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1

Genetic Diversity and Population Structure Analysis of European Hexaploid Bread Wheat (Triticum aestivum L.)  

E-print Network

Genetic Diversity and Population Structure Analysis of European Hexaploid Bread Wheat (Triticum, Jahoor A (2014) Genetic Diversity and Population Structure Analysis of European Hexaploid Bread Wheat Progress in plant breeding is facilitated by accurate information about genetic structure and diversity

Schierup, Mikkel Heide

2

Genetic map of Triticum turgidum based on a hexaploid wheat population without genetic recombination for D genome  

PubMed Central

Background A synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population. Results Of the 606 markers used to assemble the genetic map, 588 (97%) were assigned to linkage groups. These included 513 Diversity Arrays Technology (DArT) markers, 72 simple sequence repeat (SSR), one insertion site-based polymorphism (ISBP), and two high-molecular-weight glutenin subunit (HMW-GS) markers. These markers were assigned to the 14 chromosomes, covering 2048.79?cM, with a mean distance of 3.48?cM between adjacent markers. This map showed good coverage of the A and B genome chromosomes, apart from 3A, 5A, 6A, and 4B. Compared with previously reported maps, most shared markers showed highly consistent orders. This map was successfully used to identify five quantitative trait loci (QTL), including two for spikelet number on chromosomes 7A and 5B, two for spike length on 7A and 3B, and one for 1000-grain weight on 4B. However, differences in crossability QTL between the two T. turgidum parents may explain the segregation distortion regions on chromosomes 1A, 3B, and 6B. Conclusions A genetic map of T. turgidum including 588 markers was constructed using a synthetic doubled haploid (SynDH) hexaploid wheat population. Five QTLs for three agronomic traits were identified from this population. However, more markers are needed to increase the density and resolution of this map in the future study. PMID:22888829

2012-01-01

3

Inheritance of Russian wheat aphid resistance from tetraploid wheat accessions during transfer to hexaploid wheat  

Microsoft Academic Search

Identification of new sources of resistance to Russian wheat aphid (RWA) (Diuraphis noxia (Kurdjumov) in wheat (Triticum aestivum L.) has become very important with the identification of several new biotypes since 2003. Our objective was to characterize\\u000a inheritance and expression of resistance to RWA biotype 2 from three tetraploid wheat landraces (Triticum turgidum L. subsp. dicoccon) during transfer to hexaploid

Benjamin M. Beyer; Scott D. Haley; Nora L. V. Lapitan; Junhua H. Peng; Frank B. Peairs

2011-01-01

4

Virus-Induced Gene Silencing in Hexaploid Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Functional genomics analysis in hexaploid wheat is greatly impeded by the genetic redundancy of polyploidy and the difficulties in generating large numbers of transgenic plants required in insertional mutagenesis strategies. Virus-induced gene silencing (VIGS), however, is a strategy for creating g...

5

Evolution of physiological responses to salt stress in hexaploid wheat  

PubMed Central

Hexaploid bread wheat (Triticum aestivum L., genome BBAADD) is generally more salt tolerant than its tetraploid wheat progenitor (Triticum turgidum L.). However, little is known about the physiological basis of this trait or about the relative contributions of allohexaploidization and subsequent evolutionary genetic changes on the trait development. Here, we compared the salt tolerance of a synthetic allohexaploid wheat (neo-6x) with its tetraploid (T. turgidum; BBAA) and diploid (Aegilops tauschii; DD) parents, as well as a natural hexaploid bread wheat (nat-6x). We studied 92 morphophysiological traits and analyzed homeologous gene expression of a major salt-tolerance gene High-Affinity K+ Transporter 1;5 (HKT1;5). We observed that under salt stress, neo-6x exhibited higher fitness than both of its parental genotypes due to inheritance of favorable traits like higher germination rate from the 4x parent and the stronger root Na+ retention capacity from the 2x parent. Moreover, expression of the D-subgenome HKT1;5 homeolog, which is responsible for Na+ removal from the xylem vessels, showed an immediate transcriptional reprogramming following allohexaploidization, i.e., from constitutive high basal expression in Ae. tauschii (2x) to salt-induced expression in neo-6x. This phenomenon was also witnessed in the nat-6x. An integrated analysis of 92 traits showed that, under salt-stress conditions, neo-6x resembled more closely the 2x than the 4x parent, suggesting that the salt stress induces enhanced expressivity of the D-subgenome homeologs in the synthetic hexaploid wheat. Collectively, the results suggest that condition-dependent functionalization of the subgenomes might have contributed to the wide-ranging adaptability of natural hexaploid wheat. PMID:25074914

Yang, Chunwu; Zhao, Long; Zhang, Huakun; Yang, Zongze; Wang, Huan; Wen, Shanshan; Zhang, Chunyu; Rustgi, Sachin; von Wettstein, Diter; Liu, Bao

2014-01-01

6

Suspension and protoplast culture of hexaploid wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Suspension cultures have been initiated from embryogenic callus of hexaploid wheat (Triticum aestivum L.). Most commonly, these “suspensions” are composed of callus-like clusters (up to 2 mm in diameter). Two rapidly-growing lines (MBE6 and C82d) have been obtained, which consist of smaller aggregates of cytoplasmic cells, and these have been maintained for more than 4 years. These lines show very

S. E. Maddock

1987-01-01

7

Chromosomes form into seven groups in hexaploid and tetraploid wheat as a prelude to meiosis  

E-print Network

Chromosomes form into seven groups in hexaploid and tetraploid wheat as a prelude to meiosis. The present study reveals that, as a prelude to meiosis, these 21 chromosome pairs in hexaploid (and. This results in the association of multiple chromosomes, which then need to be resolved as meiosis progresses

Shaw, Peter

8

Quality Characteristics of Waxy Hexaploid Wheat ( Triticum aestivum L.): Properties of Starch Gelatinization and Retrogradation  

Microsoft Academic Search

Cereal Chem. 74(5):576-580 The viscoelastic properties and molecular structure of the starch isolated from waxy (amylose-free) hexaploid wheat (WHW) (Triticum aestivum L.) were examined. WHW starch generally had lower gelatinization onset temperature, peak viscosity, and setback than the starch isolated from normal hexaploid wheat (NHW). Differential scanning calorimetry (DSC) showed that WHW starch had higher transition temperatures (To, Tp, and

Katsuyuki Hayakawa; Keiko Tanaka; Toshiki Nakamura; Shigeru Endo; Tsuguhiro Hoshino

1997-01-01

9

Genetic association of OPR genes with resistance to Hessian fly in hexaploid wheat  

PubMed Central

Background Hessian fly (Mayetiola destructor) is one of the most destructive pests of wheat. The genes encoding 12-oxo-phytodienoic acid reductase (OPR) and lipoxygenase (LOX) play critical roles in insect resistance pathways in higher plants, but little is known about genes controlling resistance to Hessian fly in wheat. Results In this study, 154 F6:8 recombinant inbred lines (RILs) generated from a cross between two cultivars, ‘Jagger’ and ‘2174’ of hexaploid wheat (2n?=?6?×?=42; AABBDD), were used to map genes associated with resistance to Hessian fly. Two QTLs were identified. The first one was a major QTL on chromosome 1A (QHf.osu-1A), which explained 70% of the total phenotypic variation. The resistant allele at this locus in cultivar 2174 could be orthologous to one or more of the previously mapped resistance genes (H9, H10, H11, H16, and H17) in tetraploid wheat. The second QTL was a minor QTL on chromosome 2A (QHf.osu-2A), which accounted for 18% of the total phenotypic variation. The resistant allele at this locus in 2174 is collinear to an Yr17-containing-fragment translocated from chromosome 2N of Triticum ventricosum (2n?=?4?×?=28; DDNN) in Jagger. Genetic mapping results showed that two OPR genes, TaOPR1-A and TaOPR2-A, were tightly associated with QHf.osu-1A and QHf.osu-2A, respectively. Another OPR gene and three LOX genes were mapped but not associated with Hessian fly resistance in the segregating population. Conclusions This study has located two major QTLs/genes in bread wheat that can be directly used in wheat breeding programs and has also provided insights for the genetic association and disassociation of Hessian fly resistance with OPR and LOX genes in wheat. PMID:23724909

2013-01-01

10

Genetic analysis of tetraploid and hexaploid wheat by utilization of monopentaploid hybrids  

Microsoft Academic Search

This report deals with a method of analysis which uses existing hexaploid wheat monosomics to establish gene-chromosome associations in a tetraploid variety. Monosomics of Triticum aestivum cv. Chinese Spring belonging to the 14 lines of A and B genomes were crossed as female parents with Triticum durum cv. Capeiti, a spring type at present widely grown in Italy. For each

A. Bozzini; B. Giorgi

1971-01-01

11

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...

12

Identification of quantitative trait loci for abscisic acid responsiveness in the D-genome of hexaploid wheat.  

PubMed

In crop species such as wheat, abiotic stresses and preharvest sprouting reduce grain yield and quality. The plant hormone abscisic acid (ABA) plays important roles in abiotic stress tolerance and seed dormancy. In previous studies, we evaluated ABA responsiveness of 67 Aegilops tauschii accessions and their synthetic hexaploid wheat lines, finding wide variation that was due to the D-genome. In this study, quantitative trait locus (QTL) analysis was performed using an F2 population derived from crosses of highly ABA-responsive and less-responsive synthetic wheat lines. A significant QTL was detected on chromosome 6D, in a similar location to that reported for ABA responsiveness using recombinant inbred lines derived from common wheat cultivars Mironovskaya 808 and Chinese Spring. A comparative map and physiological and expression analyses of the 6D QTL suggested that this locus involved in line differences among wheat synthetics is different from that involved in cultivar differences in common wheat. The common wheat 6D QTL was found to affect seed dormancy and the regulation of cold-responsive/late embryogenesis abundant genes during dehydration. However, in synthetic wheat, we failed to detect any association of ABA responsiveness with abiotic stress tolerance or seed dormancy, at least under our experimental conditions. Development of near-isogenic lines will be important for functional analyses of the synthetic wheat 6D QTL. PMID:24877675

Iehisa, Julio C M; Matsuura, Takakazu; Mori, Izumi C; Yokota, Hirokazu; Kobayashi, Fuminori; Takumi, Shigeo

2014-06-15

13

Transcript expression profile of water-limited roots of hexaploid wheat (Triticum aestivum 'Opata').  

PubMed

Triticum aestivum 'Opata' is an elite hard red spring wheat that has been used as a parent of the ITMI (International Triticeae Mapping Inititative) mapping population and also in the production of synthetically derived hexaploid wheats, some of which (following selection) show increased drought tolerance relative to Opata. Here, we describe the response of Opata roots to water withholding, using physiological variables and oligonucleotide microarrays. We identified 394 distinct transcripts whose abundance differed (p < or = 0.05) at least 1.5-fold between water-limited and control roots of Opata, of which 190 transcripts increased and 204 decreased following water limitation. In addition to previously characterized markers of abiotic stress and many genes of unknown function, we identified multiple putative glucanases and class III peroxidases as being particularly responsive to stress. We also compared these data to previously described microarray analyses of Opata's more drought-tolerant, synthetic-derived progeny, and found a relatively high correlation (r = 0.7) between responsive transcripts in the two genotypes, despite differing physiological responses. Some of the transcripts that we confirmed by qRT-PCR as being differentially expressed between Opata and the more tolerant synthetic-derived genotype under stress include a class III peroxidase, an AP2-family transcription factor, and several transcripts of unknown function. PMID:18438439

Mohammadi, Mohsen; Kav, Nat N V; Deyholos, Michael K

2008-05-01

14

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...

15

Characterization of HMW-GS and evaluation of their diversity in morphologically elite synthetic hexaploid wheats  

PubMed Central

High molecular weight glutenin subunit composition and variation in 95 Elite-1 synthetic hexaploid (SH) wheats (Triticum turgidum/Aegilops tauschii; 2n = 6× = 42; AABBDD) were determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis method (SDS-PAGE). Twenty two different alleles at Glu-1 loci in SHs were observed. Forty four different patterns of HMW-GS in synthetics were found. This higher HMW glutenin composition was due to higher proportion of D-genome encoded subunits in these SHs. 8% urea/SDS-PAGE better discriminated subunit 2* than 12% gels. However 12% urea/SDS-PAGE allowed differentiated mobility of Glu-Dt1 subunits. Genetic variability at Glu-Dt1 locus was greater than Glu-A1 and Glu-B1 loci. The relative high frequency of superior alleles, Glu-B1b and Glu-Dt1d indicated the superior bread making quality attributes embedded in these synthetic hexaploid wheats. Of the 95 Elite-1 SHs 27.1% possessed superior alleles at Glu-A1 and 51% had superior alleles at Glu-B1 locus. At Glu-Dt1 frequency of inferior allele 1Dx2 + 1Dy12 was very low (5.26%) and nine different rare alleles along with the higher frequency (22.1%) of D-genome encoded subunit, 1Dx5 + 1Dy10, were observed. These superior alleles shall form the priority selective sieve for their usage in wheat improvement efforts. PMID:23341752

Rasheed, Awais; Safdar, Tania; Gul-Kazi, Alvina; Mahmood, Tariq; Akram, Zahid; Mujeeb-Kazi, Abdul

2012-01-01

16

Genome-wide association mapping for seedling and adult plant resistance to stripe rust in synthetic hexaploid wheat.  

PubMed

Use of genetic diversity from related wild and domesticated species has made a significant contribution to improving wheat productivity. Synthetic hexaploid wheats (SHWs) exhibit natural genetic variation for resistance and/or tolerance to biotic and abiotic stresses. Stripe rust caused by (Puccinia striiformis f. sp. tritici; Pst), is an important disease of wheat worldwide. To characterise loci conferring resistance to stripe rust in SHWs, we conducted a genome-wide association study (GWAS) with a panel of 181 SHWs using the wheat 9 K SNP iSelect array. The SHWs were evaluated for their response to the prevailing races of Pst at the seedling and adult plant stages, the latter in replicated field trials at two sites in Ethiopia in 2011. About 28% of the SHWs exhibited immunity at the seedling stage while 56% and 83% were resistant to Pst at the adult plant stage at Meraro and Arsi Robe, respectively. A total of 27 SNPs in nine genomic regions (1 BS, 2 AS, 2 BL, 3 BL, 3 DL, 5A, 5 BL, 6DS and 7A) were linked with resistance to Pst at the seedling stage, while 38 SNPs on 18 genomic regions were associated with resistance at the adult plant stage. Six genomic regions were commonly detected at both locations using a mixed linear model corrected for population structure, kinship relatedness and adjusted for false discovery rate (FDR). The loci on chromosome regions 1 AS, 3 DL, 6 DS and 7 AL appeared to be novel QTL; our results confirm that resynthesized wheat involving its progenitor species is a rich source of new stripe (yellow) rust resistance that may be useful in choosing SHWs and incorporating diverse yellow rust (YR) resistance loci into locally adapted wheat cultivars. PMID:25153126

Zegeye, Habtemariam; Rasheed, Awais; Makdis, Farid; Badebo, Ayele; Ogbonnaya, Francis C

2014-01-01

17

Genome-Wide Association Mapping for Seedling and Adult Plant Resistance to Stripe Rust in Synthetic Hexaploid Wheat  

PubMed Central

Use of genetic diversity from related wild and domesticated species has made a significant contribution to improving wheat productivity. Synthetic hexaploid wheats (SHWs) exhibit natural genetic variation for resistance and/or tolerance to biotic and abiotic stresses. Stripe rust caused by (Puccinia striiformis f. sp. tritici; Pst), is an important disease of wheat worldwide. To characterise loci conferring resistance to stripe rust in SHWs, we conducted a genome-wide association study (GWAS) with a panel of 181 SHWs using the wheat 9K SNP iSelect array. The SHWs were evaluated for their response to the prevailing races of Pst at the seedling and adult plant stages, the latter in replicated field trials at two sites in Ethiopia in 2011. About 28% of the SHWs exhibited immunity at the seedling stage while 56% and 83% were resistant to Pst at the adult plant stage at Meraro and Arsi Robe, respectively. A total of 27 SNPs in nine genomic regions (1BS, 2AS, 2BL, 3BL, 3DL, 5A, 5BL, 6DS and 7A) were linked with resistance to Pst at the seedling stage, while 38 SNPs on 18 genomic regions were associated with resistance at the adult plant stage. Six genomic regions were commonly detected at both locations using a mixed linear model corrected for population structure, kinship relatedness and adjusted for false discovery rate (FDR). The loci on chromosome regions 1AS, 3DL, 6DS and 7AL appeared to be novel QTL; our results confirm that resynthesized wheat involving its progenitor species is a rich source of new stripe (yellow) rust resistance that may be useful in choosing SHWs and incorporating diverse yellow rust (YR) resistance loci into locally adapted wheat cultivars. PMID:25153126

Makdis, Farid; Badebo, Ayele; Ogbonnaya, Francis C.

2014-01-01

18

Population Dynamics of Diploid and Hexaploid Populations of a Perennial Herb  

PubMed Central

Background and Aims Despite the recent enormous increase in the number of studies on polyploid species, no studies to date have explored the population dynamics of these taxa. It is thus not known whether the commonly reported differences in single life-history traits between taxa of different ploidy levels result in differences in population dynamics. Methods This study explores differences in single life-history traits and in the complete life cycle between populations of different ploidy levels and compares these differences with differences observed between different habitat types and years. Diploid and hexaploid populations of a perennial herb, Aster amellus, are used as the study system. Transition matrix models were used to describe the dynamics of the populations, and population growth rates, elasticity values and life-table response experiments were used to compare the dynamics between populations and years. Key Results The results indicate that between-year variation in population dynamics is much larger than variation between different ploidy levels and different habitat conditions. Significant differences exist, however, in the structure of the transition matrices, indicating that the dynamics of the different ploidy levels are different. Strong differences in probability of extinction of local populations were also found, with hexaploid populations having higher probability than diploid populations, indicating strong potential differences in persistence of these populations. Conclusions This is the first study on complete population dynamics of plants of different ploidy levels. This knowledge will help to understand the ability of new ploidy levels to spread into new areas and persist there, and the interactions of different ploidy levels in secondary contact zones. This knowledge will also contribute to understanding of interactions of different ploidy levels with other plant species or other interacting organisms such as pollinators or herbivores. PMID:17881342

Münzbergová, Zuzana

2007-01-01

19

Genome-wide association for grain morphology in synthetic hexaploid wheats using digital imaging analysis  

PubMed Central

Background Grain size and shape greatly influence grain weight which ultimately enhances grain yield in wheat. Digital imaging (DI) based phenomic characterization can capture the three dimensional variation in grain size and shape than has hitherto been possible. In this study, we report the results from using digital imaging of grain size and shape to understand the relationship among different components of this trait, their contribution to enhance grain weight, and to identify genomic regions (QTLs) controlling grain morphology using genome wide association mapping with high density diversity array technology (DArT) and allele-specific markers. Results Significant positive correlations were observed between grain weight and grain size measurements such as grain length (r?=?0.43), width, thickness (r?=?0.64) and factor from density (FFD) (r?=?0.69). A total of 231 synthetic hexaploid wheats (SHWs) were grouped into five different sub-clusters by Bayesian structure analysis using unlinked DArT markers. Linkage disequilibrium (LD) decay was observed among DArT loci?>?10 cM distance and approximately 28% marker pairs were in significant LD. In total, 197 loci over 60 chromosomal regions and 79 loci over 31 chromosomal regions were associated with grain morphology by genome wide analysis using general linear model (GLM) and mixed linear model (MLM) approaches, respectively. They were mainly distributed on homoeologous group 2, 3, 6 and 7 chromosomes. Twenty eight marker-trait associations (MTAs) on the D genome chromosomes 2D, 3D and 6D may carry novel alleles with potential to enhance grain weight due to the use of untapped wild accessions of Aegilops tauschii. Statistical simulations showed that favorable alleles for thousand kernel weight (TKW), grain length, width and thickness have additive genetic effects. Allelic variations for known genes controlling grain size and weight, viz. TaCwi-2A, TaSus-2B, TaCKX6-3D and TaGw2-6A, were also associated with TKW, grain width and thickness. In silico functional analysis predicted a range of biological functions for 32 DArT loci and receptor like kinase, known to affect plant development, appeared to be common protein family encoded by several loci responsible for grain size and shape. Conclusion Conclusively, we demonstrated the application and integration of multiple approaches including high throughput phenotyping using DI, genome wide association studies (GWAS) and in silico functional analysis of candidate loci to analyze target traits, and identify candidate genomic regions underlying these traits. These approaches provided great opportunity to understand the breeding value of SHWs for improving grain weight and enhanced our deep understanding on molecular genetics of grain weight in wheat. PMID:24884376

2014-01-01

20

Genotype-dependent Burst of Transposable Element Expression in Crowns of Hexaploid Wheat (Triticum aestivum L.) during Cold Acclimation  

PubMed Central

The expression of 1,613 transposable elements (TEs) represented in the Affymetrix Wheat Genome Chip was examined during cold treatment in crowns of four hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throughout the experiment in three of the genotypes. In winter Norstar, the most cold-hardy of the four genotypes, a subset of the TEs showed a burst of expression after vernalization saturation was achieved. About 47% of the TEs were expressed, and both Class I (retrotransposons) and Class II (DNA transposons) types were well represented. Gypsy and Copia were the most represented among the retrotransposons while CACTA and Mariner were the most represented DNA transposons. The data suggests that the Vrn-A1 region plays a role in the stage-specific induction of TE expression in this genotype. PMID:22474410

Laudencia-Chingcuanco, Debbie; Fowler, D. Brian

2012-01-01

21

Whole genome QTL analysis of Stagonospora nodorum blotch resistance and validation of the SnTox4-Snn4 interaction in hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Abeysekara, N.S., Faris, J.D., Chao, S., McClean, P.E., and Friesen, T.L. 201_. Whole genome QTL analysis of Stagonospora nodorum blotch resistance and validation of the SnTox4- Snn4 interaction in hexaploid wheat. Phytopathology Necrotrophic effectors (also known as host-selective toxins) are impor...

22

QTug.sau-3B Is a Major Quantitative Trait Locus for Wheat Hexaploidization  

PubMed Central

Meiotic nonreduction resulting in unreduced gametes is thought to be the predominant mechanism underlying allopolyploid formation in plants. Until now, however, its genetic base was largely unknown. The allohexaploid crop common wheat (Triticum aestivum L.), which originated from hybrids of T. turgidum L. with Aegilops tauschii Cosson, provides a model to address this issue. Our observations of meiosis in pollen mother cells from T. turgidum×Ae. tauschii hybrids indicated that first division restitution, which exhibited prolonged cell division during meiosis I, was responsible for unreduced gamete formation. A major quantitative trait locus (QTL) for this trait, named QTug.sau-3B, was detected on chromosome 3B in two T. turgidum×Ae. tauschii haploid populations. This QTL is situated between markers Xgwm285 and Xcfp1012 and covered a genetic distance of 1 cM in one population. QTug.sau-3B is a haploid-dependent QTL because it was not detected in doubled haploid populations. Comparative genome analysis indicated that this QTL was close to Ttam-3B, a collinear homolog of tam in wheat. Although the relationship between QTug.sau-3B and Ttam requires further study, high frequencies of unreduced gametes may be related to reduced expression of Ttam in wheat. PMID:25128436

Hao, Ming; Luo, Jiangtao; Zeng, Deying; Zhang, Li; Ning, Shunzong; Yuan, Zhongwei; Yan, Zehong; Zhang, Huaigang; Zheng, Youliang; Feuillet, Catherine; Choulet, Frédéric; Yen, Yang; Zhang, Lianquan; Liu, Dengcai

2014-01-01

23

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

PubMed Central

Background ?-gliadins form a multigene protein family encoded by multiple ?-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 ?-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 ?-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 ?-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 ?-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 'gene family-specific quantitative transcriptome profiling'. PMID:19171027

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

24

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

PubMed

For map-based cloning of genes conferring important traits in the hexaploid wheat line 92R137, a bacterial artificial chromosome (BAC) library, including two sublibraries, was constructed using the genomic DNA of 92R137 digested with restriction enzymes HindIII and BamHI. The BAC library was composed of total 765,696 clones, of which 390,144 were from the HindIII digestion and 375,552 from the BamHI digestion. Through pulsed-field gel electrophoresis (PFGE) analysis of 453 clones randomly selected from the HindIII sublibrary and 573 clones from the BamHI sublibrary, the average insert sizes were estimated as 129 and 113 kb, respectively. Thus, the HindIII sublibrary was estimated to have a 3.01-fold coverage and the BamHI sublibrary a 2.53-fold coverage based on the estimated hexaploid wheat genome size of 16,700 Mb. The 765,696 clones were arrayed in 1,994 384-well plates. All clones were also arranged into plate pools and further arranged into 5-dimensional (5D) pools. The probability of identifying a clone corresponding to any wheat DNA sequence (such as gene Yr26 for stripe rust resistance) from the library was estimated to be more than 99.6%. Through polymerase chain reaction screening the 5D pools with Xwe173, a marker tightly linked to Yr26, six BAC clones were successfully obtained. These results demonstrate that the BAC library is a valuable genomic resource for positional cloning of Yr26 and other genes of interest. PMID:24895618

Zeng, Qingdong; Yuan, Fengping; Xu, Xin; Shi, Xue; Nie, Xiaojun; Zhuang, Hua; Chen, Xianming; Wang, Zhonghua; Wang, Xiaojie; Huang, Lili; Han, Dejun; Kang, Zhensheng

2014-01-01

25

SYNTHETIC HEXAPLOID WHEATS CAN EXPAND THE RANGE OF PUROINDOLINE HAPLOTYPES AND KERNEL TEXTURE IN TRITICUM AESTIVUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

The kernel softness of wheat is limited by the sole,‘wild-type’ puroindoline gene sequences contributed by wheat’s wild ancestor. Greater genetic variability in the puroindoline genes may expand the range of kernel texture in wheat. “Synthetic” wheats provide greater and direct access to the wild a...

26

Types and Rates of Sequence Evolution at the High-Molecular-Weight Glutenin Locus in Hexaploid Wheat and Its Ancestral Genomes  

PubMed Central

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. PMID:17028342

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

2006-01-01

27

Molecular biology and genetics \\/ Biologie et génétique moléculaires Cloning, identification, expression analysis and phylogenetic relevance of two NADP-dependent malic enzyme genes from hexaploid wheat  

Microsoft Academic Search

The NADP-dependent malic enzyme (NADP-ME; EC1.1.1.40) found in many metabolic pathways catalyzes the oxidative de- carboxylation of L-malate, producing pyruvate, CO2 and NADPH. The NADP-MEs have been well studied in C4 plants but not well in C3 plants. In this study, we identified the NADP-ME isoforms from hexaploid wheat (Triticum aestivum L). Two different NADP-ME transcripts were first identified in

Zhen-Yan Fu; Zheng-Bin Zhang; Xiao-Jun Hu; Hong-Bo Shao; Xu Ping

28

Identification and characterization of the three homeologues of a new sucrose transporter in hexaploid wheat (Triticum aestivum L.)  

PubMed Central

Background Sucrose transporters (SUTs) play important roles in regulating the translocation of assimilates from source to sink tissues. Identification and characterization of new SUTs in economically important crops such as wheat provide insights into their role in determining seed yield. To date, however, only one SUT of wheat has been reported and functionally characterized. The present study reports the isolation and characterization of a new SUT, designated as TaSUT2, and its homeologues (TaSUT2A, TaSUT2B and TaSUT2D) in hexaploid wheat (Triticum aestivum L.). Results TaSUT2A and TaSUT2B genes each encode a protein with 506 amino acids, whereas TaSUT2D encodes a protein of 508 amino acids. The molecular mass of these proteins is predicted to be?~?54 kDA. Topological analysis of the amino acid sequences of the three homeologues revealed that they contain 12 transmembrane spanning helices, which are described as distinct characteristic features of glycoside-pentoside-hexuronide cation symporter family that includes all known plant SUTs, and a histidine residue that appears to be localized at and associated conformationally with the sucrose binding site. Yeast SUSY7/ura3 strain cells transformed with TaSUT2A, TaSUT2B and TaSUT2D were able to uptake sucrose and grow on a medium containing sucrose as a sole source of carbon; however, our subcellular localization study with plant cells revealed that TaSUT2 is localized to the tonoplast. The expression of TaSUT2 was detected in the source, including flag leaf blade, flag leaf sheath, peduncle, glumes, palea and lemma, and sink (seed) tissues. The relative contributions of the three genomes of wheat to the total expression of TaSUT2 appear to differ with tissues and developmental stages. At the cellular level, TaSUT2 is expressed mainly in the vein of developing seeds and subepidermal mesophyll cells of the leaf blade. Conclusion This study demonstrated that TaSUT2 is a new wheat SUT protein. Given that TaSUT2 is localized to the tonoplast and sucrose is temporarily stored in the vacuoles of both source and sink tissues, our data imply that TaSUT2 is involved in the intracellular partitioning of sucrose, particularly between the vacuole and cytoplasm. PMID:24237613

2013-01-01

29

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

PubMed Central

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

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

30

Molecular and cytological characterization of genomic variability in hexaploid wheat 'Lindström'.  

PubMed

'Lindström' wheat (AABBDD+rye B chromosomes) was used to study the effects of alien chromatin introgressed into a wheat genetic background, subjecting the wheat genome to a new and transient allopolyploidisation episode. Using this experimental material, we have previously demonstrated that no large-scale chromosomal translocations occurred as a result of the genomic constitution of the addition line. However, we have shown that the presence of a number of rye B chromosomes is associated with changes in the interphase organization and expression patterns of wheat rDNA loci. We have now extended our studies to focus on a further characterization of 'Lindström' 5S rDNA loci and also on high molecular weight glutenin subunit (HMW-GS) patterns. In the process, we have uncovered an unusually large variant of the 5S rDNA locus on wheat chromosome 1B (not to be confused with rye B chromosomes) and 2 novel HMW glutenin y-type alleles. These changes are not directly related to variation in rye B chromosome number in the present material, but the fact that a new, and still segregating, 1Dy HMW-GS gene was identified indicates a recent timescale for its origin. Strikingly, the 'Lindström' 5S rDNA 1B locus integrates a unit sharing 94% homology with a rye 5S rDNA sequence, suggesting the possibility that the wheat locus was colonized by highly homologous rye sequences during the breeding of 'Lindström', when the rye and wheat genomes were together, albeit briefly, in the same nucleus. PMID:16391695

Costa-Nunes, Pedro; Ribeiro, Teresa; Delgado, Margarida; Morais-Cecílio, Leonor; Jones, Neil; Viegas, Wanda

2005-10-01

31

The genetic control of grain esterases in hexaploid wheat : 2. Homoeologous loci in related species.  

PubMed

A comparison of EST-5 grain esterase phenotypes from wheat-alien amphiploid, addition and substitution genotypes, resolved by flat-bed isoelectric focusing identified homoeologous Est-5 loci on chromosome 3H of Hordeum vulgare, 3H(ch) of H. chilense, 3S(b) of Aegilops bicornis, 3S(1) of Ae. sharonensis and Ae. longissima and 6R of Secale cereale and 6R(m) of S. montanum. The Est-5 genes in alien species provide evidence for chromosome homoeology with wheat. PMID:24247837

Ainsworth, C C; Miller, T E; Gale, M D

1986-03-01

32

Genetic studies of the crossability of hexaploid wheat with rye and Hordeum bulbosum  

Microsoft Academic Search

Crosses of wheat (Triticum aestivum L.) Group 5 chromosome substitution lines from three different cultivar backgrounds indicate that there may be multiple alleles for reduced crossability with rye (Secale cereale L.) and H. bulbosum on both 5A and 5B chromosomes. No reduction in seed set was observed from any of the 5D substitution lines. It was found that the Kr1

D. E. Falk; K. J. Kasha

1983-01-01

33

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...

34

Comparative analysis of physio-biochemical responses to cold stress in tetraploid and hexaploid wheat.  

PubMed

The cellular changes induced by cold stress (CS) include responses that lead to oxidative stress and limits plant growth, metabolism, and productivity. In this study, responses of physio-biochemical to CS phases were comparatively studied in three genotypes of bread and durum wheats differing in sensitivity, two of them (Norstar, bread wheat and Gerdish, durum wheat) were tolerant to CS and the other one, SRN (durum wheat) was sensitive to CS. 14-day-old seedlings were subjected to CS (12 and 24 h) with or without cold acclimation (CA) phase. During CS, the elevated levels of electrolyte leakage index, contents of hydrogen peroxide (H2O2), and malondialdehyde in Norstar and Gerdish were lower than that of SRN plants. Positive correlation and co-regulation of reactive oxygen species (ROS) scavenging systems, superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and proline especially after CA phase suggested crucial role for holding back toxic ROS levels in CS phase. However, different activities of this system resulted in different intensities of oxidative stress in acclimated and non-acclimated plants. Our results showed that a CA phase induced oxidative stress tolerance by modulating antioxidative systems. These responses confirmed the existence of wide range of genetic capacity in durum wheat to increase cold tolerance particularly in Gerdish so that the sensitivity of SRN plants to CS was linearly correlated with the more decrease of antioxidant systems. These general responses may be a sign for associating other metabolites or enzymes activities to create partly tolerance against cold-induced oxidative stress. Eventually, assessing the dynamic of cell responses in short intervals after CS without CA phases profitably could be a novel path in plant stress response investigations in a short period of time. PMID:24691928

Nejadsadeghi, Leila; Maali-Amiri, Reza; Zeinali, Hassan; Ramezanpour, Sanaz; Sadeghzade, Behzad

2014-09-01

35

A comparison of the levels of hydroxamic acids in Aegilops speltoides and a hexaploid wheat and effects on Rhopalosiphum padi behaviour and fecundity.  

PubMed

Hydroxamic acids (HAs) are plant secondary metabolites produced by certain cereals, which have been found to be toxic to pest aphids in artificial diet assays. Previous studies have shown that tetraploid and hexaploid wheat varieties, the leaf tissues of which contained higher levels of these compounds than used in artificial diets, did not reduce aphid settling or fecundity. This current study reports findings on a high HA producing B genome accession of the diploid ancestor of wheat, Aegilops speltoides. We found that this accession does have a negative impact on aphid host selection and substantially reduces nymph production. Whole leaf tissue assays showed very high levels of HAs, well in excess of the toxic level determined in the artificial diet assays. Extraction of the apoplast fluid (AF) from this accession showed that the HA level is much lower than that of the whole tissue, but is still close to the artificial diet toxic level. Furthermore the HA level in the AF increases in response to aphid feeding. These observations could explain why hexaploid wheat remains susceptible to aphids, despite having whole leaf tissue HA levels in excess of the toxic levels determined in artificial diets. PMID:24561893

Elek, Henriett; Smart, Lesley; Ahmad, S; Anda, Angéla; Werner, C P; Pickett, J A

2014-03-01

36

Membrane fatty acid compositions and cold-induced responses in tetraploid and hexaploid wheats.  

PubMed

Plant cells often increase cold tolerance by reprogramming their genes expression which results in adjusted metabolic alternations, a process enhanced under cold acclimation. In present study, we assessed the changes of membrane fatty acid compositions along with physio-biochemical indices like H2O2 and malondialdehyde (MDA) contents and lipoxygenase (LOX) activity during cold stress (CS) phases in acclimated and non-acclimated durum (SRN and Gerdish) and bread (Norstar) wheat genotypes. During thermal treatments, MDA was an end product of lipid peroxidation via oxidative stress (H2O2 content) rather than LOX activity. LOX activity plays a double role in mechanism of cold tolerance in wheat, particularly at severe stress. With increase in severity of CS especially in non-acclimated plants, LOX activity decreased along with an increase in MDA and other responses helped increase or maintaine unsaturated fatty acids (FAs) whereas in acclimated plants (moderate CS), increasing of LOX activity along with a decrease in MDA indicates probably its role in secondary metabolites like jasmonic acid signaling pathway. Significant increase of total FAs and particularly unsaturated FAs showed distinct cell endeavor to protect against CS in Norstar and Gerdish compared to SRN genotype. Results showed that an increase in double bond index and LOX activity and low MDA under CS could be reasons for plant cold tolerance. PMID:25266238

Nejadsadeghi, Leila; Maali-Amiri, Reza; Zeinali, Hassan; Ramezanpour, Sanaz; Sadeghzade, Behzad

2015-02-01

37

Transcriptomic Analysis of Starch Biosynthesis in the Developing Grain of Hexaploid Wheat  

PubMed Central

The expression of genes involved in starch synthesis in wheat was analyzed together with the accumulation profiles of soluble sugars, starch, protein, and starch granule distribution in developing caryopses obtained from the same biological materials used for profiling of gene expression using DNA microarrays. Multiple expression patterns were detected for the different starch biosynthetic gene isoforms, suggesting their relative importance through caryopsis development. Members of the ADP-glucose pyrophosphorylase, starch synthase, starch branching enzyme, and sucrose synthase gene families showed different expression profiles; expression of some members of these gene families coincided with a period of high accumulation of starch while others did not. A biphasic pattern was observed in the rates of starch and protein accumulation which paralleled changes in global gene expression. Metabolic and regulatory genes that show a pattern of expression similar to starch accumulation and granule size distribution were identified, suggesting their coinvolvement in these biological processes. PMID:20224818

Stamova, Boryana S.; Laudencia-Chingcuanco, Debbie; Beckles, Diane M.

2009-01-01

38

Genetic analysis of resistance to yellow rust in hexaploid wheat using a mixture model for multiple crosses.  

PubMed

DNA-based molecular markers have been used in numerous studies for tagging specific genes in wheat for subsequent use in marker-assisted selection. Usually in plant breeding, procedures for mapping genes are based on analysis of a single segregating population. However, breeding programmes routinely evaluate large numbers of progeny derived from multiple-related crosses with some parental lines shared. In most such related crosses, the number of progeny is quite small. Thus, statistical techniques for detecting quantitative trait loci (QTLs) using data from conventional multi-cross breeding programmes are interesting. The objective of this study is to present a mixture model for QTL mapping in crosses of multiple inbred varieties with non-normal phenotype distributions and to use this model to map QTLs for yellow rust resistance in elite wheat breeding material. Three doubled haploid populations consisting of 41, 42 and 55 lines, respectively, originating from four parental varieties were studied. Multi-cross QTL analysis with three specific pathogen isolates of Puccinia striiformis f. sp. tritici and a mixture of the isolates revealed QTLs for resistance at four different genomic locations. These QTLs were found on chromosome 2AL, 2AS, 2BL and 6BL and explained between 21 and 41% of the phenotypic variation. Two of these QTLs, one on the long arm of chromosome 2A and one on the short arm of chromosome 2A were identical to the known yellow rust resistance genes Yr32 and Yr17, respectively, whereas the QTLs located on the long arms of chromosomes 2B and 6B may reflect types of resistance to yellow rust, which have not previously been mapped. PMID:16395570

Christiansen, M J; Feenstra, B; Skovgaard, I M; Andersen, S B

2006-02-01

39

RNA-Seq bulked segregant analysis enables the identification of high-resolution genetic markers for breeding in hexaploid wheat.  

PubMed

The identification of genetic markers linked to genes of agronomic importance is a major aim of crop research and breeding programmes. Here, we identify markers for Yr15, a major disease resistance gene for wheat yellow rust, using a segregating F2 population. After phenotyping, we implemented RNA sequencing (RNA-Seq) of bulked pools to identify single-nucleotide polymorphisms (SNP) associated with Yr15. Over 27 000 genes with SNPs were identified between the parents, and then classified based on the results from the sequenced bulks. We calculated the bulk frequency ratio (BFR) of SNPs between resistant and susceptible bulks, selecting those showing sixfold enrichment/depletion in the corresponding bulks (BFR > 6). Using additional filtering criteria, we reduced the number of genes with a putative SNP to 175. The 35 SNPs with the highest BFR values were converted into genome-specific KASP assays using an automated bioinformatics pipeline (PolyMarker) which circumvents the limitations associated with the polyploid wheat genome. Twenty-eight assays were polymorphic of which 22 (63%) mapped in the same linkage group as Yr15. Using these markers, we mapped Yr15 to a 0.77-cM interval. The three most closely linked SNPs were tested across varieties and breeding lines representing UK elite germplasm. Two flanking markers were diagnostic in over 99% of lines tested, thus providing a reliable haplotype for marker-assisted selection in these breeding programmes. Our results demonstrate that the proposed methodology can be applied in polyploid F2 populations to generate high-resolution genetic maps across target intervals. PMID:25382230

Ramirez-Gonzalez, Ricardo H; Segovia, Vanesa; Bird, Nicholas; Fenwick, Paul; Holdgate, Sarah; Berry, Simon; Jack, Peter; Caccamo, Mario; Uauy, Cristobal

2014-11-01

40

ATOMIC FORCE MICROSCOPY OF A HYBRID HIGH-MOLECULAR-WEIGHT GLUTENIN SUBUNIT FROM A TRANSGENIC HEXAPLOID WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

The high-molecular-weight glutenin subunits (HMW-GS) of wheat gluten in their native form are incorporated into an intermolecularly disulfide-linked, polymeric system that gives rise to the elasticity of wheat flour doughs. These protein subunits range in molecular weight from about ''K-90K and are...

