop technologies have to move incredibly fast just to keep up. Remarkably, over the past 50 years they have, with yields (production per hectare of land) for most crops more than doubling since 1960, and real prices of food falling for most of the period. In many ways we have come to take continued yield growth for granted. But, as Lin and Huybers show [1] elsewhere in this issue, there is increasing evidence that this growth has stalled in many regions. The question is not new—people have worried about the pace of yield growth since at least the days of Malthus [2, 3]. But Lin and Huybers [1] use updated data and bring a new rigor to identifying where stagnation is statistically significant, for example by taking care to account for year-to-year correlation in yields. They report that for slightly more than half of the regions that they inspected, it is likely (80% chance) that yield growth has already flattened out. For many of these countries, responsible for about one quarter of global wheat production, the stagnation has very likely occurred (95% chance). Why are yields of wheat stagnating in so many areas? At least four suspects seem plausible. One narrative is that for years the real price of wheat was declining, providing little incentive for innovation. The most obvious consequence was a major decline in investment in research and development in most

  17. Proteome analysis of wheat lemma.

    PubMed

    Woo, Sun-Hee; Kimura, Makoto; Higa-Nishiyama, Arisa; Dohmae, Naoshi; Hamamoto, Hiroshi; Jong, Seung-Keun; Yamaguchi, Isamu

    2003-11-01

    We report here for the first time on the construction of proteomes from wheat lemma at the anthesis stage. After transfer of lemma proteins to polyvinylidene difluoride membranes, seventy larger spots were subjected to peptide sequence analysis; the amino acid sequences could be described for forty-eight of these proteins. The result suggested that wheat proteins were less N-terminally blocked compared to rice proteins, which are known to have a much higher ratio of N-terminal blocks. We further analyzed the internal sequences of eight blocked proteins by the Cleveland peptide mapping method. Out of these total 56 amino acid sequences, forty-one could be assigned to the corresponding expressed sequence tags (ESTs). The expression profile of lemma proteins was generally similar to that of leaf, and the majority of identified proteins were related to cellular metabolisms. We analyzed the internal sequences of one protein spot present in lemma, which was not present in leaf.

  18. Winter wheat and summer shade

    NASA Astrophysics Data System (ADS)

    Artru, S.; Garre, S.; Lassois, L.; Dupraz, C.

    2014-12-01

    Agroforestry research is in full expansion, but uncertainty remains on the performance of combinations of species with regard to the broad range of possible species associations. In addition, the variability of environmental conditions under which agroforestry stands can be successfully developed is unknown. Under Belgian pedoclimatic conditions, tree-crop competition for light might be the principal limiting factor in the agroforestry context. Most studies show that shade stress induces a systematic reduction of final crop yield. However, the response of a specific crop to shade is highly dependent on environmental conditions. In agroforestry systems, the tree canopy reduces the incident radiation for the crop following a dynamic spatio-temporal pattern. In this study, we will report on the efficiency of wheat under artificial dynamic shade in the experimental farm of Gembloux Agro-Bio Tech, Belgium in order to evaluate it's potential for agroforestry purposes in the same region. Wheat productivity and development under artificial shade conditions have been monitored during 1 year and the observations will be continued for 2 more years. We constructed an artificial shade structure, which mimics the light environment observed under hybrid walnut agroforestry trees: periodic fluctuation in radiation transmittance and discontinuous light quantity. We collected information on biomass development, soil state and radiation patterns in the field. Using this data, we evaluated the influence of dynamic shade, light availability and the efficiency with which energy is converted in wheat dry matter under the artificial shade treatment. This, in combination with modeling, will allow a thorough study of the potential of wheat-walnut agroforestry systems in the Hesbaye region in Belgium.

