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1

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

PubMed Central

Progress in plant breeding is facilitated by accurate information about genetic structure and diversity. Here, Diversity Array Technology (DArT) was used to characterize a population of 94 bread wheat (Triticum aestivum L.) varieties of mainly European origin. In total, 1,849 of 7,000 tested markers were polymorphic and could be used for population structure analysis. Two major subgroups of wheat varieties, GrI and GrII, were identified using the program STRUCTURE, and confirmed by principal component analysis (PCA). These subgroups were largely separated according to origin; GrI comprised varieties from Southern and Eastern Europe, whereas GrII contained mostly modern varieties from Western and Northern Europe. A large proportion of the markers contributing most to the genetic separation of the subgroups were located on chromosome 2D near the Reduced height 8 (Rht8) locus, and PCR-based genotyping suggested that breeding for the Rht8 allele had a major impact on subgroup separation. Consistently, analysis of linkage disequilibrium (LD) suggested that different selective pressures had acted on chromosome 2D in the two subgroups. Our data provides an overview of the allele composition of bread wheat varieties anchored to DArT markers, which will facilitate targeted combination of alleles following DArT-based QTL studies. In addition, the genetic diversity and distance data combined with specific Rht8 genotypes can now be used by breeders to guide selection of crossing parents. PMID:24718292

Nielsen, Nanna Hellum; Backes, Gunter; Stougaard, Jens; Andersen, Stig Uggerhøj; Jahoor, Ahmed

2014-01-01

2

Characterization of greenbug (Homoptera: Aphididae) resistance in synthetic hexaploid wheats.  

PubMed

Twelve greenbug (Schizaphis graminum (Rondani)) biotype E-resistant synthetic hexaploid wheats synthesized by crossing Triticum dicoccum Schrank. and Aegilops tauschii (Coss.) Schmal. were evaluated for the three known insect resistance categories, including antibiosis, anti-xenosis, and tolerance. Different methods were evaluated for calculating antibiosis and tolerance. Calculating intrinsic rate of population increase and measuring leaf chlorophyll content with a SPAD chlorophyll meter proved to be time- and labor-efficient for antibiosis and tolerance determination, respectively. The resistance in all synthetic hexaploids proved to be the result of a combination of antibiosis, antixenosis, and tolerance, which makes them valuable sources of greenbug resistance. To assist plant breeders in selecting the best germplasm for greenbug resistance, a plant resistance index was created that revealed differences among the synthetic hexaploid wheats. PMID:14977134

Lage, J; Skovmand, B; Andersen, S B

2003-12-01

3

Genetic Variation of Seed Dormancy in Synthetic Hexaploid Wheat-Derived Populations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aegilops tauschii, the D-genome donor of wheat (Triticum aestivum), has very strong seed dormancy and genes controlling the trait may be used in breeding programs to manipulate germinability of improved cultivars. Thus, this research was conducted to initiate a project to identify dormancy genes fro...

4

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

E-print Network

(Triticum aestivum L.) varieties of mainly European origin. In total, 1,849 of 7,000 tested markers were (Triticum aestivum L.) Varieties. PLoS ONE 9(4): e94000. doi:10.1371/journal.pone.0094000 Editor: Nicholas A bread wheat (Triticum aestivum L.) is one of the most important cereal crops in the world, covering

Schierup, Mikkel Heide

5

Improving yield and quality traits of durum wheat by introgressing chromosome segments from hexaploid wheat.  

PubMed

Durum wheat (Triticum turgidum durum; 2n = 4x = 28; genome AABB) has long been an important food resource for human diets. The projected increase of the world's population to 9.1 billion by 2050 has highlighted the importance and urgency for improving the yield and quality performance of durum wheat. A backcrossed population, which was derived from the durum wheat variety 'Bellaroi' (recurrent parent) and the hexaploid genotype 'CSCR6' (donor parent), was used to investigate the feasibility of improving yield- and quality-related traits of durum wheat by introgressing chromosome fragments from hexaploid wheat. The population means for grain protein content, gluten content, spike length, and spikelet number were improved compared with those of the recurrent parent 'Bellaroi'. A small proportion of the backcross population lines showed significant improvements in spike length and spikelet number compared with the recurrent parent 'Bellaroi'. Some loci with significant effects for plant height, spike length, spikelet number, and thousand-grain weight were identified. Several of these loci affected more than one trait. These results showed that the introgression of chromosome fragments from 'CSCR6' into the durum genetic background could be an effective method for improving yield and quality traits of durum wheat. In addition, the loci showing significant effects on desired traits in this study could be fine mapped using an F2 population obtained by backcrossing the lines that carry the positive allele(s) with the recurrent parent. PMID:24338405