41

Comparison of genetic and cytogenetic maps of hexaploid wheat ( Triticum aestivum L.) using SSR and DArT markers  

Microsoft Academic Search

A number of technologies are available to increase the abundance of DNA markers and contribute to developing high resolution\\u000a genetic maps suitable for genetic analysis. The aim of this study was to expand the number of Diversity Array Technology (DArT)\\u000a markers on the wheat array that can be mapped in the wheat genome, and to determine their chromosomal location with

Michael G. Francki; Esther Walker; Allison C. Crawford; Sue Broughton; Herbert W. Ohm; Iain Barclay; Robin E. Wilson; Robyn McLean

2009-01-01

42

Determination of the linkage relationships and the gene-centromere genetic distances for endopeptidase structural genes in hexaploid wheat  

E-print Network

Acph2, Acph3 Acph5, Acph6 Lpx-A2 Lpx-E2 Lpx-D2 Got-A1, Amp-Al Got-81, Amp-Bl Got-D1, Amp ? Dl Got-A2, esterase, o, -aa ylase Got-B2, esterase, a-amylase Got-D2, esterase, a-amylase Ep-A1, a-amylase Ep-81, Epl, a-amylase Ep-Dl, a-amylase...: Wheat and Wheat ~im rove- ment. Edited by K. S. Quisenberry and L. P. Reitz. American Society of Agronomy, Inc. , Madison, Wisconsin. Nishikawa, K- and M. Nobuhara, 1971 Genetic studies of O, -amylase isozymes in wheat l. location of genes...

McMillin, David Edwin

2012-06-07

43

Synthesis and cytological analyses of hybrids between hexaploid wheat, with and without Ph1, and diploid wheatgrass  

Technology Transfer Automated Retrieval System (TEKTRAN)

The usefulness of wide hybridization in genetic enhancement of crop plants is well documented. Diploid wheatgrass is a source of several desirable traits including Fusarium head blight resistance. The objective of this study was to report on the synthesis and cytological analyses of wheat × wheatg...

44

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

Microsoft Academic Search

BACKGROUND: ?-gliadins form a multigene protein family encoded by multiple ?-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 ?-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the

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

2009-01-01

45

Comparative High-Resolution Mapping of the Wax Inhibitors Iw1 and Iw2 in Hexaploid Wheat  

PubMed Central

The wax (glaucousness) on wheat leaves and stems is mainly controlled by two sets of genes: glaucousness loci (W1 and W2) and non-glaucousness loci (Iw1 and Iw2). The non-glaucousness (Iw) loci act as inhibitors of the glaucousness loci (W). High-resolution comparative genetic linkage maps of the wax inhibitors Iw1 originating from Triticum dicoccoides, and Iw2 from Aegilops tauschii were developed by comparative genomics analyses of Brachypodium, sorghum and rice genomic sequences corresponding to the syntenic regions of the Iw loci in wheat. Eleven Iw1 and eight Iw2 linked EST markers were developed and mapped to linkage maps on the distal regions of chromosomes 2BS and 2DS, respectively. The Iw1 locus mapped within a 0.96 cM interval flanked by the BE498358 and CA499581 EST markers that are collinear with 122 kb, 202 kb, and 466 kb genomic regions in the Brachypodium 5S chromosome, the sorghum 6S chromosome and the rice 4S chromosome, respectively. The Iw2 locus was located in a 4.1 to 5.4-cM interval in chromosome 2DS that is flanked by the CJ886319 and CJ519831 EST markers, and this region is collinear with a 2.3 cM region spanning the Iw1 locus on chromosome 2BS. Both Iw1 and Iw2 co-segregated with the BF474014 and CJ876545 EST markers, indicating they are most likely orthologs on 2BS and 2DS. These high-resolution maps can serve as a framework for chromosome landing, physical mapping and map-based cloning of the wax inhibitors in wheat. PMID:24376835

Han, Jun; Zhao, Xiaojie; Ouyang, Shuhong; Liang, Yong; Zhang, Dong; Wang, Zhenzhong; Wu, Qiuhong; Xie, Jingzhong; Cui, Yu; Peng, Huiru; Sun, Qixin; Liu, Zhiyong

2013-01-01

46

Development and Characterization of a New TILLING Population of Common Bread Wheat (Triticum aestivum L.)  

PubMed Central

Mutagenesis is an important tool in crop improvement. However, the hexaploid genome of wheat (Triticum aestivum L.) presents problems in identifying desirable genetic changes based on phenotypic screening due to gene redundancy. TILLING (Targeting Induced Local Lesions IN Genomes), a powerful reverse genetic strategy that allows the detection of induced point mutations in individuals of the mutagenized populations, can address the major challenge of linking sequence information to the biological function of genes and can also identify novel variation for crop breeding. Wheat is especially well-suited for TILLING due to the high mutation densities tolerated by polyploids. However, only a few wheat TILLING populations are currently available in the world, which is far from satisfying the requirement of researchers and breeders in different growing environments. In addition, current TILLING screening protocols require costly fluorescence detection systems, limiting their use, especially in developing countries. We developed a new TILLING resource comprising 2610 M2 mutants in a common wheat cultivar ‘Jinmai 47’. Numerous phenotypes with altered morphological and agronomic traits were observed from the M2 and M3 lines in the field. To simplify the procedure and decrease costs, we use unlabeled primers and either non-denaturing polyacrylamide gels or agarose gels for mutation detection. The value of this new resource was tested using PCR with RAPD and Intron-spliced junction (ISJ) primers, and also TILLING in three selected candidate genes, in 300 and 512 mutant lines, revealing high mutation densities of 1/34 kb by RAPD/ISJ analysis and 1/47 kb by TILLING. In total, 31 novel alleles were identified in the 3 targeted genes and confirmed by sequencing. The results indicate that this mutant population represents a useful resource for the wheat research community. We hope that the use of this reverse genetics resource will provide novel allelic diversity for wheat improvement and functional genomics. PMID:22844501

Chen, Liang; Huang, Linzhou; Min, Donghong; Phillips, Andy; Wang, Shiqiang; Madgwick, Pippa J.; Parry, Martin A. J.; Hu, Yin-Gang

2012-01-01

47

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....

48

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

PubMed Central

Background 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 population structure in a panel of 478 spring and winter wheat cultivars (Triticum aestivum) from 17 populations across the United States and Mexico. Results Most of the wheat oligo pool assay (OPA) SNPs that were polymorphic within the complete set of 478 cultivars were also polymorphic in all subpopulations. Higher levels of genetic differentiation were observed among wheat lines within populations than among populations. A total of nine genetically distinct clusters were identified, suggesting that some of the pre-defined populations shared significant proportion of genetic ancestry. Estimates of population structure (FST) at individual loci showed a high level of heterogeneity across the genome. In addition, seven genomic regions with elevated FST were detected between the spring and winter wheat populations. Some of these regions overlapped with previously mapped flowering time QTL. Across all populations, the highest extent of significant LD was observed in the wheat D-genome, followed by lower LD in the A- and B-genomes. The differences in the extent of LD among populations and genomes were mostly driven by differences in long-range LD ( > 10 cM). Conclusions Genome- and population-specific patterns of genetic differentiation and LD were discovered in the populations of wheat cultivars from different geographic regions. Our study demonstrated that the estimates of population structure between spring and winter wheat lines can identify genomic regions harboring candidate genes involved in the regulation of growth habit. Variation in LD suggests that breeding and selection had a different impact on each wheat genome both within and among populations. The 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

2010-01-01

49

Conservation of the genetic variation of Triticum tauschii (Coss.) Schmalh. (Aegilops squarrosa auct. non L.) in synthetic hexaploid wheats (T. turgidum L. s.lat. x T. tauschii; 2n=6x=42, AABBDD) and its potential utilization for wheat improvement  

Microsoft Academic Search

Triticum tauschii (Coss.) Schmalh. (Aegilops squarrosa auct. non L., 2n=2x=14, DD genome) with its diverse range of accessions and distribution provides a unique opportunity for exploiting novel genetic variability for wheat (T. aestivum L.) improvement associated with biotic\\/abiotic stress factors. From our working collection of 490 T. tauschii accessions we have so far produced 430 different synthetic hexaploids (2n=6x=42, AABBDD)

A. Mujeeb-Kazi; V. Rosas; S. Roldan

1996-01-01

50

Spring Wheat Breeding  

Microsoft Academic Search

Wheat (various species of the genus Triticum) is a grass originating from the Levant area of the Middle East. However, only hexaploid common wheat (Triticum eastivum), and tetraploid durum wheat (Triticum turgidum ssp. durum) are presently cultivated worldwide. Not only is wheat an important crop today, it may well have influenced human history.\\u000a Wheat was a key factor enabling the

M. Mergoum; P. K. Singh; J. A. Anderson; R. J. Peña; R. P. Singh; S. S. Xu; J. K. Ransom

51

Wheat curl mite resistance: interactions of mite feeding with wheat streak mosaic virus infection.  

PubMed

The majority of plant viruses are dependent on arthropod vectors for spread between plants. Wheat streak mosaic virus (family Potyviridae, genus Tritimovirus, WSMV) is transmitted by the wheat curl mite, Aceria tosichella Keifer, and this virus and vector cause extensive yield losses in most major wheat (Triticum aestivum L.)-growing regions of the world. Many cultivars in use are susceptible to this vector-virus complex, and yield losses of 10-99% have been documented. wheat curl mite resistance genes have been identified in goat grass, Aegilops tauschii (Coss) Schmal., and transferred to hexaploid wheat, but very few varieties contain effectively wheat curl mite resistance, due to virulent wheat curl mite populations. However, wheat curl mite resistance remains an effective strategy to reduce losses due to WSMV. The goal of our project was to identify the most effective, reproducible, and rapid method for assessing wheat curl mite resistance. We also wanted to determine whether mite resistance is affected by WSMV infection, because the pathogen and pest commonly occur together. Single and group wheat curl mite infestations produced similar amounts of leaf rolling and folding on wheat curl mite-susceptible wheat varieties that were independent of initial wheat curl mite infestation. This finding will allow accurate, efficient, large-scale screening of wheat germplasm for wheat curl mite resistance by infesting plants with sections of wheat leaf tissue containing mixed stages of wheat curl mite. The wheat curl mite-resistant breeding line 'OK05312' displayed antibiosis (reduced wheat curl mite population development). The effect of WSMV infection on wheat curl mite reproduction was genotype-dependent. Mite populations increased on infected wheat curl mite- and WSMV-susceptible plants compared with uninfected plants, but WSMV infection had no significant effect on wheat curl mite populations on resistant plants. OK05312 is a strong source of wheat curl mite resistance for wheat breeding programs. PMID:21882710

Murugan, M; Sotelo Cardona, P; Duraimurugan, P; Whitfield, A E; Schneweis, D; Starkey, S; Smith, C M

2011-08-01

52

A diploid wheat TILLING resource for wheat functional genomics  

PubMed Central

Background Triticum monococcum L., an A genome diploid einkorn wheat, was the first domesticated crop. As a diploid, it is attractive genetic model for the study of gene structure and function of wheat-specific traits. Diploid wheat is currently not amenable to reverse genetics approaches such as insertion mutagenesis and post-transcriptional gene silencing strategies. However, TILLING offers a powerful functional genetics approach for wheat gene analysis. Results We developed a TILLING population of 1,532 M2 families using EMS as a mutagen. A total of 67 mutants were obtained for the four genes studied. Waxy gene mutation frequencies are known to be 1/17.6 - 34.4 kb DNA in polyploid wheat TILLING populations. The T. monococcum diploid wheat TILLING population had a mutation frequency of 1/90 kb for the same gene. Lignin biosynthesis pathway genes- COMT1, HCT2, and 4CL1 had mutation frequencies of 1/86 kb, 1/92 kb and 1/100 kb, respectively. The overall mutation frequency of the diploid wheat TILLING population was 1/92 kb. Conclusion The mutation frequency of a diploid wheat TILLING population was found to be higher than that reported for other diploid grasses. The rate, however, is lower than tetraploid and hexaploid wheat TILLING populations because of the higher tolerance of polyploids to mutations. Unlike polyploid wheat, most mutants in diploid wheat have a phenotype amenable to forward and reverse genetic analysis and establish diploid wheat as an attractive model to study gene function in wheat. We estimate that a TILLING population of 5, 520 will be needed to get a non-sense mutation for every wheat gene of interest with 95% probability. PMID:23134614

2012-01-01

53

Vernalization treatment induces site-specific DNA hypermethylation at the VERNALIZATION-A1 (VRN-A1) locus in hexaploid winter wheat  

PubMed Central

Background Certain temperate species require prolonged exposure to low temperature to initiate transition from vegetative growth to flowering, a process known as vernalization. In wheat, winter cultivars require vernalization to initiate flowering, making vernalization requirement a trait of key importance in wheat agronomy. The genetic bases of vernalization response have been largely studied in wheat, leading to the characterization of a regulation pathway that involves the key gene VERNALIZATION1 (VRN1). While previous studies in wheat and barley have revealed the functional role of histone modification in setting VRN1 expression, other mechanisms might also be involved. Here, we were interested in determining whether the cold-induced expression of the wheat VRN-A1 gene is associated with a change in DNA methylation. Results We provide the first DNA methylation analysis of the VRN-A1 gene, and describe the existence of methylation at CG but also at non CG sites. While CG sites show a bell-shape profile typical of gene-body methylation, non CG methylation is restricted to the large (8.5 kb) intron 1, in a region harboring fragments of transposable elements (TEs). Interestingly, cold induces a site-specific hypermethylation at these non CG sites. This increase in DNA methylation is transmitted through mitosis, and is reset to its original level after sexual reproduction. Conclusions These results demonstrate that VRN-A1 has a particular DNA methylation pattern, exhibiting rapid shift within the life cycle of a winter wheat plant following exposure to particular environmental conditions. The finding that this shift occurs at non CG sites in a TE-rich region opens interesting questions onto the possible consequences of this type of methylation in gene expression. PMID:24330651

2013-01-01

54

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

PubMed

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. PMID:22034626

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

55

Isolation and molecular characterization of high molecular weight glutenin subunit genes 1Bx13 and 1By16 from hexaploid wheat.  

PubMed

The high molecular weight glutenin subunit (HMW-GS) pair 1Bx13 + 1By16are recognized to positively correlate with bread-making quality; however, their molecular data remain unknown. In order to reveal the mechanism by which 1By16 and 1Bx13 creates high quality, their open reading frames (ORFs) were amplified from common wheat Atlas66 and Jimai 20 using primers that were designed based on published sequences of HMW glutenin genes. The ORF of 1By16 was 2,220 bp, deduced into 738 amino acid residues with seven cysteines including 59 hexapeptides and 22 nanopeptides motifs. The ORF of 1Bx13 was 2,385 bp, deduced into 795 amino acid residues with four cysteines including 68 hexapeptides, 25 nanopeptides and six tripeptides motifs. We found that 1By16 was the largest y-type HMW glutenin gene described to date in common wheat. The 1By16 had 36 amino acid residues inserted in the central repetitive domain compared with 1By15. Expression in bacteria and western-blot tests confirmed that the sequence cloned was the ORF of HMW-GS 1By16, and that 1Bx13 was one of the largest 1Bx genes that have been described so far in common wheat, exhibiting a hexapeptide (PGQGQQ) insertion in the end of central repetitive domain compared with 1Bx7. A phylogenetic tree based on the deduced full-length amino acid sequence alignment of the published HMW-GS genes showed that the 1By16 was clustered with Glu-1B-2, and that the 1Bx13 was clustered with Glu-1B-1 alleles. PMID:18713365

Pang, Bin-Shuang; Zhang, Xue-Yong

2008-03-01

56

Genetics and molecular mapping of resistance to necrosis inducing race 5 of Pyrenophora tritici-repentis in tetraploid wheat  

Microsoft Academic Search

Race 5 of Pyrenophora tritici-repentis, causal agent of tan spot, induces two distinct symptoms, necrosis and chlorosis in susceptible tetraploid and hexaploid\\u000a wheat, respectively. This study was conducted under controlled environmental conditions to determine the inheritance of resistance\\u000a to P. tritici-repentis, race 5, in a tetraploid wheat population and to map the resistance genes. Additionally, the relationship between the resistance

P. K. Singh; M. Mergoum; J. L. Gonzalez-Hernandez; S. Ali; T. B. Adhikari; S. F. Kianian; E. M. Elias; G. R. Hughes

2008-01-01

57

Resistance to Soil-borne cereal mosaic virus in durum wheat is controlled by a major QTL on chromosome arm 2BS and minor loci  

Microsoft Academic Search

Soil-borne cereal mosaic (SBCM) is a viral disease, which seriously affects hexaploid as well as tetraploid wheat crops in Europe. In durum wheat\\u000a (Triticum durum Desf.), the elite germplasm is characterized by a wide range of responses to SBCMV, from susceptibility to almost complete\\u000a resistance. In this study, the genetic analysis of SBCMV resistance was carried out using a population

Marco Maccaferri; Claudio Ratti; Concepcion Rubies-Autonell; Victor Vallega; Andrea Demontis; Sandra Stefanelli; Roberto Tuberosa; Maria Corinna Sanguineti

58

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

SciTech Connect

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.

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

1986-07-01

59

Cytogenetically Engineered Rye Chromosomes 1R to Improve Bread-making Quality of Hexaploid Triticale  

Microsoft Academic Search

Hexaploid triticale (X Triticosecale Wittmack) is rarely used for human consumption because of its poor bread-making quality. To create the genetic potential for bread-making quality similar to that of bread wheat (Triticum aestivum L), rye (Secale cereale L.) chromo- some 1R in triticale cv. Presto was cytogenetically engineered to remove secalin loci Sec-1 and Sec-3, and to introduce wheat storage

Adam J. Lukaszewski

2006-01-01

60

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 ...

61

Genetic Diversity In Abiotic Stress Tolerances Among Wheat Species  

Technology Transfer Automated Retrieval System (TEKTRAN)

Landraces and close related species of hexaploid wheat (Triticum aestivum L.) offer a vast reservoir of genetic resources for wheat improvement to production on abiotic stressed soils. In order to utilize the wheat landrace and close relative gene pools, the evaluation of wheat landrace and close r...

62

Mapping QTL for Soft Wheat Quality in Multiple Populations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soft wheat is used to make a wide variety of products and thus variation for quality parameters is important to breed soft wheat cultivars suitable for different uses. Breeders need more knowledge about the genetics of soft wheat quality and systems for marker-assisted selection (MAS). MAS is best...

63

Rapid linkage disequilibrium decay in the Lr10 gene in wild emmer wheat ( Triticum dicoccoides ) populations  

Microsoft Academic Search

Introduction  Recombination is a key evolutionary factor enhancing diversity. However, the effect of recombination on diversity in inbreeding\\u000a species is expected to be low. To estimate this effect, recombination and diversity patterns of Lr10 gene were studied in natural populations of the inbreeder species, wild emmer wheat (Triticum dicoccoides). Wild emmer wheat is the progenitor of most cultivated wheats and it

Hanan Sela; Caroline Loutre; Beat Keller; Alan Schulman; Eviatar Nevo; Abraham Korol; Tzion Fahima

2011-01-01

64

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

PubMed Central

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. PMID:23047200

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

2013-01-01

65

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

PubMed

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. PMID:18459426

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

2008-04-01

66

EMS-treated hexaploid wheat genotype Scarlet has enhanced tolerance to the soilborne necrotrophic pathogens Rhizoctonia solani AG-8 and R. oryzae. 2009. Theor. Appl. Genet. 119(February): 293-303  

Technology Transfer Automated Retrieval System (TEKTRAN)

R. solani AG-8 and R. oryzae cause Rhizoctonia root rot and pre-emergence damping-off, yield-limiting diseases that pose a barrier to the adoption of reduced tillage wheat production systems intended to reduce soil erosion. We report the first genetic resistance to necrotrophic root pathogens Rhizo...

67

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

PubMed

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. PMID:22030277

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

2012-04-01

68

Transfer of high kernel weight and high protein from wild tetraploid wheat (Triticum turgidum dicoccoides) to bread wheat (T. aestivum) using homologous and homoeologous recombination  

Microsoft Academic Search

Wheat pentaploids were produced by hybridizing a high kernel weight (1000 grain wt=56 g), high protein (25.4%) line of wild tetraploid wheat (Triticum turgidum dicoccoides) as male parent, with the three hexaploids (T. aestivum) — normal Chinese Spring and its two homoeologous pairing mutants, ph1b and ph2. The pentaploids were crossed as female parents to the two commercial hexaploid cultivars

U. Kushnir; G. M. Halloran

1984-01-01

69

Genetic characterization of North American populations of the wheat curl mite and dry bulb mite.  

PubMed

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 disease of winter wheat in the western Great Plains. One component of managing this disease has been developing mite resistance in wheat; however, identification of mite biotypes has complicated deployment and stability of resistance. This biotypic variability in mites and differential virus transmission by different mite populations underscores the need to better understand mite identity. However, A. tosichella has a history of serious taxonomic confusion, especially as it relates to A. tulipae Keifer, the dry bulb mite. Molecular techniques were used to genetically characterize multiple A. tosichella populations and compare them to populations of A. tulipae. DNA from these populations was polymerase chain reaction amplified and the ribosomal ITS2 region sequenced and compared. These results indicated limited variability between these two species, but two distinct types within A. tosichella were found that corresponded to previous work with Australian mite populations. Further work using sequencing of several mitochondrial DNA genes also demonstrated two distinct types of A. tosichella populations. Furthermore, the separation between these two A. tosichella types is comparable to their separation with A. tulipae, suggesting that species scale differences exist between these two types ofA. tosichella. These genetic differences correspond to important biological differences between the types (e.g., biotypic and virus transmission differences). In light of these differences, it is important that future studies on biological response differences account for these mite differences. PMID:23156180

Hein, Gary L; French, Roy; Siriwetwiwat, Benjawan; Amrine, James W

2012-10-01

70

Populations of methanogenic bacteria in paddy field soil under double cropping conditions (rice-wheat)  

Microsoft Academic Search

The methanogenic populations able to use H2-CO2, methanol, and acetate were investigated in paddy field soil in situ under double cropping conditions [rice (Oryza sativa L.) as a summer crop under flooded conditions and wheat (Triticum aestivum L.) as an upland winter crop] over 2 years approximately bimonthly by the most probable number method. Three fields, one without fertilizer, one

S. Asakawa; K. Hayano

1995-01-01

71

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...

72

Evidence for wheat-rye nucleolar competition (amphiplasty) in triticale by silver-staining procedure  

Microsoft Academic Search

Amphiplasty in hexaploid triticale, the artificial amphiploid of tetraploid wheat and diploid rye, is analyzed for the first time using a modified, highly reproducible, silver-staining procedure. A comparative analysis of metaphase somatic cells by phase contrast, C-banding and silver-staining of the hexaploid triticale cv. ‘Cachirulo’ and its parents, namely, the tetraploid durum wheat cv. ‘Enano de Andujar’ and the diploid

J. R. Lacadena; M. C. Cermeño; J. Orellana; J. L. Santos

1984-01-01

73

The cuticular wax inhibitor locus Iw2 in wild diploid wheat Aegilops tauschii : phenotypic survey, genetic analysis, and implications for the evolution of common wheat.  

PubMed

BackgroundCuticular wax production on plant surfaces confers a glaucous appearance and plays important roles in plant stress tolerance. Most common wheat cultivars, which are hexaploid, and most tetraploid wheat cultivars are glaucous; in contrast, a wild wheat progenitor, Aegilops tauschii, can be glaucous or non-glaucous. A dominant non-glaucous allele, Iw2, resides on the short arm of chromosome 2D, which was inherited from Ae. tauschii through polyploidization. Iw2 is one of the major causal genes related to variation in glaucousness among hexaploid wheat. Detailed genetic and phylogeographic knowledge of the Iw2 locus in Ae. tauchii may provide important information and lead to a better understanding of the evolution of common wheat.ResultsGlaucous Ae. tauschii accessions were collected from a broad area ranging from Armenia to the southwestern coastal part of the Caspian Sea. Linkage analyses with five mapping populations showed that the glaucous versus non-glaucous difference was mainly controlled by the Iw2 locus in Ae. tauschii. Comparative genomic analysis of barley and Ae. tauschii was then used to develop molecular markers tightly linked with Ae. tauschii Iw2. Chromosomal synteny around the orthologous Iw2 regions indicated that some chromosomal rearrangement had occurred during the genetic divergence leading to Ae. tauschii, barley, and Brachypodium. Genetic associations between specific Iw2-linked markers and respective glaucous phenotypes in Ae. tauschii indicated that at least two non-glaucous accessions might carry other glaucousness-determining loci outside of the Iw2 locus.ConclusionAllelic differences at the Iw2 locus were the main contributors to the phenotypic difference between the glaucous and non-glaucous accessions of Ae. tauschii. Our results supported the previous assumption that the D-genome donor of common wheat could have been any Ae. tauschii variant that carried the recessive iw2 allele. PMID:25224598

Nishijima, Ryo; Iehisa, Julio C M; Matsuoka, Yoshihiro; Takumi, Shigeo

2014-09-16

74

Genetic Structure of Mycosphaerella Graminicola Populations in the Major Wheat-Growing Regions of the United States  

Technology Transfer Automated Retrieval System (TEKTRAN)

Septoria tritici blotch (STB), caused by Mycosphaerella graminicola, is one of the major diseases of wheat worldwide. However, there is little information available on the population genetic structure of this pathogen in the major wheat-growing regions of the United States. We analyzed the genetic s...

75

Sequence variability in three wheat germ agglutinin isolectins: Products of multiple genes in polyploid wheat  

Microsoft Academic Search

Summary Three highly homologous wheat germ isolectins (95–97%) are distinct gene products in hexaploid wheat. The amino acid sequences of two of these [wheat germ agglutinin 1 (WGA1) and 2 (WGA2)] are compared with sequence date derived from a complementary DNA (cDNA) clone for the third isolection (WGA3). This comparison includes three corrections to earlier amino acid sequences data of

Christine S. Wright; Natasha Raikhel

1989-01-01

76

Genetic Loci Related to Kernal Quality Differences Between a Soft and a Hard Wheat Cultivar  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hybridizations between hard and soft wheat types could be a source of novel variation for wheat quality improvement. This study was conducted to identify genomic regions related to differences in milling and baking quality between a soft and a hard cultivar of hexaploid wheat (Triticum aestivum L.)...

77

A developmentally unstable character in wheat: Glume fertility  

Microsoft Academic Search

In some wheat cultivars the terminal spikelet of the ear may contain a flower or a rudimentary floret in the axil of the second (upper) glume. The expression of this “glume fertility” depends on growing conditions, being more common when growth is vigorous. Examples have been found in all the groups of aestivum and durum wheat examined, and several hexaploid

G. M. Wright

1969-01-01

78

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...

79

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

PubMed Central

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. PMID:23169557

Münzbergová, Z; Šurinová, M; Castro, S

2013-01-01

80

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...

81

[Introgression of Aegilops genetic material into the genome of hexaploid triticale].  

PubMed

Cytological analysis of different meiosis stages was performed in F4 hybrids in comparison with the F1 hybrids obtained through crosses between the hexaploid triticale and genome-substitution forms of Aurolata (AABBUU) and Aurosis (AABBS(sh)S(sh)) wheat, in which D genome of common wheat Aurora was substituted for the genomes of Aegilops umbellulata and Ae. sharonensis, respectively. It was demonstrated that in F4 the level of bivalent conjugation was substantially higher than the expected one. However, the value of meiotic index in F4 hybrids was still small, pointing to incomplete process of the meiosis stabilization, specifically, of the stages following the metaphase I. Based on the data of morphological and biochemical analyses of the hybrids produced, the forms of triticale carrying some properties of the genus Aegilops, which were of interest for genetic and breeding studies, were isolated. PMID:17486755

Orlovskaia, O A; Kaminskaia, L N; Khotyleva, L V

2007-03-01

82

Inferring recent outcrossing rates using multilocus individual heterozygosity: application to evolving wheat populations.  

PubMed Central

Using multilocus individual heterozygosity, a method is developed to estimate the outcrossing rates of a population over a few previous generations. Considering that individuals originate either from outcrossing or from n successive selfing generations from an outbred ancestor, a maximum-likelihood (ML) estimator is described that gives estimates of past outcrossing rates in terms of proportions of individuals with different n values. Heterozygosities at several unlinked codominant loci are used to assign n values to each individual. This method also allows a test of whether populations are in inbreeding equilibrium. The estimator's reliability was checked using simulations for different mating histories. We show that this ML estimator can provide estimates of outcrossing rates for the final generation outcrossing rate (t(0)) and a mean of the preceding rates (t(p)) and can detect major temporal variation in the mating system. The method is most efficient for low to intermediate outcrossing levels. Applied to nine populations of wheat, this method gave estimates of t(0) and t(p). These estimates confirmed the absence of outcrossing t(0) = 0 in the two populations subjected to manual selfing. For free-mating wheat populations, it detected lower final generation outcrossing rates t(0) = 0-0.06 than those expected from global heterozygosity t = 0.02-0.09. This estimator appears to be a new and efficient way to describe the multilocus heterozygosity of a population, complementary to Fis and progeny analysis approaches. PMID:11102388

Enjalbert, J; David, J L

2000-01-01

83

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

PubMed

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 future analyses of multiparental populations. PMID:25406468

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

2015-02-01

84

CONTRIBUTION TO THE STUDY OF CICADA (HOMOPTERA-AUCHEENARRHYNCHA) POPULATIONS FROM WINTER WHEAT CROPS IN OLTENIA PLAIN  

Microsoft Academic Search

The populations of cicadas existing in wheat crops of Ol- tenia, represent 2-67 % from the total insect pests. Arid climate (frequent drought years) from sandy soils area, the low level of crop technologies, the neighbourhood with perennial grasses are the main factors determining a high rate of the increasing of insect populations. Under such conditions the populations could reach

Emilia Baniþã; Margareta Cantoreanu; Aurelia Jilãveanu

85

Strong linkage disequilibrium near the selected Yr17 resistance gene in a wheat experimental population.  

PubMed

Dynamic management (DM) is a method of genetic resources conservation that aims at maintaining evolutionary process in subdivided populations cultivated in contrasted environments. Such populations are often submitted to strong natural selection as it was the case for experimental wheat populations maintained under DM. Understanding impacts of selection on genetic diversity around selected genes is necessary for the middle-term maintenance of genetic variability in DM populations. Evolution of diversity at six neutral markers located near the yellow rust resistance gene Yr17 has been studied for the parental lines and for generations 1, 5, 10 and 17 in one of the DM populations. Yr17 provided complete resistance to yellow rust in France until 1997 and thus was suspected to be under strong selection. The gene is located on a fragment introgressed in winter wheat from a wild species. The presence of the gene was estimated using a marker closely related to the gene. We showed that the Yr17 gene has been selected between generations 5 and 10. Generally, selection tends to reduce diversity around selected genes, generating linkage disequilibrium (LD) between a gene and adjacent markers. Here, the major effect of the Yr17 gene selection was a reduction of multilocus diversity and the maintenance of strong pre-existing LD in the zone surrounding the gene for a distance of 20 cM. As expected, the presence of the exogenous introgression was responsible for restrictions to recombination which contributed to the maintenance of strong correlations between loci. However, we found a noticeable number of recombinations around the gene indicating a progressive incorporation of the fragment into the wheat genome. PMID:17177061

Rhoné, Bénédicte; Raquin, Anne-Laure; Goldringer, Isabelle

2007-03-01

86

Wheat pre-breeding using wild progenitors  

Microsoft Academic Search

To facilitate the use of wheat wild relatives in conventional breedingprograms, a wheat pre-breeding activity started at ICARDA in 1994\\/1995season. Preliminary results of gene introgression from wild diploidprogenitors, Triticum urartu, T. baeoticum, Aegilops speltoides andAe. tauschii and tetraploid T. dicoccoides are described. Crosseswith wild diploid Triticum spp. yielded high variation in plant andspike morphology. Synthetic hexaploids were produced from crosses

J. J. Valkoun

2001-01-01

87

Identification and validation of a major quantitative trait locus for slow-rusting resistance to stripe rust in wheat.  

PubMed

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Eriks (Pst), is one of the most important wheat (Triticum aestivum L.) diseases and causes significant yield losses. A recombinant inbred (RI) population derived from a cross between Yanzhan 1 and Xichang 76-9 cultivars was evaluated for resistance to wheat stripe rust strain CYR32 at both the seedling and adult plant stages. Four resistance quantitative trait loci (QTLs) were detected in this population, in which the major one, designated as Yrq1, was mapped on chromosome 2DS. The strategy of using the Brachypodium distachyon genome, wheat expressed sequence tags and a draft DNA sequences (scaffolds) of the D-genome (Aegilops tauschii Coss.) for the development of simple sequence repeat (SSR) markers was successfully used to identify 147 SSRs in hexaploid wheat. Of the 19 polymorphic SSRs in the RI population, 17 SSRs were mapped in the homeologous group 2 chromosomes near Yrq1 region and eight SSRs were genetically mapped in the 2.7 cM region of Yrq1, providing abundant DNA markers for fine-mapping of Yrq1 and marker-assisted selection in wheat breeding program. The effectiveness of Yrq1 was validated in an independent population, indicating that this resistance QTL can be successfully transferred into a susceptible cultivar for improvement of stripe rust resistance. PMID:22349012

Cao, Xiaohua; Zhou, Jianghong; Gong, Xiaoping; Zhao, Guangyao; Jia, Jizeng; Qi, Xiaoquan

2012-05-01

88

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

PubMed

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. PMID:17947425

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

89

Association Analysis of Historical Bread Wheat Germplasm Using Additive Genetic Covariance of Relatives and Population Structure  

PubMed Central

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 × environment interaction, thereby making possible the identification of markers contributing to both additive and additive × additive interaction effects of traits. PMID:17947425

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

2007-01-01

90

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

PubMed

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". PMID:22812121

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

2012-06-01

91

Evidence of hexaploid karyotype in shortnose sturgeon.  

PubMed

A karyotype analysis by several staining techniques was carried out on triplicate samples of the shortnose sturgeon, Acipenser brevirostrum. The chromosome number was found to be 2n = 372 +/- 6. A representative karyotype of 374 chromosomes was composed of 178 metacentrics/submetacentrics and 196 telocentrics/acrocentrics and microchromosomes. The signals of fluorescent in situ hybridization (FISH) with a HindIII satellite DNA probe were visible on 14 chromosomes. The signals obtained with a PstI satellite DNA probe appeared on 12 chromosomes. The FISH with a 5S rDNA probe revealed fluorescent signals on 6 chromosomes. These last results, compared with 2 signals in species with about 120 chromosomes and 4 in species with 240, support the hypothesis that A. brevirostrum is a hexaploid species, probably of hybrid origin. Based on these results, we propose a model explaining speciation events occurring in sturgeons by hybridization, genome duplication, and diploidization. PMID:18356945

Fontana, Francesco; Congiu, Leonardo; Mudrak, Vincent A; Quattro, Joseph M; Smith, Theodore I J; Ware, Kent; Doroshov, Serge I

2008-02-01

92

Data Mining of ESTs for Genetic Improvement of Salt Tolerance in Wheat  

Microsoft Academic Search

A total of 4,131 expressed sequence tags (ESTs) were selected from wheat EST database (http:\\/\\/wheat.pw.usda.gov\\/cgi-bin\\/westsql\\/est_lib.cgi.) to identify genic regions differing at structural and functional level between durum wheat (tetraploid genome, AABB) and bread wheat (hexaploid genome, AABBDD) cultivars in response to salt stress. Selected ESTs from salt stressed Triticum aestivum cDNA libraries (922 seedling, 2055 root, 1154 sheat ESTs) were

Meral Unal; Ismail Cakmak; Yildiz Aydin; Aysen Yumurtaci; Ahu Altinkut; Emel Yesil; Sema Karanlik; Hikmet Budak

2006-01-01

93

The importance of donor population identity and habitat type when creating new populations of small cow-wheat Melampyrum sylvaticum from seed in Perthshire, Scotland  

Microsoft Academic Search

SUMMARY Small cow-wheat Melampyrum sylvaticum , a nationally scarce annual identified as a priori ty species in the UK Biodiversity Action Plan, was the focus of a translocation attempt aiming to establish new populations within the extent of its former Scottis h range. Seeds were collected (from wild Scottish populations) in three phases (in the years 2005, 20 06 and

Sarah E. Dalrymple; Alice Broome

2010-01-01

94

Differential transmission of Triticum mosaic virus by wheat curl mite populations collected in the Great Plains  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is an important food grain worldwide, and the primary dryland crop in the western Great Plains. A complex of three wheat curl mite (WCM)-transmitted viruses [Wheat streak mosaic, High plains, and Triticum mosaic viruses (TriMV)] is a cause of serious loss in winter wheat production in the Grea...

95

Reconstruction of the synthetic W7984 x Opata M85 wheat reference population.  

PubMed

Reference populations are valuable resources in genetics studies for determining marker order, marker selection, trait mapping, construction of large-insert libraries, cross-referencing marker platforms, and genome sequencing. Reference populations can be propagated indefinitely, they are polymorphic and have normal segregation. Described are two new reference populations who share the same parents of the original wheat reference population Synthetic W7984 (Altar84/ Aegilops tauschii (219) CIGM86.940) x Opata M85, an F(1)-derived doubled haploid population (SynOpDH) of 215 inbred lines and a recombinant inbred population (SynOpRIL) of 2039 F(6) lines derived by single-plant self-pollinations. A linkage map was constructed for the SynOpDH population using 1446 markers. In addition, a core set of 42 SSR markers was genotyped on SynOpRIL. A new approach to identifying a core set of markers used a step-wise selection protocol based on polymorphism, uniform chromosome distribution, and reliability to create nested sets starting with one marker per chromosome, followed by two, four, and six. It is suggested that researchers use these markers as anchors for all future mapping projects to facilitate cross-referencing markers and chromosome locations. To enhance this public resource, researchers are strongly urged to validate line identities and deposit their data in GrainGenes so that others can benefit from the accumulated information. PMID:21999208

Sorrells, Mark E; Gustafson, J Perry; Somers, Daryl; Chao, Shiaoman; Benscher, David; Guedira-Brown, Gina; Huttner, Eric; Kilian, Andrezj; McGuire, Patrick E; Ross, Kathleen; Tanaka, James; Wenzl, Peter; Williams, Keith; Qualset, Calvin O

2011-11-01

96

The Major Threshability Genes Soft Glume (sog) and Tenacious Glume (Tg), of Diploid and Polyploid Wheat, Trace Their Origin to Independent Mutations at Non-Orthologous Loci  

Technology Transfer Automated Retrieval System (TEKTRAN)

Threshability is an important crop domestication trait. The wild wheat progenitors have tough glumes enveloping the floret that make spikes difficult to thresh, whereas cultivated wheats have soft glumes and are free-threshing. In hexaploid wheat, the glume tenacity gene Tg along with the major dome...

97

The Major Threshability Genes Soft Glume (sog) and Tenacious Glume (Tg), of Diploid and Polyploid Wheat, Trace Their Origin to Independent Mutations at Non-Orthogous Loci  

Technology Transfer Automated Retrieval System (TEKTRAN)

Threshability is an important crop domestication trait. The wild wheat progenitors have tough glumes enveloping the floret that make spikes difficult to thresh, whereas cultivated wheats have soft glumes and are free-threshing. In hexaploid wheat, the glume tenacity gene Tg along with the major dome...

98

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...

99

Assessing genetic diversity of wheat ( Triticum aestivum L.) germplasm using microsatellite markers  

Microsoft Academic Search

A set of 24 wheat microsatellite markers, representing at least one marker from each chromosome, was used for the assessment of genetic diversity in 998 accessions of hexaploid bread wheat (Triticum aestivum L.) which originated from 68 countries of five continents. A total of 470 alleles were detected with an average allele number of 18.1 per locus. The highest number

X. Q. Huang; A. Börner; M. S. Röder; M. W. Ganal

2002-01-01

100

Variation in nucleolar organiser rRNA gene multiplicity in wheat and rye  

Microsoft Academic Search

In hexaploid wheat and diploid rye, different varieties have different numbers of ribosomal RNA genes as indicated by rRNA\\/DNA hybridisation. Wheat has four different chromosomes which carry nucleolar organisers. Analyses of DNA isolated from substitution lines in which each of these nucleolar organiser chromosomes of several varieties has been substituted one at a time into a common genetic background, have

R. B. Flavell; D. B. Smith

1974-01-01

101

Population Dynamics of Fusarium spp. and Microdochium nivale in Crops and Crop Residues of Winter Wheat.  

PubMed

ABSTRACT Naturally occurring populations of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, and Microdochium nivale were studied in two field experiments from anthesis in June 2003 until harvest in crops of winter wheat, and subsequently during 10 months after harvest until June 2004 on their residues exposed on the soil surface under field conditions. The dynamics of the different pathogens were estimated by quantifying the amount of DNA present in wheat tissues using TaqMan-polymerase chain reaction. While colonization of grain by Fusarium spp. and M. nivale was low, high amounts of DNA of F. avenaceum, F. graminearum, and F. culmorum were found in ear residues, internodes, and nodes of the mature crop. Amounts of DNA of pathogens decreased significantly during the following 10 months in residues of internodes and nodes, but not in residues of stem bases. Knowledge on population dynamics of pathogens will help to develop preventive measures aimed at reduction of inoculum sources of head blight pathogens. PMID:18943637

Köhl, J; de Haas, B H; Kastelein, P; Burgers, S L G E; Waalwijk, C

2007-08-01

102

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

PubMed Central

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. PMID:24759634

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.

2014-01-01

103

Genetic relationships, carbendazim sensitivity and mycotoxin production of the Fusarium graminearum populations from maize, wheat and rice in eastern China.  