  19. Response of Russian wheat aphid resistance in wheat and barley to four Diuraphis (Hemiptera: Aphididae) species.

    PubMed

    Puterka, Gary J; Scott, J Nicholson; Brown, Michael J; Hammon, R W

    2013-04-01

    Three Diuraphis species, Diuraphis frequens (Walker), Diuraphis mexicana (McVicar Baker), and Diuraphis tritici (Gillette), were known to exist in the United States before the 1986 appearance of the Russian wheat aphid, Diuraphis noxia Kurdjumov. The Russian wheat aphid soon became a significant pest of wheat although other endemic Diuraphis species were known to infest wheat. Wheat and barley entries resistant and susceptible to Russian wheat aphid biotype 2 were evaluated against all four Diuraphis species to determine their host interrelationships. Leaf chlorosis, leaf roll, leaf number, plant height, and infestation levels were assessed 21 d after the plants were infested by aphids in a no-choice caged environment. D. mexicana was unable to survive on wheat by 21 d after infestation and effects on the plant damage variables were negligible. D. frequens survived at low levels on resistant and susceptible plant entries and had a low impact on plant damage and growth. Russian wheat aphid biotype 2 and D. tritici were damaged most wheat and barley lines except the Russian wheat aphid biotype 2-resistant wheat lines containing genes from Dn7, STARS 2414-11, and CI2401; and resistant barley containing genes from STARS 9577B and 9301B. Russian wheat aphid biotype 2 and D. tritici reduced the growth of resistant plants by 25-50% and susceptible entries by 65-75%. Reductions at this level are typical under no-choice studies but resistant cultivars do not have these reductions under field conditions. The Russian wheat aphid biotype 2 resistant wheat lines would be effective in managing both wheat pest species.

  20. Salt acclimation processes in wheat.

    PubMed

    Janda, Tibor; Darko, Éva; Shehata, Sami; Kovács, Viktória; Pál, Magda; Szalai, Gabriella

    2016-04-01

    Young wheat plants (Triticum aestivum L. cv. Mv Béres) were exposed to 0 or 25 mM NaCl for 11 days (salt acclimation). Thereafter the plants were irrigated with 500 mM NaCl for 5 days (salt stress). Irrigating the plants with a low concentration of NaCl successfully led to a reduction in chlorotic symptoms and in the impairment of the photosynthetic processes when the plants were exposed to subsequent high-dose salt treatment. After exposure to a high concentration of NaCl there was no difference in leaf Na content between the salt-acclimated and non-acclimated plants, indicating that salt acclimation did not significantly modify Na transport to the shoots. While the polyamine level was lower in salt-treated plants than in the control, salt acclimation led to increased osmotic potential in the leaves. Similarly, the activities of certain antioxidant enzymes, namely glutathione reductase, catalase and ascorbate peroxidase, were significantly higher in salt-acclimated plants. The results also suggest that while SOS1, SOS2 or NHX2 do not play a decisive role in the salt acclimation processes in young wheat plants; another stress-related gene, WALI6, may contribute to the success of the salt acclimation processes. The present study suggested that the responses of wheat plants to acclimation with low level of salt and to treatment with high doses of salt may be fundamentally different.

  1. A radiation hybrid map of chromosome ID reveals synteny conservation at a wheat speciation locus.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The species cytoplasm specific (scs) genes affect nuclear-cytoplasmic interactions in interspecific hybrids. A radiation hybrid (RH) mapping population of 188 individuals was employed to refine the location of the scsae locus of Tritcum aestivum chromosome 1D. ‘Wheat Zapper’, a comparative genomic...

  2. Characterization of Fusarium strains recovered from wheat with symptoms of head blight in Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium graminearum species complex (FGSC) members cause Fusarium head blight (FHB) of wheat (Triticum aestivum L.) and small grains in the United States. The U.S. population is diverse, and includes several genetically distinct local emergent subpopulations, some more aggressive and toxigenic than...

  3. Genetic architecture of resistance to stripe rust in a global winter wheat germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virulence shifts in populations of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of Pst, necessitating the identification and intr...

  4. Genetic mapping analysis of bread-making quality traits in spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study we assess the genetic architecture of bread-making quality traits in spring wheat. A mapping population derived from BR34 and Grandin, a soft x hard cross, was used to measure 20 end-use quality traits including six kernel characteristics, seven milling and flour traits, four dough mi...

  5. Efficient use of historical data for genomic selection: a case study of rust resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic selection (GS) is a new methodology that can improve wheat breeding efficiency. To implement GS, a training population (TP) with both phenotypic and genotypic data is required to train a statistical model used to predict genotyped selection candidates (SCs). Several factors impact prediction...

  6. Predicting Hybrid Performances for Quality Traits through Genomic-Assisted Approaches in Central European Wheat

    PubMed Central

    Liu, Guozheng; Zhao, Yusheng; Gowda, Manje; Longin, C. Friedrich H.; Reif, Jochen C.; Mette, Michael F.