Ma, J; Zhang, C Y; Yan, G J; Liu, C J

2013-01-01

6

Identification of quantitative trait loci controlling grain size and shape in the D genome of synthetic hexaploid wheat lines  

PubMed Central

Synthetic hexaploid wheat is an effective genetic resource for transferring agronomically important genes from Aegilops tauschii to common wheat. Wide variation in grain size and shape, one of the main targets for wheat breeding, has been observed among Ae. tauschii accessions. To identify the quantitative trait loci (QTLs) responsible for grain size and shape variation in the wheat D genome under a hexaploid genetic background, six parameters related to grain size and shape were measured using SmartGrain digital image software and QTL analysis was conducted using four F2 mapping populations of wheat synthetic hexaploids. In total, 18 QTLs for the six parameters were found on five of the seven D-genome chromosomes. The identified QTLs significantly contributed to the variation in grain size and shape among the synthetic wheat lines, implying that the D-genome QTLs might be at least partly functional in hexaploid wheat. Thus, synthetic wheat lines with diverse D genomes from Ae. tauschii are useful resources for the identification of agronomically important loci that function in hexaploid wheat. PMID:24399915

Okamoto, Yuki; Nguyen, Anh T.; Yoshioka, Motohiro; Iehisa, Julio C.M.; Takumi, Shigeo

2013-01-01

7

Genetic structure of Argentinean hexaploid wheat germplasm  

PubMed Central

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

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

2013-01-01

8

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

9

Evolution of physiological responses to salt stress in hexaploid wheat.  

PubMed

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

2014-08-12

10

Molecular genetic maps of the group 6 chromosomes of hexaploid wheat (Triticum aestivum L. em. Thell.).  

PubMed

Restriction fragment length polymorphism (RFLP) maps of chromosomes 6A, 6B, and 6D of hexaploid wheat (Triticum aestivum L. em. Thell.) have been produced. They were constructed using a population of F7-8 recombinant inbred lines derived from a synthetic wheat x bread wheat cross. The maps consist of 74 markers assigned to map positions at a LOD >= 3 (29 markers assigned to 6A, 24 to 6B, and 21 to 6D) and 2 markers assigned to 6D ordered at a LOD of 2.7. Another 78 markers were assigned to intervals on the maps. The maps of 6A, 6B, and 6D span 178, 132, and 206 cM, respectively. Twenty-one clones detected orthologous loci in two homoeologues and 3 detected an orthologous locus in each chromosome. Orthologous loci are located at intervals of from 1.5 to 26 cM throughout 70% of the length of the linkage maps. Within this portion of the maps, colinearity (homosequentiality) among the three homoeologues is strongly indicated. The remainder of the linkage maps consists of three segments ranging in length from 47 to 60 cM. Colinearity among these chromosomes and other Triticeae homoeologous group 6 chromosomes is indicated and a consensus RFLP map derived from maps of the homoeologous group 6 chromosomes of hexaploid wheat, tetraploid wheat, Triticum tauschii, and barley is presented. Key words : RFLP, wheat, linkage maps, molecular markers. PMID:18469899

Marino, C L; Tuleen, N A; Hart, G E; Nelson, J C; Sorrells, M E; Lu, Y H; Leroy, P; Lopes, C R

1996-04-01

11

Field evaluation of emmer wheat-derived synthetic hexaploid wheat for resistance to Russian wheat aphid (Homoptera: Aphididae).  