PubMed

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 1? 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

Qiu, Jianbo; Shi, Jianrong

2014-08-01

104

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

PubMed Central

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 1? 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

Qiu, Jianbo; Shi, Jianrong

2014-01-01

105

Characterization of Ferredoxin-Dependent Glutamine-Oxoglutarate Amidotransferase (Fd-GOGAT) Genes and Their Relationship with Grain Protein Content QTL in Wheat  

PubMed Central

Background In higher plants, inorganic nitrogen is assimilated via the glutamate synthase cycle or GS-GOGAT pathway. GOGAT enzyme occurs in two distinct forms that use NADH (NADH-GOGAT) or Fd (Fd-GOGAT) as electron carriers. The goal of the present study was to characterize wheat Fd-GOGAT genes and to assess the linkage with grain protein content (GPC), an important quantitative trait controlled by multiple genes. Results We report the complete genomic sequences of the three homoeologous A, B and D Fd-GOGAT genes from hexaploid wheat (Triticum aestivum) and their localization and characterization. The gene is comprised of 33 exons and 32 introns for all the three homoeologues genes. The three genes show the same exon/intron number and size, with the only exception of a series of indels in intronic regions. The partial sequence of the Fd-GOGAT gene located on A genome was determined in two durum wheat (Triticum turgidum ssp. durum) cvs Ciccio and Svevo, characterized by different grain protein content. Genomic differences allowed the gene mapping in the centromeric region of chromosome 2A. QTL analysis was conducted in the Svevo×Ciccio RIL mapping population, previously evaluated in 5 different environments. The study co-localized the Fd-GOGAT-A gene with the marker GWM-339, identifying a significant major QTL for GPC. Conclusions The wheat Fd-GOGAT genes are highly conserved; both among the three homoeologous hexaploid wheat genes and in comparison with other plants. In durum wheat, an association was shown between the Fd-GOGAT allele of cv Svevo with increasing GPC - potentially useful in breeding programs. PMID:25099972

2014-01-01

106

Rapid Differentiation of Experimental Populations of Wheat for Heading Time in Response to Local Climatic Conditions  

PubMed Central

• Background and Aims Dynamic management (DM) of genetic resources aims at maintaining genetic variability between different populations evolving under natural selection in contrasting environments. In 1984, this strategy was applied in a pilot experiment on wheat (Triticum aestivum). Spatio-temporal evolution of earliness and its components (partial vernalization sensitivity, daylength sensitivity and earliness per se that determines flowering time independently of environmental stimuli) was investigated in this multisite and long-term experiment. • Methods Heading time of six populations from the tenth generation was evaluated under different vernalization and photoperiodic conditions. • Key Results Although temporal evolution during ten generations was not significant, populations of generation 10 were genetically differentiated according to a north–south latitudinal trend for two components out of three: partial vernalization sensitivity and narrow-sense earliness. • Conclusions It is concluded that local climatic conditions greatly influenced the evolution of population earliness, thus being a major factor of differentiation in the DM system. Accordingly, a substantial proportion (?25?%) of genetic variance was distributed among populations, suggesting that diversity was on average conserved during evolution but was differently distributed by natural selection (and possibly drift). Earliness is a complex trait and each genetic factor is controlled by multiple homeoalleles; the next step will be to look for spatial divergence in allele frequencies. PMID:16868000

GOLDRINGER, ISABELLE; PROUIN, CLAIRE; ROUSSET, MICHEL; GALIC, NATHALIE; BONNIN, ISABELLE

2006-01-01

107

Reduction of pesticide use can increase earthworm populations in wheat crops in a European1 temperate region2  

E-print Network

of pesticide use can increase earthworm populations in wheat crops in a European1 temperate region2 3 C-input cropping systems have not yet been3 precisely assessed. Earthworm, having important agro indicator of pesticide pressure - and the abundance of three important earthworm species. We8 found

Paris-Sud XI, Université de

108

Induction and characterization of Ph1 wheat mutants.  

PubMed Central

The cloning of genes for complex traits in polyploid plants that possess large genomes, such as hexaploid wheat, requires an efficient strategy. We present here one such strategy focusing on the homologous pairing suppressor (Ph1) locus of wheat. This locus has been shown to affect both premeiotic and meiotic processes, possibly suggesting a complex control. The strategy combined the identification of lines carrying specific deletions using multiplex PCR screening of fast-neutron irradiated wheat populations with the approach of physically mapping the region in the rice genome equivalent to the deletion to reveal its gene content. As a result, we have located the Ph1 factor controlling the euploid-like level of homologous chromosome pairing to the region between two loci (Xrgc846 and Xpsr150A). These loci are located within 400 kb of each other in the rice genome. By sequencing this region of the rice genome, it should now be possible to define the nature of this factor. PMID:10581295

Roberts, M A; Reader, S M; Dalgliesh, C; Miller, T E; Foote, T N; Fish, L J; Snape, J W; Moore, G

1999-01-01

109

POPULATION GENETICS OF THE WHEAT LEAF RUST FUNGUS, PUCCINIA TRITICINA IN CENTRAL ASIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat leaf rust, caused by Puccinia triticina, is a major disease of wheat in Central Asia. Single uredinial isolates from Armenia, Azerbaijan, Tajikistan, Kazakhstan, Uzbekistan, and Kyrgyzstan, 131 in total, were tested for virulence to 20 isolines of Thatcher wheat with single leaf rust resistanc...

110

POPULATION GENETICS OF THE WHEAT LEAF RUST FUNGUS, PUCCINIA TRITICINA IN CENTRAL ASIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat leaf rust, caused by Puccinia triticina, is a major disease of wheat in Central Asia. Single uredinial isolates from Armenia, Azerbaijan, Tajikistan, Kazakhstan, Uzbekistan, and Kyrgyzstan, 131 in total, were tested for virulence to 20 isolines of Thatcher wheat with single leaf rust resistan...

111

Mapping stripe rust resistance in a BrundageXCoda winter wheat recombinant inbred line population.  

PubMed

A recombinant inbred line (RIL) mapping population developed from a cross between winter wheat (Triticum aestivum L.) cultivars Coda and Brundage was evaluated for reaction to stripe rust (caused by Puccinia striiformis f. sp. tritici). Two hundred and sixty eight RIL from the population were evaluated in replicated field trials in a total of nine site-year locations in the U.S. Pacific Northwest. Seedling reaction to stripe rust races PST-100, PST-114 and PST-127 was also examined. A linkage map consisting of 2,391 polymorphic DNA markers was developed covering all chromosomes of wheat with the exception of 1D. Two QTL on chromosome 1B were associated with adult plant and seedling reaction and were the most significant QTL detected. Together these QTL reduced adult plant infection type from a score of seven to a score of two reduced disease severity by an average of 25% and provided protection against race PST-100, PST-114 and PST-127 in the seedling stage. The location of these QTL and the race specificity provided by them suggest that observed effects at this locus are due to a complementation of the previously known but defeated resistances of the cultivar Tres combining with that of Madsen (the two parent cultivars of Coda). Two additional QTL on chromosome 3B and one on 5B were associated with adult plant reaction only, and a single QTL on chromosome 5D was associated with seedling reaction to PST-114. Coda has been resistant to stripe rust since its release in 2000, indicating that combining multiple resistance genes for stripe rust provides durable resistance, especially when all-stage resistance genes are combined in a fashion to maximize the number of races they protect against. Identified molecular markers will allow for an efficient transfer of these genes into other cultivars, thereby continuing to provide excellent resistance to stripe rust. PMID:24642574

Case, Austin J; Naruoka, Yukiko; Chen, Xianming; Garland-Campbell, Kimberly A; Zemetra, Robert S; Carter, Arron H

2014-01-01

112

Geographic limits of a clonal population of wheat yellow rust in the Mediterranean region.  

PubMed

Most plant pathogens present complex life cycles, in which the clonal reproduction may impede the delimitation of population entities. By studying the genetic structure of the wheat yellow rust caused by Puccinia striiformis f.sp. tritici (PST), we highlighted difficulties impeding population delimitation in highly clonal species. Despite the high dispersal potential of PST, southern France isolates were shown to be divergent from a northwestern European population. A 2-year survey was performed in the Mediterranean region to assess the geographic distribution of southern isolates: 453 isolates collected in 11 countries were genotyped using 15 simple sequence repeat markers. A subsample was analysed for virulence against 23 resistance genes. The dominant strain in the western Mediterranean region was further studied with amplified fragment length polymorphism markers to test for a geographic substructure. Both 'individual'- and 'population'-centred analyses of polymorphism markers revealed two south-specific groups: a predominant group, with a broad variability and a wide distribution in both western and eastern Mediterranean countries, and a minor group in the western Mediterranean. The east-west gradient of genetic diversity suggested gene flow from the Middle East with subsequent founder effects and genetic divergence, and demonstrated the local survival of a western Mediterranean population. The high frequency of the resistance gene Yr8 observed in cultivars from Tunisia and Algeria may contribute to maintain the north/south structure observed in France. In addition to migration and local adaptation, the dynamics of clonal lineage diversification and replacement should be considered to define population entities in strongly clonal species. PMID:19769694

Bahri, B; Leconte, M; Ouffroukh, A; De Vallavieille-Pope, C; Enjalbert, J

2009-10-01

113

Population structure in a wheat core collection and genomic loci associated with yield under contrasting environments.  

PubMed

A set of 96 winter wheat accessions sampled from a variety of geographic origins, including cultivars and breeding lines, were characterized with 46 genome-wide SSR loci for genetic diversity and population structure. The genetic diversity within these accessions was examined using a genetic distance-based and a model-based clustering method. The model-based analysis identified an underlying population structure comprising of four distinct sub-populations which corresponded well with distance-based groupings. Information on the population structure is taken into account in an association mapping study of grain yield from a 3-years field trial incorporating fully irrigated, rainfed and drought stress treatments. A total of 21 marker-grain yield associations (P < 0.01) were identified with nine SSR markers. Most associations were detected only in one to three environments (treatment/year combination), with an average R ( 2 ) value around 13 %. However, marker gwm484 (on chromosome 2D) was associated with yield in six environments, including irrigated, rainfed and drought stress treatments, suggesting it could be used to improve grain yield across a range of environments. Variation in grain yield at this locus was associated with earliness, early vigour, kernels per spikelet and harvest index. Microsatellite locus psp3200 (on chromosome 6D) was associated with yield in dry and hot environments, which was related to earliness, early vigour, productive tillering and total biomass per plant. Partial least squares regression, with nine environmental factors, showed that precipitation from tillering to maturity was the main environmental factor causing marker × environment associations for grain yield. PMID:22968391

Zori?, Miroslav; Dodig, Dejan; Kobiljski, Borislav; Quarrie, Steve; Barnes, Jeremy

2012-06-01

114

Evidence of genetic recombination in wheat yellow rust populations of a Chinese oversummering area.  

PubMed

Wheat yellow rust (Puccinia striiformis f.sp. tritici) (PST) has been described as a strongly clonal species in both European and Australian populations, with very limited molecular diversity but rapidly evolving virulences. Contrastingly, marked genetic diversity has been reported in Chinese PST populations. To test whether such variability could originate from oversummering areas, we assessed the diversity of virulence and molecular markers (AFLP and SSR) using 412 PST isolates from the highlands of Tianshui county in Gansu province. Very marked phenotypic and genotypic diversity (38% and 89%, respectively) was found. No genetic structure dependent on the sites sampled (Fst=0.004) or altitude distribution (Fst=0.0098) was detected, indicating important gene flow at the county scale. This study also revealed genetic recombination between molecular markers and thus strongly suggests the existence of a sexual or parasexual cycle in PST in Tianshui county. The observations of higher rates of sexual spore production in genotypes originating from Tianshui are the very first elements suggestive of the existence of a sexual cycle in this species. PMID:19570502

Mboup, M; Leconte, M; Gautier, A; Wan, A M; Chen, W; de Vallavieille-Pope, C; Enjalbert, J

2009-04-01

115

Variation among hexaploid Paspalum dilatum Poir. regenerants from tissue culture.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The common biotype of Paspalum dilatatum, called paspalum in Australia and dallisgrass in the U.S.A., is a pentaploid obligate apomict and efforts to improve the grass have not been successful because of its asexual reproduction and irregular meiosis. An apomictic hexaploid biotype, known as Urugua...

116

Structure and Temporal Dynamics of Populations within Wheat Streak Mosaic Virus Isolates  

PubMed Central

Variation within the Type and Sidney 81 strains of wheat streak mosaic virus was assessed by single-strand conformation polymorphism (SSCP) analysis and confirmed by nucleotide sequencing. Limiting-dilution subisolates (LDSIs) of each strain were evaluated for polymorphism in the P1, P3, NIa, and CP cistrons. Different SSCP patterns among LDSIs of a strain were associated with single-nucleotide substitutions. Sidney 81 LDSI-S10 was used as founding inoculum to establish three lineages each in wheat, corn, and barley. The P1, HC-Pro, P3, CI, NIa, NIb, and CP cistrons of LDSI-S10 and each lineage at passages 1, 3, 6, and 9 were evaluated for polymorphism. By passage 9, each lineage differed in consensus sequence from LDSI-S10. The majority of substitutions occurred within NIa and CP, although at least one change occurred in each cistron except HC-Pro and P3. Most consensus sequence changes among lineages were independent, with substitutions accumulating over time. However, LDSI-S10 bore a variant nucleotide (G6016) in NIa that was restored to A6016 in eight of nine lineages by passage 6. This near-global reversion is most easily explained by selection. Examination of nonconsensus variation revealed a pool of unique substitutions (singletons) that remained constant in frequency during passage, regardless of the host species examined. These results suggest that mutations arising by viral polymerase error are generated at a constant rate but that most newly generated mutants are sequestered in virions and do not serve as replication templates. Thus, a substantial fraction of variation generated is static and has yet to be tested for relative fitness. In contrast, nonsingleton variation increased upon passage, suggesting that some mutants do serve as replication templates and may become established in a population. Replicated mutants may or may not rise to prominence to become the consensus sequence in a lineage, with the fate of any particular mutant subject to selection and stochastic processes such as genetic drift and population growth factors. PMID:11581391

Hall, Jeffrey S.; French, Roy; Morris, T. Jack; Stenger, Drake C.

2001-01-01

117

Identification and Molecular Mapping of a Gene in Wheat Conferring Resistance to Mycosphaerella graminicola.  

PubMed

ABSTRACT Septoria tritici leaf blotch (STB), caused by the ascomycete Mycosphaerella graminicola (anamorph Septoria tritici), is an economically important disease of wheat. Breeding for resistance to STB is the most effective means to control this disease and can be facilitated through the use of molecular markers. However, molecular markers linked to most genes for resistance to STB are not yet available. This study was conducted to test for resistance in the parents of a standard wheat mapping population and to map any resistance genes identified. The population consisted of 130 F(10) recombinant-inbred lines (RILs) from a cross between the synthetic hexaploid wheat W7984 and cv. Opata 85. Genetic analysis indicated that a single major gene controls resistance to M. graminicola in this population. This putative resistance gene is now designated Stb8 and was mapped with respect to amplified fragment length polymorphism (AFLP) and microsatellite markers. An AFLP marker, EcoRI-ACG/MseI-CAG5, was linked in repulsion with the resistance gene at a distance of approximately 5.3 centimorgans (cM). Two flanking microsatellite markers, Xgwm146 and Xgwm577, were linked to the Stb8 gene on the long arm of wheat chromosome 7B at distances of 3.5 and 5.3 cM, respectively. The microsatellite markers identified in this study have potential for use in marker-assisted selection in breeding programs and for pyramiding of Stb8 with other genes for resistance to M. graminicola in wheat. PMID:18944101

Adhikari, Tika B; Anderson, Joseph M; Goodwin, Stephen B

2003-09-01

118

Influence of commodity type, percentage of cracked kernels, and wheat class on population growth of stored-product psocids (Psocoptera: Liposcelidae).  

PubMed

Differences in stored-product psocid progeny production as a function of commodity type, percentage of cracked kernels, and wheat class were examined using laboratory bioassays. Population growth of Liposcelis bostrychophila Badonnel, Liposcelis decolor (Pearman), Liposcelis paeta Pearman, and Liposcelis entomophila (Enderlein) (Psocoptera: Liposcelididae) was highest on sorghum Sorghum bicolor (L.) Moench, followed by wheat, Triticum aestivum L., and rice, Oryza sativa L., whereas progeny production was negligible on wheat germ. In a second experiment that did not include L. entomophila, population growth was examined on wheat containing 0, 1, 5, 10, 20, 50, and 100% cracked kernels. Progeny production did not increase as cracked kernel content increased. Instead, progeny production peaked at 20% for L. bostrychophila adults and nymphs, at 10% for L. decolor, and at 50% for L. paeta adults; no further increases were noted beyond these levels of cracked wheat content. In a third experiment that did not include L. entomophila, progeny production was examined on eight classes of wheat: hard red winter, hard red spring, soft white winter, soft white spring, soft club, durum, soft red winter, and hard white. Overall, progeny production was higher on durum wheat than on the other classes. The results indicate that there are considerable variations in psocid population growth among the different commodities tested, and this information may be used to predict the degree to which stored commodities are susceptible to psocid infestation. PMID:20568647

Athanassiou, Christos G; Opit, George P; Throne, James E

2010-06-01

119

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

PubMed Central

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 found in wheat grains/bread products significantly increased intestinal beneficial bacterial population in Fe deficient broiler chickens. With this short-term feeding trial we were not able to show differences in the Fe-status of broilers. Nevertheless, the increase in relative amounts of bifidobacteria and lactobacilli in the presence of wheat prebiotics is an important finding as these bacterial populations may affect Fe bioavailability in long-term studies. PMID:24924421

2014-01-01

120

A high-density genetic map with array-based markers facilitates structural and quantitative trait locus analyses of the common wheat genome.  

PubMed

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

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

2014-10-01

121

A Species Cytoplasm Specific Gene in Euplasmic Durum Wheat Does Not Alter Field Performance  

Microsoft Academic Search

vii cytoplasm with the T. turgidum nucleus, however, produced weak, sterile plants (Maan, 1992). The en- Wild related Triticum species have been and will be a useful reser- hanced NC compatibility found in hexaploid wheat was voir of genetic diversity for solving problems in the development of thought to be associated with the D-genome (Maan, 1992). improved durum (Triticum turgidum

Sarah B. Gehlhar; Kristin J. Simons; Elias M. Elias; Schivcharan S. Maan; Shahryar F. Kianian

122

Effect of Microbial Inoculants on the Indigenous Actinobacterial Endophyte Population in the Roots of Wheat as Determined by Terminal Restriction Fragment Length Polymorphism  

PubMed Central

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. PMID:15528499

Conn, Vanessa M.; Franco, Christopher M. M.

2004-01-01

123

PHENOTYPIC DIVERGENCE IN THE META-POPULATION OF THE HOURANI DURUM WHEAT LANDRACE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Hourani durum wheat landrace was cultivated for millennia in the Houran plateau of northern Jordan and southern Syria as a source of flat bread and grain-based products. Since the 1980s, however, it became highly fragmented due to the introduction of high yielding varieties and new cropping syst...

124

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...

125

Genetic and Molecular Characterization of the VRN2 Loci in Tetraploid Wheat1[W][OA  

PubMed Central

Winter wheat (Triticum spp.) varieties require long exposures to low temperatures to flower, a process called vernalization. The VRN2 locus includes two completely linked zinc finger-CCT domain genes (ZCCT1 and ZCCT2) that act as flowering repressors down-regulated during vernalization. Deletions or mutations in these two genes result in the elimination of the vernalization requirement in diploid wheat (Triticum monococcum). However, natural allelic variation in these genes has not been described so far in polyploid wheat (tetraploid Triticum turgidum and hexaploid Triticum aestivum). A tetraploid wheat population segregating for both VRN-A2 and VRN-B2 loci facilitated the characterization of different alleles. Comparisons between functional and nonfunctional alleles revealed that both ZCCT1 and ZCCT2 genes are able to confer vernalization requirement and that different ZCCT genes are functional in different genomes. ZCCT1 and ZCCT2 proteins from nonfunctional vrn2 alleles have mutations at arginine amino acids at position 16, 35, or 39 of the CCT domain. These positions are conserved between CCT and HEME ACTIVATOR PROTEIN2 (HAP2) proteins, supporting a model in which the action of CCT domains is mediated by their interactions with HAP2/HAP3/HAP5 complexes. This study also revealed natural variation in gene copy number, including a duplication of the functional ZCCT-B2 gene and deletions or duplications of the complete VRN-B2 locus. Allelic variation at the VRN-B2 locus was associated with a partially dominant effect, which suggests that variation in the number of functional ZCCT genes can be used to expand allelic diversity for heading time in polyploid wheat and, hopefully, improve its adaptation to different environments. PMID:19005084

Distelfeld, Assaf; Tranquilli, Gabriela; Li, Chengxia; Yan, Liuling; Dubcovsky, Jorge

2009-01-01

126

Quantitative trait loci for resistance against powdery mildew in a segregating wheat×spelt population  

Microsoft Academic Search

Powdery mildew is one of the major diseases of wheat in regions with a maritime or semi-continental climate and can strongly\\u000a affect grain yield. The attempt to control powdery mildew with major resistance genes (Pm genes) has not provided a durable resistance. Breeding for quantitative resistance to powdery mildew is more promising, but\\u000a is difficult to select on a phenotypic

M. Keller; B. Keller; G. Schachermayr; M. Winzeler; J. E. Schmid; P. Stamp; M. M. Messmer

1999-01-01

127

Identification and Phylogenetic Analysis of a CC-NBS-LRR Encoding Gene Assigned on Chromosome 7B of Wheat  

PubMed Central

Hexaploid wheat displays limited genetic variation. As a direct A and B genome donor of hexaploid wheat, tetraploid wheat represents an important gene pool for cultivated bread wheat. Many disease resistant genes express conserved domains of the nucleotide-binding site and leucine-rich repeats (NBS-LRR). In this study, we isolated a CC-NBS-LRR gene locating on chromosome 7B from durum wheat variety Italy 363, and designated it TdRGA-7Ba. Its open reading frame was 4014 bp, encoding a 1337 amino acid protein with a complete NBS domain and 18 LRR repeats, sharing 44.7% identity with the PM3B protein. TdRGA-7Ba expression was continuously seen at low levels and was highest in leaves. TdRGA-7Ba has another allele TdRGA-7Bb with a 4 bp deletion at position +1892 in other cultivars of tetraploid wheat. In Ae. speltoides, as a B genome progenitor, both TdRGA-7Ba and TdRGA-7Bb were detected. In all six species of hexaploid wheats (AABBDD), only TdRGA-7Bb existed. Phylogenic analysis showed that all TdRGA-7Bb type genes were grouped in one sub-branch. We speculate that TdRGA-7Bb was derived from a TdRGA-7Ba mutation, and it happened in Ae. speltoides. Both types of TdRGA-7B participated in tetraploid wheat formation. However, only the TdRGA-7Bb was retained in hexaploid wheat. PMID:23887654

Gong, Caiyan; Cao, Shuanghe; Fan, Renchun; Wei, Bo; Chen, Guiping; Wang, Xianping; Li, Yiwen; Zhang, Xiangqi

2013-01-01

128

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

PubMed

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. PMID:24584845

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

2014-06-01

129

Variation between Ethiopian and North American Barley Varieties (Hordeum vulgare) in Response to Russian Wheat Aphid (Diuraphis noxia) populations  

PubMed Central

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. PMID:25373187

Araya, Alemu; Belay, Tesfay; Hussein, Temam

2014-01-01

130

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

PubMed

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. PMID:25373187

Araya, Alemu; Belay, Tesfay; Hussein, Temam

2014-01-01

131

A Method to Produce Radiation Hybrids for the D-Genome Chromosomes of Wheat (Triticum aestivum L.)  

Microsoft Academic Search

Radiation hybrid (RH) mapping is based on radiation-induced chromosome breakage rather than meiotic recombination, as a means to induce marker segregation for mapping. To date, the implementation of this mapping approach in hexaploid (Triticum aestivum L.; 2n = 6x = 42; AABBDD) and tetraploid (T. turgidum L.; 2n = 4x = 28; AABB) wheat has concentrated on the production of

O. Riera-Lizarazu; J. M. Leonard; V. K. Tiwari; S. F. Kianian

2010-01-01

132

Association of Size Exclusion HPLC of Endosperm Proteins with Dough Mixing and Bread-making Characteristics in a Recombinant Inbred Population of Hard Red Spring Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Variation of polymeric proteins is known to affect wheat end-use quality. This research aimed to investigate the composition of polymeric proteins and their associations with dough mixing strength and bread-making characteristics in a near-homogenous population of 139 recombinant inbred lines (RILs...

133

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...

134

[Manaca, sweet potato and yam: possible substitutes of wheat in foods for two ethnic population in Venezuelan Amazon].  

PubMed

In this study, flours from manaca or acai (Euterpe oleracea Mart), sweet potato (Ipomea batatas), and yam (Dioscorea spp.), species grown in the Venezuelan Amazon, were obtained. The proximal composition, water activity (a(w)), Fe, Ca, Zn, Mg, Cu, Na and K content were determined for the flours of manaca, sweet potato and yam. These flours were used as ingredients of products for the inhabitants of the indigenous populations of the Venezuelan Amazon (Piaroa and Hiwi). Two types of products that traditionally contain wheat flour in their formulation (ingredient they know by transculturation) were formulated; an attempt to substitute it totally or partially by the manaca, sweet potato and/or yam flours was made. For the selection of the products to be formulated, the preferences and eating habits of the indigenous communities and ease and simplicity of the preparations to be developed, were considered. The two products formulated were cookies and "small cakes". To decide on the formulation(s) of the final product(s), sensorial evaluations were made in the laboratory and in the indigenous communities Piaroa and Hiwi. High fat content (16%), dietetic fiber (59.7%) and iron (25 mg / 100 g) in manaca or acai flour were remarkable. Two types of cookies and two of "small cakes" were equally accepted by the indigenous communities. Cookies supply a high iron amount (about 24%). The feasibility of substituting the wheat flour by manaca, sweet potato and yam flour in products accepted by two ethnic populations of the Venezuelan Amazon was demonstrated. PMID:16786737

Sangronis, Elba; Teixeira, Patricia; Otero, Mariana; Guerra, Marisa; Hidalgo, Glida

2006-03-01

135

Diversity of long terminal repeat retrotransposon genome distribution in natural populations of the wild diploid wheat Aegilops speltoides.  

PubMed

The environment can have a decisive influence on the structure of the genome, changing it in a certain direction. Therefore, the genomic distribution of environmentally sensitive transposable elements may vary measurably across a species area. In the present research, we aimed to detect and evaluate the level of LTR retrotransposon intraspecific variability in Aegilops speltoides (2n = 2x = 14), a wild cross-pollinated relative of cultivated wheat. The interretrotransposon amplified polymorphism (IRAP) protocol was applied to detect and evaluate the level of retrotransposon intraspecific variability in Ae. speltoides and closely related species. IRAP analysis revealed significant diversity in TE distribution. Various genotypes from the 13 explored populations significantly differ with respect to the patterns of the four explored LTR retrotransposons (WIS2, Wilma, Daniela, and Fatima). This diversity points to a constant ongoing process of LTR retrotransposon fraction restructuring in populations of Ae. speltoides throughout the species' range and within single populations in time. Maximum changes were recorded in genotypes from small stressed populations. Principal component analysis showed that the dynamics of the Fatima element significantly differ from those of WIS2, Wilma, and Daniela. In terms of relationships between Sitopsis species, IRAP analysis revealed a grouping with Ae. sharonensis and Ae. longissima forming a separate unit, Ae. speltoides appearing as a dispersed group, and Ae. bicornis being in an intermediate position. IRAP display data revealed dynamic changes in LTR retrotransposon fractions in the genome of Ae. speltoides. The process is permanent and population specific, ultimately leading to the separation of small stressed populations from the main group. PMID:22042572

Hosid, Elena; Brodsky, Leonid; Kalendar, Ruslan; Raskina, Olga; Belyayev, Alexander

2012-01-01

136

Diversity of Long Terminal Repeat Retrotransposon Genome Distribution in Natural Populations of the Wild Diploid Wheat Aegilops speltoides  

PubMed Central

The environment can have a decisive influence on the structure of the genome, changing it in a certain direction. Therefore, the genomic distribution of environmentally sensitive transposable elements may vary measurably across a species area. In the present research, we aimed to detect and evaluate the level of LTR retrotransposon intraspecific variability in Aegilops speltoides (2n = 2x = 14), a wild cross-pollinated relative of cultivated wheat. The interretrotransposon amplified polymorphism (IRAP) protocol was applied to detect and evaluate the level of retrotransposon intraspecific variability in Ae. speltoides and closely related species. IRAP analysis revealed significant diversity in TE distribution. Various genotypes from the 13 explored populations significantly differ with respect to the patterns of the four explored LTR retrotransposons (WIS2, Wilma, Daniela, and Fatima). This diversity points to a constant ongoing process of LTR retrotransposon fraction restructuring in populations of Ae. speltoides throughout the species’ range and within single populations in time. Maximum changes were recorded in genotypes from small stressed populations. Principal component analysis showed that the dynamics of the Fatima element significantly differ from those of WIS2, Wilma, and Daniela. In terms of relationships between Sitopsis species, IRAP analysis revealed a grouping with Ae. sharonensis and Ae. longissima forming a separate unit, Ae. speltoides appearing as a dispersed group, and Ae. bicornis being in an intermediate position. IRAP display data revealed dynamic changes in LTR retrotransposon fractions in the genome of Ae. speltoides. The process is permanent and population specific, ultimately leading to the separation of small stressed populations from the main group. PMID:22042572

Hosid, Elena; Brodsky, Leonid; Kalendar, Ruslan; Raskina, Olga; Belyayev, Alexander

2012-01-01

137

Population Dynamics of Meloidogyne incognita, M. arenaria,and Other Nematodes and Crop Yields in Rotations of Cotton, Peanut, and Wheat Under Minimum Tillage  

PubMed Central

Wheat, cotton, and peanut were arranged in three cropping sequences to determine the effects of fenamiphos (6.7 kg a.i./ha) and cropping sequence on nematode population densities and crop yields under conservation tillage and irrigation for 6 years. The cropping sequences included a wheat winter cover crop each year and summer crops of cotton every year, peanut every year, or cotton rotated every other year with peanut. The population densities of Meloidogyne spp. and Helicotylenchus dihystera were determined monthly during the experiment. Numbers of M. incognita increased on cotton and decreased on peanut, whereas M. arenaria increased on peanut, and decreased on cotton; both nematode species remained in moderate to high numbers in plots of wheat. Root damage was more severe on cotton than peanut and was not affected by fenamiphos treatment. The H. dihystera population densities were highest in plots with cotton every summer, intermediate in the cotton-peanut rotation, and lowest in plots with peanut every summer. Over all years and cropping sequences, yield increases in fenamiphos treatment over untreated control were 9% for wheat, 8% for cotton, and 0% for peanut. Peanut yields following cotton were generally higher than yields following peanut. These results show that nematode problems may be manageable in cotton and peanut production under conservation tillage and irrigation in the southeastern United States. PMID:19270949

Johnson, A. W.; Dowler, C. C.; Handoo, Z. A.

2000-01-01

138

Constructing an alternative wheat karyotype using barley genomic DNA.  

PubMed

The established karyotype was generated by genomic in situ hybridization (GISH) using total barley genomic DNA as labelled probe on mitotic metaphase bread wheat chromosomes. GISH produced specific banding signals on 16 of the 21 chromosome pairs. The following chromosomes showed distinctive banding patterns: 2A, 3A, 4A, 5A, 6A, 7A, 1D, 2D, 7D and all of the B chromosomes. The remaining chromosomes showed either faint bands or no hybridization signals at all. The in situ hybridization patterns corresponded to the GAA-satellite sequence, which is similar to the N-banding pattern in wheat. In situ hybridization by labelling total barley genomic DNA made it possible to identify most of the bread wheat chromosomes. The present paper describes a GISH-banding method for hexaploid wheat chromosomes. It is a valuable alternative method for fast chromosome selection without using FISH repetitive DNA clones. PMID:25027628

Icsó, Diána; Molnár-Láng, Márta; Linc, Gabriella

2015-02-01

139

GENES ENCODING PLASTID ACETYL-COA CARBOXYLASE AND 3-PHOSPHOGLYCERATE KINASE OF THE TRITICUM/AEGILOPS COMPLEX AND THE EVOLUTIONARY HISTORY OF POLYPLOID WHEAT.  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 (T. turgidum AABB, and T. timopheevii AAAGG) and hexaploid (T. aestivum, AABBDD) species. The objective of this study was to a...

140

Molecular basis of evolutionary events that shaped the hardness locus in diploid and polyploid wheat species (Triticum and Aegilops).  

PubMed

The Hardness (Ha) locus controls grain hardness in hexaploid wheat (Triticum aestivum) and its relatives (Triticum and Aegilops species) and represents a classical example of a trait whose variation arose from gene loss after polyploidization. In this study, we investigated the molecular basis of the evolutionary events observed at this locus by comparing corresponding sequences of diploid, tertraploid, and hexaploid wheat species (Triticum and Aegilops). Genomic rearrangements, such as transposable element insertions, genomic deletions, duplications, and inversions, were shown to constitute the major differences when the same genomes (i.e., the A, B, or D genomes) were compared between species of different ploidy levels. The comparative analysis allowed us to determine the extent and sequences of the rearranged regions as well as rearrangement breakpoints and sequence motifs at their boundaries, which suggest rearrangement by illegitimate recombination. Among these genomic rearrangements, the previously reported Pina and Pinb genes loss from the Ha locus of polyploid wheat species was caused by a large genomic deletion that probably occurred independently in the A and B genomes. Moreover, the Ha locus in the D genome of hexaploid wheat (T. aestivum) is 29 kb smaller than in the D genome of its diploid progenitor Ae. tauschii, principally because of transposable element insertions and two large deletions caused by illegitimate recombination. Our data suggest that illegitimate DNA recombination, leading to various genomic rearrangements, constitutes one of the major evolutionary mechanisms in wheat species. PMID:15749759

Chantret, Nathalie; Salse, Jérôme; Sabot, François; Rahman, Sadequr; Bellec, Arnaud; Laubin, Bastien; Dubois, Ivan; Dossat, Carole; Sourdille, Pierre; Joudrier, Philippe; Gautier, Marie-Françoise; Cattolico, Laurence; Beckert, Michel; Aubourg, Sébastien; Weissenbach, Jean; Caboche, Michel; Bernard, Michel; Leroy, Philippe; Chalhoub, Boulos

2005-04-01

141

IN VITRO BACTERIAL GROWTH AND IN VIVO RUMEN MICROBIOTA POPULATIONS ASSOCIATED WITH BLOAT IN STEERS GRAZING WHEAT FORAGE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The role of rumen bacteria in the frothy bloat complex common to cattle grazing winter wheat has not been previously elucidated. A series of in vitro and in vivo experiments were designed to elucidate the effect of fresh wheat forage on the bacterial growth, bio-film complexes, rumen fermentation e...

142

Homoeologous recombination within bread wheat to develop novel combinations of HMW-GS genes: transfer of the Glu-A1 locus to chromosome 1D  

Microsoft Academic Search

In an attempt to improve the bread-making quality within hexaploid wheat by elaborating novel high-molecular weight glutenin\\u000a subunits (HMW-GS) combinations useful in wheat-breeding programmes, a 1A chromosome fragment carrying the Glu-A1 locus encoding the subunit Ax2*, was translocated to the long arm of chromosome 1D. The partially isohomoeoallelic line,\\u000a designated RR239, had a meiotic behaviour as regular as cv. Courtot.

Jérôme Dumur; Gérard Branlard; Anne-Marie Tanguy; Mireille Dardevet; Olivier Coriton; Virginie Huteau; Jocelyne Lemoine; Joseph Jahier

2009-01-01

143

A polyphasic approach to study the dynamics of microbial population of an organic wheat sourdough during its conversion to gluten-free sourdough.  

PubMed

To develop a method for organic gluten-free (GF) sourdough bread production, a long-term and original wheat sourdough was refreshed with GF flours. The dynamics of the sourdough microbiota during five months of back-slopping were analyzed by classical enumeration and molecular methods, including PCR-temporal temperature gel electrophoresis (PCR-TTGE), multiplex PCR, and pulsed field gel electrophoresis (PFGE). The results showed that the yeast counts remained constant, although Saccharomyces cerevisiae, present in the initial wheat sourdough, was no longer detected in the GF sourdough, while lactic acid bacteria (LAB) counts increased consistently. In the first phase, which was aimed at obtaining a GF sourdough from wheat sourdough, Lactobacillus sanfranciscensis, L. plantarum, and L. spicheri were the main LAB species detected. During the second phase, aimed at maintaining the GF sourdough, the L. plantarum and L. spicheri populations decreased whereas L. sanfranciscensis persisted and L. sakei became the predominant species. Multiplex PCRs also revealed the presence of several L. sakei strains in the GF sourdough. In a search for the origin of the LAB species, PCR-TTGE was performed on the flour samples but only L. sanfranciscensis was detected, suggesting a flour origin for this typical sourdough species. Thus, while replacement of the wheat flour by GF flour influenced the sourdough microbiota, some of the original sourdough LAB and yeast species remained in the GF sourdough. PMID:25296441

Lhomme, Emilie; Mezaize, Sandra; Ducasse, Maren Bonnand; Chiron, Hubert; Champomier-Vergès, Marie-Christine; Chaillou, Stéphane; Zagorec, Monique; Dousset, Xavier; Onno, Bernard

2014-03-01

144

Transposable elements in a marginal plant population: temporal fluctuations provide new insights into genome evolution of wild diploid wheat  

PubMed Central

Background How new forms arise in nature has engaged evolutionary biologists since Darwin's seminal treatise on the origin of species. Transposable elements (TEs) may be among the most important internal sources for intraspecific variability. Thus, we aimed to explore the temporal dynamics of several TEs in individual genotypes from a small, marginal population of Aegilops speltoides. A diploid cross-pollinated grass species, it is a wild relative of the various wheat species known for their large genome sizes contributed by an extraordinary number of TEs, particularly long terminal repeat (LTR) retrotransposons. The population is characterized by high heteromorphy and possesses a wide spectrum of chromosomal abnormalities including supernumerary chromosomes, heterozygosity for translocations, and variability in the chromosomal position or number of 45S and 5S ribosomal DNA (rDNA) sites. We propose that variability on the morphological and chromosomal levels may be linked to variability at the molecular level and particularly in TE proliferation. Results Significant temporal fluctuation in the copy number of TEs was detected when processes that take place in small, marginal populations were simulated. It is known that under critical external conditions, outcrossing plants very often transit to self-pollination. Thus, three morphologically different genotypes with chromosomal aberrations were taken from a wild population of Ae. speltoides, and the dynamics of the TE complex traced through three rounds of selfing. It was discovered that: (i) various families of TEs vary tremendously in copy number between individuals from the same population and the selfed progenies; (ii) the fluctuations in copy number are TE-family specific; (iii) there is a great difference in TE copy number expansion or contraction between gametophytes and sporophytes; and (iv) a small percentage of TEs that increase in copy number can actually insert at novel locations and could serve as a bona fide mutagen. Conclusions We hypothesize that TE dynamics could promote or intensify morphological and karyotypical changes, some of which may be potentially important for the process of microevolution, and allow species with plastic genomes to survive as new forms or even species in times of rapid climatic change. PMID:20226076

2010-01-01

145

A Novel Retrotransposon Inserted in the Dominant Vrn-B1 Allele Confers Spring Growth Habit in Tetraploid Wheat (Triticum turgidum L.)  

PubMed Central

Vernalization genes determine winter/spring growth habit in temperate cereals and play important roles in plant development and environmental adaptation. In wheat (Triticum L. sp.), it was previously shown that allelic variation in the vernalization gene VRN1 was due to deletions or insertions either in the promoter or in the first intron. Here, we report a novel Vrn-B1 allele that has a retrotransposon in its promoter conferring spring growth habit. The VRN-B1 gene was mapped in a doubled haploid population that segregated for winter-spring growth habit but was derived from two spring tetraploid wheat genotypes, the durum wheat (T. turgidum subsp. durum) variety ‘Lebsock’ and T. turgidum subsp. carthlicum accession PI 94749. Genetic analysis revealed that Lebsock carried the dominant Vrn-A1 and recessive vrn-B1 alleles, whereas PI 94749 had the recessive vrn-A1 and dominant Vrn-B1 alleles. The Vrn-A1 allele in Lebsock was the same as the Vrn-A1c allele previously reported in hexaploid wheat. No differences existed between the vrn-B1 and Vrn-B1 alleles, except that a 5463-bp insertion was detected in the 5?-UTR region of the Vrn-B1 allele. This insertion was a novel retrotransposon (designated as retrotrans_VRN), which was flanked by a 5-bp target site duplication and contained primer binding site and polypurine tract motifs, a 325-bp long terminal repeat, and an open reading frame encoding 1231 amino acids. The insertion of retrotrans_VRN resulted in expression of Vrn-B1 without vernalization. Retrotrans_VRN is prevalent among T. turgidum subsp. carthlicum accessions, less prevalent among T. turgidum subsp. dicoccum accessions, and rarely found in other tetraploid wheat subspecies. PMID:22384375

Chu, C.-G.; Tan, C. T.; Yu, G.-T; Zhong, S.; Xu, S. S.; Yan, L.

2011-01-01

146

SNP discovery and chromosome anchoring provide the first physically-anchored hexaploid oat map and reveal synteny with model species.  