    2016-01-01

    Bread-making quality traits are central targets for wheat breeding. The objectives of our study were to (1) examine the presence of major effect QTLs for quality traits in a Central European elite wheat population, (2) explore the optimal strategy for predicting the hybrid performance for wheat quality traits, and (3) investigate the effects of marker density and the composition and size of the training population on the accuracy of prediction of hybrid performance. In total 135 inbred lines of Central European bread wheat (Triticum aestivum L.) and 1,604 hybrids derived from them were evaluated for seven quality traits in up to six environments. The 135 parental lines were genotyped using a 90k single-nucleotide polymorphism array. Genome-wide association mapping initially suggested presence of several quantitative trait loci (QTLs), but cross-validation rather indicated the absence of major effect QTLs for all quality traits except of 1000-kernel weight. Genomic selection substantially outperformed marker-assisted selection in predicting hybrid performance. A resampling study revealed that increasing the effective population size in the estimation set of hybrids is relevant to boost the accuracy of prediction for an unrelated test population. PMID:27383841

  7. Quantitative Trait Loci for Aluminum Resistance in Chinese Wheat Landrace FSW

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) toxicity is a major constraint for wheat production in acid soils worldwide. Chinese landrace FSW demonstrates a high level of Al resistance. A population of 170 F6 recombinant inbred lines (RILs) was developed from a cross between FSW and an Al-sensitive Chinese line, ND35, using sing...

  8. Knock out of the PHOSPHATE 2 Gene TaPHO2-A1 Improves Phosphorus Uptake and Grain Yield under Low Phosphorus Conditions in Common Wheat

    PubMed Central

    Ouyang, Xiang; Hong, Xia; Zhao, Xueqiang; Zhang, Wei; He, Xue; Ma, Wenying; Teng, Wan; Tong, Yiping

    2016-01-01

    MiR399 and its target PHOSPHATE2 (PHO2) play pivotal roles in phosphate signaling in plants. Loss of function mutation in PHO2 leads to excessive Pi accumulation in shoots and growth retardation in diploid plants like Arabidopsis thaliana and rice (Oryza sativa). Here we isolated three PHO2 homologous genes TaPHO2-A1, -B1 and -D1 from hexaploid wheat (Triticum aestivum). These TaPHO2 genes all contained miR399-binding sites and were able to be degraded by tae-miR399. TaPHO2-D1 was expressed much more abundantly than TaPHO2-A1 and -B1. The ion beam-induced deletion mutants were used to analyze the effects of TaPHO2s on phosphorus uptake and plant growth. The tapho2-a1, tapho2-b1 and tapho2-d1 mutants all had significant higher leaf Pi concentrations than did the wild type, with tapho2-d1 having the strongest effect, and tapho2-b1 the weakest. Two consecutive field experiments showed that knocking out TaPHO2-D1 reduced plant height and grain yield under both low and high phosphorus conditions. However, knocking out TaPHO2-A1 significantly increased phosphorus uptake and grain yield under low phosphorus conditions, with no adverse effect on grain yield under high phosphorus conditions. Our results indicated that TaPHO2s involved in phosphorus uptake and translocation, and molecular engineering TaPHO2 shows potential in improving wheat yield with less phosphorus fertilizer. PMID:27416927

  9. Interplay between wheat cultivars, biocontrol pseudomonads, and soil.

    PubMed

    Meyer, Joana Beatrice; Lutz, Matthias Peter; Frapolli, Michele; Péchy-Tarr, Maria; Rochat, Laurène; Keel, Christoph; Défago, Geneviève; Maurhofer, Monika

    2010-09-01

    There is a significant potential to improve the plant-beneficial effects of root-colonizing pseudomonads by breeding wheat genotypes with a greater capacity to sustain interactions with these bacteria. However, the interaction between pseudomonads and crop plants at the cultivar level, as well as the conditions which favor the accumulation of beneficial microorganisms in the wheat rhizosphere, is largely unknown. Therefore, we characterized the three Swiss winter wheat (Triticum aestivum) cultivars Arina, Zinal, and Cimetta for their ability to accumulate naturally occurring plant-beneficial pseudomonads in the rhizosphere. Cultivar performance was measured also by the ability to select for specific genotypes of 2,4-diacetylphloroglucinol (DAPG) producers in two different soils. Cultivar-specific differences were found; however, these were strongly influenced by the soil type. Denaturing gradient gel electrophoresis (DGGE) analysis of fragments of the DAPG biosynthetic gene phlD amplified from natural Pseudomonas rhizosphere populations revealed that phlD diversity substantially varied between the two soils and that there was a cultivar-specific accumulation of certain phlD genotypes in one soil but not in the other. Furthermore, the three cultivars were tested for their ability to benefit from Pseudomonas inoculants. Interestingly, Arina, which was best protected against Pythium ultimum infection by inoculation with Pseudomonas fluorescens biocontrol strain CHA0, was the cultivar which profited the least from the bacterial inoculant in terms of plant growth promotion in the absence of the pathogen. Knowledge gained of the interactions between wheat cultivars, beneficial pseudomonads, and soil types allows us to optimize cultivar-soil combinations for the promotion of growth through beneficial pseudomonads. Additionally, this information can be implemented by breeders into a new and unique breeding strategy for low-input and organic conditions.