PubMed

Broadening the genetic base for resistance to Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), in bread wheat, Triticum aestivum L., is desirable. To date, identified Russian wheat aphid resistance genes are either located to the D chromosomes or to rye translocation of wheat, and resistance derived from the A or B genomes of tetraploid Triticum spp. would therefore be highly beneficial. Fifty-eight synthetic hexaploid wheat, derived from interspecific crosses of Triticum dicoccum Schrank. and Aegilops tauschii (Coss.) Schmal. and their parents were evaluated for resistance to Russian wheat aphid under field conditions. Plots infested with aphids were compared with plots protected with insecticides. The T. dicoccum parents were highly resistant to Russian wheat aphids, whereas the Ae. tauschii parents were susceptible. Resistance levels observed in the synthetic hexaploids were slightly below the levels of their T. dicoccum parents when a visual damage scale was used. but no major resistance suppression was observed among the synthetics. Russian wheat aphid infestation on average reduced plant height and kernel weight at harvest in the synthetic hexaploids and the T. dicoccum parents by 3-4%, whereas the susceptible control 'Seri M82' suffered losses of above 20%. Because resistance in the synthetic hexaploid wheat is derived from their T. dicoccum parent, resistance gene(s) must be located on the A and/or B genomes. They must therefore be different from previously identified Russian wheat aphid resistance genes, which have all been located on the D genome of wheat or on translocated segments. PMID:15279292

Lage, J; Skovmand, B; Andersen, S B

2004-06-01

12

A modified TILLING approach to detect induced mutations in tetraploid and hexaploid wheat  

PubMed Central

Background Wheat (Triticum ssp.) is an important food source for humans in many regions around the world. However, the ability to understand and modify gene function for crop improvement is hindered by the lack of available genomic resources. TILLING is a powerful reverse genetics approach that combines chemical mutagenesis with a high-throughput screen for mutations. Wheat is specially well-suited for TILLING due to the high mutation densities tolerated by polyploids, which allow for very efficient screens. Despite this, few TILLING populations are currently available. In addition, current TILLING screening protocols require high-throughput genotyping platforms, limiting their use. Results We developed mutant populations of pasta and common wheat and organized them for TILLING. To simplify and decrease costs, we developed a non-denaturing polyacrylamide gel set-up that uses ethidium bromide to detect fragments generated by crude celery juice extract digestion of heteroduplexes. This detection method had similar sensitivity as traditional LI-COR screens, suggesting that it represents a valid alternative. We developed genome-specific primers to circumvent the presence of multiple homoeologous copies of our target genes. Each mutant library was characterized by TILLING multiple genes, revealing high mutation densities in both the hexaploid (~1/38 kb) and tetraploid (~1/51 kb) populations for 50% GC targets. These mutation frequencies predict that screening 1,536 lines for an effective target region of 1.3 kb with 50% GC content will result in ~52 hexaploid and ~39 tetraploid mutant alleles. This implies a high probability of obtaining knock-out alleles (P = 0.91 for hexaploid, P = 0.84 for tetraploid), in addition to multiple missense mutations. In total, we identified over 275 novel alleles in eleven targeted gene/genome combinations in hexaploid and tetraploid wheat and have validated the presence of a subset of them in our seed stock. Conclusion We have generated reverse genetics TILLING resources for pasta and bread wheat and achieved a high mutation density in both populations. We also developed a modified screening method that will lower barriers to adopt this promising technology. We hope that the use of this reverse genetics resource will enable more researchers to pursue wheat functional genomics and provide novel allelic diversity for wheat improvement. PMID:19712486

Uauy, Cristobal; Paraiso, Francine; Colasuonno, Pasqualina; Tran, Robert K; Tsai, Helen; Berardi, Steve; Comai, Luca; Dubcovsky, Jorge

2009-01-01

13

Evaluation and haplotype analysis of elite synthetic hexaploid wheat lines for resistance to Hessian fly  

Technology Transfer Automated Retrieval System (TEKTRAN)

Synthetic hexaploid wheat (SHW), derived from tetraploid wheat ' Aegilops tauschii hybrid, is an excellent source of resistance genes for various diseases and insects in wheat. The objectives of this study were to evaluate the elite SHW lines developed at the International Maize and Wheat Improvemen...

14

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

15

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

16

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

17

C-banding polymorphism and the analysis of nucleolar activity in Dasypyrum villosum (L.) Candargy, its added chromosomes to hexaploid wheat and the amphiploid Triticum dicoccum — D. villosum  

Microsoft Academic Search

C-banding patterns and nucleolar activity were analyzed in Dasypyrum villosum, its added chromosomes to hexaploid wheat and the hexaploid amphiploid Triticum dicoccum-D. villosum. Two different populations of the allogamous species D. villosum (2n= 14, VV) from Greece and Italy were analyzed showing a similar polymorphism for C-banding pattern. Six of the seven addition lines were identified by their characteristic C-banding

B. Friebe; M. C. Cermeño; F. J. Zeller

1987-01-01

18

Molecular and genetic characterization of Hessian fly-resistance genes in synthetic hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Synthetic hexaploid wheat (SHW), derived from crosses between tetraploid wheat (Triticum turgidum) and Aegilops tauschii, has proven to be an excellent source of resistance genes for various diseases and pests in wheat (T. aestivum). We previously evaluated a large collection of SHW lines for resis...