PubMed

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

Oliver, Rebekah E; Tinker, Nicholas A; Lazo, Gerard R; 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; Jackson, Eric W

2013-01-01

147

A diagnostic molecular marker allowing the study of Th. intermedium-derived resistance to BYDV in bread wheat segregating populations  

Microsoft Academic Search

Barley yellow dwarf (BYD) is the most important viral disease of small cereal grains. True resistance to the disease is not\\u000a found in wheat (Triticum aestivum L.), but it has been introgressed from Thinopyrum intermedium (Ti) on chromosome 7DL of recombinant wheat lines designated TC. The objectives of our study were to identify a high through-put\\u000a scoring tool for the

L. Ayala; M. Henry; D. González-de-León; M. van Ginkel; A. Mujeeb-Kazi; B. Keller; M. Khairallah

2001-01-01

148

Genetic control of adenylate kinase and fructokinase in hexaploid wheat and other Triticeae species  

E-print Network

of the Hordeum vulgare cv. Betzes chromosome 3H, long arm of the Elytrigia elongata chromosome 3E, and Secale cereale cv. Imperial and cv. King II chromosome 3R. These alien ADK and FRK gene locations provide further evidence that T. !ongissium chromosome 3S..., H. vulgare cv. Betzes chromosome 3H, E. elongata chromosome 3E and S. cereale cv. Imperial, and cv. King II chromosome 3R are at least partly homoeologous to the group 3 chromosomes of Chinese Spring and also that H. vulgare cv. Betzes chromosome...

Yang, Yaw-Ching

1989-01-01

149

Methods for Virus-Induced Gene Silencing in Hexaploid Wheat using barley stripe mosaic virus vectors  

Technology Transfer Automated Retrieval System (TEKTRAN)

Virus-induced gene silencing (VIGS) is a useful functional genomics tool for rapidly creating gene knockout phenotypes that can be used to infer gene function. Until recently, VIGS has only been possible in dicotyledonous plants. However, the development of vectors based on barley stripe mosaic vi...

150

Analysis and annotation of the hexaploid oat seed transcriptome  

PubMed Central

Background Next generation sequencing provides new opportunities to explore transcriptomes. However, challenges remain for accurate differentiation of homoeoalleles and paralogs, particularly in polyploid organisms with no supporting genome sequence. In this study, RNA-Seq was employed to generate and characterize the first gene expression atlas for hexaploid oat. Results The software packages Trinity and Oases were used to produce a transcript assembly from nearly 134 million 100-bp paired-end reads from developing oat seeds. Based on the quality-parameters employed, Oases assemblies were superior. The Oases 67-kmer assembly, denoted dnOST (de novo Oat Seed Transcriptome), is over 55 million nucleotides in length and the average transcript length is 1,043 nucleotides. The 74.8× sequencing depth was adequate to differentiate a large proportion of putative homoeoalleles and paralogs. To assess the robustness of dnOST, we successfully identified gene transcripts associated with the biosynthetic pathways of three compounds with health-promoting properties (avenanthramides, tocols, ?-glucans), and quantified their expression. Conclusions To our knowledge, this study provides the first direct performance comparison between two major assemblers in a polyploid organism. The workflow we developed provides a useful guide for comparable analyses in other organisms. The transcript assembly developed here is a major advance. It expands the number of oat ESTs 3-fold, and constitutes the first comprehensive transcriptome study in oat. This resource will be a useful new tool both for analysis of genes relevant to nutritional enhancement of oat, and for improvement of this crop in general. PMID:23845136

2013-01-01

151

The origin of the B-genome of bread wheat (Triticum aestivum L.).  

PubMed

Understanding the origin of cultivated wheats would further their genetic improvement. The hexaploid bread wheat (Triticum aestivum L., AABBDD) is believed to have originated through one or more rare hybridization events between Aegilops tauschii (DD) and the tetraploid T. turgidum (AABB). Progenitor of the A-genome of the tetraploid and hexaploid wheats has generally been accepted to be T. urartu. In spite of the large number of attempts and published reports about the origin of the B-genome in cultivated wheats, the donor of the B-genome is still relatively unknown and controversial and, hence, remains open. This genome has been found to be closely related to the S-genome of the Sitopsis section (Ae. speltoides, Ae. longissima, Ae. sharonensis, Ae. searsii, and Ae. bicornis) of the genus Aegilops L. Among Sitopsis species, the most positive evidence has been accumulated for Ae. speltoides as the progenitor of the B-genome. Therefore, one or more of the Sitopsis species were proposed frequently as the B-genome donor. Although several reviews have been written on the origin of the genomes of wheat over the years, this paper will attempt for the first time to review the immense literature on the subject, with a particular emphasis on the B-genome which has attracted a huge attention over some 100 years. The ambiguity and conflicting results in most of the methods employed in deducing the precise B-genome donor/s to bread wheat are also discussed. PMID:23755530

Haider, N

2013-03-01

152

Construction and Characterization of Three Wheat Bacterial Artificial Chromosome Libraries  

PubMed Central

We have constructed three bacterial artificial chromosome (BAC) libraries of wheat cultivar Triticum aestivum Wangshuibai, germplasms T. monococcum TA2026 and TA2033. A total of 1,233,792,170,880 and 263,040 clones were picked and arrayed in 384-well plates. On the basis of genome sizes of 16.8 Gb for hexaploid wheat and 5.6 Gb for diploid wheat, the three libraries represented 9.05-, 2.60-, and 3.71-fold coverage of the haploid genomes, respectively. An improved descending pooling system for BAC libraries screening was established. This improved strategy can save 80% of the time and 68% of polymerase chain reaction (PCR) with the same successful rate as the universal 6D pooling strategy. PMID:25464379

Cao, Wenjin; Fu, Bisheng; Wu, Kun; Li, Na; Zhou, Yan; Gao, Zhongxia; Lin, Musen; Li, Guoqiang; Wu,  Xinyi; Ma, Zhengqiang; Jia, Haiyan

2014-01-01

153

Molecular Basis of Evolutionary Events That Shaped the Hardness Locus in Diploid and Polyploid Wheat Species (Triticum and Aegilops)W?  

PubMed Central

The Hardness (Ha) locus controls grain hardness in hexaploid wheat (Triticum aestivum) and its relatives (Triticum and Aegilops species) and represents a classical example of a trait whose variation arose from gene loss after polyploidization. In this study, we investigated the molecular basis of the evolutionary events observed at this locus by comparing corresponding sequences of diploid, tertraploid, and hexaploid wheat species (Triticum and Aegilops). Genomic rearrangements, such as transposable element insertions, genomic deletions, duplications, and inversions, were shown to constitute the major differences when the same genomes (i.e., the A, B, or D genomes) were compared between species of different ploidy levels. The comparative analysis allowed us to determine the extent and sequences of the rearranged regions as well as rearrangement breakpoints and sequence motifs at their boundaries, which suggest rearrangement by illegitimate recombination. Among these genomic rearrangements, the previously reported Pina and Pinb genes loss from the Ha locus of polyploid wheat species was caused by a large genomic deletion that probably occurred independently in the A and B genomes. Moreover, the Ha locus in the D genome of hexaploid wheat (T. aestivum) is 29 kb smaller than in the D genome of its diploid progenitor Ae. tauschii, principally because of transposable element insertions and two large deletions caused by illegitimate recombination. Our data suggest that illegitimate DNA recombination, leading to various genomic rearrangements, constitutes one of the major evolutionary mechanisms in wheat species. PMID:15749759

Chantret, Nathalie; Salse, Jérôme; Sabot, François; Rahman, Sadequr; Bellec, Arnaud; Laubin, Bastien; Dubois, Ivan; Dossat, Carole; Sourdille, Pierre; Joudrier, Philippe; Gautier, Marie-Françoise; Cattolico, Laurence; Beckert, Michel; Aubourg, Sébastien; Weissenbach, Jean; Caboche, Michel; Bernard, Michel; Leroy, Philippe; Chalhoub, Boulos

2005-01-01

154

Development of high amylose wheat through TILLING  

PubMed Central

Background Wheat (Triticum spp.) is an important source of food worldwide and the focus of considerable efforts to identify new combinations of genetic diversity for crop improvement. In particular, wheat starch composition is a major target for changes that could benefit human health. Starches with increased levels of amylose are of interest because of the correlation between higher amylose content and elevated levels of resistant starch, which has been shown to have beneficial effects on health for combating obesity and diabetes. TILLING (Targeting Induced Local Lesions in Genomes) is a means to identify novel genetic variation without the need for direct selection of phenotypes. Results Using TILLING to identify novel genetic variation in each of the A and B genomes in tetraploid durum wheat and the A, B and D genomes in hexaploid bread wheat, we have identified mutations in the form of single nucleotide polymorphisms (SNPs) in starch branching enzyme IIa genes (SBEIIa). Combining these new alleles of SBEIIa through breeding resulted in the development of high amylose durum and bread wheat varieties containing 47-55% amylose and having elevated resistant starch levels compared to wild-type wheat. High amylose lines also had reduced expression of SBEIIa RNA, changes in starch granule morphology and altered starch granule protein profiles as evaluated by mass spectrometry. Conclusions We report the use of TILLING to develop new traits in crops with complex genomes without the use of transgenic modifications. Combined mutations in SBEIIa in durum and bread wheat varieties resulted in lines with significantly increased amylose and resistant starch contents. PMID:22584013

2012-01-01

155

Haplotype Variation of Glu-D1 Locus and the Origin of Glu-D1d Allele Conferring Superior End-Use Qualities in Common Wheat  

PubMed Central

In higher plants, seed storage proteins (SSPs) are frequently expressed from complex gene families, and allelic variation of SSP genes often affects the quality traits of crops. In common wheat, the Glu-D1 locus, encoding 1Dx and 1Dy SSPs, has multiple alleles. The Glu-D1d allele frequently confers superior end-use qualities to commercial wheat varieties. Here, we studied the haplotype structure of Glu-D1 genomic region and the origin of Glu-D1d. Using seven diagnostic DNA markers, 12 Glu-D1 haplotypes were detected among common wheat, European spelt wheat (T. spelta, a primitive hexaploid relative of common wheat), and Aegilops tauschii (the D genome donor of hexaploid wheat). By comparatively analyzing Glu-D1 haplotypes and their associated 1Dx and 1Dy genes, we deduce that the haplotype carrying Glu-D1d was likely differentiated in the ancestral hexaploid wheat around 10,000 years ago, and was subsequently transmitted to domesticated common wheat and T. spelta. A group of relatively ancient Glu-D1 haplotypes was discovered in Ae. tauschii, which may serve for the evolution of other haplotypes. Moreover, a number of new Glu-D1d variants were found in T. spelta. The main steps in Glu-D1d differentiation are proposed. The implications of our work for enhancing the utility of Glu-D1d in wheat quality improvement and studying the SSP alleles in other crop species are discussed. PMID:24098671

Li, Yiwen; Zhang, Kunpu; Lou, Haijuan; An, Xueli; Dong, Lingli; Gu, Yong Qiang; Anderson, Olin D.; Liu, Xin; Qin, Huanju; Wang, Daowen

2013-01-01

156

Analogy potential effects of planting methods and t ank mixed herbicides on wheat yield and weed populations  

Microsoft Academic Search

The aim of integrated weed management (IWM) was to use the combination of different practices to maintain weed densities at manageable levels. A field experiment was conducted at Agricultural College, Tehran of University, in K araj city 2005-2006 by planting wheat, to investigate the response of planting methods and ta nk mixed herbicides. The experiment was laid out using a

S. Sedigheh

2009-01-01

157

Population Structure, Linkage Disequilibrium, and Genetic Diversity in Soft Winter Wheat Enriched for Fusarium Head Blight Resistance  

Technology Transfer Automated Retrieval System (TEKTRAN)

The occurrence of epidemics of Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, in U.S. winter wheat (Triticum aestivum L.) during the past two decades has resulted in increased emphasis on development of resistant cultivars. Understanding the effect of focused breeding efforts fo...

158

Nucleotide sequence of a gene from chromosome 1D of wheat encoding a HMW-glutenin subunit.  

PubMed Central

A high molecular weight glutenin gene in hexaploid wheat has been isolated by cloning in bacteriophage lambda and characterized. The gene corresponds to polypeptide 12 encoded by chromosome 1D in the variety "Chinese Spring". The coding sequence predicted contains seven cysteine residues six of which flank a central repetitive region comprising more than 70% of the polypeptide. These findings are related to the role of high molecular weight subunits in the viscoelastic theory of gluten structure. Images PMID:3840588

Thompson, R D; Bartels, D; Harberd, N P

1985-01-01

159

The making of a new pathogen: Insights from comparative population genomics of the domesticated wheat pathogen Mycosphaerella graminicola and its wild sister species  

PubMed Central

The fungus Mycosphaerella graminicola emerged as a new pathogen of cultivated wheat during its domestication ?11,000 yr ago. We assembled 12 high-quality full genome sequences to investigate the genetic footprints of selection in this wheat pathogen and closely related sister species that infect wild grasses. We demonstrate a strong effect of natural selection in shaping the pathogen genomes with only ?3% of nonsynonymous mutations being effectively neutral. Forty percent of all fixed nonsynonymous substitutions, on the other hand, are driven by positive selection. Adaptive evolution has affected M. graminicola to the highest extent, consistent with recent host specialization. Positive selection has prominently altered genes encoding secreted proteins and putative pathogen effectors supporting the premise that molecular host–pathogen interaction is a strong driver of pathogen evolution. Recent divergence between pathogen sister species is attested by the high degree of incomplete lineage sorting (ILS) in their genomes. We exploit ILS to generate a genetic map of the species without any crossing data, document recent times of species divergence relative to genome divergence, and show that gene-rich regions or regions with low recombination experience stronger effects of natural selection on neutral diversity. Emergence of a new agricultural host selected a highly specialized and fast-evolving pathogen with unique evolutionary patterns compared with its wild relatives. The strong impact of natural selection, we document, is at odds with the small effective population sizes estimated and suggest that population sizes were historically large but likely unstable. PMID:21994252

Stukenbrock, Eva H.; Bataillon, Thomas; Dutheil, Julien Y.; Hansen, Troels T.; Li, Ruiqiang; Zala, Marcello; McDonald, Bruce A.; Wang, Jun; Schierup, Mikkel H.

2011-01-01

160

Wheat Allergy  

MedlinePLUS

... contain wheat. Wheat has been found in some brands of ice cream, marinara sauce, play dough, potato ... Camp List College Traveling Work For Employers Education & Awareness Education Working Group Annual Conference Speaker Proposals Webinars ...

161

Effect of hosts on competition among clones and evidence of differential selection between pathogenic and saprophytic phases in experimental populations of the wheat pathogen Phaeosphaeria nodorum  

PubMed Central

Background Monoculture, multi-cropping and wider use of highly resistant cultivars have been proposed as mechanisms to explain the elevated rate of evolution of plant pathogens in agricultural ecosystems. We used a mark-release-recapture experiment with the wheat pathogen Phaeosphaeria nodorum to evaluate the impact of two of these mechanisms on the evolution of a pathogen population. Nine P. nodorum isolates marked with ten microsatellite markers and one minisatellite were released onto five replicated host populations to initiate epidemics of Stagonospora nodorum leaf blotch. The experiment was carried out over two consecutive host growing seasons and two pathogen collections were made during each season. Results A total of 637 pathogen isolates matching the marked inoculants were recovered from inoculated plots over two years. Genetic diversity in the host populations affected the evolution of the corresponding P. nodorum populations. In the cultivar mixture the relative frequencies of inoculants did not change over the course of the experiment and the pathogen exhibited a low variation in selection coefficients. Conclusions Our results support the hypothesis that increasing genetic heterogeneity in host populations may retard the rate of evolution in associated pathogen populations. Our experiment also provides indirect evidence of fitness costs associated with host specialization in P. nodorum as indicated by differential selection during the pathogenic and saprophytic phases. PMID:21718545

2011-01-01

162

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

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

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

2012-01-01

163

Next-generation survey sequencing and the molecular organization of wheat chromosome 6B.  

PubMed

Common wheat (Triticum aestivum L.) is one of the most important cereals in the world. To improve wheat quality and productivity, the genomic sequence of wheat must be determined. The large genome size (?17 Gb/1 C) and the hexaploid status of wheat have hampered the genome sequencing of wheat. However, flow sorting of individual chromosomes has allowed us to purify and separately shotgun-sequence a pair of telocentric chromosomes. Here, we describe a result from the survey sequencing of wheat chromosome 6B (914 Mb/1 C) using massively parallel 454 pyrosequencing. From the 4.94 and 5.51 Gb shotgun sequence data from the two chromosome arms of 6BS and 6BL, 235 and 273 Mb sequences were assembled to cover ?55.6 and 54.9% of the total genomic regions, respectively. Repetitive sequences composed 77 and 86% of the assembled sequences on 6BS and 6BL, respectively. Within the assembled sequences, we predicted a total of 4798 non-repetitive gene loci with the evidence of expression from the wheat transcriptome data. The numbers and chromosomal distribution patterns of the genes for tRNAs and microRNAs in wheat 6B were investigated, and the results suggested a significant involvement of DNA transposon diffusion in the evolution of these non-protein-coding RNA genes. A comparative analysis of the genomic sequences of wheat 6B and monocot plants clearly indicated the evolutionary conservation of gene contents. PMID:24086083

Tanaka, Tsuyoshi; Kobayashi, Fuminori; Joshi, Giri Prasad; Onuki, Ritsuko; Sakai, Hiroaki; Kanamori, Hiroyuki; Wu, Jianzhong; Simkova, Hana; Nasuda, Shuhei; Endo, Takashi R; Hayakawa, Katsuyuki; Doležel, Jaroslav; Ogihara, Yasunari; Itoh, Takeshi; Matsumoto, Takashi; Handa, Hirokazu

2014-01-01

164

Sequence polymorphism in polyploid wheat and their d-genome diploid ancestor.  

PubMed Central

Sequencing was used to investigate the origin of the D genome of the allopolyploid species Triticum aestivum and Aegilops cylindrica. A 247-bp region of the wheat D-genome Xwye838 locus, encoding ADP-glucopyrophosphorylase, and a 326-bp region of the wheat D-genome Gss locus, encoding granule-bound starch synthase, were sequenced in a total 564 lines of hexaploid wheat (T. aestivum, genome AABBDD) involving all its subspecies and 203 lines of Aegilops tauschii, the diploid source of the wheat D genome. In Ae. tauschii, two SNP variants were detected at the Xwye838 locus and 11 haplotypes at the Gss locus. Two haplotypes with contrasting frequencies were found at each locus in wheat. Both wheat Xwye838 variants, but only one of the Gss haplotypes seen in wheat, were found among the Ae. tauschii lines. The other wheat Gss haplotype was not found in either Ae. tauschii or 70 lines of tetraploid Ae. cylindrica (genomes CCDD), which is known to hybridize with wheat. It is concluded that both T. aestivum and Ae. cylindrica originated recurrently, with at least two genetically distinct progenitors contributing to the formation of the D genome in both species. PMID:15238542

Caldwell, Katherine S; Dvorak, Jan; Lagudah, Evans S; Akhunov, Eduard; Luo, Ming-Cheng; Wolters, Petra; Powell, Wayne

2004-01-01

165

Complete mitochondrial genome of the natural hexaploid loach, Misgurnus anguillicaudatus (Teleostei: Cypriniformes: Cobitididae).  

PubMed

The complete mitochondrial genome of the natural hexaploid loach Misgurnus anguillicaudatus is a circular molecule of 16,643 bp in size, containing 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and 2 main noncoding regions (the control region and the origin of the light strand replication). Most of the genes are encoded on the heavy strand, except for ND6 and eight tRNAs. The control region is 918 bp in length and located between the tRNA(Pro) and tRNA(Phe) genes, some typical conserved elements (TAS, CSB1-3 and CSB D-F) were found in this region. All these features reflect a typical vertebrate mitochondrial gene arrangement of the hexaploid M. anguillicaudatus. PMID:23586342

Yu, Yong-Yao; Li, Yan-He; Li, Ru-Wei; Wang, Wei-Min; Zhou, Xiao-Yun

2014-04-01

166

QTL for root angle and number in a population developed from bread wheats (Triticum aestivum) with contrasting adaptation to water-limited environments.  

PubMed

Root architecture traits in wheat are important in deep soil moisture acquisition and may be used to improve adaptation to water-limited environments. The genetic architecture of two root traits, seminal root angle and seminal root number, were investigated using a doubled haploid population derived from SeriM82 and Hartog. Multiple novel quantitative trait loci (QTL) were identified, each one having a modest effect. For seminal root angle, four QTL (-log10(P) >3) were identified on 2A, 3D, 6A and 6B, and two suggestive QTL (-log10(P) >2) on 5D and 6B. For root number, two QTL were identified on 4A and 6A with four suggestive QTL on 1B, 3A, 3B and 4A. QTL for root angle and root number did not co-locate. Transgressive segregation was found for both traits. Known major height and phenology loci appear to have little effect on root angle and number. Presence or absence of the T1BL.1RS translocation did not significantly influence root angle. Broad sense heritability (h (2)) was estimated as 50 % for root angle and 31 % for root number. Root angle QTL were found to be segregating between wheat cultivars adapted to the target production region indicating potential to select for root angle in breeding programs. PMID:23525632

Christopher, Jack; Christopher, Mandy; Jennings, Raeleen; Jones, Shirley; Fletcher, Susan; Borrell, Andrew; Manschadi, Ahmad M; Jordan, David; Mace, Emma; Hammer, Graeme

2013-06-01

167

Discrimination of the Closely Related A and D Genomes of the Hexaploid Oat Avena sativa L  

Microsoft Academic Search

A satellite DNA sequence, As120a, specific to the A-genome chromosomes in the hexaploid oat, Avena sativa L., was isolated by subcloning a fragment with internal tandem repeats from a plasmid, pAs120, that had been obtained from an Avena strigosa (As genome) genomic library. Southern and in situ hybridization showed that sequences with homology to sequences within pAs120 were dispersed throughout

Concha Linares; Esther Ferrer; Araceli Fominaya

1998-01-01

168

Structural and functional partitioning of bread wheat chromosome 3B.  

PubMed

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. PMID:25035497

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

169

Resistance among U.S. wheat Triticum aestivum cultivars to the wheat pathotype of Magnaporthe oryzae  

Technology Transfer Automated Retrieval System (TEKTRAN)

Magnaporthe oryzae is the causal agent of blast on several graminaceous plants. The M. oryzae population causing wheat blast has not been found outside South America. U.S. wheat production is at risk to this pathogen if introduced and established. Proactive testing of US wheat cultivars for their re...

170

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...

171

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...

172

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 ...

173

Origin, migration routes and worldwide population genetic structure of the wheat yellow rust pathogen Puccinia striiformis f.sp. tritici.  

PubMed

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 South African populations. Although most geographic populations are not markedly affected by recent dispersal events, this study emphasizes the influence of human activities on recent long-distance spread of the pathogen. PMID:24465211

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

2014-01-01

174

Contrasted microcolinearity and gene evolution within a homoeologous region of wheat and barley species.  

PubMed

We study here the evolution of genes located in the same physical locus using the recently sequenced Ha locus in seven wheat genomes in diploid, tetraploid, and hexaploid species and compared them with barley and rice orthologous regions. We investigated both the conservation of microcolinearity and the molecular evolution of genes, including coding and noncoding sequences. Microcolinearity is restricted to two groups of genes (Unknown gene-2, VAMP, BGGP, Gsp-1, and Unknown gene-8 surrounded by several copies of ATPase), almost conserved in rice and barley, but in a different relative position. Highly conserved genes between wheat and rice run along with genes harboring different copy numbers and highly variable sequences between close wheat genomes. The coding sequence evolution appeared to be submitted to heterogeneous selective pressure and intronic sequences analysis revealed that the molecular clock hypothesis is violated in most cases. PMID:18274696

Chantret, Nathalie; Salse, Jérôme; Sabot, François; Bellec, Arnaud; Laubin, Bastien; Dubois, Ivan; Dossat, Carole; Sourdille, Pierre; Joudrier, Philippe; Gautier, Marie-Françoise; Cattolico, Laurence; Beckert, Michel; Aubourg, Sébastien; Weissenbach, Jean; Caboche, Michel; Leroy, Philippe; Bernard, Michel; Chalhoub, Boulos

2008-02-01

175

Influence of volunteer wheat plant condition on movement of the wheat curl mite, Aceria tosichella, in winter wheat.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer, is the vector of wheat streak mosaic virus and high plains virus which cause significant crop loss in winter wheat throughout the western Great Plains. Volunteer wheat emerging before harvest, as a result of severe hail, is the primary source of mites and virus that infect fall-planted winter wheat. Wind-borne movement of the WCM is of key importance in the spread and infection of the virus complex. Significant movement of WCM from wheat has been thought to be closely tied to the senescence or deterioration of the host. Results from field and greenhouse studies indicated that movement from un-vernalized winter wheat was not closely associated with the deterioration of the wheat host. Greenhouse studies showed no correlation between WCM movement and plant condition, but there was a highly significant relationship between WCM movement and mite population on the host plant. Field studies did not demonstrate increased movement associated with deteriorating un-vernalized winter wheat. However, healthier hosts which were able to support a larger population of mites were associated with increased movement. The main influence on the level of mite movement relates to the size of the source population and not the condition of the host plant, but plant condition appears to be a factor in limiting the increase of the WCM population. PMID:14974690

Thomas, John A; Hein, Gary L

2003-01-01

176

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

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

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

177

Homoeolog-specific transcriptional bias in allopolyploid wheat  

PubMed Central

Background Interaction between parental genomes is accompanied by global changes in gene expression which, eventually, contributes to growth vigor and the broader phenotypic diversity of allopolyploid species. In order to gain a better understanding of the effects of allopolyploidization on the regulation of diverged gene networks, we performed a genome-wide analysis of homoeolog-specific gene expression in re-synthesized allohexaploid wheat created by the hybridization of a tetraploid derivative of hexaploid wheat with the diploid ancestor of the wheat D genome Ae. tauschii. Results Affymetrix wheat genome arrays were used for both the discovery of divergent homoeolog-specific mutations and analysis of homoeolog-specific gene expression in re-synthesized allohexaploid wheat. More than 34,000 detectable parent-specific features (PSF) distributed across the wheat genome were used to assess AB genome (could not differentiate A and B genome contributions) and D genome parental expression in the allopolyploid transcriptome. In re-synthesized polyploid 81% of PSFs detected mid-parent levels of gene expression, and only 19% of PSFs showed the evidence of non-additive expression. Non-additive expression in both AB and D genomes was strongly biased toward up-regulation of parental type of gene expression with only 6% and 11% of genes, respectively, being down-regulated. Of all the non-additive gene expression, 84% can be explained by differences in the parental genotypes used to make the allopolyploid. Homoeolog-specific co-regulation of several functional gene categories was found, particularly genes involved in photosynthesis and protein biosynthesis in wheat. Conclusions Here, we have demonstrated that the establishment of interactions between the diverged regulatory networks in allopolyploids is accompanied by massive homoeolog-specific up- and down-regulation of gene expression. This study provides insights into interactions between homoeologous genomes and their role in growth vigor, development, and fertility of allopolyploid species. PMID:20849627

2010-01-01

178

IMPROVING BIOLOGICAL CONTROL OF AN INVASIVE PEST WITH MOLECULAR PHYLOGEOGRAPHIC AND POPULATION GENETIC APPROACHES: THE WHEAT STEM SAWFLY, CEPHUS CINCTUS NORTON, (HYMENOPTERA : CEPHIDAE) AS A CASE STUDY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The wheat stem sawfly (WSS), Cephus cinctus Norton (Hymenoptera: Cephidae) has become a chronic pest of wheat in the semi-arid steppe region of the North American Great Plains. To develop a more general and conceptual framework with predictive value for the biological control of this pest, it is imp...

179

Quanah Wheat.  

E-print Network

.* , . + , "r-,."* $,' . - .-A$ . -. EXAS AGRICULTURAL EXPERIMEE~T STATION r R. D. Mjtector. Wege Station, Texas % Au!ui& 734 Ahq 1951 QUANAH WHEAT I. M. ATKINS Digest This bulletin reports the development and characteristics of Quanah, a... new disease-resistant hard red winter wheat of excellent quality, which is now available to Texas farmers. This new variety was developed in the cooperative small grain improvement program of the Texas Agricultural Experiment Station...

Atkins, Irvin Milburn

1951-01-01

180

Wheat: The Whole Story.  

ERIC Educational Resources Information Center

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…

Oklahoma State Dept. of Education, Oklahoma City.

181

Hypersensitive Response-Like Reaction Is Associated with Hybrid Necrosis in Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii Coss  

PubMed Central

Background Hybrid speciation is classified into homoploid and polyploid based on ploidy level. Common wheat is an allohexaploid species that originated from a naturally occurring interploidy cross between tetraploid wheat and diploid wild wheat Aegilops tauschii Coss. Aegilops tauschii provides wide naturally occurring genetic variation. Sometimes its triploid hybrids with tetraploid wheat show the following four types of hybrid growth abnormalities: types II and III hybrid necrosis, hybrid chlorosis, and severe growth abortion. The growth abnormalities in the triploid hybrids could act as postzygotic hybridization barriers to prevent formation of hexaploid wheat. Methodology/Principal Findings Here, we report on the geographical and phylogenetic distribution of Ae. tauschii accessions inducing the hybrid growth abnormalities and showed that they are widely distributed across growth habitats in Ae. tauschii. Molecular and cytological characterization of the type III necrosis phenotype was performed. The hybrid abnormality causing accessions were widely distributed across growth habitats in Ae. tauschii. Transcriptome analysis showed that a number of defense-related genes such as pathogenesis-related genes were highly up-regulated in the type III necrosis lines. Transmission electron microscope observation revealed that cell death occurred accompanied by generation of reactive oxygen species in leaves undergoing type III necrosis. The reduction of photosynthetic activity occurred prior to the appearance of necrotic symptoms on the leaves exhibiting hybrid necrosis. Conclusions/Significance Taking these results together strongly suggests that an autoimmune response might be triggered by intergenomic incompatibility between the tetraploid wheat and Ae. tauschii genomes in type III necrosis, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in Arabidopsis intraspecific and Nicotiana interspecific hybrids. Only Ae. tauschii accessions without such inhibiting factors could be candidates for the D-genome donor for the present hexaploid wheat. PMID:20593003

Mizuno, Nobuyuki; Hosogi, Naoki; Park, Pyoyun; Takumi, Shigeo

2010-01-01

182

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

PubMed

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. PMID:14663527

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

2003-12-01

183

Electrophoretic survey of seedling esterases in wheats in relation to their phylogeny.  

PubMed

Evolutionary and ontogenetic variation of six seedling esterases of independent genetic control is studied in polyploid wheats and their diploid relatives by means of polyacrylamide gel electrophoresis. Four of them are shown to be controlled by homoeoallelic genes in chromosomes of third, sixth and seventh homoeologous groups.The isoesterase electrophoretic data are considered supporting a monophyletic origin of both the primitive tetraploid and the primitive hexaploid wheat from which contemporary taxa of polyploid wheats have emerged polyphyletically and polytopically through recurrent introgressive hybridization and accumulation of mutations. Ancestral diploids belonging or closely related to Triticum boeoticum, T. urartu, Aegilops speltoides and Ae. tauschii ssp. strangulata are genetically the most suitable genome donors of polyploid wheats. Diploids of the Emarginata subsection of the section Sitopsis, Aegilops longissima s.str., Ae. sharonensis, Ae. searsii and Ae. bicornis, are unsuitable for the role of the wheat B genome donors, being all fixed for the esterase B and D electromorphs different from those of tetraploid wheats. PMID:24305916

Jaaska, V

1980-11-01

184

DETERMINATION OF PLOIDY LEVELS OF SOME POPULATIONS OF AGROPYRON CRISTATUM (POACEAE) IN IRAN BY FLOW CYTOMETRY  

Microsoft Academic Search

Flow cytometry (FCM) was used to determine the ploidy levels of six different populations of Agropyron cristatum (L.) Gaertn. (Poaceae) in Iran, using a diploid cultivated barley (Hordeum vulgare L.) as an internal reference. According to flow cytometric data, tetraploid (2n = ± 28) and hexaploid (2n = ± 42) levels were detected among the examined populations and these results

M. YOUSOFI; Payam Noor

185

Small RNAs, DNA methylation and transposable elements in wheat  

PubMed Central

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 the short-term suppression of TEs in the wheat genome, whereas DNA methylation and increased mutation rates may provide a long-term mechanism to inactivate TEs. PMID:20584339

2010-01-01

186

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

PubMed Central

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

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

2008-01-01

187

Phylogenetic relationships of hexaploid large-sized barbs (genus Labeobarbus, Cyprinidae) based on mtDNA data.  

PubMed

The phylogenetic relationships among species of the Labeobarbus genus (Teleostei, Cyprinidae) which comprises large body-sized hexaploid taxa were inferred using complete cytochrome b mitochondrial gene sequences. Molecular data suggest two main evolutionary groups which roughly correspond to a Northern (Middle East and Northwest Africa) and a sub-Saharan lineage. The splitting of the African hexaploids from their Asian ancestors and their subsequent diversification on the African continent occurred in the Late Miocene, a period in which other cyprinins also invaded Africa and radiated in the Mediterranean region. Finally, systematic implications of these results to the taxonomic validity of genera or subgenera such as Varicorhinus, Kosswigobarbus, Carasobarbus and Capoeta are further discussed. PMID:20152918

Tsigenopoulos, Costas S; Kasapidis, Panagiotis; Berrebi, Patrick

2010-08-01

188

Isolation and characterization of simple sequence repeat markers in the hexaploid forage grass timothy ( Phleum pratense L.)  

Microsoft Academic Search

To develop simple sequence repeat (SSR) markers for the hexaploid forage grass timothy (Phleum pratense L.), we used four SSR-enriched genomic libraries to isolate 1,331 SSR-containing clones. All four libraries contained a high percentage of perfect clones, ranging from 78.1% to 91.6%. From these clones, we developed 355 SSR markers when tested from 502 SSR primer pairs. Using all 355

Hong-Wei Cai; Nana Yuyama; Hiroyuki Tamaki; Akira Yoshizawa

2003-01-01

189

Sequencing of Chloroplast Genomes from Wheat, Barley, Rye and Their Relatives Provides a Detailed Insight into the Evolution of the Triticeae Tribe  

PubMed Central

Using Roche/454 technology, we sequenced the chloroplast genomes of 12 Triticeae species, including bread wheat, barley and rye, as well as the diploid progenitors and relatives of bread wheat Triticum urartu, Aegilops speltoides and Ae. tauschii. Two wild tetraploid taxa, Ae. cylindrica and Ae. geniculata, were also included. Additionally, we incorporated wild Einkorn wheat Triticum boeoticum and its domesticated form T. monococcum and two Hordeum spontaneum (wild barley) genotypes. Chloroplast genomes were used for overall sequence comparison, phylogenetic analysis and dating of divergence times. We estimate that barley diverged from rye and wheat approximately 8–9 million years ago (MYA). The genome donors of hexaploid wheat diverged between 2.1–2.9 MYA, while rye diverged from Triticum aestivum approximately 3–4 MYA, more recently than previously estimated. Interestingly, the A genome taxa T. boeoticum and T. urartu were estimated to have diverged approximately 570,000 years ago. As these two have a reproductive barrier, the divergence time estimate also provides an upper limit for the time required for the formation of a species boundary between the two. Furthermore, we conclusively show that the chloroplast genome of hexaploid wheat was contributed by the B genome donor and that this unknown species diverged from Ae. speltoides about 980,000 years ago. Additionally, sequence alignments identified a translocation of a chloroplast segment to the nuclear genome which is specific to the rye/wheat lineage. We propose the presented phylogeny and divergence time estimates as a reference framework for future studies on Triticeae. PMID:24614886

Middleton, Christopher P.; Senerchia, Natacha; Stein, Nils; Akhunov, Eduard D.; Keller, Beat

2014-01-01

190

Functional characterisation of wheat Pgip genes reveals their involvement in the local response to wounding.  

PubMed

Polygalacturonase-inhibiting proteins (PGIPs) are cell wall leucine-rich repeat (LRR) proteins involved in plant defence. The hexaploid wheat (Triticum aestivum, genome AABBDD) genome contains one Pgip gene per genome. Tapgip1 (B genome) and Tapgip2 (D genome) are expressed in all tissues, whereas Tapgip3 (A genome) is inactive because of a long terminal repeat, Copia retrotransposon insertion within the coding region. To verify whether Tapgip1 and Tapgip2 encode active PGIPs and are involved in the wheat defence response, we expressed them transiently and analysed their expression under stress conditions. Neither TaPGIP1 nor TaPGIP2 showed inhibition activity in vitro against fungal polygalacturonases. Moreover, a wheat genotype (T. turgidum ssp. dicoccoides) lacking active homologues of Tapgip1 or Tapgip2 possesses PGIP activity. At transcript level, Tapgip1 and Tapgip2 were both up-regulated after fungal infection and strongly induced following wounding. This latter result has been confirmed in transgenic wheat plants expressing the ?-glucuronidase (GUS) gene under control of the 5'-flanking region of Tdpgip1, a homologue of Tapgip1 with an identical sequence. Strong and transient GUS staining was mainly restricted to the damaged tissues and was not observed in adjacent tissues. Taken together, these results suggest that Tapgips and their homologues are involved in the wheat defence response by acting at the site of the lesion caused by pathogen infection. PMID:23574379

Janni, M; Bozzini, T; Moscetti, I; Volpi, C; D'Ovidio, R

2013-11-01

191

Evidence for AEGILOPS SHARONENSIS Eig as the Donor of the B Genome of Wheat.  

PubMed

A number of lines of evidence are advanced for the candidacy of Aegilops sharonensis Eig as the donor of the B genome of wheat. The cytoplasm of Ae. sharonensis is compatible with tetraploid wheat Triticum turgidum dicoccoides, as evidenced by the high level of chromosome pairing and fertility of the amphiploid Ae. sharonensisxT. turgidum dicoccoides. Ae. sharonensis chromosomes exhibit high levels of pairing with those of the B genome of wheat in hybrids with Ph-deficient hexaploid wheat and low levels of homoeologous pairing with T. monococcum chromosomes.--The amphidiploid between Ae. sharonensis and T. monococcum is very similar to T. turgidum dicoccoides in spike, spikelet and grain morphology. The karyotype of Ae. sharonensis resembles more closely that of extrapolated B genome karyotypes of wheat than do the karyotypes of other proposed B-genome donor species of Aegilops. Because of distinctiveness in cytological affinity and karyotype morphology between Ae. sharonensis and Ae. longissima, a separate genome symbol S(sh) is proposed for the former species. PMID:17249127

Kushnir, U; Halloran, G M

1981-11-01

192

Evidence for AEGILOPS SHARONENSIS Eig as the Donor of the B Genome of Wheat  

PubMed Central

A number of lines of evidence are advanced for the candidacy of Aegilops sharonensis Eig as the donor of the B genome of wheat. The cytoplasm of Ae. sharonensis is compatible with tetraploid wheat Triticum turgidum dicoccoides, as evidenced by the high level of chromosome pairing and fertility of the amphiploid Ae. sharonensis x T. turgidum dicoccoides. Ae. sharonensis chromosomes exhibit high levels of pairing with those of the B genome of wheat in hybrids with Ph-deficient hexaploid wheat and low levels of homoeologous pairing with T. monococcum chromosomes.——The amphidiploid between Ae. sharonensis and T. monococcum is very similar to T. turgidum dicoccoides in spike, spikelet and grain morphology. The karyotype of Ae. sharonensis resembles more closely that of extrapolated B genome karyotypes of wheat than do the karyotypes of other proposed B-genome donor species of Aegilops. Because of distinctiveness in cytological affinity and karyotype morphology between Ae. sharonensis and Ae. longissima, a separate genome symbol Ssh is proposed for the former species. PMID:17249127

Kushnir, U.; Halloran, G. M.

1981-01-01

193

Analysis of agronomic and domestication traits in a cultivated emmer × durum wheat population using a high-density single nucleotide polymorphism-based linkage map  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cultivated emmer wheat (Triticum turgidum ssp. dicoccum) is tetraploid and considered one of the eight founder crops that spawned the Agricultural Revolution about 10,000 years ago. Cultivated emmer has non-free-threshing seed and a somewhat fragile rachis, but mutations in genes governing these an...

194

Analysis of the endophytic actinobacterial population in the roots of wheat (Triticum aestivum L.) by terminal restriction fragment length polymorphism and sequencing of 16S rRNA clones.  