  10. Registration of ‘Ripper’ Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Ripper’ (Reg. No. CV-1016, PI 644222) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2006 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado S...

  11. Stem rust resistance in 'Jagger' winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    "Jagger" has been utilized widely as a parent to develop hard red winter wheat varieties throughout the U.S. southern Great Plains. Jagger has resistance to stem rust pathogen race TTTTF, which is virulent to many winter wheat cultivars, yet the genetic basis of this resistance remains unknown. Mark...

  12. Selecting wheat varieties for tortilla production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat flour tortillas are the second most consumed bread product behind white pan bread. Manufactured tortillas are formulated with highly viscoelastic hard red wheat flours selected and grown for bread making. However, the inherent properties of the bread making flours require costly reducing agent...

  13. Genetic mapping of flavor loci in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavor is an essential aspect of consumer acceptance, especially with whole-wheat foods. However, little if any selection is performed during breeding of new wheat cultivars for flavor, and little is known regarding the genetics of flavor. Our research is aimed at identifying genes that impart eithe...

  14. Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance.

    PubMed

    Ali, N; Heslop-Harrison, Js Pat; Ahmad, H; Graybosch, R A; Hein, G L; Schwarzacher, T

    2016-08-01

    Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a cost-effective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chromatin in four genetically diverse populations of wheat (Triticum aestivum) lines incorporating chromosome segments from Thinopyrum intermedium and Secale cereale (rye). Out of 20 experimental lines, 10 carried Th. intermedium chromatin as T4DL*4Ai#2S translocations, while, unexpectedly, 7 lines were positive for alien chromatin (Th. intermedium or rye) on chromosome 1B. The newly described rye 1RS chromatin, transmitted from early in the pedigree, was associated with enhanced WSMV resistance. Under field conditions, the 1RS chromatin alone showed some resistance, while together with the Th. intermedium 4Ai#2S offered superior resistance to that demonstrated by the known resistant cultivar Mace. Most alien wheat lines carry whole chromosome arms, and it is notable that these lines showed intra-arm recombination within the 1BS arm. The translocation breakpoints between 1BS and alien chromatin fell in three categories: (i) at or near to the centromere, (ii) intercalary between markers UL-Thin5 and Xgwm1130 and (iii) towards the telomere between Xgwm0911 and Xbarc194. Labelled genomic Th. intermedium DNA hybridised to the rye 1RS chromatin under high stringency conditions, indicating the presence of shared tandem repeats among the cereals. The novel small alien fragments may explain the difficulty in developing well-adapted lines carrying Wsm1 despite improved tolerance to the virus. The results will facilitate directed chromosome engineering producing agronomically desirable WSMV-resistant germplasm.

  15. Chromosomal Localization of Genes Conferring Desirable Agronomic Traits from Wheat-Agropyron cristatum Disomic Addition Line 5113.

    PubMed

    Li, Qingfeng; Lu, Yuqing; Pan, Cuili; Yao, Miaomiao; Zhang, Jinpeng; Yang, Xinming; Liu, Weihua; Li, Xiuquan; Xi, Yajun; Li, Lihui

    2016-01-01

    Creation of wheat-alien disomic addition lines and localization of desirable genes on alien chromosomes are important for utilization of these genes in genetic improvement of common wheat. In this study, wheat-Agropyron cristatum derivative line 5113 was characterized by genomic in situ hybridization (GISH) and specific-locus amplified fragment sequencing (SLAF-seq), and was demonstrated to be a novel wheat-A. cristatum disomic 6P addition line. Compared with its parent Fukuhokomugi (Fukuho), 5113 displayed multiple elite agronomic traits, including higher uppermost internode/plant height ratio, larger flag leaf, longer spike length, elevated grain number per spike and spikelet number per spike, more kernel number in the middle spikelet, more fertile tiller number per plant, and enhanced resistance to powdery mildew and leaf rust. Genes conferring these elite traits were localized on the A. cristatum 6P chromosome by using SLAF-seq markers and biparental populations (F1, BC1F1 and BC1F2 populations) produced from the crosses between Fukuho and 5113. Taken together, chromosomal localization of these desirable genes will facilitate transferring of high-yield and high-resistance genes from A. cristatum into common wheat, and serve as the foundation for the utilization of 5113 in wheat breeding.