19

NOTICE OF RELEASE OF HARD KERNEL PUROINDOLINE ALLELE NEAR-ISOGENIC LINE HEXAPLOID WHEAT GENETIC STOCKS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Agricultural Research Service, U.S. Department of Agriculture announces the release of seven hard kernel puroindoline allele near-isogenic line (NIL) hexaploid wheat (Triticum aestivum L.) genetic stocks (PI xxxxxx – PI xxxxxx) developed by Dr. Craig F. Morris at the USDA-ARS Western Wheat Quali...

20

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

21

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

22

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

PubMed

Polyploid species have long been thought to be recalcitrant to whole-genome assembly. By combining high-throughput sequencing, recent developments in parallel computing, and genetic mapping, we derive, de novo, a sequence assembly representing 9.1 Gbp of the highly repetitive 16 Gbp genome of hexaploid wheat, Triticum aestivum, and assign 7.1 Gb of this assembly to chromosomal locations. The genome representation and accuracy of our assembly is comparable or even exceeds that of a chromosome-by-chromosome shotgun assembly. Our assembly and mapping strategy uses only short read sequencing technology and is applicable to any species where it is possible to construct a mapping population. PMID:25637298

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

2015-01-01

23

Stem rust, tan spot, Stagonospora nodorum blotch, and Hessian fly resistance in Langdon durum - Aegilops tauschii synethetic hexaploid wheat lines.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Diseases and pests of wheat incur serious yield and quality losses to wheat grown worldwide. In the current study, we tested synthetic hexaploid wheat (SHW) lines developed from various Aegilops tauschii lines crossed with the tetraploid durum wheat line Langdon. The SHW lines were tested along wi...

24

High frequncies of fertilization and embryo formation in hexaploid wheat x Tripsacum dactyloides crosses.  

PubMed

The Hexaploid wheat variety Fukuho was crossed with Tripsacum dactyloides (2n=4x=72). The total fertilization frequencies for the egg cell, polar nuclei, and both, were 58.3%, 26.8% and 58.9% of the 168 ovaries examined. However, the fertilization frequency of single polar nuclei was much lower at only 0.6%. The total frequency of fertilization was higher than that in wheat x maize crosses. A total of 49 hexaploid wheat varieties, including Hope carrying the dominant genes Kr1 and Kr2, were crossed with T. dactyloides, and most gave embryos. The embryoformation frequencies ranged from 0.5% to 59.0%. A higher frequency of 32.0% embryo formation was obtained following pollination of the variety Hope. In comparison with embryo formation in wheat x maize crosses the difference of embryo-formation frequencies between the two crosses was significant. The results of high frequencies of fertilization and embryo formation in wheat x T. dactyloides crosses indicated that the Kr genes are as inactive in wheat x T. dactyloides, as they are in wheat x maize crosses, and also that the efficiency of fertilization and embryo formation is higher in wheat x T. dactyloides than in what x maize crosses. The potential of wheat x T. dactyloides crosses for wheat haploid production and wheat improvement is discussed. PMID:24166643

Li, D W; Qio, J W; Ouyang, P; Yao, Q X; Dawei, L D; Jiwen, Q; Ping, O; Qingxiao, Y

1996-06-01

25

EVALUATION OF 10 CHEMICALS FOR ANEUPLOIDY INDUCTION IN THE HEXAPLOID WHEAT ASSAY  

EPA Science Inventory

This study was a part of an international project sponsored by the Commission of the European Communities to evaluate the utility of the hexaploid wheat assay (Redei and Sandhu, 1988) to detect chemically induced aneuploidy. en known or suspect spindle poisons; i.e., colchicine (...

26

Relationship of Gliadin Protein Components to Chromosomes in Hexaploid Wheats (Triticum aestivum L.)  