PubMed

The endophytic actinobacterial population in the roots of wheat grown in three different soils obtained from the southeast part of South Australia was investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of the amplified 16S rRNA genes. A new, validated approach was applied to the T-RFLP analysis in order to estimate, to the genus level, the actinobacterial population that was identified. Actinobacterium-biased primers were used together with three restriction enzymes to obtain terminal restriction fragments (TRFs). The TRFs were matched to bacterial genera by the T-RFLP Analysis Program, and the data were analyzed to validate and semiquantify the genera present within the plant roots. The highest diversity and level of endophytic colonization were found in the roots of wheat grown in a dark loam from Swedes Flat, and the lowest were found in water-repellent sand from Western Flat. This molecular approach detected a greater diversity of actinobacteria than did previous culture-dependent methods, with the predominant genera being Mycobacterium (21.02%) in Swedes Flat, Streptomyces (14.35%) in Red Loam, and Kitasatospora (15.02%) in Western Flat. This study indicates that the soil that supported a higher number of indigenous organisms resulted in wheat roots with higher actinobacterial diversity and levels of colonization within the plant tissue. Sequencing of 16S rRNA clones, obtained using the same actinobacterium-biased PCR primers that were used in the T-RFLP analysis, confirmed the presence of the actinobacterial diversity and identified a number of Mycobacterium and Streptomyces species. PMID:15006805

Conn, Vanessa M; Franco, Christopher M M

2004-03-01

195

High-throughput genotyping of wheat-barley amphiploids utilising diversity array technology (DArT)  

PubMed Central

Background Hordeum chilense, a native South American diploid wild barley, is one of the species of the genus Hordeum with a high potential for cereal breeding purposes, given its high crossability with other members of the Triticeae tribe. Hexaploid tritordeum (×Tritordeum Ascherson et Graebner, 2n=6×=42, AABBHchHch) is the fertile amphiploid obtained after chromosome doubling of hybrids between Hordeum chilense and durum wheat. Approaches used in the improvement of this crop have included crosses with hexaploid wheat to promote D/Hch chromosome substitutions. While this approach has been successful as was the case with triticale, it has also complicated the genetic composition of the breeding materials. Until now tritordeum lines were analyzed based on molecular cytogenetic techniques and screening with a small set of DNA markers. However, the recent development of DArT markers in H. chilense offers new possibilities to screen large number of accessions more efficiently. Results Here, we have applied DArT markers to genotype composition in forty-six accessions of hexaploid tritordeum originating from different stages of tritordeum breeding program and to H. chilense-wheat chromosome addition lines to allow their physical mapping. Diversity analyses were conducted including dendrogram construction, principal component analysis and structure inference. Euploid and substituted tritordeums were clearly discriminated independently of the method used. However, dendrogram and Structure analyses allowed the clearest discrimination among substituted tritordeums. The physically mapped markers allowed identifying these groups as substituted tritordeums carrying the following disomic substitutions (DS): DS1D (1Hch), DS2D (2Hch), DS5D (5Hch), DS6D (6Hch) and the double substitution DS2D (2Hch), DS5D (5Hch). These results were validated using chromosome specific EST and SSR markers and GISH analysis. Conclusion In conclusion, DArT markers have proved to be very useful to detect chromosome substitutions in the tritordeum breeding program and thus they are expected to be equally useful to detect translocations both in the tritordeum breeding program and in the transference of H. chilense genetic material in wheat breeding programs. PMID:23725040

2013-01-01

196

Winter and Specialty Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The two main commercial types of wheat are durum (Triticum durum L., 2n=4x= 28) and common (T. aestivum L, 2n=6x=42.) wheat, the latter being the more widely grown. Wheat has three growth habits, namely winter (wheats grown over the winter months that require vernalization and can withstand prolong...

197

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

PubMed Central

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

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

2002-01-01

198

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  

Microsoft Academic Search

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,

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

1996-01-01

199

Genetic diversity and linkage disequilibrium studies on a 3.1Mb genomic region of chromosome 3B in European and Asian bread wheat ( Triticum aestivum L.) populations  

Microsoft Academic Search

Genetic diversity and linkage disequilibrium (LD) were investigated in 376 Asian and European accessions of bread wheat (Triticum aestivum L.). After a first and rapid screening about diversity and genetic structure at the whole genome scale using 70 simple sequence\\u000a repeats (SSRs), we focused on a sequenced contig (ctg954) of 3.1 Mb located on the short arm of chromosome 3B of

C. Y. Hao; M. R. Perretant; F. Choulet; L. F. Wang; E. Paux; P. Sourdille; X. Y. Zhang; C. Feuillet; Francois Balfourier

2010-01-01

200

Populations  

NSDL National Science Digital Library

This chapter introduces population as a group of the same kind of organisms in a given space at a given time. The activities in this section will provide students with the opportunity to define population, estimate populations in a community, and count and compare populations within a community. Students will gain the knowledge in describing plant and animal populations living in a community. They will also experiment with plant populations to control growth and development, not to mention discuss the effects of abiotic conditions on a community.

Galle, Janet R.; Warren, Patricia A.

2005-01-01

201

BAC Libraries from Wheat Chromosome 7D: Efficient Tool for Positional Cloning of Aphid Resistance Genes  

PubMed Central

Positional cloning in bread wheat is a tedious task due to its huge genome size and hexaploid character. BAC libraries represent an essential tool for positional cloning. However, wheat BAC libraries comprise more than million clones, which makes their screening very laborious. Here, we present a targeted approach based on chromosome-specific BAC libraries. Such libraries were constructed from flow-sorted arms of wheat chromosome 7D. A library from the short arm (7DS) consisting of 49,152 clones with 113?kb insert size represented 12.1 arm equivalents whereas a library from the long arm (7DL) comprised 50,304 clones of 116?kb providing 14.9x arm coverage. The 7DS library was PCR screened with markers linked to Russian wheat aphid resistance gene DnCI2401, the 7DL library was screened by hybridization with a probe linked to greenbug resistance gene Gb3. The small number of clones combined with high coverage made the screening highly efficient and cost effective. PMID:21318113

Šimková, Hana; Šafá?, Jan; Kubaláková, Marie; Suchánková, Pavla; ?íhalíková, Jarmila; Robert-Quatre, Heda; Azhaguvel, Perumal; Weng, Yiqun; Peng, Junhua; Lapitan, Nora L. V.; Ma, Yaqin; You, Frank M.; Luo, Ming-Cheng; Bartoš, Jan; Doležel, Jaroslav

2011-01-01

202

Potential new sources of wheat curl mite resistance in wheat to prevent the spread of yield-reducing pathogens.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer (Trombidiformes: Eriophyidae), is a major pest in cropping regions of the world and is recognised as the primary vector of several yield-reducing pathogens, primarily affecting wheat. Management of WCM is complicated due to several aspects of the mite's biology and ecology; however, commercially viable mite resistant wheat varieties may offer practical long-term management options. Unfortunately, mite populations have adapted to previously identified sources of resistance, highlighting the need for further sources of resistance and the value of stacking different resistances to give greater degrees and longevity of control. In this study we assessed the susceptibility of 42 wheat-derived genotypes to mite population growth using a new experimental method that overcomes methodological limitations of previous studies. Experimental wheat lines included a variety of wheat genotypes, related Triticeae species, wheat-alien chromosome amphiploids, and chromosome addition or substitution lines. From these we identify new promising sources of WCM resistance associated with Thinopyrum intermedium, Th. ponticum and Hordeum marinum chromosomes. More specifically we identify group 1J and 5J chromosomes of the L3 and L5 wheat-Th. intermedium addition lines as new sources of resistance that could be exploited to transfer resistance onto homoeologous wheat chromosomes. This study offers new methods for reliable in situ estimations of mite abundance on cereal plants, and new sources of WCM resistance that may assist management of WCM and associated viruses in wheat. PMID:24705793

Richardson, Kelly; Miller, Adam D; Hoffmann, Ary A; Larkin, Philip

2014-09-01

203

Reproduction and development of Russian wheat aphid biotype 2 on crested wheatgrass, intermediate wheatgrass, and susceptible and resistant wheat.  

PubMed

The Russian wheat aphid, Diuraphis noxia (Kurdjumov), is an economically important pest of small grains. Since its introduction into North America in 2003, Russian wheat aphid Biotype 2 has been found to be virulent to all commercially available winter wheat, Triticum aestivum L., cultivars. Our goal was to examine differences in Russian wheat aphid reproduction and development on a variety of plant hosts to gain information about 1) potential alternate host refuges, 2) selective host pressures on Russian wheat aphid genetic variation, and 3) general population dynamics of Russian wheat aphid Biotype 2. We studied host quality of two wheatgrasses (crested wheatgrass, Agropyron cristatum [L.] Gaertn., and intermediate wheatgrass, Agropyron intermedium [Host] Beauvoir) and two types of winter wheat (T. aestivum, one Biotype 2 susceptible wheat, 'Custer' and one biotype 2 resistant wheat, STARS02RWA2414-11). The susceptible wheat had the highest intrinsic rate of increase, greatest longevity and greatest fecundity of the four host studied. Crested wheatgrass and the resistant wheat showed similar growth rates. Intermediate wheatgrass had the lowest intrinsic rate of increase and lowest fecundity of all tested hosts. PMID:18459422

Merrill, Scott C; Peairs, Frank B; Miller, Hayley R; Randolph, Terri L; Rudolph, Jeff B; Talmich, Emili E

2008-04-01

204

Population.  

ERIC Educational Resources Information Center

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…

King, Pat; Landahl, John

205

Solid-Stemmed Wheat Does Not Affect Overwintering Mortality of the Wheat Stem Sawfly, Cephus cinctus  

PubMed Central

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. PMID:22235942

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

2011-01-01

206

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

PubMed

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. PMID:22235942

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

2011-01-01

207

Wheat grass selection  

NSDL National Science Digital Library

The wheat grass on the right is not tolerant of high salinity, or high salt conditions. The wheat grass on the left is a hybrid that has a high salt tolerance. It grows well in high salinity environments.

Richard Wang (USDA;ARS)

2006-09-25

208

Genetic diversity of wild emmer wheat in Israel and Turkey  

Microsoft Academic Search

Allozyme variation in the tetraploid wild emmer wheat, Triticum dicoccoides, the progenitor of all cultivated wheats, was studied for the proteins encoded by 42 gene loci in 1815 plants representing 37 populations - 33 from Israel and 4 from Turkey - sampled in 33 localities from 1979 to 1987. The results showed that: (a) 6 loci (14%) were monomorphic in

E. Nevo; A. Beiles

1989-01-01

209

Molecular, Physicochemical and Rheological Characteristics of Introgressive Triticale/Triticum monococcum ssp. monococcum Lines with Wheat 1D/1A Chromosome Substitution  

PubMed Central

Three sets of hexaploid introgressive triticale lines, with Triticum monococcum ssp. monococcum (cultivated einkorn wheat) genes and a bread wheat chromosome 1D substituted for chromosome 1A, and one set of secondary triticale lines were evaluated for grain and flour physicochemical and dough rheological characteristics in two generations (F7 and F8). Genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) confirmed the 1D/1A chromosome substitution. The presence or absence of einkorn high-molecular-weight (HMW) glutenin subunits and the wheat Glu-D1d locus encoding the 5 + 10 subunits was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), capillary zone electrophoresis, and allele-specific molecular markers. Significant differences were found among physicochemical properties (with the exception of the Hagberg falling number) of all introgressive Triticale/T. monococcum lines and the secondary triticale lines. The wheat 1D/1A chromosome substitution also affected these properties. The results showed that in all introgressive triticale lines, the protein and gluten content, Zeleny sedimentation value, and water absorption capacity, were increased. The rheological parameters estimated using micro-farinograph, reomixer, and Kieffer dough extensibility systems also showed an appreciable increase in dough-mixing properties, maximum resistance to extension (Rmax), and dough extensibility. Introgressive Triticale/T. monococcum lines with 5 + 10 subunits have particularly favorable rheological parameters. The results obtained in this study suggest that the cultivated einkorn genome Am, in the context of hexaploid secondary triticale lines and with a wheat 1D/1A substitution, has the potential to improve gluten polymer interactions and be a valuable genetic resource for triticale quality improvement. PMID:23896593

Salmanowicz, Boles?aw P.; Langner, Monika; Wi?niewska, Halina; Apolinarska, Barbara; Kwiatek, Micha?; B?aszczyk, Lidia

2013-01-01

210

Wheat: Science and Trade  

Technology Transfer Automated Retrieval System (TEKTRAN)

This is for a book review of Wheat: science and trade, edited by B.F. Carver. The book provides an indepth review of wheat biology, production, breeding, processing, and trade and is organized in four sections. "Making of a Wheat Plant" reviews domestication, evolution, development, and molecular ...

211

Wheat Stripe Rust  

Technology Transfer Automated Retrieval System (TEKTRAN)

This is a chapter on wheat stripe rust in a book entitled “Wheat: Science and Trade”. The chapter provides an overview on various aspects of wheat stripe rust and control, including distribution and epidemiology; origin and historical importance; taxonomy, lifecycle, and host range; genetic variati...

212

Population.  

ERIC Educational Resources Information Center

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,…

International Planned Parenthood Federation, London (England).

213

NADP-dependent aromatic alcohol dehydrogenase in polyploid wheats and their diploid relatives. On the origin and phylogeny of polyploid wheats.  

PubMed

The three major isoenzymes of the NADP-dependent aromatic alcohol dehydrogenase (ADH-B), distinguished in polyploid wheats by means of polyacrylamide gel electrophoresis, are shown to be coded by homoeoalleles of the locus Adh-2 on short arms of chromosomes of the fifth homoeologous group. Essentially codominant expression of the Adh-2 homoeolleles of composite genomes was observed in young seedlings of hexaploid wheats (T. aestivum s.l.) and tetraploid wheats of the emmer group (T. turgidum s.l.), whereas only the isoenzyme characteristic of the A genome is present in the seedlings of the timopheevii-group tetraploids (T. timopheevii s.str. and T. araraticum).The slowest-moving B(3) isoenzyme of polyploid wheats, coded by the homoeoallele of the B genome, is characteristic of the diploid species Aegilops speltoides S.l., including both its awned and awnless forms, but was not encountered in Ae. bicornis, Ae. sharonensis and Ae. longissima. The last two diploids, as well as Ae. tauschii, Ae. caudata, Triticum monococcum s.str., T. boeoticum s.l. (incl. T. thaoudar) and T. urartu all shared a common isoenzyme coinciding electrophoretically with the band B(2) controlled by the A and D genome homoeoalleles in polyploid wheats. Ae. bicomis is characterized by the slowest isoenzyme, B(4), not found in wheats and in the other diploid Aegilops species studied.Two electrophoretic variants of ADH-B, B(1) and B(2), considered to be alloenzymes of the A genome homoeoallele, were observed in T. dicoccoides, T. dicoccon, T. turgidum. s.str. and T. spelta, whereas B(2) was characteristic of T. timopheevii s.l. and only B(1) was found in the remaining taxa of polyploid wheats. The isoenzyme B(1), not encountered among diploid species, is considered to be a mutational derivative which arose on the tetraploid level from its more ancestral form B(2) characteristic of diploid wheats.The implication of the ADH-B isoenzyme data to the problems of wheat phylogeny and gene evolution is discussed. PMID:24309759

Jaaska, V

1978-09-01

214

Inferring the contribution of sexual reproduction, migration and off-season survival to the temporal maintenance of microbial populations: a case study on the wheat fungal pathogen Puccinia striiformis f.sp. tritici.  

PubMed

Understanding the mode of temporal maintenance of plant pathogens is an important domain of microbial ecology research. Due to the inconspicuous nature of microbes, their temporal maintenance cannot be studied directly through tracking individuals and their progeny. Here, we suggest a series of population genetic analyses on molecular marker variation in temporally spaced samples to infer about the relative contribution of sexual reproduction, off-season survival and migration to the temporal maintenance of pathogen populations. We used the proposed approach to investigate the temporal maintenance of wheat yellow rust pathogen, Puccinia striiformis f.sp. tritici (PST), in the Himalayan region of Pakistan. Multilocus microsatellite genotyping of PST isolates revealed high genotypic diversity and recombinant population structure across all locations, confirming the existence of sexual reproduction in this region. The genotypes were assigned to four genetic groups, revealing a clear differentiation between zones with and without Berberis spp., the alternate host of PST, with an additional subdivision within the Berberis zone. The lack of any differentiation between samples across two sampling years, and the very infrequent resampling of multilocus genotypes over years at a given location was consistent with limited over-year clonal survival, and a limited genetic drift. The off-season oversummering population in the Berberis zone, likely to be maintained locally, served as a source of migrants contributing to the temporal maintenance in the non-Berberis zone. Our study hence demonstrated the contribution of both sexual recombination and off-season oversummering survival to the temporal maintenance of the pathogen. These new insights into the population biology of PST highlight the general usefulness of the analytical approach proposed. PMID:24354737

Ali, Sajid; Gladieux, Pierre; Rahman, Hidayatur; Saqib, Muhammad S; Fiaz, Muhammad; Ahmad, Habib; Leconte, Marc; Gautier, Angélique; Justesen, Annemarie F; Hovmøller, Mogens S; Enjalbert, Jérôme; de Vallavieille-Pope, Claude

2014-02-01

215

of wheat. Socrates Overview  

E-print Network

Canada, the company publicly pledged that it would not commercially release the world’s first strain of genetically engineered wheat until several conditions were met. First, Monsanto pledged to gain market acceptance for genetically engineered wheat by convincing major international wheat buyers to agree to purchase it. Second, regulatory agencies in the United States and Canada would have to approve Monsanto’s genetically engineered wheat simultaneously, so as not to give one country a market advantage over the other. Third, Monsanto pledged to work with the wheat industry and the regulatory agencies to establish “appropriate ” contami-150 Hard Red Spring Wheat 151 nation thresholds. 1 And finally, Monsanto committed to work with the wheat industry and the regulatory agencies to resolve unanswered questions about the costs of segregation and to address outstanding agronomic stewardship concerns (Monsanto Canada 2003). By March of 2004 Monsanto had failed to meet virtually all these self-imposed conditions, but

R. Dennis Olson

216

Cash Wheat in a Wheat-Ryegrass Grazing System.  

E-print Network

~-~ash Wheat ? Ina B~1452 November 1983 t Wheat--Ryegrass Grazing System ~ THE TEXAS AGRICULTURAL EXPERIMENT STATION / Neville P. Clarke, Director / The Texas A&M University System / College Station, 'l"exas SUMMARY Wheat is an important...

Nelson, L.R.; Rouquette, F.M. Jr.; Randel, R.D.

1983-01-01

217

Differential expression and properties of starch branching enzyme isoforms in developing wheat endosperm.  

PubMed

Three forms of starch branching enzyme (BE) from developing hexaploid wheat (Triticum aestivum) endosperm have been partially purified and characterized. Immunological cross-reactivities indicate that two forms (WBE-IAD, 88 kD, and WBE-IB, 87 kD) are related to the maize BE I class and that WBE-II (88 kD) is related to maize BE II. Comparison of the N-terminal sequences from WBE-IAD and WBE-II with maize and rice BEs confirms these relationships. Evidence is presented from the analysis of nullisomic-tetrasomic wheat lines demonstrating that WBE-IB is located on chromosome 7B and that the WBE-IAD fraction contains polypeptides that are encoded on chromosomes 7A and 7D. The wheat endosperm BE classes are differentially expressed during endosperm development. WBE-II is expressed at a constant level throughout mid and late endosperm development. In contrast, WBE-IAD and WBE-IB are preferentially expressed in late endosperm development. Differences are also observed in the kinetic characteristics of the enzymes. The WBE-I isoforms have a 2- to 5-fold higher affinity for amylose than does WBE-II, and the WBE-I isoforms are activated up to 5-fold by phosphorylated intermediates and inorganic phosphate, whereas WBE-II is activated only 50%. The potential implications of this activation of BE I for starch biosynthesis are discussed. PMID:9008395

Morell, M K; Blennow, A; Kosar-Hashemi, B; Samuel, M S

1997-01-01

218

Wheat alleles introgress into selfing wild relatives: empirical estimates from approximate Bayesian computation in Aegilops triuncialis.  

PubMed

Extensive gene flow between wheat (Triticum sp.) and several wild relatives of the genus Aegilops has recently been detected despite notoriously high levels of selfing in these species. Here, we assess and model the spread of wheat alleles into natural populations of the barbed goatgrass (Aegilops triuncialis), a wild wheat relative prevailing in the Mediterranean flora. Our sampling, based on an extensive survey of 31 Ae. triuncialis populations collected along a 60 km × 20 km area in southern Spain (Grazalema Mountain chain, Andalousia, totalling 458 specimens), is completed with 33 wheat cultivars representative of the European domesticated pool. All specimens were genotyped with amplified fragment length polymorphism with the aim of estimating wheat admixture levels in Ae. triuncialis populations. This survey first confirmed extensive hybridization and backcrossing of wheat into the wild species. We then used explicit modelling of populations and approximate Bayesian computation to estimate the selfing rate of Ae. triuncialis along with the magnitude, the tempo and the geographical distance over which wheat alleles introgress into Ae. triuncialis populations. These simulations confirmed that extensive introgression of wheat alleles (2.7 × 10(-4) wheat immigrants for each Ae. triuncialis resident, at each generation) into Ae. triuncialis occurs despite a high selfing rate (Fis ? 1 and selfing rate = 97%). These results are discussed in the light of risks associated with the release of genetically modified wheat cultivars in Mediterranean agrosystems. PMID:25223217

Pajkovic, Mila; Lappe, Sylvain; Barman, Rachel; Parisod, Christian; Neuenschwander, Samuel; Goudet, Jerome; Alvarez, Nadir; Guadagnuolo, Roberto; Felber, François; Arrigo, Nils

2014-10-01

219

Characterization of FLOWERING LOCUS T1 (FT1) Gene in Brachypodium and Wheat  

PubMed Central

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. PMID:24718312

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

2014-01-01

220

Isolation and sequence analysis of the wheat B genome subtelomeric DNA  

PubMed Central

Background Telomeric and subtelomeric regions are essential for genome stability and regular chromosome replication. In this work, we have characterized the wheat BAC (bacterial artificial chromosome) clones containing Spelt1 and Spelt52 sequences, which belong to the subtelomeric repeats of the B/G genomes of wheats and Aegilops species from the section Sitopsis. Results The BAC library from Triticum aestivum cv. Renan was screened using Spelt1 and Spelt52 as probes. Nine positive clones were isolated; of them, clone 2050O8 was localized mainly to the distal parts of wheat chromosomes by in situ hybridization. The distribution of the other clones indicated the presence of different types of repetitive sequences in BACs. Use of different approaches allowed us to prove that seven of the nine isolated clones belonged to the subtelomeric chromosomal regions. Clone 2050O8 was sequenced and its sequence of 119 737 bp was annotated. It is composed of 33% transposable elements (TEs), 8.2% Spelt52 (namely, the subfamily Spelt52.2) and five non-TE-related genes. DNA transposons are predominant, making up 24.6% of the entire BAC clone, whereas retroelements account for 8.4% of the clone length. The full-length CACTA transposon Caspar covers 11 666 bp, encoding a transposase and CTG-2 proteins, and this transposon accounts for 40% of the DNA transposons. The in situ hybridization data for 2050O8 derived subclones in combination with the BLAST search against wheat mapped ESTs (expressed sequence tags) suggest that clone 2050O8 is located in the terminal bin 4BL-10 (0.95-1.0). Additionally, four of the predicted 2050O8 genes showed significant homology to four putative orthologous rice genes in the distal part of rice chromosome 3S and confirm the synteny to wheat 4BL. Conclusion Satellite DNA sequences from the subtelomeric regions of diploid wheat progenitor can be used for selecting the BAC clones from the corresponding regions of hexaploid wheat chromosomes. It has been demonstrated for the first time that Spelt52 sequences were involved in the evolution of terminal regions of common wheat chromosomes. Our research provides new insights into the microcollinearity in the terminal regions of wheat chromosomes 4BL and rice chromosome 3S. PMID:19732459

Salina, Elena A; Sergeeva, Ekaterina M; Adonina, Irina G; Shcherban, Andrey B; Afonnikov, Dmitry A; Belcram, Harry; Huneau, Cecile; Chalhoub, Boulos

2009-01-01

221

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

PubMed Central

Background Triticum monococcum (2n) is a close ancestor of T. urartu, the A-genome progenitor of cultivated hexaploid wheat, and is therefore a useful model for the study of components regulating photomorphogenesis in diploid wheat. In order to develop genetic and genomic resources for such a study, we constructed genome-wide transcriptomes of two Triticum monococcum subspecies, the wild winter wheat T. monococcum ssp. aegilopoides (accession G3116) and the domesticated spring wheat T. monococcum ssp. monococcum (accession DV92) by generating de novo assemblies of RNA-Seq data derived from both etiolated and green seedlings. Principal Findings The de novo transcriptome assemblies of DV92 and G3116 represent 120,911 and 117,969 transcripts, respectively. We successfully mapped ?90% of these transcripts from each accession to barley and ?95% of the transcripts to T. urartu genomes. However, only ?77% transcripts mapped to the annotated barley genes and ?85% transcripts mapped to the annotated T. urartu genes. Differential gene expression analyses revealed 22% more light up-regulated and 35% more light down-regulated transcripts in the G3116 transcriptome compared to DV92. The DV92 and G3116 mRNA sequence reads aligned against the reference barley genome led to the identification of ?500,000 single nucleotide polymorphism (SNP) and ?22,000 simple sequence repeat (SSR) sites. Conclusions De novo transcriptome assemblies of two accessions of the diploid wheat T. monococcum provide new empirical transcriptome references for improving Triticeae genome annotations, and insights into transcriptional programming during photomorphogenesis. The SNP and SSR sites identified in our analysis provide additional resources for the development of molecular markers. PMID:24821410

Naithani, Sushma; Sullivan, Chris; Preece, Justin; Tiwari, Vijay K.; Elser, Justin; Leonard, Jeffrey M.; Sage, Abigail; Gresham, Cathy; Kerhornou, Arnaud; Bolser, Dan; McCarthy, Fiona; Kersey, Paul; Lazo, Gerard R.; Jaiswal, Pankaj

2014-01-01

222

Molecular cytogenetic analysis of wheat - Elymus repens introgression lines with resistance to Fusarium head blight.  

PubMed

Elymus repens (L.) Gould (2n = 6x = 42, StStStStHH) is a hexaploid perennial wheatgrass species from the tribe Triticeae, distantly related to bread wheat Triticum aestivum L. (2n = 6x = 42, AABBDD). As a potential source of resistance to Fusarium head blight (FHB), E. repens was crossed to common wheat to transfer resistance genes. The progeny were advanced to homozygosity by single seed descent. A total of eight BC(1)F(9) progeny lines were selected and characterized in this study. The chromosome numbers of these derived lines ranged from 42 to 56, including lines with 44, 52, and 54 chromosomes. All of the lines were cytologically stable in terms of meiotic chromosome behavior. The univalent frequency in the lines varied between 0.34 and 2.36 per cell. Similarly, the multivalent frequency did not exceed 1% in any of the lines. GISH analysis revealed that the number of intact wheat chromosomes in the various lines varied between 40 and 44. Numerous translocated chromosomes were detected in all lines. The translocations involved chromosomal segments from wheat, and the St and H genomes of E. repens. Furthermore, trigenomic translocated chromosomes were detected in some of the lines. The introgression into wheat chromosomes included not only terminal types but also interstitial segments. The Fusarium head blight resistance of the eight lines, following point inoculation, varied from 5.65% infected florets to 11.46% compared with the check cultivars T. aestivum 'Roblin' and T. aestivum 'Crocus' at 100% and 85%, respectively. PMID:23379340

Zeng, J; Cao, W; Hucl, P; Yang, Y; Xue, A; Chi, D; Fedak, G

2013-01-01

223

Wheat Evolution: Dough Washing  

NSDL National Science Digital Library

In this activity (page 5), learners investigate the evolution of wheat by washing different types of dough with water and comparing the results. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant.

Biotechnology and Biological Sciences Research Council

2012-01-01

224

Wheat Production in Texas.  

E-print Network

grain or forage varieties and the development of short stat- ure, strong-strawed varieties for growing under irrigation and high fertility conditions. RECOMMENDED AND ACCEPTABLE WHEAT VARIETIES BY AREAS Area Recommended Acceptable 1 Tascosa Comanche.... wheat are different from those used in dryland production. The land usually is plowed with a disc or moldboard plow and the straw is turned under. Weeds and volunteer wheat are controlled with the usual implements. In many cases the land may...

Atkins, I. M.; Porter, K. B.; Lahr, Keith; Merkle, Owen G.; Futrell, M. C.

1960-01-01

225

Isolation and characterization of microsatellite loci in wheat stem sawfly Cephus cinctus and cross-species amplification in related species  

Technology Transfer Automated Retrieval System (TEKTRAN)

The wheat stem sawfly is an important insect pest of wheat that can cause significant damage to yield and grain quality. Five microsatellite loci were isolated and characterized in wheat stem sawfly, Cephus cinctus, to facilitate future population genetic studies and help delineate their geographica...

226

The homoeologous genes encoding chalcone-flavanone isomerase in Triticum aestivum L.: structural characterization and expression in different parts of wheat plant.  

PubMed

Chalcone-flavanone isomerase (CHI; EC 5.5.1.6.) participates in the early step of flavonoid biosynthesis, related to plant adaptive and protective responses to environmental stress. The bread wheat genomic sequences encoding CHI were isolated, sequenced and mapped to the terminal segment of the long arms of chromosomes 5A, 5B and 5D. The loss of the final Chi intron and junction of the two last exons was found in the wheat A, B and D genomes compared to the Chi sequences of most other plant species. Each of the three diploid genomes of hexaploid wheat encodes functional CHI; however, transcription of the three homoeologous genes is not always co-regulated. In particular, the three genes demonstrated different response to salinity in roots: Chi-D1 was up-regulated, Chi-A1 responds medially, whereas Chi-B1 was not activated at all. The observed variation in transcriptional activity between the Chi homoeologs is in a good agreement with structural diversification of their promoter sequences. In addition, the correlation between Chi transcription and anthocyanin pigmentation in different parts of wheat plant has been studied. The regulatory genes controlling anthocyanin pigmentation of culm and pericarp modulated transcription of the Chi genes. However, in other organs, there was no strong relation between tissue pigmentation and the transcription of the Chi genes, suggesting complex regulation of the Chi expression in most parts of wheat plant. PMID:24480448

Shoeva, Olesya Y; Khlestkina, Elena K; Berges, Helene; Salina, Elena A

2014-04-01

227

Evolution of new disease specificity at a simple resistance locus in a crop-weed complex: reconstitution of the Lr21 gene in wheat.  

PubMed

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 F(2) 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

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

2009-06-01

228

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

PubMed Central

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

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

2013-01-01

229

Influence of Commodity Type, Percentage of Cracked Kernels, and Wheat Class on Population Growth of Stored-Product Psocids (Psocoptera: Liposcelidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of the type of grain commodity on population growth of four psocid species, Liposcelis bostrychophila Badonnel, L. decolor (Pearman), L. paeta Pearman, and L. entomophila (Enderlein) (Psocoptera: Liposcelididae), was examined under laboratory conditions. Sorghum was the most suitable for ...

230

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...

231

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...

232

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...

233

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...

234

Registration of ‘Kelse’ wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard red spring (HRS) wheat (Triticum aestivum L.) grain must have high grain protein concentration (GPC) to maximize market value. The objective of this research was to develop a HRS wheat cultivar with high GPC and durable resistance to stripe rust (Puccinia striiformis Westend f. sp. tritici), a ...

235

REGISTRATION OF 'MCCORMICK' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘McCormick’ (Reg. no. CV-959, PI 632691) is a soft red winter wheat (Triticum aestivum L.) developed and released May 2002 by the Virginia Agricultural Experiment Station. McCormick wheat was named in tribute of Robert Hall of Walnut Grove in Rockbridge County, VA, and his sons, including Cyrus Hal...

236

REGISTRATION OF 'TRIBUTE' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Tribute’ (Reg. no. CV-958, PI 632689) is a soft red winter wheat (Triticum aestivum L.) developed and released May 2002 by the Virginia Agricultural Experiment Station. Tribute is broadly adapted and has performed well over most of the soft red winter wheat production regions in the U.S.A. and Can...

237

Advanced backcross QTL analysis in progenies derived from a cross between a German elite winter wheat variety and a synthetic wheat ( Triticum aestivum L.)  

Microsoft Academic Search

We report here the second advanced backcross quantitative trait locus (AB-QTL) analysis carried out in winter wheat. Seven agronomic traits were studied in a BC 2F 1population derived from a cross between the German winter wheat variety Flair and the synthetic wheat line XX86 developed in Japan. We selected 111 BC 2F 1 lines and genotyped these with 197 microsatellite

X. Q. Huang; H. Kempf; M. W. Ganal; M. S. Röder

2004-01-01

238

Coverage and consistency: bioinformatics aspects of the analysis of multirun iTRAQ experiments with wheat leaves.  

PubMed

The hexaploid genome of bread wheat (Triticum aestivum) is large (17 Gb) and repetitive, and this has delayed full sequencing and annotation of the genome, which is a prerequisite for effective quantitative proteomics analysis. Aware of these constraints we investigated the most effective approaches for shotgun proteomic analyses of bread wheat that would support large-scale quantitative comparisons using iTRAQ reagents. We used a data set that was generated by two-dimensional LC-MS of iTRAQ labeled peptides from wheat leaves. The main items considered in this study were the choice of sequence database for matching LC-MS data, the consistency of identification when multiple LC-MS runs were acquired, and the options for downstream functional analysis to generate useful insight. For peptide identification we examined the extensive NCBInr plant database, a smaller composite cereals database, the Brachypodium distachyon model plant genome, the EST-based SuperWheat database, as well as the genome sequence from the recently sequenced D-genome progenitor Aegilops tauschii. While the most spectra were assigned by using the SuperWheat database, this extremely large database could not be readily manipulated for the robust protein grouping that is required for large-scale, multirun quantitative experiments. We demonstrated a pragmatic alternative of using the composite cereals database for peptide spectra matching. The stochastic aspect of protein grouping across LC-MS runs was investigated using the smaller composite cereals database where we found that attaching the Brachypodium best BLAST hit reduced this problem. Further, assigning quantitation to the best Brachypodium locus yielded promising results enabling integration with existing downstream data mining and functional analysis tools. Our study demonstrated viable approaches for quantitative proteomics analysis of bread wheat samples and shows how these approaches could be similarly adopted for analysis of other organisms with unsequenced or incompletely sequenced genomes. PMID:24015675

Pascovici, Dana; Gardiner, Donald M; Song, Xiaomin; Breen, Edmond; Solomon, Peter S; Keighley, Tim; Molloy, Mark P

2013-11-01

239

Whole Wheat Pizza Dough Ingredients  

E-print Network

Whole Wheat Pizza Dough Ingredients: 1 cup flour, white, for breads 1 cup whole wheat flour 1. Blend yeast with flour mixture. Add hot water; stir to form dough. 3. Add enough whole wheat flour whole wheat flour on the kneading surface; turn out dough onto floured surface; knead to form stiff

Liskiewicz, Maciej

240

Wheat-related disorders: A broad spectrum of ‘evolving’ diseases  

PubMed Central

Throughout the world, cereals have always been recognized as a fundamental food. Human evolution, through the development of cooking, led to the production of food rich in gluten, in order to take full advantage of the nutritional properties of this food. The result has been that gluten intolerance has arisen only in those populations that developed the art of cooking wheat. It is also recognized that wheat, one of the central elements of the Mediterranean diet, cannot be tolerated in some individuals. Among the wheat-related pathologies, coeliac disease is the best known: it is a chronic inflammatory condition affecting the gastrointestinal tract, which develops in genetically predisposed individuals. The most common manifestation is the malabsorption of nutrients. Recently, another wheat-related disease has appeared: non-coeliac gluten sensitivity, defined as the onset of a variety of manifestations related to wheat, rye and barley ingestion, in patients in whom coeliac disease and wheat allergy have been excluded. In this paper we will explore the damaging power of wheat, analysing the harmful process by which it realizes the onset of clinical manifestations associated with wheat-related disorders. PMID:25083282

Gasbarrini, GB

2014-01-01

241

Sequence-Based Mapping of the Polyploid Wheat Genome  

PubMed Central

The emergence of new sequencing technologies has provided fast and cost-efficient strategies for high-resolution mapping of complex genomes. Although these approaches hold great promise to accelerate genome analysis, their application in studying genetic variation in wheat has been hindered by the complexity of its polyploid genome. Here, we applied the next-generation sequencing of a wheat doubled-haploid mapping population for high-resolution gene mapping and tested its utility for ordering shotgun sequence contigs of a flow-sorted wheat chromosome. A bioinformatical pipeline was developed for reliable variant analysis of sequence data generated for polyploid wheat mapping populations. The results of variant mapping were consistent with the results obtained using the wheat 9000 SNP iSelect assay. A reference map of the wheat genome integrating 2740 gene-associated single-nucleotide polymorphisms from the wheat iSelect assay, 1351 diversity array technology, 118 simple sequence repeat/sequence-tagged sites, and 416,856 genotyping-by-sequencing markers was developed. By analyzing the sequenced megabase-size regions of the wheat genome we showed that mapped markers are located within 40?100 kb from genes providing a possibility for high-resolution mapping at the level of a single gene. In our population, gene loci controlling a seed color phenotype cosegregated with 2459 markers including one that was located within the red seed color gene. We demonstrate that the high-density reference map presented here is a useful resource for gene mapping and linking physical and genetic maps of the wheat genome. PMID:23665877

Saintenac, Cyrille; Jiang, Dayou; Wang, Shichen; Akhunov, Eduard

2013-01-01

242

Sina and Sinb genes in triticale do not determine grain hardness contrary to their orthologs Pina and Pinb in wheat  

PubMed Central

Background Secaloindoline a (Sina) and secaloindoline b (Sinb) genes of hexaploid triticale (x Triticosecale Wittmack) are orthologs of puroindoline a (Pina) and puroindoline b (Pinb) in hexaploid wheat (Triticum aestivum L.). It has already been proven that RNA interference (RNAi)-based silencing of Pina and Pinb genes significantly decreased the puroindoline a and puroindoline b proteins in wheat and essentially increased grain hardness (J Exp Bot 62:4025-4036, 2011). The function of Sina and Sinb in triticale was tested by means of RNAi silencing and compared to wheat. Results Novel Sina and Sinb alleles in wild-type plants of cv. Wanad were identified and their expression profiles characterized. Alignment with wheat Pina-D1a and Pinb-D1a alleles showed 95% and 93.3% homology with Sina and Sinb coding sequences. Twenty transgenic lines transformed with two hpRNA silencing cassettes directed to silence Sina or Sinb were obtained by the Agrobacterium-mediated method. A significant decrease of expression of both Sin genes in segregating progeny of tested T1 lines was observed independent of the silencing cassette used. The silencing was transmitted to the T4 kernel generation. The relative transcript level was reduced by up to 99% in T3 progeny with the mean for the sublines being around 90%. Silencing of the Sin genes resulted in a substantial decrease of secaloindoline a and secaloindoline b content. The identity of SIN peptides was confirmed by mass spectrometry. The hardness index, measured by the SKCS (Single Kernel Characterization System) method, ranged from 22 to 56 in silent lines and from 37 to 49 in the control, and the mean values were insignificantly lower in the silent ones, proving increased softness. Additionally, the mean total seed protein content of silenced lines was about 6% lower compared with control lines. Correlation coefficients between hardness and transcript level were weakly positive. Conclusions We documented that RNAi-based silencing of Sin genes resulted in significant decrease of their transcripts and the level of both secaloindoline proteins, however did not affect grain hardness. The unexpected, functional differences of Sin genes from triticale compared with their orthologs, Pin of wheat, are discussed. PMID:24279512

2013-01-01

243

Adaptation of wheat rusts to the wheat cultivars in former Czechoslovakia  

Microsoft Academic Search

In former Czechoslovakia virulence of rusts attacking wheat was studied since the sixties. Since the same time genes for resistance in the registered cultivars were identified. The role of Berberis and Thalictrum as alternate hosts for stem rust and leaf rust, respectively, was investigated as well. Determined changes of virulence in rust populations could only partially be ascribed to changes

Pavel Bartoš; Eva Stuchlíková; Renata Hanušová

1996-01-01

244

Wheat Evolution: Dough Rising  

NSDL National Science Digital Library

In this activity (p.6-7 of PDF), learners investigate the evolution of wheat by creating dough from different flours, observing the samples of dough as they rise, and then baking the dough. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant.

Biotechnology and Biological Sciences Research Council

2012-01-01

245

Wheat Evolution: Sedimentation Testing  

NSDL National Science Digital Library

In this activity (p.8-9 of PDF), learners investigate the evolution of wheat by conducting sedimentation tests on different flours. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant. Note: Sedimentation test can also be done using SDS detergent and lactic acid instead of soap and vinegar.

Council, Biotechnology A.

2012-01-01

246

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...

247

Multiple categories of resistance to wheat curl mite (Acari: Eriophyidae) expressed in accessions of Aegilops tauschii.  

PubMed

The wheat curl mite, Aceria tosichella Keifer, is an important pest in the western plains of the United States as well as in most major wheat-growing regions of the world. This mite is a vector of the economically important diseases wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and High Plains virus (HPV). This study looked at seven accessions of Aegilops tauschii (Coss) Schmal to determine if they exhibit antibiosis, tolerance, and/or antixenosis to the wheat curl mite using 'Jagger', a known wheat curl mite-susceptible variety, and OK05312, a known wheat curl mite-resistant variety, as controls. Four of the seven tested accessions showed antibiotic effects on the population growth of wheat curl mite, as demonstrated by low number of wheat curl mite adults and nymphs at the end of the experiment. Three accessions and the commercial wheat variety Jagger showed some level of tolerance to wheat curl mite infestations, as demonstrated by a significantly reduced percentage proportional tissue dry weight and by tolerance index values. Four accessions demonstrated a strong antixenotic effect on the wheat curl mite, as demonstrated by significantly reduced numbers of mite adults at the end of the experiment. This study also established an effective method for determining antixenosis to the wheat curl mite in wheat that can be used for future experiments. All accessions demonstrated at least one type of plant resistance that could provide a genetic source for control of the wheat curl mite that may have the potential to be transferred into commercial wheat varieties. PMID:23356085

Carrera, Sandra Garcés; Davis, Holly; Aguirre-Rojas, Lina; Murugan, Marimuthu; Smith, C Mike

2012-12-01

248

Isolation and characterization of a gene encoding a polyethylene glycol-induced cysteine protease in common wheat.  