  16. Chromosomal Localization of Genes Conferring Desirable Agronomic Traits from Wheat-Agropyron cristatum Disomic Addition Line 5113

    PubMed Central

    Pan, Cuili; Yao, Miaomiao; Zhang, Jinpeng; Yang, Xinming; Liu, Weihua; Li, Xiuquan; Xi, Yajun; Li, Lihui

    2016-01-01

    Creation of wheat-alien disomic addition lines and localization of desirable genes on alien chromosomes are important for utilization of these genes in genetic improvement of common wheat. In this study, wheat-Agropyron cristatum derivative line 5113 was characterized by genomic in situ hybridization (GISH) and specific-locus amplified fragment sequencing (SLAF-seq), and was demonstrated to be a novel wheat-A. cristatum disomic 6P addition line. Compared with its parent Fukuhokomugi (Fukuho), 5113 displayed multiple elite agronomic traits, including higher uppermost internode/plant height ratio, larger flag leaf, longer spike length, elevated grain number per spike and spikelet number per spike, more kernel number in the middle spikelet, more fertile tiller number per plant, and enhanced resistance to powdery mildew and leaf rust. Genes conferring these elite traits were localized on the A. cristatum 6P chromosome by using SLAF-seq markers and biparental populations (F1, BC1F1 and BC1F2 populations) produced from the crosses between Fukuho and 5113. Taken together, chromosomal localization of these desirable genes will facilitate transferring of high-yield and high-resistance genes from A. cristatum into common wheat, and serve as the foundation for the utilization of 5113 in wheat breeding. PMID:27824906

  17. The role of natural enemy foraging guilds in controlling cereal aphids in Michigan wheat.

    PubMed

    Safarzoda, Shahlo; Bahlai, Christine A; Fox, Aaron F; Landis, Douglas A

    2014-01-01

    Insect natural enemies (predators and parasitoids) provide important ecosystem services by suppressing populations of insect pests in many agricultural crops. However, the role of natural enemies against cereal aphids in Michigan winter wheat (Triticum aestivum L.) is largely unknown. The objectives of this research were to characterize the natural enemy community in wheat fields and evaluate the role of different natural enemy foraging guilds (foliar-foraging versus ground-dwelling predators) in regulating cereal aphid population growth. We investigated these objectives during the spring and summer of 2012 and 2013 in four winter wheat fields on the Michigan State University campus farm in East Lansing, Michigan. We monitored and measured the impact of natural enemies by experimentally excluding or allowing their access to wheat plants infested with Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hemiptera: Aphidae). Our results indicate that the natural enemy community in the wheat fields consisted mostly of foliar-foraging and ground-dwelling predators with relatively few parasitoids. In combination, these natural enemy groups were very effective at reducing cereal aphid populations. We also investigated the role of each natural enemy foraging guild (foliar-foraging versus ground-dwelling predators) independently. Overall, our results suggest that, in combination, natural enemies can almost completely halt early-season aphid population increase. Independently, ground-dwelling predators were more effective at suppressing cereal aphid populations than foliar-foraging predators under the conditions we studied. Our results differ from studies in Europe and the US Great Plains where foliar foraging predators and parasitoids are frequently more important cereal aphid natural enemies.

  18. Genetic loci associated with stem elongation and winter dormancy release in wheat.

    PubMed

    Chen, Yihua; Carver, Brett F; Wang, Shuwen; Zhang, Fengqiu; Yan, Liuling

    2009-03-01

    In winter wheat (Triticum aestivum L.), the stem begins to elongate after the vernalization requirement is satisfied during winter and when favorable temperature and photoperiod conditions are attained in spring. In this study, we precisely measured elongation of the first extended internode on 96 recombinant inbred lines of a population that was generated from a cross between two winter wheat cultivars, Jagger (early stem elongation) and 2174 (late stem elongation). We mapped a major locus for stem elongation to the region where VRN-A1 resides in chromosome 5A. Visible assessment of winter dormancy release was concomitantly associated with this locus. VRN1 was previously cloned based on variation in vernalization requirement between spring wheat carrying a dominant Vrn-1 allele and winter wheat carrying a recessive vrn-1 allele. Both of two winter wheat cultivars in this study carry a recessive vrn-A1 allele; therefore, our results suggest that either VRN-A1 might invoke a new regulatory mechanism or a new gene residing close to VRN-A1 plays a regulatory role in winter wheat development. Phenotypic expression of the vrn-A1a allele of Jagger was more sensitive to the year of measurement of stem elongation than that of the vrn-A1b allele of 2174. In addition to QSte.osu.5A, several loci were also found to have minor effects on initial stem elongation of winter wheat. Seventeen of nineteen locally adapted cultivars in the southern Great Plaints contained the vrn-A1b allele. Hence, breeders in this area have inadvertently selected this allele, contributing to later stem elongation and more conducive developmental patterns for grain production.