Microsoft Academic Search

The synthesis of the A-gliadin protein fraction derived from the endosperm of the grain of hexaploid bread wheats (Triticum aestivum L.), which is toxic in celiac disease, was associated with the alpha arm of the 6A chromosome through use of the substitution lines of `Cheyenne' chromosomes in `Chinese Spring'. The association was made through the use of ditelocentric stocks of

Donald D. Kasarda; John E. Bernardin; Calvin O. Qualset

1976-01-01

27

Spontaneous and Divergent Hexaploid Triticales Derived from Common Wheat × Rye by Complete Elimination of D-Genome Chromosomes  

PubMed Central

Background Hexaploid triticale could be either synthesized by crossing tetraploid wheat with rye, or developed by crossing hexaploid wheat with a hexaploid triticale or an octoploid triticale. Methodology/Principal Findings Here two hexaploid triticales with great morphologic divergence derived from common wheat cultivar M8003 (Triticum aestivum L.) × Austrian rye (Secale cereale L.) were reported, exhibiting high resistance for powdery mildew and stripe rust and potential for wheat improvement. Sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) karyotyping revealed that D-genome chromosomes were completely eliminated and the whole A-genome, B-genome and R-genome chromosomes were retained in both lines. Furthermore, plentiful alterations of wheat chromosomes including 5A and 7B were detected in both triticales and additionally altered 5B, 7A chromosome and restructured chromosome 2A was assayed in N9116H and N9116M, respectively, even after selfing for several decades. Besides, meiotic asynchrony was displayed and a variety of storage protein variations were assayed, especially in the HMW/LMW-GS region and secalins region in both triticales. Conclusion This study confirms that whole D-genome chromosomes could be preferentially eliminated in the hybrid of common wheat × rye, “genome shock” was accompanying the allopolyploidization of nascent triticales, and great morphologic divergence might result from the genetic variations. Moreover, new hexaploid triticale lines contributing potential resistance resources for wheat improvement were produced. PMID:25781330

Wang, Changyou; Ji, Wanquan

2015-01-01

28

Synthetic Hexaploid Wheat as a Source of Improvement for Winter Wheat (Triticum aestivum L.) in Texas  

E-print Network

and seed weight was the most heritable trait. Synthetic lines combined better with TAM 111 than TAM 112 in high yielding environments. populations across five Texas locations. Similar to crosses with spring wheat, synthetics contributed to yield through...

Cooper, Jessica Kay

2012-02-14

29

Patterns of homoeologous gene expression shown by RNA sequencing in hexaploid bread wheat  

PubMed Central

Background Bread wheat (Triticum aestivum) has a large, complex and hexaploid genome consisting of A, B and D homoeologous chromosome sets. Therefore each wheat gene potentially exists as a trio of A, B and D homoeoloci, each of which may contribute differentially to wheat phenotypes. We describe a novel approach combining wheat cytogenetic resources (chromosome substitution ‘nullisomic-tetrasomic’ lines) with next generation deep sequencing of gene transcripts (RNA-Seq), to directly and accurately identify homoeologue-specific single nucleotide variants and quantify the relative contribution of individual homoeoloci to gene expression. Results We discover, based on a sample comprising ~5-10% of the total wheat gene content, that at least 45% of wheat genes are expressed from all three distinct homoeoloci. Most of these genes show strikingly biased expression patterns in which expression is dominated by a single homoeolocus. The remaining ~55% of wheat genes are expressed from either one or two homoeoloci only, through a combination of extensive transcriptional silencing and homoeolocus loss. Conclusions We conclude that wheat is tending towards functional diploidy, through a variety of mechanisms causing single homoeoloci to become the predominant source of gene transcripts. This discovery has profound consequences for wheat breeding and our understanding of wheat evolution. PMID:24726045

2014-01-01

30

C-banding polymorphism and the analysis of nucleolar activity in Dasypyrum villosum (L.) Candargy, its added chromosomes to hexaploid wheat and the amphiploid Triticum dicoccum - D. villosum.  