PubMed

Plant cysteine protease (CP) genes are induced by abiotic stresses such as drought, yet their functions remain largely unknown. We isolated the full-length cDNA encoding a Triticum aestivum CP gene, designated TaCP, from wheat by the rapid amplification of cDNA ends (RACE) method. Sequence analysis revealed that TaCP contains an open reading frame encoding a protein of 362 amino acids, which is 96% identical to barley cysteine protease HvSF42. The TaCP transcript level in wheat seedlings was upregulated during polyethylene glycol (PEG) stress, with a peak appearing around 12 h after treatment. TaCP expression level increased rapidly with NaCl treatment at 48 h. TaCP responded strongly to low temperature (4 degree C) treatment from 1 h post-treatment and reached a peak of about 40-fold at 72 h. However, it showed only a very slight response to abscisic acid (ABA). More than one copy of TaCP was present in each of the three genomes of hexaploid wheat and its diploid donors. TaCP fused with green fluorescent protein (GFP) was located in the plasma membrane of onion epidermis cells. Transgenic Arabidopsis plants overexpressing TaCP showed stronger drought tolerance and higher CP activity under water-stressed conditions than wild-type Arabidopsis plants. The results suggest that TaCP plays a role in tolerance to water deficit. PMID:20826947

Zang, Qing-Wei; Wang, Cai-Xiang; Li, Xu-Yan; Guo, Zhi-Ai; Jing, Rui-Lian; Zhao, Jun; Chang, Xiao-Ping

2010-09-01

249

Induced expression of DREB transcriptional factor and study on its physiological effects of drought tolerance in transgenic wheat.  

PubMed

Expression vector pBAC128F, which carries DREB transcriptional factor gene driven by drought inducing promoter rd29B and bar gene driven by CaMV 35S promoter and maize Adh1 gene first intron, was transferred into the explants of immature inflorescence and immature embryos of hexaploid winter wheat cv. 8901, 5-98, 99-92 and 104 by particle bombardment. More than 70 resistant transgenic plants were obtained. Genomic PCR and RNA dot blotting analyses showed that DREB gene had been integrated into wheat genome of the transgenic plants (T0 and T1) and was well expressed in offspring seed of different transgenic lines. The content of proline in leaves and seeds of T2 transgenic lines was analyzed. Among 16 tested transgenic lines, 10 transgenic lines exhibited more than two fold of proline level in leaves as compared with CK plants. Under drought condition, after stopping water for 15 days the leaves of transgenic lines were still green, while CK were faded. After rewatering for 10 days, the leaves of transgenic lines maintained their green, while all CK plants were dead. Our research suggested that introducing a novel DREB transcriptional factor into wheat is an effective way to improve its drought-tolerance ability. PMID:16722342

Wang, Jun-Wei; Yang, Feng-Ping; Chen, Xu-Qing; Liang, Rong-Qi; Zhang, Li-Quan; Geng, Dong-Mei; Zhang, Xiao-Dong; Song, Ya-Zhen; Zhang, Gai-Sheng

2006-05-01

250

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

PubMed

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. PMID:25135325

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

2014-08-19

251

The wheat D-genome HMW-glutenin locus: BAC sequencing, gene distribution, and retrotransposon clusters.  

PubMed

A bacterial-artificial-chromosome (BAC) clone from the genome of Triticum tauschii, the D-genome ancestor of hexaploid bread wheat, was sequenced and the presence of the two paralogous x- and y-type high-molecular-weight (HMW) glutenin genes of the Glu-D1 locus was confirmed. These two genes occur in the same orientation, are 51,893 bp apart, and the separating DNA includes a 31,000-bp cluster of retrotransposons. A second retrotransposon cluster of 32,000 bp follows the x-type HMW-glutenin gene region. Each HMW-glutenin gene is found within a region of mainly unique DNA sequence which includes multiple additional genes including an active endosperm globulin gene not previously reported in the Triticeae family, a leucine-rich-repeat (LRR) type gene truncated at the 5' end of the BAC, a kinase gene of unknown activity, remnants of a paralogous second globulin gene, and genes similar to two hypothetical rice genes. The newly identified globulin genes are assigned to a locus designated Glo-2. Comparison to available orthologous regions of the wheat A and B genomes show rapid sequence divergences flanking the HMW-glutenin genes, and the absence of two hypothetical and unknown genes found 5' to the B-genome x-type ortholog. The region surrounding the Glu-D1 locus is similar to other reported Triticeae BAC sequences; i.e. small gene islands separated by retrotransposon clusters. PMID:12590343

Anderson, O D; Rausch, C; Moullet, O; Lagudah, E S

2003-03-01

252

Genetic Behavior of 2Ai2 Chromosome in Thinopyrum intermedium–Wheat Substitution Lines  

Microsoft Academic Search

The aim of this study was to provide cytogenetical evidence on the behavior of chromosome 2Ai-2 from Thinopyrum intermedium in different wheat (Triticum aestivum L.) chromosome substitution backgrounds. Five wheat-alien disomic or ditelosomic substitution lines were crossed with the common wheat variety Chinese Spring to produce the BC1 and F2 populations, which were tested with expressed sequence target (EST)-PCR markers

Yue ZHANG; Zhi-Shan LIN; Bao-Jiu CAO; Yi-Qiang GUO; Mei-Jiao WANG; Xing-Guo YE; Zhi-Yong XIN; Qiong-Fang XU; Shi-Hua GUO

2009-01-01

253

Wheat Streak Mosaic Virus  

E-print Network

E-337 1/05 Gaylon Morgan, State Extension Small Grains Specialist, College Station, TX Carl Patrick, Extension Entomologist, Amarillo, TX Karl Steddom and Charlie Rush, Plant Pathologists, Amarillo, TX W Overview of WSMV and HPV Wheat Streak Mosaic...

Morgan, Gaylon

2005-01-26

254

The wheat transcriptional activator SPA: a seed-specific bZIP protein that recognizes the GCN4-like motif in the bifactorial endosperm box of prolamin genes.  

PubMed Central

The conserved bifactorial endosperm box found in the promoter of wheat storage protein genes comprises two different cis elements that are thought to be involved in regulating endosperm-specific gene expression. Endosperm nuclear extracts contain binding activities. One is called ESBF-I, which binds to the endosperm motif (EM), and the other is called ESBF-II, which binds to the GCN4-like motif(GLM). Here, we present a functional analysis of the endosperm box of a low-molecular-weight glutenin gene found on the 1D1 chromosome of hexaploid wheat (LMWG-1D1) in transgenic tobacco plants. Our analysis demonstrates the necessity of the EM and GLM for endosperm-specific gene expression and suggests the presence in tobacco of functional counterparts of wheat ESBF-I and ESBF-II. Furthermore, we describe the isolation and characterization of cDNA clones encoding SPA, a seed-specific basic leucine zipper protein from wheat that can activate transcription from the GLMs of the -326-bp LMWG-1D1 promoter in both maize and tobacco leaf protoplasts. This activation is also partially dependent on the presence of functional EMs, suggesting interactions between SPA with ESBF-I-like activities. PMID:9061949

Albani, D; Hammond-Kosack, M C; Smith, C; Conlan, S; Colot, V; Holdsworth, M; Bevan, M W

1997-01-01

255

Development of microsatellite markers in the hexaploid aquatic macrophyte, Myriophyllum spicatum (Haloragaceae)1  

PubMed Central

• Premise of the study: We developed microsatellite primers to investigate genetic diversity and population genetic structure of the cosmopolitan submerged plant Myriophyllum spicatum. • Methods and Results: Twenty microsatellite loci were identified in M. spicatum using the microsatellite-enriched library method. The numbers of alleles per locus ranged from one to 13, and the expected heterozygosity varied from 0 to 0.873 with a mean of 0.504 in two Chinese populations of M. spicatum. All of the loci were also found to be amplifiable in the related species M. verticillatum and M. sibiricum. • Conclusions: The results indicate that these markers will be significant for studies of population genetic structure and evolutionary history of M. spicatum as well as some of its related species. PMID:25202514

Wu, Zhi-Gang; Yu, Dan; Xu, Xin-Wei

2013-01-01

256

Durum Wheat Breeding  

Microsoft Academic Search

This chapter summarizes the scientific and technical knowledge for durum wheat breeding, giving some examples of the methods\\u000a applied in national programs. Section 1 refers to the importance of durum wheat in the world. Sections 2 and 3 give technical\\u000a details on genetic diversity and the choice of germplasm, while the main varietal groups are explained in Section 4. Information

Conxita Royo; Elias M. Elias; Frank A. Manthey

257

Insects which challenge global wheat production: Russian wheat aphid  

Technology Transfer Automated Retrieval System (TEKTRAN)

The book chapter on Russian wheat aphid, (Diuraphis noxia (Mord.)), is one of several that addresses significant pests in the book entitled, Wheat Science and Trade. The chapter gives a detailed account of the history of the Russian wheat aphid as global pest, and its biology, ecology and managemen...

258

Flowering time control in European winter wheat  

PubMed Central

Flowering time is an important trait in wheat breeding as it affects adaptation and yield potential. The aim of this study was to investigate the genetic architecture of flowering time in European winter bread wheat cultivars. To this end a population of 410 winter wheat varieties was evaluated in multi-location field trials and genotyped by a genotyping-by-sequencing approach and candidate gene markers. Our analyses revealed that the photoperiod regulator Ppd-D1 is the major factor affecting flowering time in this germplasm set, explaining 58% of the genotypic variance. Copy number variation at the Ppd-B1 locus was present but explains only 3.2% and thus a comparably small proportion of genotypic variance. By contrast, the plant height loci Rht-B1 and Rht-D1 had no effect on flowering time. The genome-wide scan identified six QTL which each explain only a small proportion of genotypic variance and in addition we identified a number of epistatic QTL, also with small effects. Taken together, our results show that flowering time in European winter bread wheat cultivars is mainly controlled by Ppd-D1 while the fine tuning to local climatic conditions is achieved through Ppd-B1 copy number variation and a larger number of QTL with small effects. PMID:25346745

Langer, Simon M.; Longin, C. Friedrich H.; Würschum, Tobias

2014-01-01

259

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...

260

Whole Wheat Strawberry Muffins Ingredients  

E-print Network

Whole Wheat Strawberry Muffins Ingredients: Non stick cooking spray 1 cup strawberries, chopped 2 wheat flour 1/2 cup brown sugar, packed 1 1/2 teaspoons baking soda Directions 1. Heat oven to 400º bowl mix together whole wheat flour, brown sugar and baking soda. Mix well. 5. Add strawberry mixture

Liskiewicz, Maciej

261

Uniquely identifying wheat plant structures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Uniquely naming wheat (Triticum aestivum L. em Thell) plant parts is useful for communicating plant development research and the effects of environmental stresses on normal wheat development. Over the past 30+ years, several naming systems have been proposed for wheat shoot, leaf, spike, spikelet, ...

262

Studies of yield and quality of grain, yield components, effect of leaf rust, and forage production of mixed varietal populations, and pure stands of varieties in wheat and oats  

E-print Network

in protein may not affect the sof't wheat flours, which are primarily used for pastry and biscuits. However, the lower protein would impair the quality of hard winter wheats where high gluten st, ength and high protein are desirable. Phipps (25) showed... in Milliliters) 1. kustfn ? sof't red winter 2. Bowie ? sof't red winter 3. Coneho ? hard red wfnter 4. Qusnah ? hard red vinter 5. Milam ? hard red vinter 6. Mobster-Travis ? hard -red spring 7. Minn. III-54. -58 ? hard red winter 8. Denton ? soft red...

Da Gama Rose, Renaud Wilfred

2012-06-07

263

Short, natural, and extended photoperiod response in BC2F4 lines of bread wheat with different photoperiod-1 (Ppd-1) alleles.  

PubMed

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. PMID:23420880

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

264

Biolistics Transformation of Wheat  

NASA Astrophysics Data System (ADS)

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).

Sparks, Caroline A.; Jones, Huw D.

265

Chromosome arm-specific BAC end sequences permit comparative analysis of homoeologous chromosomes and genomes of polyploid wheat  

PubMed Central

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 Insertion Site Based Polymorphisms (ISBPs). Of the 96 ISBP primer pairs tested, 28 (29%) were 3A-specific and compared to 17 (18%) for 96 SSRs. Conclusion This work reports on the use of wheat chromosome arm 3AS-specific BAC library for the targeted generation of sequence data from a particular region of the huge genome of wheat. A large quantity of sequences were generated from the A genome of hexaploid wheat for comparative genome analysis with homoeologous B and D genomes and other model grass genomes. Hundreds of molecular markers were developed from the 3AS arm-specific sequences; these and other sequences will be useful in gene discovery and physical mapping. PMID:22559868

2012-01-01

266

New Insights into the Organization, Recombination, Expression and Functional Mechanism of Low Molecular Weight Glutenin Subunit Genes in Bread Wheat  

PubMed Central

The bread-making quality of wheat is strongly influenced by multiple low molecular weight glutenin subunit (LMW-GS) proteins expressed in the seeds. However, the organization, recombination and expression of LMW-GS genes and their functional mechanism in bread-making are not well understood. Here we report a systematic molecular analysis of LMW-GS genes located at the orthologous Glu-3 loci (Glu-A3, B3 and D3) of bread wheat using complementary approaches (genome wide characterization of gene members, expression profiling, proteomic analysis). Fourteen unique LMW-GS genes were identified for Xiaoyan 54 (with superior bread-making quality). Molecular mapping and recombination analyses revealed that the three Glu-3 loci of Xiaoyan 54 harbored dissimilar numbers of LMW-GS genes and covered different genetic distances. The number of expressed LMW-GS in the seeds was higher in Xiaoyan 54 than in Jing 411 (with relatively poor bread-making quality). This correlated with the finding of higher numbers of active LMW-GS genes at the A3 and D3 loci in Xiaoyan 54. Association analysis using recombinant inbred lines suggested that positive interactions, conferred by genetic combinations of the Glu-3 locus alleles with more numerous active LMW-GS genes, were generally important for the recombinant progenies to attain high Zeleny sedimentation value (ZSV), an important indicator of bread-making quality. A higher number of active LMW-GS genes tended to lead to a more elevated ZSV, although this tendency was influenced by genetic background. This work provides substantial new insights into the genomic organization and expression of LMW-GS genes, and molecular genetic evidence suggesting that these genes contribute quantitatively to bread-making quality in hexaploid wheat. Our analysis also indicates that selection for high numbers of active LMW-GS genes can be used for improvement of bread-making quality in wheat breeding. PMID:20975830

Fan, Huajie; Sun, Jiazhu; Zhang, Zhongjuan; Qin, Huanju; Li, Bin; Hao, Shanting; Li, Zhensheng; Wang, Daowen; Zhang, Aimin; Ling, Hong-Qing

2010-01-01

267

Genetic analysis of wheat domestication and evolution under domestication  

PubMed Central

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. PMID:21778183

Peleg, Zvi; Fahima, Tzion; Korol, Abraham B.; Abbo, Shahal; Saranga, Yehoshua

2011-01-01

268

Genetic control over silica deposition in wheat awns.  

PubMed

Awns are long, stiff filamentous extensions of glumes in many grasses. In wheat, awns contribute up to 40% of the grain's photosynthetic assimilates, and assist in seed dispersal. Awns accumulate silica in epidermal hairs and papillae, and silica has been positively associated with yield and environmental stress tolerance. Here, the awns of a set of domesticated wheat genotypes and their direct progenitor, Triticum turgidum ssp. dicoccoides were characterized. In addition, the silica concentration in awns was genetically dissected in a tetraploid wheat population of recombinant inbred lines (RILs) derived from a cross between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Scanning electron micrographs revealed a continuous silica layer under the cuticle. Extended silicification was identified in the epidermis cell wall and in sclerenchyma cells near the vascular bundles, but not in the stomata, suggesting that an active process directs the soluble silica away from the water evaporation stream. The number of silicified cells was linearly correlated to silica concentration in dry weight (DW), suggesting cellular control over silicification. Domesticated wheat awns contained up to 19% silica per DW, as compared with 7% in the wild accessions, suggesting selection pressure associated with the domestication process. Six quantitative trait loci (QTLs) for silica were identified in the awns, with a LOD score of 3.7-6.3, three of which overlapped genomic regions that contribute to high grain protein. Localization of silica in the awns and identification of QTLs help illuminate mechanisms associated with silica metabolism in wheat. PMID:20444192

Peleg, Zvi; Saranga, Yehoshua; Fahima, Tzion; Aharoni, Asaph; Elbaum, Rivka

2010-09-01

269

Registration of 'Chesapeake' Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Chesapeake’ (Reg. No. CV-1011, PI 643935) is a soft red winter wheat (Triticum aestivum L.) that was jointly developed and released by the Maryland Agricultural Experiment Station, Department of Plant Science and Landscape Architecture, and the Virginia Agricultural Experiment Station in 2005. Ches...

270

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, ...

271

REGISTRATION OF ‘CHOPTANK’ WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Choptank’ (Reg. no. CV-976, PI 639724) is a soft red winter wheat (triticum aestivum L.) that was jointly developed and released by the Maryland Agricultural Experiment Station, Department of Natural Resource Sciences and Landscape Architecture, and the Virginia Agricultural Experiment Station in 2...

272

REGISTRATION OF GOODSTREAK WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Goodstreak¿ (Reg. No. Cv- , PI ) is a hard red winter wheat (Triticum aestivum L.) cultivar developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in 2000 by the developing institutions and the Wyoming Agricultural Experiment Station. Goodstreak was re...

273

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 ...

274

Registration of ‘Coral’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Coral’ soft white winter wheat (Triticum aestivum L.) was developed by the Michigan Agricultural Experiment Station and released March 28, 2008, via an exclusive licensing agreement through Michigan State University (MSU) Technologies. Coral was selected from the cross MSU D3913 / MSU D0331 made i...

275

Registration of ‘Jamestown’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Jamestown’ (Reg. No. CV-, PI 653731) soft red winter wheat (Triticum aestivum L.) was developed and released by the Virginia Agricultural Experiment Station in March 2007. Jamestown was derived from the cross ‘Roane’ (PI 612958)/Pioneer Brand ‘2691’ (PI 590941 PVPO) and was tested under the experim...

276

Registration of ‘Jamestown’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Jamestown’ (Reg. No. CV-1041, PI 653731) soft red winter wheat (Triticum aestivum L.) was developed and released by the Virginia Agricultural Experiment Station in March 2007. Jamestown was derived from the cross ‘Roane’/Pioneer Brand ‘2691’ and was tested under the experimental number VA02W-370. J...

277

Wheat Germ DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from wheat germ using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Lana Hays

2009-01-01

278

Registration of Howard Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Howard’ (Reg. no. CV-998, PI 642367) is a hard red spring wheat (HRSP) (Triticum aestivum L.) cultivar developed at North Dakota State University (NDSU) and released by the North Dakota Agricultural Experiment Station (NDAES) in January 2006. Howard was released because it combines a good level of...

279

Drought resistance in wheat  

Microsoft Academic Search

Summary 1.The general trend of various factors in the leaves of the wheat varieties Currawa, Federation and Major, respectively, has been followed throughout the season of the year 1933.2.The factors observed included the water content of the leaves, the sap expressed from the leaves under pressure, the water content of the pressed leaves, the total, free and bound water and

J. Calvert

1935-01-01

280

Registration of ‘3434’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soft red winter (SRW) wheat (Triticum aestivum L.) cultivar ‘3434’ (Reg. No. CV-, PI) was developed by the Virginia Agricultural Experiment Station and released in March 2008. Cultivar 3434 was derived from the three-way cross ‘Roane’ (PI 612958) / ’Coker 9835’ (PI 548846 PVPO) // VA96W-270. Cul...

281

Registration of ‘Shirley’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Shirley’ (Reg. No. CV-1039, PI 656753) soft red winter (SRW) wheat (Triticum aestivum L.), developed and tested as VA03W-409 by the Virginia Agricultural Experiment Station, was released in March 2008. Shirley was derived from the three-way cross VA94-52-25/‘Coker 9835’//VA96-54-234. Shirley is wid...

282

REGISTRATION OF 'BAUERMEISTER' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Bauermeister' (J981107, WA007939) hard red winter wheat (HRW)(Triticum aestivum L.) (Reg. No. CV-XXX, PI 634717) was released in 2005 by the Agricultural Research Center of Washington State University (WSU) in cooperation with the USDA-ARS. Bauermeister is a semidwarf cultivar adapted to the low- ...

283

Registration of ‘Shirley’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Shirley’ (Reg. No. CV-, PI) soft red winter (SRW) wheat (Triticum aestivum L.) was developed by the Virginia Agricultural Experiment Station and released in March 2008. Shirley was derived from the three-way cross VA94-52-25 / ‘Coker 9835’ (PI 548846 PVPO) // VA96-54-234. Shirley is widely adapted ...

284

Registration of ‘5205’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soft red winter (SRW) wheat (Triticum aestivum L.) cultivar ‘5205’ (Reg. No. CV-, PI) was developed by the Virginia Agricultural Experiment Station and released in March 2008. Cultivar 5205 was derived from the three-way cross Pioneer Brand ‘2684’ (PI 566923 PVPO) / VA93-54-185 // ’Pocahontas’ ...

285

Registration of ‘3434’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soft red winter (SRW) wheat (Triticum aestivum L.) cultivar 3434 (Reg. No. CV-1040, PI 656754) developed and tested as VA03W-434 by the Virginia Agricultural Experiment Station was released in March 2008. Cultivar 3434 was derived from the three-way cross ‘Roane’/‘Coker 9835’//VA96W-270. Cultivar 34...

286

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...

287

Registration of ‘Decade’ wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Decade’ (Reg. No. CV-1058, PI 660291) hard red winter (HRW) wheat (Triticum aestivum L.) was developed and released jointly by the Montana and North Dakota Agricultural Experiment Stations in 2010. The name “Decade” denotes the extended time period (1997–2010) during which the Montana State Univers...

288

Registration of 'Guymon' wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Guymon' (Reg. No. CV-_______, PI 643133) is a hard white (HW) winter wheat (Triticum aestivum L.) cultivar developed and released cooperatively by the Oklahoma Agric. Exp. Stn. (AES) and the USDA-ARS in 2005. It is recommended for grain-only and dual-purpose production systems in an area of the so...

289

REGISTRATION OF 'DELIVER' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Deliver’ (Reg. No. CV-_______, PI 639232) hard red winter wheat (Triticum aestivum L.) was released to certified seed growers with permission of the Oklahoma Agricultural Experiment Station (AES) and the USDA-ARS in 2004. Deliver, an awnletted cultivar, was named for its unique and competitive abil...

290

REGISTRATION OF 'MASAMI' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Masami' soft white winter wheat (Triticum aestivum L.) (Reg. no. CV- , PI 634715) was developed by the Agricultural Research Center of Washington State University (WSU) in cooperation with the USDA-ARS. Masami was jointly released by Washington and Idaho Agricultural Experiment Stations and the ...

291

Registration of ‘Endurance’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Endurance’ (Reg. No. CV-994, PI 639233) hard red winter wheat (Triticum aestivum L.) was released to certified seed growers with permission of the Oklahoma Agricultural Experiment Station and the USDA-ARS in 2004. Its name derives from the unique ability to endure and recover from extended and inte...

292

Registration of 'Juniper' Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Juniper’ (PI 639951) is a hard red winter wheat (Triticum aestivum L.) developed by the Idaho Agricultural Experimental Station and released in February 2006. Juniper, named for the town of Juniper, Idaho, was released for its superior yield and quality compared with previous full stature hard red...

293

Gene flow between wheat and wild relatives: empirical evidence from Aegilops geniculata, Ae. neglecta and Ae. triuncialis  

PubMed Central

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

Arrigo, Nils; Guadagnuolo, Roberto; Lappe, Sylvain; Pasche, Sophie; Parisod, Christian; Felber, François

2011-01-01

294

Metaphase I-bound arms frequency and genome analysis in wheat-Aegilops hybrids. 3. Similar relationships between the B genome of wheat and S or S (l) genomes of Ae. speltoides, Ae. longissima and Ae. sharonensis.  

PubMed

The meiotic behaviour of Triticum aestivum × Aegilops speltoides, T. aestivum × Ae. sharonensis and T. aestivum × Ae. longissima tetraploid hybrids (genome constitution ABDS, ABDS (l) , and ABDS (l) , respectively) has been analysed by the C-banding technique. Of the six types of pairing normally occurring, at metaphase I three were recognized: A-D, AD-BS/AD-BS (l) and B-S/B-S (l) . The relative order observed in the low pairing hybrid, A-D> B-S (l) >AD-BS (l) , as well as that found in high-pairing 'Chinese Spring' × Ae. speltoides hybrids, A-D>AD-BS>ß-S, revealed the existence of preferential pairing patterns among the different genomes that are in competition. In all of the hybrids analysed the mean number of bound arms per cell for the A-D type was significantly higher than the mean number of associations between the B and S/S (l) genomes. Usually the relative contribution of each type of pairing is maintained among hybrids with different Aegilops species. These results indicate that the genomes of Ae. speltoides, Ae. sharonensis and Ae. longissima show a similar affinity with the genomes of hexaploid wheat; therefore none of these species can be considered to be a distinct donor of the B genome of wheats. PMID:24186260

Fernández-Calvín, B; Orellana, J

1994-09-01

295

Fate of Aegilops speltoides-derived, repetitive DNA sequences in diploid Aegilops species, wheat-Aegilops amphiploids and derived chromosome addition lines.  

PubMed

The present study reports the cloning and characterization of an Aegilops speltoides-derived subtelomeric repeat, designated as pSp1B16. Clone pSp1B16 has 98% sequence homology with the previously isolated Ae. speltoides repeat Spelt1. The distribution of pSp1B16 and another Ae. speltoides repeat, pGc1R1, was analyzed in diploid Aegilops species, tetra- and hexaploid wheats, wheat-Aegilops amphiploids and derived chromosome addition lines by fluorescence in situ hybridization (FISH). Clones pSp1B16 and pGc1R1 revealed FISH sites in Ae. speltoides, Ae. sharonensis and Triticum timopheevii, whereas additional pGc1R1 FISH sites were observed in Ae. longissima and Ae. caudata. The pSp1B16 and pGc1R1 FISH patterns of the Aegilops chromosomes in the wheat-Aegilops amphiploids and chromosome addition lines are similar to those present in the Aegilops parent accession. We did not observe any evidence of pSp1B16 and pGc1R1 sequence elimination, which is in contrast to previous studies using similar hybrids and repeats. The presented data suggest that the genomic changes in synthetic amphiploids observed in previous studies might be caused by homoeologous recombination, which was suppressed in the amphiploid analyzed in this study. PMID:20551615

Kumar, S; Friebe, B; Gill, B S

2010-07-01

296

Analysis of ascorbate peroxidase genes expressed in resistant and susceptible wheat lines infected by the cereal cyst nematode, Heterodera avenae.  

PubMed

Changes in ascorbate peroxidase (APX) enzyme activity in response to nematode (Heterodera avenae) attack were studied in roots of three hexaploid wheat lines carrying Cre2, Cre5, or Cre7 nematode resistance genes and the susceptible Triticum aestivum cv. Anza. A spectrophotometric analysis was carried out with root extracts of infected plants 4, 7, 11, and 14 days after nematode inoculation using uninfected plant as control. APX induction in infected resistant genotypes was similar and higher than in the susceptible control. The introgression wheat/Aegilops ventricosa H-93-8 line, carrying the Cre2 gene, and its parental line H-10-15 as susceptible control were used to analyze whether this increase of activity was correlated with the induction of APX gene expression. Genes encoding cytosolic forms of APX were induced in roots of both lines in response to nematode infection. This induction took place both earlier and with greater intensity in the resistant line than in the susceptible one, and it was also higher in the root area at the site of nematode attachment. PMID:20690022

Simonetti, Ester; Alba, Eva; Montes, María Jesús; Delibes, Angeles; López-Braña, Isidoro

2010-10-01

297

Development of a set of oligonucleotide primers specific for genes at the Glu-1 complex loci of wheat.  

PubMed

Specific amplification of the complete coding region of all six high-molecular-weight (HMW) glutenin genes present in hexaploid wheat was obtained by the polyerase chain reaction (PCR). Primers specific for the N-terminal region of the 1Dx gene and for the repetitive domain of the y-type HMW glutenin genes were also developed. Although the primers were constructed on the basis of the nucleotide sequences of HMW glutenin genes present in T. aestivum L. cv 'Cheyenne', they were very efficient in amplifying HMW glutenin genes of diploid and tetraploid wheat species. PCR analysis of HMW glutenin genes of T. urartu Tuman., T. longissimum (Schweinf. & Muschl.) Bowden and T. speltoides (Tausch) Gren. ex Richt, showed a high degree of length polymorphism, whereas a low degree of length variation was found in accessions of T. tauschii (Coss.) Schmal. Furthermore, using primers specific for the repetitive regions of HMW genes, we could demonstrate that the size variation observed was due to a different length of the central repetitive domain. The usefulness of the PCR-based approach to analyze the genetic polymorphism of HMW glutenin genes, to isolate new allelic variants, to estimate their molecular size and to verify the number of cysteine residues is discussed. PMID:24169762

D'Ovidio, R; Masci, S; Porceddu, E

1995-07-01

298

QTL analysis of genetic loci affecting domestication-related spike characters in common wheat.  

PubMed

Domestication-related changes that govern a spike morphology suitable for seed harvesting in cereals have resulted from mutation and selection of the genes. A synthetic hexaploid wheat (S-6214, genome AABBDD) produced by a cross between durum wheat (AABB) and wild goat grass (DD) showed partial non-domestication-related phenotypes due to genetic effects of the wild goat grass genome. Quantitative trait loci (QTLs) affecting wheat domestication-related spike characters including spike threshability, rachis fragility and spike compactness were investigated in F2 progeny of a cross between Chinese Spring (CS) wheat (AABBDD) and S-6214. Of 15 relevant QTLs identified, eight seemed to be consistent with peaks previously reported in wheat, while four QTL regions were novel. Four QTLs that affected spike threshability were localized to chromosomes 2BS, 2DS, 4D and 5DS. The QTL on 2DS probably represents the tenacious glume gene, Tg-D1. Based on its map position, the QTL located on 2BS coincides with Ppd-B1 and seems to be a homoeolocus of the soft glume gene. Two novel QTLs were detected on 4D and 5DS, and their goat grass alleles increased glume tenacity. Three novel QTLs located on 2DL, 3DL and 4D for rachis fragility were found. Based on the map position, the QTL on 3DL seems different from Br1 and Br2 loci and its CS allele appears to promote the generation of barrel-type diaspores. Three disarticulation types of spikelets were found in F2 individuals: wedge-type, barrel-type and both types. Among eight QTL peaks that governed spike morphology, six, located on 2AS, 2BS, 2DS, 4AL and 5AL, coincided with ones previously reported. A QTL for spike compactness on 5AL was distinct from the Q gene. A novel QTL that controls spike length was detected on 5DL. Complex genetic interactions between genetic background and the action of each gene were suggested. PMID:25475935

Katkout, Mazen; Kishii, Masahiro; Kawaura, Kanako; Mishina, Kouhei; Sakuma, Shun; Umeda, Kazuko; Takumi, Shigeo; Nitta, Miyuki; Nasuda, Shuhei; Ogihara, Yasunari

2014-01-01

299

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2010 CFR

...of gliadin and glutenin. Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its...

2010-04-01

300

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2011 CFR

...Wheat gluten is obtained by hydrating wheat flour and mechanically working the sticky mass to separate the wheat gluten from the starch and other flour components. Vital gluten is dried gluten that has retained its elastic properties. (b) The...

2011-04-01

301

Comparison of statistical models for analyzing wheat yield time series.  

PubMed

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

Michel, Lucie; Makowski, David

2013-01-01

302

Genetic analysis of root morphological traits in wheat.  

PubMed

Traits related to root architecture are of great importance for yield performance of crop species, although they remain poorly understood. The present study is aimed at identifying the genomic regions involved in the control of root morphological traits in durum wheat (Triticum durum Desf.). A set of 123 recombinant inbred lines derived from the durum wheat cross of cvs. 'Creso' × 'Pedroso' were grown hydroponically to two growth stages, and were phenotypically evaluated for a number of root traits. In addition, meta-(M)QTL analysis was performed that considered the results of other root traits studies in wheat, to compare with the 'Creso' × 'Pedroso' cross and to increase the QTL detection power. Eight quantitative trait loci (QTL) for traits related to root morphology were identified on chromosomes 1A, 1B, 2A, 3A, 6A and 6B in the 'Creso' × 'Pedroso' segregating population. Twenty-two MQTL that comprised from two to six individual QTL that had widely varying confidence intervals were found on 14 chromosomes. The data from the present study provide a detailed analysis of the genetic basis of morphological root traits in wheat. This study of the 'Creso' × 'Pedroso' durum-wheat population has revealed some QTL that had not been previously identified. PMID:25416422

Petrarulo, Maria; Marone, Daniela; Ferragonio, Pina; Cattivelli, Luigi; Rubiales, Diego; De Vita, Pasquale; Mastrangelo, Anna Maria

2014-11-22

303

Wheat leaf and stem rust in the United States  

Microsoft Academic Search

Leaf rust, caused by Puccinia triticina, is a common and widespread disease of wheat in the US. On an annual basis, over 50 races of the leaf rust fungus are detected. There are at least 5 major groups of genetically distinct P. triticina isolates in the US based on allelic variation at microsatellite loci. Distinct regional race populations of P.

J. A. KolmerA; Y. Jin; D. L. LongA

2007-01-01

304

Desarrollo folicular y tasa ovulatoria en cabras criollas después de un periodo corto de consumo de trigo protegido de la degradación ruminal Follicular development and ovulation rate in Creole goats after short- term consumption of wheat protected from ruminal degradation  

Microsoft Academic Search

To determine ovarian effects after consumption of wheat protected from ruminal degradation, 40 Creole female goats received for 11 d before a synchronized estrous, 33.2 g\\/kg.75 of durum wheat treated with 5 % formaldehyde and mixed with 15 % saponified tallow (TW, n=20) or milled durum wheat and separately 15 % saponified tallow (NTW, n=20). Ovarian follicular populations were characterized

Xochitl Pastrana Martínez; Martín Ramírez Sánchez; Juan López; Eugenio Villagómez; Everardo González Padilla; Héctor Raymundo Vera Ávila

305

Registration of ‘Guymon’ Wheat  

Microsoft Academic Search

green-up, heading date, test weight, grain yield, wheat protein content, kernel hardness, and kernel size. Subsequent genera- tions were advanced by bulk-selfi ng in the fi eld. Minimal rogu- ing of slightly taller variants was performed each year until 2004 despite this line being F 2 -derived. With an initial frequency of 1.5% red kernels, seed from the 2003 harvest

B. F. Carver; R. M. Hunger; J. T. Edwards; P. Rayas-Duarte; A. R. Klatt; D. R. Porter; B. W. Seabourn; G.-H. Bai; F. E. Dowell; L.-L. Yan; B. C. Martin

2008-01-01

306

Virulence and biotype analyses of Hessian Fly (Mayetiola destructor) populations from Texas, Louisiana, and Oklahoma  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Hessian fly is a major pest of wheat, and is controlled mainly through deploying fly-resistant wheat cultivars. Changes in Hessian fly populations in the field may quickly overcome fly-resistance of wheat cultivars within a few years, thus continuous monitoring dynamics of Hessian fly populatio...

307

THE MAS WHEAT PROJECT: IMPACT OF GENOMICS ON WHEAT BREEDING  

Technology Transfer Automated Retrieval System (TEKTRAN)

In 2001 twelve wheat breeding center and research laboratories formed a consortium designed to increase the use of marker assisted selection (MAS) in public wheat breeding programs. The strategy of the project is to introgress by backcrossing more than 23 disease resistance genes and 21 quality-rela...

308

Preliminary assessment of resistance among U.S. wheat cultivars to the Triticum pathotype of Magnaporthe oryzae  

Technology Transfer Automated Retrieval System (TEKTRAN)

Magnaporthe oryzae is the causal agent of blast disease on several graminaceous plants. The M. oryzae population causing wheat blast has not been officially reported outside South America. U.S. wheat production is at risk to this pathogen if it is introduced and established. Proactive testing of U.S...

309

Quantifying Russian wheat aphid pest intensity across the Great Plains.  

PubMed

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. PMID:23321099

Merrill, Scott C; Peairs, Frank B

2012-12-01

310

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...

311

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...

312

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...

313

Wheat Surplus and its Cause  

Microsoft Academic Search

THE comment made by Prof. Piaggio in NATURE of March 21, upon the address by Sir Arthur Eddington, cites the famous prophecy by Sir William Crookes, made near the end of the last century, as to the probable wheat supply in the future, say thirty years from the time of his address. The comment indicates that the present wheat surplus

L. R. Waldron

1931-01-01

314

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

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

Hill, Camilla B.; Taylor, Julian D.; Edwards, James; Mather, Diane; Bacic, Antony; Langridge, Peter; Roessner, Ute

2013-01-01

315

Varietal Trials Results Wheat, Hard Red Winter  

E-print Network

Varietal Trials Results Wheat, Hard Red Winter 47 Winter wheat varieties were compared in trial plots at Crookston, Lamberton, Roseau and St. Paul. Wheat varieties were grown in replicated plots. These winter wheat trials are not designed for crop (species) compar- isons because the various crops are grown

Thomas, David D.

316

Dynamics of the evolution of orthologous and paralogous portions of a complex locus region in two genomes of allopolyploid wheat.  

PubMed

Two overlapping bacterial artificial chromosome (BAC) clones from the B genome of the tetraploid wheat Triticum turgidum were identified, each of which contains one of the two high-molecular-weight (HMW) glutenin genes, comprising the complex Glu-B1 locus. The complete sequence (285 506 bp of DNA) of this chromosomal region was determined. The two paralogous x-type ( Glu-1-1 ) and y-type ( Glu-1-2 ) HMW-glutenin genes of the complex Glu-B1 locus were found to be separated by ca. 168 000 bp instead of the 51 000 bp separation previously reported for the orthologous Glu-D1 locus of Aegilops tauschii, the D-genome donor of hexaploid wheat. This difference in intergene spacing is due almost entirely to be the insertion of clusters of nested retrotransposons. Otherwise, the orientation and order of the HMW glutenins and adjacent genes were identical in the two genomes. A comparison of these orthologous regions indicates modes and patterns of sequence divergence, with implications for the overall Triticeae genome structure and evolution. A duplicate globulin gene, found 5' of each HMW-glutenin gene, assists to tentatively define the original duplication event leading to the paralogous x- and y-type HMW-glutenin genes. The intergenic regions of the two loci are composed of different patterns and classes of retrotransposons, indicating that insertion times of these retroelements were after the divergence of the two wheat genomes. In addition, a putative receptor kinase gene near the y-type HMW-glutenin gene at the Glu-B1 locus is likely active as it matches recently reported ESTs from germinating barley endosperm. The presence of four genes represented only in the Triticeae endosperm ESTs suggests an endosperm-specific chromosome domain. PMID:15159634

Kong, Xiu-Ying; Gu, Yong Qiang; You, Frank M; Dubcovsky, Jorge; Anderson, Olin D

2004-01-01

317

Plant-Parasitic Nematodes Associated with Reduced Wheat Yield in Oregon: Heterodera avenae.  

PubMed Central

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

Smiley, Richard W.; Whittaker, Ruth G.; Gourlie, Jennifer A.; Easley, Sandra A.; Ingham, Russell E.

2005-01-01

318

Molecular Genetics of Resistance to the Wheat Stem Sawfly Jamie Sherman, Plant Sciences and Plant Pathology Department  

E-print Network

in resistance to WSS in oats. If differences are observed then crosses will be made to create a population to further study resistance in oats following the same process as has been successful in wheat ­ creating

Maxwell, Bruce D.

319

Drought Tolerance in Wheat  

PubMed Central

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

Prodhan, Zakaria Hossain; Faruq, Golam

2013-01-01

320

Cytokinin Oxidase from Wheat  

PubMed Central

As part of the study of the possible role(s) of CBF-1, a cytokinin-binding protein abundant in wheat embryo, a cytokinin oxidase was found in wheat (Triticum aestivum L.) germ and partially purified by conventional purification techniques and high performance chromatofocusing. This preparation catalyzes conversion of N6-(?2-isopentenyl)adenosine to adenosine at a Vmax of 0.4 nanomol per milligram protein per minute at 30°C and pH 7.5, the Km being 0.3 micromolar. This high affinity and the apparent molecular weight of 40,000 estimated by high performance gel permeation on a Spherogel TSK-3000 SW column indicate that this enzyme is different from other cytokinin oxidases previously reported. Oxygen is required for the reaction, as for other cytokinin oxidases already described. N6-(?2-isopentenyl)adenine and zeatin riboside are also degraded, but N6-(?2-isopentenyl)adenosine-5?-monophosphate is apparently not a substrate. Benzyladenine is degraded, but to a small extent, and it inhibits slightly the degradation of N6-(?2-isopentenyl)adenosine. The degradation of N6-(?2-isopentenyl)adenosine is strongly inhibited by diphenylurea and its highly active derivative N-(2-chloro-4-pyridyl)-N?-phenylurea. PMID:16666895

Laloue, Michel; Fox, J. Eugene

1989-01-01

321

Effects of starch synthase IIa gene dosage on grain, protein and starch in endosperm of wheat  

Microsoft Academic Search

Starch synthases (SS) are responsible for elongating the ?-1,4 glucan chains of starch. A doubled haploid population was generated\\u000a by crossing a line of wheat, which lacks functional ssIIa genes on each genome (abd), and an Australian wheat cultivar, Sunco, with wild type ssIIa alleles on each genome (ABD). Evidence has been presented previously indicating that the SGP-1 (starch granule

Christine Konik-Rose; Jenny Thistleton; Helene Chanvrier; Ihwa Tan; Peter Halley; Michael Gidley; Behjat Kosar-Hashemi; Hong Wang; Oscar Larroque; Joseph Ikea; Steve McMaugh; Ahmed Regina; Sadequr Rahman; Matthew Morell; Zhongyi Li

2007-01-01

322

Mapping QTLs for pre-harvest sprouting traits in the spring wheat cross ‘RL4452\\/AC Domain’  

Microsoft Academic Search

Pre-harvest sprouting (PHS) in spring wheat (Triticum aestivum L.) is a major downgrading factors for grain producers and can significantly reduce end-use quality. PHS resistance is a\\u000a complex trait influenced by genotype, environment and plant morphological factors. A population of 185 doubled haploid (DH)\\u000a lines from the spring wheat cross ‘RL4452\\/AC Domain’ were used as the mapping population to detect

G. Rasul; D. G. Humphreys; A. Brûlé-Babel; C. A. McCartney; R. E. Knox; R. M. DePauw; D. J. Somers

2009-01-01

323

Linkage Disequilibrium and Genome-Wide Association Mapping in Tetraploid Wheat (Triticum turgidum L.)  