  19. Comparison of aeration and spinosad for suppressing insects in stored wheat.

    PubMed

    Flinn, P W; Subramanyam, Bh; Arthur, F H

    2004-08-01

    Field studies were conducted from July 2002 to January 2003 for evaluating the effects of controlled aeration and a commercial biological insecticide, spinosad, in suppressing insect populations in stored wheat. Six cylindrical steel bins were filled with newly harvested (2002 crop year) hard red winter wheat on 9 and 10 July 2002. Each bin contained 30.7 metric tons (1,100 bu) of wheat. Wheat in two bins was left untreated (control), whereas wheat in two bins was treated with spinosad, and in another two bins was subjected to aeration by using aeration controllers. Spinosad was applied to wheat at the time of bin filling to obtain a rate of 1 mg ([AI])/kg. Aeration controllers were set to run the fans when ambient air temperature fell below 23.9, 18.3, and 7.2 degrees C for the first, second, and third cooling cycles, respectively. We added 400 adults each of the rusty grain beetle, Cryptolestes ferrugineus (Stephens); lesser grain borer, Rhyzopertha dominica (F.); and red flour beetle, Tribolium castaneum (Herbst), to the grain at monthly intervals between July and October 2002. Insect density in the bins was estimated monthly by taking 3-kg grain samples from 21 locations within each bin by using a pneumatic grain sampler. No live T. castaneum or C. ferrugineus and very low densities of R. dominica (<0.008 adults per kilogram) were found in wheat treated with spinosad during the 6-mo sampling period. Density of C. ferrugineus and T. castaneum in aerated bins did not exceed two adults per kilogram (the Federal Grain Inspection Service standard for infested wheat), whereas R. dominica increased to 12 adults per kilogram in November 2002, which subsequently decreased to three adults per kilogram in January 2003. In the untreated (control) bins, R. dominica density increased faster than that of C. ferrugineus or T. castaneum. Density of R. dominica peaked at 58 adults per kilogram in October 2002 and decreased subsequently, whereas T. castaneum density was 10 adults

  20. 7 CFR 810.2201 - Definition of wheat.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of wheat. 810.2201 Section 810.2201... GRAIN United States Standards for Wheat Terms Defined § 810.2201 Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club...

  1. 7 CFR 782.17 - Wheat purchased for resale.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Wheat purchased for resale. 782.17 Section 782.17... § 782.17 Wheat purchased for resale. (a) This section applies to an importer or subsequent buyer who imports or purchases Canadian-produced wheat for the purpose of reselling the wheat. (b) The importer...

  2. 7 CFR 810.2201 - Definition of wheat.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Definition of wheat. 810.2201 Section 810.2201... GRAIN United States Standards for Wheat Terms Defined § 810.2201 Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club...

  3. 21 CFR 139.180 - Wheat and soy noodle products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Wheat and soy noodle products. 139.180 Section 139... and Noodle Products § 139.180 Wheat and soy noodle products. (a) Wheat and soy noodle products are the... wheat and soy ingredients used (the soy flour used is made from heat-processed, dehulled soybeans,...

  4. 7 CFR 782.17 - Wheat purchased for resale.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Wheat purchased for resale. 782.17 Section 782.17... § 782.17 Wheat purchased for resale. (a) This section applies to an importer or subsequent buyer who imports or purchases Canadian-produced wheat for the purpose of reselling the wheat. (b) The importer...

  5. 7 CFR 810.2201 - Definition of wheat.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Definition of wheat. 810.2201 Section 810.2201... GRAIN United States Standards for Wheat Terms Defined § 810.2201 Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club...

  6. 7 CFR 810.2201 - Definition of wheat.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Definition of wheat. 810.2201 Section 810.2201... GRAIN United States Standards for Wheat Terms Defined § 810.2201 Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club...

  7. 7 CFR 782.17 - Wheat purchased for resale.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Wheat purchased for resale. 782.17 Section 782.17... § 782.17 Wheat purchased for resale. (a) This section applies to an importer or subsequent buyer who imports or purchases Canadian-produced wheat for the purpose of reselling the wheat. (b) The importer...

  8. 7 CFR 782.17 - Wheat purchased for resale.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Wheat purchased for resale. 782.17 Section 782.17... § 782.17 Wheat purchased for resale. (a) This section applies to an importer or subsequent buyer who imports or purchases Canadian-produced wheat for the purpose of reselling the wheat. (b) The importer...

  9. 7 CFR 782.17 - Wheat purchased for resale.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Wheat purchased for resale. 782.17 Section 782.17... § 782.17 Wheat purchased for resale. (a) This section applies to an importer or subsequent buyer who imports or purchases Canadian-produced wheat for the purpose of reselling the wheat. (b) The importer...

  10. 7 CFR 810.2201 - Definition of wheat.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Definition of wheat. 810.2201 Section 810.2201... GRAIN United States Standards for Wheat Terms Defined § 810.2201 Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club...

  11. Registration of “Pritchett” soft white winter club wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soft white club winter wheat (Triticium aestivum L. ssp. compactum) is a unique component of the wheat production in the PNW, comprising 6-10% of the wheat crop. It is valued for milling and baking functionality and marketed for export in a 20-30% blend with soft white wheat as Western White. Our g...

  12. A latent-period duration model for wheat stem rust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat stem rust caused by Puccinia graminis subsp. graminis (Pgg) is a highly destructive disease of wheat and other small grains. The discovery of a Pgg race (Ug99) that overcomes durable resistance in wheat raises concerns for global wheat production and food security. There is currently no mat...

  13. Glutenin alleles in U.S. Pacific Northwest wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The U.S. Pacific Northwest (PNW), comprised of the states of Washington, Idaho and Oregon, produces about 8 million metric tonnes of wheat annually. This region is somewhat unique in that it grows winter and spring wheats, hard and soft wheats, white and red-grained wheats, and club and lax-head (‘c...

  14. Seasonal dynamics of wheat aphid complex and predator Coccinella septempunctata in relation to abiotic and biotic factors.

    PubMed

    Soni, Rajesh; Deol, G S; Singh, Satnam

    2013-07-01

    Seasonal dynamics studies on wheat aphid complex, comprising of four major species and its predator Coccinella septempunctata were conducted in context to abiotic and biotic factors. The alate form of aphids appeared on the crop during the 1st week of December. The colony build up of aphid complex started during the 2nd week of January and peak was observed after the 1st week of March. Wheat aphid complex started declining in the last week of March and disappeared by mid April. The abiotic factors like maximum temperature and evaporation were most important for the build up of aphids. The grubs and adults of C. septempunctata appeared on the crop during mid February and their population increased with the increase in aphid population. The grubs and adult population showed a strong positive correlation with aphid complex. The population of predators had significant positive correlation with maximum, minimum, mean temperature, sunshine and vapour pressure. The population of aphids declined after the 2nd week of March due to the rise in temperature, crop maturity and this in turn resulted in the lowering of the predator population. The studies evaluate in detail the abiotic and biotic factors regulating the wheat aphid complex and C. septempunctata populations under wheat agro-ecosystem.

  15. A study of the tolerance block approach to special stratification. [winter wheat in Kansas

    NASA Technical Reports Server (NTRS)

    Richardson, W. (Principal Investigator)

    1979-01-01

    The author has identified the following significant results. Twelve winter wheat LACIE segments in Kansas were used to compare the performance of three clustering methods: (1) BCLUST, which uses a spectral distance function to accumulate clusters; (2) blocks-alone, which divides spectral space into equally populated blocks; and (3) block-seeds, which uses spectral means of blocks-alone as seeds for accumulating distance-type clusters. Both BCLUST and block-seeds performed equally well and outperformed blocks-alone significantly. Their average variance ratio of about 0.5 showed imperfect separation of wheat from non-wheat. This result points to the need to explore the achievable crop separability in the spectral/temporal domain, and suggest evaluating derived features rather than data channels as a means to achieve purer spectral strata.