PubMed Central

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

Laidò, Giovanni; Marone, Daniela; Russo, Maria A.; Colecchia, Salvatore A.; Mastrangelo, Anna M.; De Vita, Pasquale; Papa, Roberto

2014-01-01

324

Estimating climate change, CO2 and technology development effects on wheat yield in northeast Iran  

NASA Astrophysics Data System (ADS)

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.

Bannayan, M.; Mansoori, H.; Rezaei, E. Eyshi

2014-04-01

325

Estimating climate change, CO2 and technology development effects on wheat yield in northeast Iran.  

PubMed

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. PMID:23397072

Bannayan, M; Mansoori, H; Rezaei, E Eyshi

2014-04-01

326

Expression divergence of TaMBD2 homoeologous genes encoding methyl CpG-binding domain proteins in wheat (Triticum aestivum L.).  

PubMed

Most hexaploid wheat genes are present as triplicate homoeologs derived from the ancestral species. Previously, we isolated six wheat cDNAs with open reading frame, encoding methyl CpG-binding domain proteins (MBDs). In this study, the genomic and cDNA sequences of three TaMBD2 homoeologous genes were obtained and mapped on chromosomes 5A, 5B and 5D, respectively. These sequences showed a very high conservation in the coding region and the exon/intron structure, but the cDNA sequences are distinguishable by a 9-bp insertion in coding region and a size polymorphism in the 3'-untranslated region (UTR). The expression patterns of each homeologous gene in different tissues of various developmental stages and in response to abiotic stress were analyzed by using real-time PCR. Relative mRNA abundance of the three homoeologs varied considerably in different developmental stages from seedling to developing seeds. Most notably, TaMBD2-5B and TaMBD2-5D were highly responsive to salt stress and TaMBD2-5B was specifically upregulated by low temperature in the seedling leaves. These results provide further evidence for the expression variation of genes duplicated in allopolyploids. Moreover, the variation of TaMBD2 homoeologous gene expression in response to environmental stress may enable plants to better cope with stresses in their natural environments. PMID:20951189

Hu, Zhaorong; Yu, Ying; Wang, Rui; Yao, Yingyin; Peng, Huiru; Ni, Zhongfu; Sun, Qixin

2011-01-15

327

Comparison of Statistical Models for Analyzing Wheat Yield Time Series  

PubMed Central

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

Michel, Lucie; Makowski, David

2013-01-01

328

Molecular characterization of Fusarium globosum strains from South African maize and Japanese wheat.  

PubMed

The fungus Fusarium globosum was first isolated from maize in South Africa and subsequently from wheat in Japan. Here, multiple analyses revealed that, despite morphological similarities, South African maize and Japanese wheat isolates of the fungus exhibit multiple differences. An amplified fragment length polymorphism-based similarity index for the two groups of isolates was only 45%. Most maize isolates produced relatively high levels of fumonisins, whereas wheat isolates produced little or no fumonisins. The fumonisin biosynthetic gene FUM1 was detected in maize isolates by Southern blot analysis but not in the wheat isolates. In addition, most of the maize isolates produced sclerotia, and all of them produced large orange to dark purple sporodochia in carrot agar culture, whereas wheat isolates did not produce either structure. In contrast, individual isolates from both maize and wheat carried markers for both mating type idiomorphs, which indicates that the fungus may be homothallic. However, a sexual stage of F. globosum was not formed under standard self-fertilization conditions developed for other homothallic species of Fusarium. The inability to produce the sexual stage is consistent with the high similarity of 87-100% and G (ST) index of 1.72 for the maize isolates, which suggests that these isolates are undergoing asexual but not sexual reproduction. Together, the results suggest that the South African maize and Japanese wheat isolates of F. globosum are distinct populations and could be different species. PMID:20495873

Moses, Lorraine M; Marasas, Walter F O; Vismer, Hester F; De Vos, Lieschen; Rheeder, John P; Proctor, Robert H; Wingfield, Brenda D

2010-10-01

329

Climate change induced rainfall patterns affect wheat productivity and agroecosystem functioning dependent on soil types  

NASA Astrophysics Data System (ADS)

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 (?13C) 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.

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

330

SURVIVAL OF WHEAT CURL MITES ON DIFFERENT SOURCES OF RESISTANCE IN WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat yield is limited by wheat streak mosaic virus which is vectored by the wheat curl mite (WCM) Aceria tosicheilla (Keifer).Host resistance to WCM has reduced losses. This study evaluated the effectiveness of resistance in wheat to WCM collected from various locations in the Great Plains. Collect...

331

Wheat and Stocker Cattle Production Stocker cattle grazing wheat pasture is an important  

E-print Network

Wheat and Stocker Cattle Production Challenges Stocker cattle grazing wheat pasture is an important part of the economy in the Texas Rolling Plains region. Wheat and stocker cattle business decisions are impacted by a variety of issues, including cattle and wheat prices, animal health, weather

332

COMPARISON OF THREE CEREALS : WHEAT, MAIZE, BARLEY AND MAIZE-BARLEY, MAIZE-WHEAT MIXTURES  

E-print Network

SUMMARY COMPARISON OF THREE CEREALS : WHEAT, MAIZE, BARLEY AND MAIZE-BARLEY, MAIZE-WHEAT MIXTURES IN GROWING-FINISHING PIG DIETS The purpose of our experiment was to compare the feeding value of maize, wheat and barley and of maize-wheat, maize-barley mixtures (at two levels : 2/3-1/3- r/3-2/3) in the rations

Paris-Sud XI, Université de

333

Characterization of polyploid wheat genomic diversity using a high-density 90 000 single nucleotide polymorphism array  

PubMed Central

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

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

334

Technological properties of bakers' yeasts in durum wheat semolina dough.  

PubMed

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. PMID:20039189

Giannone, Virgilio; Longo, Chiara; Damigella, Arcangelo; Raspagliesi, Domenico; Spina, Alfio; Palumbo, Massimo

2010-04-01

335

Ethanol production from mixtures of wheat straw and wheat meal  

PubMed Central

Background Bioethanol can be produced from sugar-rich, starch-rich (first generation; 1G) or lignocellulosic (second generation; 2G) raw materials. Integration of 2G ethanol with 1G could facilitate the introduction of the 2G technology. The capital cost per ton of fuel produced would be diminished and better utilization of the biomass can be achieved. It would, furthermore, decrease the energy demand of 2G ethanol production and also provide both 1G and 2G plants with heat and electricity. In the current study, steam-pretreated wheat straw (SPWS) was mixed with presaccharified wheat meal (PWM) and converted to ethanol in simultaneous saccharification and fermentation (SSF). Results Both the ethanol concentration and the ethanol yield increased with increasing amounts of PWM in mixtures with SPWS. The maximum ethanol yield (99% of the theoretical yield, based on the available C6 sugars) was obtained with a mixture of SPWS containing 2.5% water-insoluble solids (WIS) and PWM containing 2.5% WIS, resulting in an ethanol concentration of 56.5 g/L. This yield was higher than those obtained with SSF of either SPWS (68%) or PWM alone (91%). Conclusions Mixing wheat straw with wheat meal would be beneficial for both 1G and 2G ethanol production. However, increasing the proportion of WIS as wheat straw and the possibility of consuming the xylose fraction with a pentose-fermenting yeast should be further investigated. PMID:20598120

2010-01-01

336

Hard Spring Wheat Technical Committee 2009 Crop  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thirteen hard spring wheat lines that were developed by breeders throughout the spring wheat region of the U. S. were grown at up to five locations in 2009 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Samples of wheat were milled at the USDA Hard Red ...

337

Disease Update in Wheat Gaylon Morgan  

E-print Network

Disease Update in Wheat Gaylon Morgan State Extension Small Grains Specialist March 3, 2005 There are three major foliar leaf diseases that commonly occur in Texas wheat fields, including Leaf Rust, Stripe of Powdery Mildew that occurred in 2004. Factors to Consider for Managing Foliar Diseases in Wheat: 1

Mukhtar, Saqib

338

Wheat Production Under Alternative Production Functions  

Microsoft Academic Search

In an earlier study [1, pp. 407-415] it was assumed that a linear production function would be the best to depict the relationship between wheat production and explanatory variables in the Punjab. After a careful scrutiny, four of the explanatory variables, viz., area under Mexican Wheat varieties, area under local wheat, fertilizer application and rainfall, were employed to explain variations

M. GHAFFAR CHAUDHRY; A. R. KEMAL

1974-01-01

339

HEDONIC PRICE ESTIMATION FOR KANSAS WHEAT CHARACTERISTICS  

Microsoft Academic Search

A hedonic price model is applied to a cross-sectional time-series data set of Kansas wheat characteristics. Results indicate that prices received by wheat producers reflect the presence of conventional quality characteristics of wheat and also milling and dough characteristics. Furthermore, the results indicate that the alternative sets of characteristics exhibit quality information that is, to some degree, independent of one

Juan Andres Espinosa; Barry K. Goodwin

1991-01-01

340

Rust-Resistant Wheats for India  

Microsoft Academic Search

ALL the three rusts of wheat occur in India. It has been shown that in the plains of India the severe summer heat kills the rust spores and that the wheat crop is infected anew each season by spores blown down from the hills, where wheat is cultivated up to an altitude of about 9,000 ft. above sea-level. The barberry,

K. C. Mehta; B. P. Pal

1940-01-01

341

Removing celiac disease-related gluten proteins from bread wheat while retaining technological properties: a study with Chinese Spring deletion lines  

PubMed Central

Background Gluten proteins can induce celiac disease (CD) in genetically susceptible individuals. In CD patients gluten-derived peptides are presented to the immune system, which leads to a CD4+ T-cell mediated immune response and inflammation of the small intestine. However, not all gluten proteins contain T-cell stimulatory epitopes. Gluten proteins are encoded by multigene loci present on chromosomes 1 and 6 of the three different genomes of hexaploid bread wheat (Triticum aestivum) (AABBDD). Results The effects of deleting individual gluten loci on both the level of T-cell stimulatory epitopes in the gluten proteome and the technological properties of the flour were analyzed using a set of deletion lines of Triticum aestivum cv. Chinese Spring. The reduction of T-cell stimulatory epitopes was analyzed using monoclonal antibodies that recognize T-cell epitopes present in gluten proteins. The deletion lines were technologically tested with respect to dough mixing properties and dough rheology. The results show that removing the ?-gliadin locus from the short arm of chromosome 6 of the D-genome (6DS) resulted in a significant decrease in the presence of T-cell stimulatory epitopes but also in a significant loss of technological properties. However, removing the ?-gliadin, ?-gliadin, and LMW-GS loci from the short arm of chromosome 1 of the D-genome (1DS) removed T-cell stimulatory epitopes from the proteome while maintaining technological properties. Conclusion The consequences of these data are discussed with regard to reducing the load of T-cell stimulatory epitopes in wheat, and to contributing to the design of CD-safe wheat varieties. PMID:19351412

van den Broeck, Hetty C; van Herpen, Teun WJM; Schuit, Cees; Salentijn, Elma MJ; Dekking, Liesbeth; Bosch, Dirk; Hamer, Rob J; Smulders, Marinus JM; Gilissen, Ludovicus JWJ; van der Meer, Ingrid M

2009-01-01

342

Biofortification of wheat grain with iron and zinc: integrating novel genomic resources and knowledge from model crops  

PubMed Central

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

Borrill, Philippa; Connorton, James M.; Balk, Janneke; Miller, Anthony J.; Sanders, Dale; Uauy, Cristobal

2014-01-01

343

Microbial interactions on the phylloplane of wheat and barley after applications of mancozeb and triadimefon  

Microsoft Academic Search

In field experiments mancozeb significantly reduced fungal populations on wheat and barley leaves whereas triadimefon had\\u000a only a minor effect. Bacterial populations were not directly affected by either fungicide nor did bacteria colonise and populate\\u000a the vacant niche resulting from fungicide application. The effect of the two fungicides on phylloplane fungi was closely related\\u000a to their effect on the growth

R. J. Southwell; J. F. Brown; Sara M. Welsby

1999-01-01

344

Enhancement of Wheat Root Colonization and Plant Development by Azospirillum brasilense Cd. Following Temporary Depression of Rhizosphere Microflora  

PubMed Central

Inoculation of wheat with Azospirillum brasilense, combined with the application of four fungal and bacterium-inhibiting substances to which A. brasilense is resistant in the soil, decreased the rhizosphere population, while it increased wheat root colonization by A. brasilense, even in cases of poor inoculation. The inoculation significantly increased the following wheat plant parameters as well: plant dry weight, number of tillers per plant, spikelet fertility, harvest index, and grain yield. This model may provide a new approach to improve control of root colonization by beneficial bacteria. PMID:16347052

Bashan, Yoav

1986-01-01

345

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...

346

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...

347

Registration of ‘Faller’ Spring Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Faller’ (Reg. No. CV-1026, PI 648350) hard red spring wheat (HRSW) (Triticum aestivum L.) was developed at North Dakota State University(NDSU) and released by the North Dakota Agricultural Experiment Station (NDAES). Faller was derived from the ND2857/ND2814 cross made at NDSU in fall 1997. ND2857 ...

348

Registration of ‘USG 3555’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘USG 3555’ (Reg. No. CV-, PI 654454) soft red winter wheat (Triticum aestivum L.) was developed and released by the Virginia Agricultural Experiment Station in March 2007. USG 3555 was derived from the cross VA94-52-60 / Pioneer Brand ‘2643’ (PI 583739 PVPO) // ’USG 3209’ (PI 617055 PVPO) and was t...

349

Mechanistic analysis of wheat chlorophyllase  

Microsoft Academic Search

Chlorophyllase catalyzes the initial step in the degradation of chlorophyll and plays a key role in leaf senescence and fruit ripening. Here, we report the cloning of chlorophyllase from Triticum aestivum (wheat) and provide a detailed mechanistic analysis of the enzyme. Purification of recombinant chlorophyllase from an Escherichia coli expression system indicates that the enzyme functions as a dimeric protein.

Kiani A. J. Arkus; Edgar B. Cahoon; Joseph M. Jez

2005-01-01

350

REGISTRATION OF 'OK 101' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Ok101' is a hard red winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station and the USDA-ARS, and released in March 2001, in cooperation with the USDA-ARS. Motivation for its release was a unique combination of high tolerance to acidic soil, bro...

351

Registration of TAM401 wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

'TAM 401', a hard red winter wheat (Triticum aestivum L) cultivar (PI658500) with experimental designation TX03M1096, was developed and released by Texas AgriLife Research in 2008. TAM 401 is an F4 derived line from the cross 'Mason' (PI 594044)/'Jagger' (PI593688). TAM 401 is an early maturing apic...

352

Registration of ‘Ok102’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Ok102’ (Reg. no. CV-941, PI 632635) is a hard red winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agric. Exp. Stn. and the USDA-ARS. Ok102 was released in March 2002, primarily on the basis of its resistance to several foliar diseases, excellent milling quality, and desi...

353

REGISTRATION OF 'OK102' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Ok102' is a hard red winter (HRW) wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station and the USDA-ARS. Ok102 was released in March 2002, primarily based on its resistance to several foliar diseases, excellent milling quality, and desirable dough st...

354

Registration of 'TAM 113' wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘TAM 113’ (Reg. No. CV-1081, PI 666125), a hard red winter wheat (Triticum aestivum L.) cultivar with experimental designation TX02A0252, was developed and released by Texas AgriLife Research in 2010. TAM 113 is an F5–derived line from the cross TX90V6313/TX94V3724 made at Vernon, TX in 1995. Both T...

355

Introgression of a leaf rust resistance gene from Aegilops caudata to bread wheat.  

PubMed

Rusts are the most important biotic constraints limiting wheat productivity worldwide. Deployment of cultivars with broad spectrum rust resistance is the only environmentally viable option to combat these diseases. Identification and introgression of novel sources of resistance is a continuous process to combat the ever evolving pathogens. The germplasm of nonprogenitor Aegilops species with substantial amount of variability has been exploited to a limited extent. In the present investigation introgression, inheritance and molecular mapping of a leaf rust resistance gene of Ae. caudata (CC) acc. pau3556 in cultivated wheat were undertaken. An F(2) population derived from the cross of Triticum aestivum cv. WL711 - Ae. caudata introgression line T291-2 with wheat cultivar PBW343 segregated for a single dominant leaf rust resistance gene at the seedling and adult plant stages. Progeny testing in F(3) confirmed the introgression of a single gene for leaf rust resistance. Bulked segregant analysis using polymorphic D-genome-specific SSR markers and the cosegregation of the 5DS anchored markers (Xcfd18, Xcfd78, Xfd81 and Xcfd189) with the rust resistance in the F(2) population mapped the leaf rust resistance gene (LrAC) on the short arm of wheat chromosome 5D. Genetic complementation and the linked molecular markers revealed that LrAC is a novel homoeoallele of an orthologue Lr57 already introgressed from the 5M chromosome of Ae. geniculata on 5DS of wheat. PMID:22942085

Riar, Amandeep Kaur; Kaur, Satinder; Dhaliwal, H S; Singh, Kuldeep; Chhuneja, Parveen

2012-08-01

356

Iturin levels on wheat spikes linked to biological control of Fusarium head blight by Bacillus amyloliquefaciens.  

PubMed

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. PMID:23075168

Crane, J M; Gibson, D M; Vaughan, R H; Bergstrom, G C

2013-02-01

357

The Microgeographical Patterns of Morphological and Molecular Variation of a Mixed Ploidy Population in the Species Complex Actinidia chinensis  

PubMed Central

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

Liu, Yifei; Li, Dawei; Yan, Ling; Huang, Hongwen

2015-01-01

358

Cursorial spiders retard initial aphid population growth at low densities  

E-print Network

Cursorial spiders retard initial aphid population growth at low densities in winter wheat K technique that revealed species-specific aphid consump- tion rates with a factorial field experiment on aphid population growth. Only cursorial spiders retarded aphid population growth in our cage experiment

Illinois at Chicago, University of

359

Allelopathic response of Phalaris minor to crop and weed plants in rice–wheat system  

Microsoft Academic Search

Green manuring of sunflower and dhaincha reduced plant population of Phalaris minor 100 per cent under lab and 42 per cent and 15 per cent, respectively, under field conditions, thus, indicating the inhibitory role of allelo-chemicals. Grain yield of wheat was significantly higher with the green manuring of sunflower and dhaincha before rice transplanting over summer fallow. The allelopathic potential

Hari Om; S. D Dhiman; Sajjan Kumar; Hemant Kumar

2002-01-01

360

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...

361

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...

362

WHEAT RUSTS IN THE UNITED STATES IN 2004  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stem rust caused little damage to wheat in the U.S. in 2004. Wheat leaf rust caused an estimated loss of 30 million bushels of wheat in the U.S. in 2004. Losses to leaf rust were 4.7% in Texas and 1.0% total for winter wheat and 10.0% for spring wheat in Minnesota and 1.9% total for spring wheat. T...

363

Wheat puroindolines interact to form friabilin and control wheat grain hardness  

Microsoft Academic Search

Wheat grain is sold based upon several physiochemical characteristics, one of the most important being grain texture. Grain texture in wheat directly affects many end use qualities such as milling yield, break flour yield, and starch damage. The hardness (Ha) locus located on the short arm of chromosome 5D is known to control grain hardness in wheat. This locus contains

A. C. Hogg; T. Sripo; B. Beecher; J. M. Martin; M. J. Giroux

2004-01-01

364

Isolation and characterization of wheat-rye recombinants involving chromosome arm 1DS of wheat  

Microsoft Academic Search

The introgression of genetic material from alien species is assuming increased importance in wheat breeding programs. One example is the translocation of the short arm of rye chromosome 1 (1RS) onto homoeologous wheat chromosomes, which confers disease resistance and increased yield on wheat. However, this translocation is also associated with dough quality defects. To break the linkage between the desirable

P. M. Rogowsky; F. L. Y. Guidet; P. Langridge; K. W. Shepherd; R. M. D. Koebner

1991-01-01

365

Tolerance of wheat to Russian wheat aphids: Nitrogen fertilization reduces yield loss  

Microsoft Academic Search

The influence of nitrogen nutrition and Russian wheat aphid (Diuraphis noxia Mordvilko) infestation on morphology and grain yield of wheat (Triticum aestivum L.) was studied in growth chamber experiments. Plants were grown with nutrient solution containing 100, 50, 10, or 0 percent of the normal complement of nitrogen. Plants were infested with eight apterous adult Russian wheat aphids at the

Walter E. Riedell

1990-01-01

366

Grain and vegetative biomass reduction by the Russian wheat aphid in winter wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a severe pest of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), other small grains, and grasses. Although the Russian wheat aphid is a significant pest of small grains, its feeding effects on grain yield and vegetative biomass in ...

367

Association Analysis of Soft Wheat Quality Traits in Eastern US Soft Winter Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soft wheat quality is highly heritable, is controlled by multiple loci, and has been mapped in a number of bi-parental crosses. We extended the mapping information on soft wheat quality by using association analysis between genetic markers and quality phenotyping in 192 soft winter wheat cultivars ...

368

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...

369

Immunocytochemical localization of wheat germ agglutinin in wheat  

PubMed Central

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

1982-01-01

370

Model SNP development for complex genomes based on hexaploid oat using high-throughput 454 sequencing technology  

PubMed Central

Background Genetic markers are pivotal to modern genomics research; however, discovery and genotyping of molecular markers in oat has been hindered by the size and complexity of the genome, and by a scarcity of sequence data. The purpose of this study was to generate oat expressed sequence tag (EST) information, develop a bioinformatics pipeline for SNP discovery, and establish a method for rapid, cost-effective, and straightforward genotyping of SNP markers in complex polyploid genomes such as oat. Results Based on cDNA libraries of four cultivated oat genotypes, approximately 127,000 contigs were assembled from approximately one million Roche 454 sequence reads. Contigs were filtered through a novel bioinformatics pipeline to eliminate ambiguous polymorphism caused by subgenome homology, and 96 in silico SNPs were selected from 9,448 candidate loci for validation using high-resolution melting (HRM) analysis. Of these, 52 (54%) were polymorphic between parents of the Ogle1040 × TAM O-301 (OT) mapping population, with 48 segregating as single Mendelian loci, and 44 being placed on the existing OT linkage map. Ogle and TAM amplicons from 12 primers were sequenced for SNP validation, revealing complex polymorphism in seven amplicons but general sequence conservation within SNP loci. Whole-amplicon interrogation with HRM revealed insertions, deletions, and heterozygotes in secondary oat germplasm pools, generating multiple alleles at some primer targets. To validate marker utility, 36 SNP assays were used to evaluate the genetic diversity of 34 diverse oat genotypes. Dendrogram clusters corresponded generally to known genome composition and genetic ancestry. Conclusions The high-throughput SNP discovery pipeline presented here is a rapid and effective method for identification of polymorphic SNP alleles in the oat genome. The current-generation HRM system is a simple and highly-informative platform for SNP genotyping. These techniques provide a model for SNP discovery and genotyping in other species with complex and poorly-characterized genomes. PMID:21272354

2011-01-01

371

The Role of Natural Enemy Foraging Guilds in Controlling Cereal Aphids in Michigan Wheat  

PubMed Central

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. PMID:25473951

Safarzoda, Shahlo; Bahlai, Christine A.; Fox, Aaron F.; Landis, Douglas A.

2014-01-01

372

The role of natural enemy foraging guilds in controlling cereal aphids in michigan wheat.  

PubMed

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. PMID:25473951

Safarzoda, Shahlo; Bahlai, Christine A; Fox, Aaron F; Landis, Douglas A

2014-01-01

373

Achieving yield gains in wheat.  

PubMed

Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks. PMID:22860982

Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

2012-10-01

374

Systems Responses to Progressive Water Stress in Durum Wheat  

PubMed Central

Durum wheat is susceptible to terminal drought which can greatly decrease grain yield. Breeding to improve crop yield is hampered by inadequate knowledge of how the physiological and metabolic changes caused by drought are related to gene expression. To gain better insight into mechanisms defining resistance to water stress we studied the physiological and transcriptome responses of three durum breeding lines varying for yield stability under drought. Parents of a mapping population (Lahn x Cham1) and a recombinant inbred line (RIL2219) showed lowered flag leaf relative water content, water potential and photosynthesis when subjected to controlled water stress time transient experiments over a six-day period. RIL2219 lost less water and showed constitutively higher stomatal conductance, photosynthesis, transpiration, abscisic acid content and enhanced osmotic adjustment at equivalent leaf water compared to parents, thus defining a physiological strategy for high yield stability under water stress. Parallel analysis of the flag leaf transcriptome under stress uncovered global trends of early changes in regulatory pathways, reconfiguration of primary and secondary metabolism and lowered expression of transcripts in photosynthesis in all three lines. Differences in the number of genes, magnitude and profile of their expression response were also established amongst the lines with a high number belonging to regulatory pathways. In addition, we documented a large number of genes showing constitutive differences in leaf transcript expression between the genotypes at control non-stress conditions. Principal Coordinates Analysis uncovered a high level of structure in the transcriptome response to water stress in each wheat line suggesting genome-wide co-ordination of transcription. Utilising a systems-based approach of analysing the integrated wheat’s response to water stress, in terms of biological robustness theory, the findings suggest that each durum line transcriptome responded to water stress in a genome-specific manner which contributes to an overall different strategy of resistance to water stress. PMID:25265161

Habash, Dimah Z.; Baudo, Marcela; Hindle, Matthew; Powers, Stephen J.; Defoin-Platel, Michael; Mitchell, Rowan; Saqi, Mansoor; Rawlings, Chris; Latiri, Kawther; Araus, Jose L.; Abdulkader, Ahmad; Tuberosa, Roberto; Lawlor, David W.; Nachit, Miloudi M.

2014-01-01

375

Patterns of Population Differentiation and Natural Selection on the Celiac Disease Background Risk  

E-print Network

is a common small intestinal inflammatory condition induced by wheat gluten and related proteins from rye. Therefore, CD potentially negatively affected fitness in past populations utilizing wheat, barley, and rye gluten and related proteins from rye and barley [2]. Specific risk alleles of the HLA-DQA1 and DQB1 genes

Cochran-Stafira, D. Liane

376

Molecular evolution of dimeric ?-amylase inhibitor genes in wild emmer wheat and its ecological association  

PubMed Central

Background ?-Amylase inhibitors are attractive candidates for the control of seed weevils, as these insects are highly dependent on starch as an energy source. In this study, we aimed to reveal the structure and diversity of dimeric ?-amylase inhibitor genes in wild emmer wheat from Israel and to elucidate the relationship between the emmer wheat genes and ecological factors using single nucleotide polymorphism (SNP) markers. Another objective of this study was to find out whether there were any correlations between SNPs in functional protein-coding genes and the environment. Results The influence of ecological factors on the genetic structure of dimeric ?-amylase inhibitor genes was evaluated by specific SNP markers. A total of 244 dimeric ?-amylase inhibitor genes were obtained from 13 accessions in 10 populations. Seventy-five polymorphic positions and 74 haplotypes were defined by sequence analysis. Sixteen out of the 75 SNP markers were designed to detect SNP variations in wild emmer wheat accessions from different populations in Israel. The proportion of polymorphic loci P (5%), the expected heterozygosity He, and Shannon's information index in the 16 populations were 0.887, 0.404, and 0.589, respectively. The populations of wild emmer wheat showed great diversity in gene loci both between and within populations. Based on the SNP marker data, the genetic distance of pair-wise comparisons of the 16 populations displayed a sharp genetic differentiation over long geographic distances. The values of P, He, and Shannon's information index were negatively correlated with three climatic moisture factors, whereas the same values were positively correlated by Spearman rank correlation coefficients' analysis with some of the other ecological factors. Conclusion The populations of wild emmer wheat showed a wide range of diversity in dimeric ?-amylase inhibitors, both between and within populations. We suggested that SNP markers are useful for the estimation of genetic diversity of functional genes in wild emmer wheat. These results show significant correlations between SNPs in the ?-amylase inhibitor genes and ecological factors affecting diversity. Ecological factors, singly or in combination, explained a significant proportion of the variations in the SNPs, and the SNPs could be classified into several categories as ecogeographical predictors. It was suggested that the SNPs in the ?-amylase inhibitor genes have been subjected to natural selection, and ecological factors had an important evolutionary influence on gene differentiation at specific loci. PMID:18366725

2008-01-01

377

Production of fuel ethanol from wheat straw  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat straw contains about 70% carbohydrates that can serve as a low cost feedstock for production of fuel ethanol. The pretreatment of wheat straw is essential prior to enzymatic hydrolysis. Research needs to be carried out to develop an efficient pretreatment method which can greatly help enzyme...

378

TRACKING WHEAT RUST ON A CONTINENTAL SCALE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The rusts of wheat are important fungal plant pathogens that can be wind disseminated for thousands of kilometers across continents and oceans. 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...

379

Functional dissection of wheat disease resistance pathways  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is an essential component of human food supply. We are working to identify genes that mediate resistance to the most significant pathogens of wheat, so that ultimately, we can engineer improved disease resistance. We are employing virus-induced gene silencing (VIGS) to test if candidate gene...

380

Using transcriptomics to understand the wheat genome  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat (Triticum aestivum L.) is the most important food crop in the world, and transcriptomics studies of this crop promise to reveal the expression dynamics of genes that control many agriculturally important traits. In this review of wheat transcriptomics research, the current status of transcript...

381

DIATOMACEOUS EARTH SURFACE TREATMENT FOR STORED WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Diatomaceous earth (DE) can be used as a surface treatment in stored wheat to control pest infestations. However, it is not known how the thickness of the DE-treated wheat layer or grain temperature impacts effectiveness. When adult Rhizopertha dominica (F.), lesser grain borers, were released in e...

382

IMPROVING WHEAT QUALITY CONSISTENCY BY DENSITY SEGREGATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

The end-use quality of grain crops can vary significantly within a given field. Research was conducted in northeastern Oregon to determine the amount of wheat quality variability due to landscape position and if improvements in the consistency of wheat quality delivered at the farm gate could be ma...

383

Biodegradability of wheat gluten based bioplastics  

Microsoft Academic Search

A large variety of wheat gluten based bioplastics, which were plasticized with glycerol, were subjected to biodegradation. The materials covered the total range available for the biochemical control parameter Fi, which expresses the percentage of aggregated proteins. This quantity can be related to the density of covalent crosslinks in the wheat gluten network, which are induced by technological treatments. The

Sandra Domenek; Pierre Feuilloley; Jean Gratraud; Marie-Hélène Morel; Stéphane Guilbert

2004-01-01

384

[The nutritive value of wheat germ floc].  

PubMed

The experimental investigation of the food value of wheat germ floc included the study of their chemical composition, biological value, and assimilability of the protein. Basing on the results obtained the authors have made a conclusion on the high food value of wheat germ floc and on their promising use as enriching additives to varying foodstuffs. PMID:2399684

Safronova, A M; Vysotski?, V G; Narodetskaia, R V; Trushina, E N; Sandakova, G K; Kolkunova, G K

1990-01-01

385

Response of wheat to sulfur fertilization  

Microsoft Academic Search

Coker 747 wheat (Triticum aestivum L.) was grown on Keo silt loam (coarse?silty, mixed, thermic Dystric Fluventic Entrochrepts) with four S sources applied at various rates for two years. The innate S level of this soil was not adequate for optimum grain yield; therefore, additional S significantly increased grain yield and S concentration and decreased N\\/S ratios in wheat tissue.

Richard J. Mahler; Richard L. Maples

1986-01-01

386

Plant breeding Bread wheat x Agrotricum crosses as a source  

E-print Network

Plant breeding Bread wheat x Agrotricum crosses as a source of immunity and resistance to the PAV). Through a process of selection for BYDV resistance and threshable phenotypes with wheat-like seeds, wheat numbers were also ob- tained. The low frequency of expression of immunity in the bread wheat background

Paris-Sud XI, Université de

387

Laboratory milling method for whole grain soft wheat flour evaluation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole grain wheat products are a growing portion of the foods marked in North America, yet few standard methods exist to evaluate whole grain wheat flour. This study evaluated two flour milling systems to produce whole grain soft wheat flour for a standard soft wheat product, a wire-cut cookie. A...

388

376 PHYTOPATHOLOGY Ecology and Population Biology  

E-print Network

and T. bromi were sampled from wheat and two Bromus species hosts, respectively, in the Pacific differentiation observed between the T. bromi populations on different Bromus species hosts supports host for T. controver- sa and T. bromi is Bromus carinatus Hook. & Arnott, a perennial bromegrass

Peever, Tobin

389

Diversity resistance to Puccinia striiformis f. sp Tritici in rye chromosome arm 1RS expressed in wheat.  

PubMed

The 1BL.1RS wheat-rye translocation contained in the Russian cultivar Aurora has been the most widespread alien translocation in wheat-breeding programs all over the world. However, following the prevalence of new biotypes of the pathogens, disease-resistance genes in this translocation chromosome have been overcome and consequently they have been eliminated in modern wheat-breeding programs. In this paper, we report on 12 new primary 1BL.1RS translocation lines derived from the crosses of a Chinese high yield wheat cv. Mianyang 11 with three rye cultivars collected from China. GISH, C-banding and PCR techniques using the specific primers for 1BS, 1RS and centromeres of wheat and rye were applied to identify the constitution of chromosomes. The results confirmed that all 1BL.1RS chromosomes in the 12 primary translocation lines contained integrated 1RS chromosome arms. In the resistance analysis using five kinds of Pst pathotypes, the 12 primary translocation lines showed diversity resistance to stripe rust, which contained at least five different new genes (alleles), significantly different from the Yr9 gene coming from Russian wheat cultivar Aurora. The results indicated that the chromosome arm 1RS in the rye population carries abundant yet untapped genes (alleles) for resistance to wheat stripe rust, which would originate from the neutral diversity in the natural population of rye. It is suggested that creating more primary translocation lines in genome modification will be extremely important to use the diversity of alien R-genes, which was generated by long-term neutral mutation and maintained in the population of alien species. PMID:25366770

Yang, M Y; Ren, T H; Yan, B J; Li, Z; Ren, Z L

2014-01-01

390

Limiting mycotoxins in stored wheat.  

PubMed

The quality of harvested wheat grain can deteriorate markedly during the post-harvest management stages. Biotic factors, such as grain type and ripeness, coupled with the prevailing abiotic factors, such as water content and temperature, and also preservative concentration will influence the safe storage life and the level of contamination with mycotoxins. These mycotoxins include deoxynivalenol (DON) produced pre-harvest and zearalenone (ZEA) produced post-harvest by Fusarium graminearum and Fusarium poae, respectively, ochratoxin (OTA) produced by Penicillium verrucosum post-harvest in cool damp northern European climates, and perhaps T-2 and HT-2 toxins produced by Fusarium langsethiae. This review presents recent data on the relationship between dry matter losses caused by F. graminearum under different environmental regimes (water activities, temperatures) and the level of contamination with DON. This is important as poor post-harvest drying and storage management may exacerbate DON contamination already present pre-harvest. It is thus critical to relate the environmental factors in stored wheat grain during storage, especially of intergranular relative humidity (RH) and temperature, to safe storage periods without spoilage or risk from increased DON contamination. The growth/no growth and DON/no DON (F. graminearum) and OTA/no toxin production (P. verrucosum) have been used to build a model with a simple interface to link temperature and RH values to the potential risk level which may allow growth or toxin production. This paper also considers the use of modified atmospheres, preservatives and biocontrol to minimise DON and OTA in moist wheat grain. These approaches together with clear monitoring criteria and hygiene could contribute to better post-harvest management of stored temperate cereals and ensure that mycotoxin contamination is minimised during this key phase in the food/feed chain. PMID:20455159

Magan, Naresh; Aldred, David; Mylona, Kalliopi; Lambert, Ronald J W

2010-05-01

391

Mechanistic analysis of wheat chlorophyllase.  

PubMed

Chlorophyllase catalyzes the initial step in the degradation of chlorophyll and plays a key role in leaf senescence and fruit ripening. Here, we report the cloning of chlorophyllase from Triticum aestivum (wheat) and provide a detailed mechanistic analysis of the enzyme. Purification of recombinant chlorophyllase from an Escherichia coli expression system indicates that the enzyme functions as a dimeric protein. Wheat chlorophyllase hydrolyzed the phytol moiety from chlorophyll (k(cat) = 566 min(-1); K(m) = 63 microM) and was active over a broad temperature range (10-75 degrees C). In addition, the enzyme displays carboxylesterase activity toward p-nitrophenyl (PNP)-butyrate, PNP-decanoate, and PNP-palmitate. The pH-dependence of the reaction showed the involvement of an active site residue with a pK(a) of approximately 6.5 for both k(cat) and k(cat)/K(m) with chlorophyll, PNP-butyrate, and PNP-decanoate. Using these substrates, solvent kinetic isotope effects ranging from 1.5 to 1.9 and from 1.4 to 1.9 on k(cat) and k(cat)/K(m), respectively, were observed. Proton inventory experiments suggest the transfer of a single proton in the rate-limiting step. Our analysis of wheat chlorophyllase indicates that the enzyme uses a charge-relay mechanism similar to other carboxylesterases for catalysis. Understanding the activity and mechanism of chlorophyllase provides insight on the biological and chemical control of senescence in plants and lays the groundwork for biotechnological improvement of this enzyme. PMID:15913540

Arkus, Kiani A J; Cahoon, Edgar B; Jez, Joseph M

2005-06-15

392

Winter wheat cultivars with temperature sensitive resistance to wheat streak mosaic virus do not recover from early season infections  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat streak mosaic virus (WSMV), Triticum mosaic virus, and Wheat mosaic virus, all vectored by the wheat curl mite Aceria tosichella Keifer, frequently cause devastating losses to winter wheat production throughout the central and western Great Plains. Resistant 'Mace' and 'RonL' are commercially ...

393

Quantification of yield loss caused by Triticum mosaic virus and Wheat streak mosaic virus in winter wheat under field conditions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Triticum mosaic virus (TriMV) and Wheat streak mosaic virus (WSMV) infect winter wheat in the Great Plains region of the United States. The two viruses are transmitted by wheat curl mites, which also transmit High Plains virus. In a field study conducted in 2011 and 2012, winter wheat cultivars Mi...

394

Hessian Fly in Texas Wheat  

E-print Network

, early-planted wheat and other host grasses. Because they resemble flax seed, puparia often are referred to as the pest?s ?flaxseed? stage. Puparia also can become part of soil-surface organic residue from infested seedlings killed by the larvae... by larval feeding. Infested tillers are less than half the size of uninfested, healthy ones. Figure 8 shows a four-tillered seed- ling with one tiller dwarfed as a result of larval infestation. Stunted tillers, particularly those found on younger plants...

Morgan, Gaylon; Sansone, Chris; Knutson, Allen E.

2005-07-01

395

Cell Walls of Developing Wheat Starchy Endosperm: Comparison of Composition and RNA-Seq Transcriptome1[C][W][OA  

PubMed Central

The transcriptome of the developing starchy endosperm of hexaploid wheat (Triticum aestivum) was determined using RNA-Seq isolated at five stages during grain fill. This resource represents an excellent way to identify candidate genes responsible for the starchy endosperm cell wall, which is dominated by arabinoxylan (AX), accounting for 70% of the cell wall polysaccharides, with 20% (1,3;1,4)-?-d-glucan, 7% glucomannan, and 4% cellulose. A complete inventory of transcripts of 124 glycosyltransferase (GT) and 72 glycosylhydrolase (GH) genes associated with cell walls is presented. The most highly expressed GT transcript (excluding those known to be involved in starch synthesis) was a GT47 family transcript similar to Arabidopsis (Arabidopsis thaliana) IRX10 involved in xylan extension, and the second most abundant was a GT61. Profiles for GT43 IRX9 and IRX14 putative orthologs were consistent with roles in AX synthesis. Low abundances were found for transcripts from genes in the acyl-coA transferase BAHD family, for which a role in AX feruloylation has been postulated. The relative expression of these was much greater in whole grain compared with starchy endosperm, correlating with the levels of bound ferulate. Transcripts associated with callose (GSL), cellulose (CESA), pectin (GAUT), and glucomannan (CSLA) synthesis were also abundant in starchy endosperm, while the corresponding cell wall polysaccharides were confirmed as low abundance (glucomannan and callose) or undetectable (pectin) in these samples. Abundant transcripts from GH families associated with the hydrolysis of these polysaccharides were also present, suggesting that they may be rapidly turned over. Abundant transcripts in the GT31 family may be responsible for the addition of Gal residues to arabinogalactan peptide. PMID:22123899

Pellny, Till K.; Lovegrove, Alison; Freeman, Jackie; Tosi, Paola; Love, Christopher G.; Knox, J. Paul; Shewry, Peter R.; Mitchell, Rowan A.C.

2012-01-01

396

Development of sprouted wheat based probiotic beverage.  