  16. Wheat Blast: A New Fungal Inhabitant to Bangladesh Threatening World Wheat Production

    PubMed Central

    Sadat, Md. Abu; Choi, Jaehyuk

    2017-01-01

    World wheat production is now under threat due to the wheat blast outbreak in Bangladesh in early March 2016. This is a new disease in this area, indicating the higher possibility of this pathogen spreading throughout the Asia, the world’s largest wheat producing area. Occurrence of this disease caused ~3.5% reduction of the total wheat fields in Bangladesh. Its economic effect on the Bangladesh wheat market was little because wheat contributes to 3% of total cereal consumption, among which ~70% have been imported from other countries. However, as a long-term perspective, much greater losses will occur once this disease spreads to other major wheat producing areas of Bangladesh, India, and Pakistan due to the existing favorable condition for the blast pathogen. The wheat blast pathogen belongs to the Magnaporthe oryzae species complex causing blast disease on multiple hosts in the Poaceae family. Phylogenetic analysis revealed that the Bangladesh outbreak strains and the Brazil outbreak strains were the same phylogenetic lineage, suggesting that they might be migrated from Brazil to Bangladesh during the seed import. To protect wheat production of Bangladesh and its neighbors, several measures including rigorous testing of seed health, use of chemicals, crop rotation, reinforcement of quarantine procedures, and increased field monitoring should be implemented. Development of blast resistant wheat varieties should be a long-term solution and combination of different methods with partial resistant lines may suppress this disease for some time. PMID:28381956

  17. Wheat Blast: A New Fungal Inhabitant to Bangladesh Threatening World Wheat Production.

    PubMed

    Sadat, Md Abu; Choi, Jaehyuk

    2017-04-01

    World wheat production is now under threat due to the wheat blast outbreak in Bangladesh in early March 2016. This is a new disease in this area, indicating the higher possibility of this pathogen spreading throughout the Asia, the world's largest wheat producing area. Occurrence of this disease caused ~3.5% reduction of the total wheat fields in Bangladesh. Its economic effect on the Bangladesh wheat market was little because wheat contributes to 3% of total cereal consumption, among which ~70% have been imported from other countries. However, as a long-term perspective, much greater losses will occur once this disease spreads to other major wheat producing areas of Bangladesh, India, and Pakistan due to the existing favorable condition for the blast pathogen. The wheat blast pathogen belongs to the Magnaporthe oryzae species complex causing blast disease on multiple hosts in the Poaceae family. Phylogenetic analysis revealed that the Bangladesh outbreak strains and the Brazil outbreak strains were the same phylogenetic lineage, suggesting that they might be migrated from Brazil to Bangladesh during the seed import. To protect wheat production of Bangladesh and its neighbors, several measures including rigorous testing of seed health, use of chemicals, crop rotation, reinforcement of quarantine procedures, and increased field monitoring should be implemented. Development of blast resistant wheat varieties should be a long-term solution and combination of different methods with partial resistant lines may suppress this disease for some time.

  18. Genome-wide linkage disequilibrium analysis in bread wheat and durum wheat.

    PubMed

    Somers, Daryl J; Banks, Travis; Depauw, Ron; Fox, Stephen; Clarke, John; Pozniak, Curtis; McCartney, Curt

    2007-06-01

    Bread wheat and durum wheat were examined for linkage disequilibrium (LD) using microsatellite markers distributed across the genome. The allele database consisted of 189 bread wheat accessions genotyped at 370 loci and 93 durum wheat accessions genotyped at 245 loci. A significance level of p < 0.001 was set for all comparisons. The bread and durum wheat collections showed that 47.9% and 14.0% of all locus pairs were in LD, respectively. LD was more prevalent between loci on the same chromosome compared with loci on independent chromosomes and was highest between adjacent loci. Only a small fraction (bread wheat, 0.9%; durum wheat, 3.2%) of the locus pairs in LD showed R2 values > 0.2. The LD between adjacent locus pairs extended (R2 > 0.2) approximately 2-3 cM, on average, but some regions of the bread and durum wheat genomes showed high levels of LD (R2 = 0.7 and 1.0, respectively) extending 41.2 and 25.5 cM, respectively. The wheat collections were clustered by similarity into subpopulations using unlinked microsatellite data and the software Structure. Analysis within subpopulations showed 14- to 16-fold fewer locus pairs in LD, higher R2 values for those pairs in LD, and LD extending further along the chromosome. The data suggest that LD mapping of wheat can be performed with simple sequence repeats to a resolution of <5 cM.

  19. Wheat mosaic virus (WMoV), the causal agent of High Plains disease, is present in Ohio wheat fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat mosaic virus (WMoV), the causal agent of High Plains disease in wheat, was found in wheat fields in three western counties in Ohio: Auglaize, Miami, and Paulding. WMoV nucleoprotein sequence was identified from Illumina deep sequencing of RNA collected from symptomatic and asymptomatic wheat s...

  20. End-use quality of CIMMYT-derived soft kernel durum wheat germplasm. I. Grain, milling and soft wheat quality.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat kernel texture is used in part to define U.S. wheat market class due to its importance in end-use quality and utilization. Durum wheat (Triticum turgidum subsp. durum) has lower demand and fewer culinary end-uses compared to bread wheat because of its extremely hard kernel texture, which precl...