PubMed

Present study was carried out to evaluate the potential of Lactobacillus acidophilus (L. acidophilus) for development of wheat based probiotic beverage and to optimize the proportion of different ingredients viz. sprouted wheat flour, sprouted wheat bran, oat and stabilizer using response surface methodology. Acidity, pH and probiotic count of samples prepared with L. acidophilus NCDC-14 was higher than that of L. acidophilus NCDC-16 culture. Being more compatible, L. acidophilus NCDC-14 was selected for this study. Acidity (in terms of lactic acid), pH and probiotic count of the different samples ranged from 0.21 to 0.45 %, 4.0 to 4.9, and 8.30 to 10.95 log10 cfu?mL(-1), respectively. Probiotic count increased with increasing amount of sprouted wheat and oat. Optimized levels for sprouted wheat flour, oat, wheat bran and guar gum were 7.86, 5.42, 1.42 and 0.6 g, respectively per 100 mL of water. Optimized probiotic beverage provided 13.19 % total solids, 1.19 % protein, 0.33 % fat, 0.10 % ash, 0.42 % crude fibre, 1.45 mg iron, calcium 15.74 mg, 11.56 % carbohydrates, 54 kcal calories and 10.43 log10 cfu?mL(-1) probiotic count. Thus, Lactobacillus acidophilus NCDC-14 can be used for development of potentially probiotic beverage with sprouted wheat and oat. PMID:25477662

Sharma, Monika; Mridula, D; Gupta, R K

2014-12-01

397

Micromilling enhances iron bioaccessibility from wholegrain wheat.  

PubMed

Cereals constitute important sources of iron in human diet; however, much of the iron in wheat is lost during processing for the production of white flour. This study employed novel food processing techniques to increase the bioaccessibility of naturally occurring iron in wheat. Iron was localized in wheat by Perl's Prussian blue staining. Soluble iron from digested wheat flour was measured by a ferrozine spectrophotometric assay. Iron bioaccessibility was determined using an in vitro simulated peptic-pancreatic digestion, followed by measurement of ferritin (a surrogate marker for iron absorption) in Caco-2 cells. Light microscopy revealed that iron in wheat was encapsulated in cells of the aleurone layer and remained intact after in vivo digestion and passage through the gastrointestinal tract. The solubility of iron in wholegrain wheat and in purified wheat aleurone increased significantly after enzymatic digestion with Driselase, and following mechanical disruption using micromilling. Furthermore, following in vitro simulated peptic-pancreatic digestion, iron bioaccessibility, measured as ferritin formation in Caco-2 cells, from micromilled aleurone flour was significantly higher (52%) than from whole aleurone flour. Taken together our data show that disruption of aleurone cell walls could increase iron bioaccessibility. Micromilled aleurone could provide an alternative strategy for iron fortification of cereal products. PMID:25380143

Latunde-Dada, G O; Li, X; Parodi, A; Edwards, C H; Ellis, P R; Sharp, P A

2014-11-19

398

Does Wheat Genetically Modified for Disease Resistance Affect Root-Colonizing Pseudomonads and Arbuscular Mycorrhizal Fungi?  

PubMed Central

This study aimed to evaluate the impact of genetically modified (GM) wheat with introduced pm3b mildew resistance transgene, on two types of root-colonizing microorganisms, namely pseudomonads and arbuscular mycorrhizal fungi (AMF). Our investigations were carried out in field trials over three field seasons and at two locations. Serial dilution in selective King's B medium and microscopy were used to assess the abundance of cultivable pseudomonads and AMF, respectively. We developed a denaturing gradient gel electrophoresis (DGGE) method to characterize the diversity of the pqqC gene, which is involved in Pseudomonas phosphate solubilization. A major result was that in the first field season Pseudomonas abundances and diversity on roots of GM pm3b lines, but also on non-GM sister lines were different from those of the parental lines and conventional wheat cultivars. This indicates a strong effect of the procedures by which these plants were created, as GM and sister lines were generated via tissue cultures and propagated in the greenhouse. Moreover, Pseudomonas population sizes and DGGE profiles varied considerably between individual GM lines with different genomic locations of the pm3b transgene. At individual time points, differences in Pseudomonas and AMF accumulation between GM and control lines were detected, but they were not consistent and much less pronounced than differences detected between young and old plants, different conventional wheat cultivars or at different locations and field seasons. Thus, we conclude that impacts of GM wheat on plant-beneficial root-colonizing microorganisms are minor and not of ecological importance. The cultivation-independent pqqC-DGGE approach proved to be a useful tool for monitoring the dynamics of Pseudomonas populations in a wheat field and even sensitive enough for detecting population responses to altered plant physiology. PMID:23372672

Foetzki, Andrea; Luginbühl, Carolin; Winzeler, Michael; Kneubühler, Yvan; Matasci, Caterina; Mascher-Frutschi, Fabio; Kalinina, Olena; Boller, Thomas; Keel, Christoph; Maurhofer, Monika

2013-01-01

399

Induction of resistance by silicon in wheat plants to Alate and Apterous morphs of Sitobion avenae (Hemiptera: Aphididae).  

PubMed

Despite the knowledge about the effects of silicon augmenting antibiosis and nonpreference of plants by apterous aphids, few studies exist on such effects with alate aphids. This study evaluated the effects of silicon fertilization on the biology of alate and apterous morphs of Sitobion avenae (F.) (Hemiptera: Aphididae), and the effect on nonpreference by S. avenae alates for wheat plants with or without silicon fertilization. A method for rearing aphids on detached leaves was evaluated comparing the biology of apterous aphids reared on wheat leaf sections and on whole plants with and without silicon fertilization. Because the use of detached leaves was a reliable method, the effect of silicon fertilization on the biology of apterous and alate S. avenae was assessed using wheat leaf sections. Biological data of aphids were used to calculate a fertility life table. Finally, the effect of silicon fertilization on the nonpreference of alate aphids was carried out for both vegetative and reproductive phases of wheat. Thirty alate aphids were released in the center of a cage, and the number of aphids per whole plant with or without silicon fertilization was observed. Silicon fertilization induced antibiosis resistance in wheat plants to apterous morphs as shown by reduced fecundity, reproductive period, longevity, intrinsic rate of increase, and net reproductive rate; however, alates were unaffected. Plants that received silicon fertilization had fewer alate aphids in both the vegetative and reproductive phases. Thus, silicon fertilization can reduce colonization by alates, enhancing nonpreference resistance, and population growth of apterous S. avenae in wheat plants. PMID:25182615

Dias, P A S; Sampaio, M V; Rodrigues, M P; Korndörfer, A P; Oliveira, R S; Ferreira, S E; Korndörfer, G H

2014-08-01

400

Physical mapping resources for large plant genomes: radiation hybrids for wheat D-genome progenitor Aegilops tauschii  

PubMed Central

Background Development of a high quality reference sequence is a daunting task in crops like wheat with large (~17Gb), highly repetitive (>80%) and polyploid genome. To achieve complete sequence assembly of such genomes, development of a high quality physical map is a necessary first step. However, due to the lack of recombination in certain regions of the chromosomes, genetic mapping, which uses recombination frequency to map marker loci, alone is not sufficient to develop high quality marker scaffolds for a sequence ready physical map. Radiation hybrid (RH) mapping, which uses radiation induced chromosomal breaks, has proven to be a successful approach for developing marker scaffolds for sequence assembly in animal systems. Here, the development and characterization of a RH panel for the mapping of D-genome of wheat progenitor Aegilops tauschii is reported. Results Radiation dosages of 350 and 450 Gy were optimized for seed irradiation of a synthetic hexaploid (AABBDD) wheat with the D-genome of Ae. tauschii accession AL8/78. The surviving plants after irradiation were crossed to durum wheat (AABB), to produce pentaploid RH1s (AABBD), which allows the simultaneous mapping of the whole D-genome. A panel of 1,510 RH1 plants was obtained, of which 592 plants were generated from the mature RH1 seeds, and 918 plants were rescued through embryo culture due to poor germination (<3%) of mature RH1 seeds. This panel showed a homogenous marker loss (2.1%) after screening with SSR markers uniformly covering all the D-genome chromosomes. Different marker systems mostly detected different lines with deletions. Using markers covering known distances, the mapping resolution of this RH panel was estimated to be <140kb. Analysis of only 16 RH lines carrying deletions on chromosome 2D resulted in a physical map with cM/cR ratio of 1:5.2 and 15 distinct bins. Additionally, with this small set of lines, almost all the tested ESTs could be mapped. A set of 399 most informative RH lines with an average deletion frequency of ~10% were identified for developing high density marker scaffolds of the D-genome. Conclusions The RH panel reported here is the first developed for any wild ancestor of a major cultivated plant species. The results provided insight into various aspects of RH mapping in plants, including the genetically effective cell number for wheat (for the first time) and the potential implementation of this technique in other plant species. This RH panel will be an invaluable resource for mapping gene based markers, developing a complete marker scaffold for the whole genome sequence assembly, fine mapping of markers and functional characterization of genes and gene networks present on the D-genome. PMID:23127207

2012-01-01

401

Pre-Harvest Sprouting in Wheat  

E-print Network

). Once wheat seed has reached harvest maturity, it will begin to germinate when exposed to adequate moisture and tempera- tures. For wheat at a harvest-ripe stage (Feekes 11.4 or Zadock 92), any extended period of wet weather can cause pre... appear green. Sprouting in Wheat Growers should question suitability of grain for seed if germination or pre-harvest sprouting has occurred. Grains with split seed coats or exposed roots or shoots should not be kept for seed. Low test weight...

Morgan, Gaylon

2005-01-26

402

Durum wheat and allelopathy: toward wheat breeding for natural weed management  

PubMed Central

Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control. PMID:24065979

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

403

World Population  

NSDL National Science Digital Library

Access and visualize world population data using the user friendly MyWorld GIS software. Data includes total population, population density, projected population, male and female population, and age specific population, etc.

This starting point example compiled by R.M. MacKay. utilizes the MyWorld (more info) Geographic Information System (GIS) software created at Norhtwestern University.

404

Effects of break crops, and of wheat volunteers growing in break crops or in set-aside or conservation covers, all following crops of winter wheat, on the development of take-all (Gaeumannomyces graminis var. tritici) in succeeding crops of winter wheat  

PubMed Central

Experiments on the Rothamsted and Woburn Experimental Farms studied the effects on take-all of different break crops and of set-aside/conservation covers that interrupted sequences of winter wheat. There was no evidence for different effects on take-all of the break crops per se but the presence of volunteers, in crops of oilseed rape, increased the amounts of take-all in the following wheat. Severity of take-all was closely related to the numbers of volunteers in the preceding break crops and covers, and was affected by the date of their destruction. Early destruction of set-aside/conservation covers was usually effective in preventing damaging take-all in the following wheat except, sometimes, when populations of volunteers were very large. The experiments were not designed to test the effects of sowing dates but different amounts of take-all in the first wheats after breaks or covers apparently affected the severity of take-all in the following (second) wheats only where the latter were relatively late sown. In earlier-sown second wheats, take-all was consistently severe and unrelated to the severity of the disease in the preceding (first) wheats. Results from two very simple experiments suggested that substituting set-aside/conservation covers for winter wheat, for 1 year only, did not seriously interfere with the development of take-all disease or with the development or maintenance of take-all decline (TAD). With further research, it might be possible for growers wishing to exploit TAD to incorporate set-aside/conservation covers into their cropping strategies, and especially to avoid the worst effects of the disease on grain yield during the early stages of epidemics.

Jenkyn, JF; Gutteridge, RJ; White, RP

2014-01-01

405

Impact of Fertilizing Pattern on the Biodiversity of a Weed Community and Wheat Growth  

PubMed Central

Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communities. To study the effects of different fertilizing patterns on the biodiversity of a farmland weed community and their adaptive mechanisms, indices of species diversity and responses of weed species and wheat were investigated in a 17-year field trial with a winter wheat-soybean rotation. This long term field trial includes six fertilizing treatments with different N, P and K application rates. The results indicated that wheat and the four prevalent weed species (Galium aparine, Vicia sativa, Veronica persica and Geranium carolinianum) showed different responses to fertilizer treatment in terms of density, plant height, shoot biomass, and nutrient accumulations. Each individual weed population exhibited its own adaptive mechanisms, such as increased internode length for growth advantages and increased light interception. The PK treatment had higher density, shoot biomass, Shannon-Wiener and Pielou Indices of weed community than N plus P fertilizer treatments. The N1/2PK treatment showed the same weed species number as the PK treatment. It also showed higher Shannon-Wiener and Pielou Indices of the weed community, although it had a lower wheat yield than the NPK treatment. The negative effects of the N1/2PK treatment on wheat yield could be balanced by the simultaneous positive effects on weed communities, which are intermediate in terms of the effects on wheat and weeds. PMID:24416223

Tang, Leilei; Cheng, Chuanpeng; Wan, Kaiyuan; Li, Ruhai; Wang, Daozhong; Tao, Yong; Pan, Junfeng; Xie, Juan; Chen, Fang

2014-01-01

406

Molecular genetic mapping of Gby, a new greenbug resistance gene in bread wheat.  

PubMed

The greenbug, Schizaphis graminum (Rhodani),is one of the major insect pests of wheat worldwide and it is important to develop a basic understanding of the chromosomal locations of known and new greenbug resistance genes. Gby is a new greenbug resistance gene in the wheat line 'Sando's selection 4040'. A mapping population used in this study was derived from a cross of Sando's 4040 and PI220127, a greenbug susceptible wheat land race from Afghanistan. A progeny test indicated that Gby is inherited as a single semi-dominant gene. A genetic linkage map consisting of Gby, Xgwm322 (a wheat microsatellite marker), XksuD2 (an STS marker) and 18 restriction fragment length polymorphism (RFLP) loci was constructed. We used DNA from Chinese Spring 7A deletion lines to show that the gwm332 and ksuD2 amplified fragments mapped in this study are located on along arm of chromosome 7A. This suggests that Gby is located on wheat chromosome 7A. Gby was mapped to the area in the middle of the 'island' of putative defense response genes that are represented by RFLP markers(Xpsr l9, XZnfp, Xbcd98 and Prl b) previously mapped to the distal part of the short arm of wheat chromosome group 7. This region of chromosome 7A is characterized by a high recombination rate and a high physical density of markers which makes Gby a very good candidate for map-based cloning. The selection accuracy when theRFLP markers Xbcd98, Xpsrll9 or XZnfp and Prlb flanking Gby are used together to tag Gby is 99.78%,suggesting that they can be successfully used in marker assisted selection. PMID:15309299

Boyko, E; Starkey, S; Smith, M

2004-10-01

407

Virulence and molecular comparison of Puccinia striiformis f. sp. tritici populations in China and the United States  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases in both China and the United States. The Chinese and U.S. populations of the stripe rust fungus were compared for their virulence patterns on wheat cultivars used to differentiat...

408

Rising temperatures reduce global wheat production  

NASA Astrophysics Data System (ADS)

Crop models are essential tools for assessing the threat of climate change to local and global food production. Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature. Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 °C to 32 °C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each °C of further temperature increase and become more variable over space and time.

Asseng, S.; Ewert, F.; Martre, P.; Rötter, R. P.; Lobell, D. B.; Cammarano, D.; Kimball, B. A.; Ottman, M. J.; Wall, G. W.; White, J. W.; Reynolds, M. P.; Alderman, P. D.; Prasad, P. V. V.; Aggarwal, P. K.; Anothai, J.; Basso, B.; Biernath, C.; Challinor, A. J.; de Sanctis, G.; Doltra, J.; Fereres, E.; Garcia-Vila, M.; Gayler, S.; Hoogenboom, G.; Hunt, L. A.; Izaurralde, R. C.; Jabloun, M.; Jones, C. D.; Kersebaum, K. C.; Koehler, A.-K.; Müller, C.; Naresh Kumar, S.; Nendel, C.; O'Leary, G.; Olesen, J. E.; Palosuo, T.; Priesack, E.; Eyshi Rezaei, E.; Ruane, A. C.; Semenov, M. A.; Shcherbak, I.; Stöckle, C.; Stratonovitch, P.; Streck, T.; Supit, I.; Tao, F.; Thorburn, P. J.; Waha, K.; Wang, E.; Wallach, D.; Wolf, J.; Zhao, Z.; Zhu, Y.

2015-02-01

409

Texas Wheat Flows and Transportation Modes, 1975.  

E-print Network

The Texas Agricultural Experiment Station J. E. Miller, Director, College Station, Texas The Texas A&M University System 8-1179 August 1977 2 CONTENTS SUMMARy... ..... . ......... . ........... . . . ..... .. . . . . ... ...... . ... . ... . .. . . 2 INTRODUCTION .. . . . .. . ......... .. . .. ..... . ...... . .. . ........... . .... . ... 3 METHODOLOGY ......... . .................. . ..... ..... .... . .... . ........ 3 TEXAS WHEAT PRODUCTION...

Fuller, Stephen; Paggi, Mechel; Engler, Dwayne

1977-01-01

410

Identification and characterization of two wheat Glycogen Synthase Kinase 3/ SHAGGY-like kinases  

PubMed Central

Background Plant Glycogen Synthase Kinase 3/ SHAGGY-like kinases (GSKs) have been implicated in numerous biological processes ranging from embryonic, flower, stomata development to stress and wound responses. They are key regulators of brassinosteroid signaling and are also involved in the cross-talk between auxin and brassinosteroid pathways. In contrast to the human genome that contains two genes, plant GSKs are encoded by a multigene family. Little is known about Liliopsida resp. Poaceae in comparison to Brassicaceae GSKs. Here, we report the identification and structural characterization of two GSK homologs named TaSK1 and TaSK2 in the hexaploid wheat genome as well as a widespread phylogenetic analysis of land plant GSKs. Results Genomic and cDNA sequence alignments as well as chromosome localization using nullisomic-tetrasomic lines provided strong evidence for three expressed gene copies located on homoeolog chromosomes for TaSK1 as well as for TaSK2. Predicted proteins displayed a clear GSK signature. In vitro kinase assays showed that TaSK1 and TaSK2 possessed kinase activity. A phylogenetic analysis of land plant GSKs indicated that TaSK1 and TaSK2 belong to clade II of plant GSKs, the Arabidopsis members of which are all involved in Brassinosteroid signaling. Based on a single ancestral gene in the last common ancestor of all land plants, paralogs were acquired and retained through paleopolyploidization events, resulting in six to eight genes in angiosperms. More recent duplication events have increased the number up to ten in some lineages. Conclusions To account for plant diversity in terms of functionality, morphology and development, attention has to be devoted to Liliopsida resp Poaceae GSKs in addition to Arabidopsis GSKs. In this study, molecular characterization, chromosome localization, kinase activity test and phylogenetic analysis (1) clarified the homologous/paralogous versus homoeologous status of TaSK sequences, (2) pointed out their affiliation to the GSK multigene family, (3) showed a functional kinase activity, (4) allowed a classification in clade II, members of which are involved in BR signaling and (5) allowed to gain information on acquisition and retention of GSK paralogs in angiosperms in the context of whole genome duplication events. Our results provide a framework to explore Liliopsida resp Poaceae GSKs functions in development. PMID:23594413

2013-01-01

411

Cont. Rot. Rot. DC Cont. Rot. Rot. DC Cont. Rot. Rot. DC Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans  

E-print Network

Cont. Rot. Rot. DC Cont. Rot. Rot. DC Cont. Rot. Rot. DC Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Expected yield per acre2 119 127 39 62 23 149 159 49 70 29 capable of producing corn and soybeans with yields about 20% higher than average soils. Low productivity

412

Wheat Production in the Panhandle of Texas.  

E-print Network

is cooperative between the Soil Conservation Service of the U. S. Department of Agri- culture and the Texas Agricultural Experiment Station, small grain work in the Panhandle was transferred to the Amarillo station. The development of our present wheat... them- selves with high quality seed at a minimum cost. 20 BULLETIN 750, TEXAS AGRICULTURAL EXPERIMENT STATION RATE AND DATE OF SEEDING Thirty pounds of seed per acre is the most common and probably the optimum rate of seeding wheat in the Panhandle...

Whitfield, Charles J. (Charles James); Atkins, Irvin Milburn; Porter, Kenneth B.

1952-01-01

413

High-resolution genetic and physical mapping of the Yr5 gene for resistance to stripe rust of wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a destructive disease of wheat worldwide. The Yr5 gene confers resistance to all races of the pathogen identified so far in the US. To clone Yr5, an F2 segregating population consisting of 1400 plants from a cross between the susceptible...

414

Evaluation of five sampling methods for Liposcelis entomophila (Enderlein) and L. decolor (Pearman) (Psocoptera: Liposcelididae) in steel bins containing wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

An evaluation of five sampling methods for studying psocid population levels was conducted in two steel bins containing 32.6 metric tonnes of wheat in Manhattan, KS. Psocids were sampled using a 1.2-m open-ended trier, corrugated cardboard refuges placed on the underside of the bin hatch or the surf...

415

Biodegradation of wheat straw by Pleurotus ostreatus.  

PubMed

Wheat straw pretreated with chemicals as well as hot water was subjected to degradation by edible mushroom Pleurotus ostreatus. Lignin, cellulose and hemicelluloses component of both chemically as well as hot water treated wheat straw was degraded by the fungus and in turn the edible and nutritious fruiting body of the mushroom was produced. Biodegradation of wheat straw in terms of loss of lignin, cellulose and hemicellulose showed positive correlation with cellulases, xylanase, laccase and polyphenol oxidase (PPO) activity of the fungus. During vegetative growth of the fungus, lignin degradation was faster and during fructification, lignin degradation was slower than cellulose and hemicellulose. The carbon content of the wheat straw decreased while, nitrogen content increased during degradation of the waste. Hot water treated wheat straw supported better production of enzymatic activity and degraded more efficiently than chemically sterilized substrate. The cumulative yield and biological efficiency (BE) of the mushroom was maximum on the hot water treated substrate. Degradation of the hot water treated wheat straw was better and faster than chemically treated substrate. PMID:25535709

Pandey, V K; Singh, M P

2014-01-01

416

[Ecological effects of wheat-oilseed rape intercropping combined with methyl salicylate release on Sitobion avenae and its main natural enemies].  

PubMed

In order to explore the effects of wheat-oilseed rape intercropping in combining with methyl salicylate (MeSA) release on Sitobion avenae and its main natural enemies, a field experiment was conducted at the Tai'an Experimental Station of Shandong Agricultural University in East China from October 2008 to June 2010 to study the temporal dynamics of S. avenae and its main natural enemies as well as the ecological control effect on the aphid. In the plots of intercropping combined with MeSA release, the S. avenae apterae population reached a peak about 12 d in advance of the control, but the peak value was significantly lower than that of the control. The average annual number of S. avenae apterae per 100 wheat tillers decreased in the order of wheat monoculture > wheat-oilseed rape intercropping > MeSA release > wheat-oilseed rape intercropping combined with MeSA release. Moreover, the total number of ladybeetles was the highest in the plots of intercropping combined with MeSA release. The population densities of aphid parasitoids reached a peak about 10 d in advance of the control, which could play a significant role in controlling S. avenae at the filling stage of wheat. Taking the biological control index (BCI) as a quantitative indicator, and with the ladybeetles and parasitoids as the dominant control factors in fields, it was observed that wheat-oilseed rape intercropping combined with MeSA release could suppress the population increase of S. avenae apterae effectively from the heading to filling stages of wheat. PMID:23359948

Dong, Jie; Liu, Ying-Jie; Li, Pei-Ling; Lin, Fang-Jing; Chen, Ju-Lian; Liu, Yong

2012-10-01

417

Airborne multi-spectral remote sensing of Russian wheat aphid injury to wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Russian wheat aphid (RWA) is a severe pest of wheat in the High Plains region of the United States. Remote sensing could be effective for detecting RWA infestations for pest management decision-making purposes. We evaluated an airborne multi-spectral remote sensing system for its ability to di...

418

Sheep Grazing Effect on Dryland Soil Properties and Wheat Yield in the Wheat-Fallow System  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

419

Whole-genome profiling and shotgun sequencing delivers an anchored, gene-decorated, physical map assembly of bread wheat chromosome 6A  

PubMed Central

Bread wheat (Triticum aestivum L.) is the most important staple food crop for 35% of the world's population. International efforts are underway to facilitate an increase in wheat production, of which the International Wheat Genome Sequencing Consortium (IWGSC) plays an important role. As part of this effort, we have developed a sequence-based physical map of wheat chromosome 6A using whole-genome profiling (WGP™). The bacterial artificial chromosome (BAC) contig assembly tools fingerprinted contig (fpc) and linear topological contig (ltc) were used and their contig assemblies were compared. A detailed investigation of the contigs structure revealed that ltc created a highly robust assembly compared with those formed by fpc. The ltc assemblies contained 1217 contigs for the short arm and 1113 contigs for the long arm, with an L50 of 1 Mb. To facilitate in silico anchoring, WGP™ tags underlying BAC contigs were extended by wheat and wheat progenitor genome sequence information. Sequence data were used for in silico anchoring against genetic markers with known sequences, of which almost 79% of the physical map could be anchored. Moreover, the assigned sequence information led to the ‘decoration’ of the respective physical map with 3359 anchored genes. Thus, this robust and genetically anchored physical map will serve as a framework for the sequencing of wheat chromosome 6A, and is of immediate use for map-based isolation of agronomically important genes/quantitative trait loci located on this chromosome. PMID:24813060

Poursarebani, Naser; Nussbaumer, Thomas; Šimková, Hana; Šafá?, Jan; Witsenboer, Hanneke; van Oeveren, Jan; Doležel, Jaroslav; Mayer, Klaus FX; Stein, Nils; Schnurbusch, Thorsten

2014-01-01

420

[Wheat dependent exercise induced anaphylaxis possibly sensitized by the hydrolyzed wheat proteins in a facial cleansing soap].  

PubMed

There are increasing cases of wheat dependent exercise-induced anaphylaxis (WDEIA) with transcutaneous or transmucosal sensitization. Hydrolyzed wheat included in a certain brand of soap was identified as a cause of sensitization. The useful clues to detect this disorder consist of the patient's past usage of a soap containing hydrolyzed wheat, the appearance of cutaneous or mucosal symptoms after the intake of wheat or washing with this soap, and a high level of specific IgE for wheat gluten. Because hydrolyzed wheat is used as an additive in a wide variety of cosmetics, we should pay careful attention to the ingredients of cosmetics when observing WDEIA. PMID:22428462

Kobayashi, Miwa; Okura, Risa; Yoshioka, Haruna; Hiromasa, Kana; Yoshioka, Manabu; Nakamura, Motonobu

2012-03-01

421

Gene Flow and Sexual Reproduction in the Wheat Glume Blotch Pathogen Phaeosphaeria nodorum (Anamorph Stagonospora nodorum )  

Microsoft Academic Search

Keller, S. M., McDermott, J. M., Pettway, R. E., Wolfe, M. S., and McDonald, B. A. 1997. Gene flow and sexual reproduction in the wheat glume blotch pathogen Phaeosphaeria nodorum (anamorph Stagono- spora nodorum). Phytopathology 87:353-358. Restriction fragment length polymorphisms (RFLPs) were used to characterize the genetic structures of three field populations of Phaeo- sphaeria nodorum from Texas, Oregon, and

S. M. Keller; J. M. McDermott; R. E. Pettway; M. S. Wolfe; B. A. McDonald

1997-01-01

422

The case of the missing wheat  

NASA Astrophysics Data System (ADS)

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 regions. The recent rise in prices has reversed the decline, but technologies take a long time to develop and get adopted [4]. So yield increases are in the pipeline but have not arrived yet. A second narrative relates to farm policy. Farmers always have an incentive to improve profits, but this does not always mean raising yields, especially if policies encourage reducing input use. In Europe, where much of the stagnation identified by Lin and Huybers [1] is found, fertilizer rates have actually declined in recent years in response to policies. One line of evidence in support of this narrative is that total factor productivity appears to be rising steadily in many regions, including Europe, even as yields have stagnated [5]. A third story relates to biophysical limits. This narrative declares that the genetic potential of crops has not improved for a long time, and most yield growth in the past two decades was related to agronomic improvements [6, 7]. But once average yields approach genetic potential, it becomes very difficult to further raise yields, and yields will be stuck regardless of price until innovation raises genetic potential [8]. If innovation is simply a function of prices, then this story folds into the first, but it could also be that returns on breeding are becoming much harder to achieve relative to the transformative effect of dwarfing genes and rust resistance that occurred in the last century. In the fourth corner is climate change. As Lin and Huybers [1] discuss, many of their stagnating countries have experienced adverse climate trends in the past few decades. Wheat has the lowest temperature optimum of any major crop, and has been among the most affected by climate change so far [9]. So maybe the stagnation is a sign of worse things to come. Interestingly though, they find stagnation even for Northern European countries where recent warming is more likely to have helped than hurt yields [10]. The easy answer is that a combination of these factors is to blame. The real answer is we do not yet know which of these, if any, are the most importan

Lobell, David B.

2012-06-01

423

Biolistic transformation of wheat with centrophenoxine as a synthetic auxin.  

PubMed

Cereal crops, including bread wheat (Triticum aestivum L.), are an important staple food worldwide. With a growing global population, it is evident that current crop production will not meet the rising demands being placed on modern agriculture. Efforts to improve crop yield and stress-tolerance by traditional breeding are labor intensive, time consuming, and highly dependent upon the ability to capture existing and novel genetic variation from a restricted genetic pool. Genetic engineering of crop species is one of several alternatives to traditional breeding for the introduction of novel genetic variation. This recently established technology has proved useful for the introduction of novel traits like pest resistance and herbicide tolerance. As a universal tool for genetic transformation, the Biolistic Gene Gun allows for the genomic integration of novel gene sequences from various sources into a whole host of living organisms.In this chapter, we present a novel and detailed protocol for the Biolistic Transformation of bread wheat that uses the pharmaceutical compound, Centrophenoxine (CPX). The application of CPX as the main auxin-like plant growth regulator in cereal genetic transformation replaces the potent but more toxic herbicide 2,4-D. PMID:24816669

Ismagul, Ainur; Iskakova, Gulnur; Harris, John C; Eliby, Serik

2014-01-01

424

New Types of Wheat Chromosomal Structural Variations in Derivatives of Wheat-Rye Hybrids  

PubMed Central

Background Chromosomal rearrangements induced by wheat-rye hybridization is a very well investigated research topic. However, the structural alterations of wheat chromosomes in wheat-rye hybrids are seldom reported. Methodology/Principal Findings Octoploid triticale lines were derived from common wheat Triticum. aestivum L. ‘Mianyang11’×rye Secale cereale L. ‘Kustro’. Some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ and common wheat T. aestivum L. ‘Chuannong27’ followed by self-fertilization. Fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) using Oligo-pSc119.2-1, Oligo-pTa535-1 and rye genomic DNA as probes were used to analyze the mitotic chromosomes of these progeny. Alterations of wheat chromosomes including 5A, 6A, 1B, 2B, 6B, 7B, 1D, 3D and 7D were observed. 5AL arm carrying intercalary Oligo-pSc119.2-1, Oligo-pTa535-1 or both Oligo-pSc119.2-1 and Oligo-pTa535-1 signals, 6AS, 1BS and 1DL arms containing terminal Oligo-pSc119.2-1 signal, 6BS and 3DS arms without terminal Oligo-pSc119.2-1 signal, 7BS without subtelomeric Oligo-pSc119.2-1 signal and 7DL with intercalary Oligo-pSc119.2-1 signal have been observed. However, these changed wheat chromosomes have not been detected in ‘Mianyang11’ and Chuannong 27. The altered 5A, 6A, 7B and 7D chromosomes in this study have not been reported and represent several new karyotype structures of common wheat chromosomes. Conclusions/Significance These rearranged wheat chromosomes in the present study afford some new genetic variations for wheat breeding program and are valuable materials for studying the biological function of tandem repetitive DNA sequences. PMID:25302962

Chen, Lei; Wang, Yangyang; Ren, Zhenglong; Fu, Shulan

2014-01-01

425

Original article Competitive ability of wheat cultivars with wild oats  

E-print Network

Original article Competitive ability of wheat cultivars with wild oats depending on nitrogen ­ In a field experiment, wheat (Triticum aestivum L.) grew with the infesting weed wild oat (Avena sterilis ssp

Paris-Sud XI, Université de

426

The control of ryegrass in wheat with Bay SSH-0860  

E-print Network

are not uncommon in winter wheat. Cheat (Bromus secalinus L. ) and wild oat (Avena fatua L. ) have long been a problem in major wheat producing areas such as Oklahoma and Kansas. Heavy infestations are attributed to the accumulation of seed reserves in the soil... to dockage at the elevator because of cheat (Bromus ~s . ) seed contamination of wheat grain. Similar dockage occurs if ryegrass seed are present. Ryegrass usually matures later than wheat, thus delaying harvest or in- creasing moisture content...

Vaculin, Paul Dean

1983-01-01

427

Alkaline peroxide mechanical pulping of wheat straw with enzyme treatment  

Microsoft Academic Search

Alkaline peroxide mechanical pulping (APMP) of wheat straw with enzyme treatment was studied. Instead of direct enzyme pretreatment\\u000a on wheat straw, an alternative treatment method was used, in which coarse pulps from refiner defibrated wheat straw rather\\u000a than wheat straw were pretreated with a crude enzyme containing mainly xylanase, then impregnated with alkaline H2O2 solution and further refined. The optimum

Jian Zhao; Xuezhi Li; Yinbo Qu; Peiji Gao

2004-01-01

428

Identification of insect damaged wheat kernels using transmittance images  

E-print Network

Identification of insect damaged wheat kernels using transmittance images Z. Cataltepe, A. Enis Cetin and T. Pearson Transmittance images of wheat kernels are used to classify insect damaged to obtain the images shown in Fig. 1. The insect damaged kernel images were taken from wheat infested

Cataltepe, Zehra

429

Fusarium head blight: distribution in wheat in Latvia.  

PubMed

Fusarium head blight (FHB) of wheat has, in recent years, been a very important worldwide disease in intensive growing of cereal. The objectives of this study were to evaluate the occurrence of FHB in wheat in Latvia and to identify the Fusarium species involved. This paper describes the distribution of Fusarium species that were isolated from samples representing winter and spring wheat varieties in Latvia, identified both by the classical morphological analyses of J. Leslie and B. Summerell (2006) and by PCR. The FHB incidence range in winter wheat was 1-20%, in spring wheat was 1-42%. The most significant factor affecting the incidence of fusarial head blight in wheat in Latvia was heightened temperature at the time of an thesis of wheat. In winter wheat 9 Fusarium species caused FHB: F. culmorum, F. avenaceum, F. graminearum, F. equiseti, F. poae, F. oxysporum, F. cerealis, F. sporotrichoides and F. verticillioides were identified by morphological characterization, and 5 were confirmed by PCR-analysis. After experience of 5 years, it can be concluded that the most frequent in winter wheat were F. poae and F. culmorum. In spring wheat from F. culmorum was dominant among 8 Fusarium species. Among 13 varieties of spring wheat, three were sensitive ('Chamsin', 'W 166', 'Azurite') and one was resistant ('Granny') to FHB in conditions of high natural infection in 2009. The monitoring surveys demonstrate a significant presence of FHB in spring wheat in conditions of heightened temperature at the time of flowering in Latvia. PMID:21534469

Treikale, O; Priekule, I; Javoisha, B; Lazareva, L

2010-01-01

430

Control of stripe rusts of wheat and barley  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rusts of wheat and barley were monitored throughout the Pacific Northwest (PNW) using trap plots and through field surveys during the 2006 growing season. Through collaborators in other states, stripe rusts of wheat and barley were monitored throughout the US. In 2006, wheat stripe rust occurred in...

431

Mixed Nitrogen Nutrition and Productivity of Wheat Grown in Hydroponics  

Microsoft Academic Search

The objective of this study was to study the effects of nitrogen (N) supplied as either mixtures of NOa and NH. or as all NOa on the final yield of spring wheat. Two separate greenhouse experiments evaluated the durum spring wheat (Triticum durum L.) cultivar 'Inbar' in 1986, and the hard red spring wheat (Triticum aestu'um L.) cultivar' Len' in

J. A. HEBERER

432

Evidence indicates that -A PREMIX OF FPC & WHEAT FLOUR  

E-print Network

Evidence indicates that - A PREMIX OF FPC & WHEAT FLOUR CAN BE MADE & TRANSPORTED Virginia D of wheat flour and fish protein concentrate (FPC) would tend to separate during the agitation of a mechanical shaker. Mixtures of 90% wheat flour and 10% FPC were placed on a shaker for 168 hours. Despite

433

Wheat Variety Identification Using MALDI-TOF M Znamirowski1  

E-print Network

Wheat Variety Identification Using MALDI-TOF M Znamirowski1 , R G Dworschak1 , K Preston2 , K G Laboratory, Canadian Grain Comission Winnipeg, Canada The Canadian system of grading wheat and other grains. For this initial evaluation, 16 varieties of wheat from four different classes were examined. We have also analyzed

Ens, Werner

434

Wheat rusts in the United States in 2011  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat stem rust (Puccinia graminis tritici) was found in Texas, Louisiana, Oklahoma, Kansas, Nebraska, North Dakota, Minnesota, Arkansas, Missouri, Kentucky, Illinois, Indiana, Wisconsin and Michigan in 2011. Nationally, wheat only incurred a trace loss due to wheat stem rust. Race QFCS was the most...

435

ESTIMATION OF HEAT DAMAGE IN HARD RED WINTER WHEAT CULTIVARS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Heat damage occurs during the artifical drying of newly harvested wheat or at high storage temperatures. Wheat proteins can be denatured by kernel heat damage during storage or during wheat milling process. Protein denaturation limits their functional (visco eleastic) properties in flour dough and...

436

THREE-DIMENSION VISUALIZATION FOR PRIMARY WHEAT DISEASES BASED ON  

E-print Network

wheat and maize optimal fertilization expert system of Yucheng county on Huanghuai Plain; NanjingTHREE-DIMENSION VISUALIZATION FOR PRIMARY WHEAT DISEASES BASED ON SIMULATION MODEL Li Shijuan impact factors for main wheat diseases of stripe rust, leaf rust, stem rust, head blight and powdery

Boyer, Edmond

437

Acetic acid pulping of wheat straw under atmospheric pressure  

Microsoft Academic Search

Atmospheric acetic acid pulping of wheat straw was carried out. Pulping conditions and their effects on pulp properties were investigated in detail, and a comparison between acetic acid (AcOH) pulp and soda-anthraquinone (AQ) pulps of wheat straw was made of the chemical com- position, strength, and fiber morphology of the pulps. Wheat straw was successfully pulped and fractionated into pulp

Xue-Jun PanYoshihiro Sano

1999-01-01

438

Adapting wheat in Europe for climate change  

PubMed Central

Increasing cereal yield is needed to meet the projected increased demand for world food supply of about 70% by 2050. Sirius, a process-based model for wheat, was used to estimate yield potential for wheat ideotypes optimized for future climatic projections for ten wheat growing areas of Europe. It was predicted that the detrimental effect of drought stress on yield would be decreased due to enhanced tailoring of phenology to future weather patterns, and due to genetic improvements in the response of photosynthesis and green leaf duration to water shortage. Yield advances could be made through extending maturation and thereby improve resource capture and partitioning. However the model predicted an increase in frequency of heat stress at meiosis and anthesis. Controlled environment experiments quantify the effects of heat and drought at booting and flowering on grain numbers and potential grain size. A current adaptation of wheat to areas of Europe with hotter and drier summers is a quicker maturation which helps to escape from excessive stress, but results in lower yields. To increase yield potential and to respond to climate change, increased tolerance to heat and drought stress should remain priorities for the genetic improvement of wheat. PMID:24882934

Semenov, M.A.; Stratonovitch, P.; Alghabari, F.; Gooding, M.J.

2014-01-01

439

Microbial Ecology Dynamics during Rye and Wheat Sourdough Preparation  

PubMed Central

The bacterial ecology during rye and wheat sourdough preparation was described by 16S rRNA gene pyrosequencing. Viable plate counts of presumptive lactic acid bacteria, the ratio between lactic acid bacteria and yeasts, the rate of acidification, a permutation analysis based on biochemical and microbial features, the number of operational taxonomic units (OTUs), and diversity indices all together demonstrated the maturity of the sourdoughs during 5 to 7 days of propagation. Flours were mainly contaminated by metabolically active genera (Acinetobacter, Pantoea, Pseudomonas, Comamonas, Enterobacter, Erwinia, and Sphingomonas) belonging to the phylum Proteobacteria or Bacteroidetes (genus Chryseobacterium). Their relative abundances varied with the flour. Soon after 1 day of propagation, this population was almost completely inhibited except for the Enterobacteriaceae. Although members of the phylum Firmicutes were present at very low or intermediate relative abundances in the flours, they became dominant soon after 1 day of propagation. Lactic acid bacteria were almost exclusively representative of the Firmicutes by this time. Weissella spp. were already dominant in rye flour and stably persisted, though they were later flanked by the Lactobacillus sakei group. There was a succession of species during 10 days of propagation of wheat sourdoughs. The fluctuation between dominating and subdominating populations of L. sakei group, Leuconostoc spp., Weissella spp., and Lactococcus lactis was demonstrated. Other subdominant species such as Lactobacillus plantarum were detectable throughout propagation. As shown by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis, Saccharomyces cerevisiae dominated throughout the sourdough propagation. Notwithstanding variations due to environmental and technology determinants, the results of this study represent a clear example of how the microbial ecology evolves during sourdough preparation. PMID:24096427

Ercolini, Danilo; Pontonio, Erica; De Filippis, Francesca; Minervini, Fabio; La Storia, Antonietta; Gobbetti, Marco

2013-01-01

440

A red clover stand that was frost seeded into wheat. Using red clover as a cover crop in wheat  

E-print Network

better when frost seeded into well fertilized wheat fields. Benefits of red clover A red clover coverA red clover stand that was frost seeded into wheat. Using red clover as a cover crop in wheat Dan. Canadian-grown mammoth clover does not tolerate the increased shading and competition from well fertilized