PubMed

C-banding patterns and nucleolar activity were analyzed in Dasypyrum villosum, its added chromosomes to hexaploid wheat and the hexaploid amphiploid Triticum dicoccum-D. villosum. Two different populations of the allogamous species D. villosum (2n= 14, VV) from Greece and Italy were analyzed showing a similar polymorphism for C-banding pattern. Six of the seven addition lines were identified by their characteristic C-banding pattern. No polymorphism between both members of each added alien chromosome was found. Furthermore, nucleolar activity and competition were studied by using silver staining procedure. In D. villosum only one chromosome pair, A, was found to be responsible for organizing nucleoli. The results obtained in the amphiploid and in the addition lines demonstrate that nucleolar activity is restricted to SAT-chromosomes 1B and 6B of wheat, while those of D. villosum remain inactive. PMID:24240992

Friebe, B; Cermeño, M C; Zeller, F J

1987-01-01

31

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

32

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

33

Structural and molecular basis of starch viscosity in hexaploid wheat.  

PubMed

Wheat starch is considered to have a low paste viscosity relative to other starches. Consequently, wheat starch is not preferred for many applications as compared to other high paste viscosity starches. Increasing the viscosity of wheat starch is expected to increase the functionality of a range of wheat flour-based products in which the texture is an important aspect of consumer acceptance (e.g., pasta, and instant and yellow alkaline noodles). To understand the molecular basis of starch viscosity, we have undertaken a comprehensive structural and rheological analysis of starches from a genetically diverse set of wheat genotypes, which revealed significant variation in starch traits including starch granule protein content, starch-associated lipid content and composition, phosphate content, and the structures of the amylose and amylopectin fractions. Statistical analysis highlighted the association between amylopectin chains of 18-25 glucose residues and starch pasting properties. Principal component analysis also identified an association between monoesterified phosphate and starch pasting properties in wheat despite the low starch-phosphate level in wheat as compared to tuber starches. We also found a strong negative correlation between the phosphate ester content and the starch content in flour. Previously observed associations between internal starch granule fatty acids and the swelling peak time and pasting temperature have been confirmed. This study has highlighted a range of parameters associated with increased starch viscosity that could be used in prebreeding/breeding programs to modify wheat starch pasting properties. PMID:18459791

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

2008-06-11

34

A chromosome-based draft sequence of the hexaploid bread wheat (Triticum aestivum) genome.  

PubMed

An ordered draft sequence of the 17-gigabase hexaploid bread wheat (Triticum aestivum) genome has been produced by sequencing isolated chromosome arms. We have annotated 124,201 gene loci distributed nearly evenly across the homeologous chromosomes and subgenomes. Comparative gene analysis of wheat subgenomes and extant diploid and tetraploid wheat relatives showed that high sequence similarity and structural conservation are retained, with limited gene loss, after polyploidization. However, across the genomes there was evidence of dynamic gene gain, loss, and duplication since the divergence of the wheat lineages. A high degree of transcriptional autonomy and no global dominance was found for the subgenomes. These insights into the genome biology of a polyploid crop provide a springboard for faster gene isolation, rapid genetic marker development, and precise breeding to meet the needs of increasing food demand worldwide. PMID:25035500

2014-07-18

35

Genome interplay in the grain transcriptome of hexaploid bread wheat.  

PubMed

Allohexaploid bread wheat (Triticum aestivum L.) provides approximately 20% of calories consumed by humans. Lack of genome sequence for the three homeologous and highly similar bread wheat genomes (A, B, and D) has impeded expression analysis of the grain transcriptome. We used previously unknown genome information to analyze the cell type-specific expression of homeologous genes in the developing wheat grain and identified distinct co-expression clusters reflecting the spatiotemporal progression during endosperm development. We observed no global but cell type- and stage-dependent genome dominance, organization of the wheat genome into transcriptionally active chromosomal regions, and asymmetric expression in gene families related to baking quality. Our findings give insight into the transcriptional dynamics and genome interplay among individual grain cell types in a polyploid cereal genome. PMID:25035498

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

2014-07-18

36

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...

37

Uptake and retranslocation of leaf-applied cadmium (109Cd) in diploid, tetraploid and hexaploid wheats.  

PubMed

Uptake and retranslocation of leaf-applied radiolabeled cadmium (109Cd) was studied in three diploid (Triticum monococcum, AA), four tetraploid (Triticum turgidum, BBAA) and two hexaploid (Triticum aestivum, BBAADD) wheat genotypes grown for 9 d under controlled environmental conditions in nutrient solution. Among the tetraploid wheats, two genotypes were primitive (ssp. dicoccum) and two genotypes modern wheats (ssp. durum). Radiolabelled Cd was applied by immersing the tips (3 cm) of mature leaf into a 109Cd radiolabelled solution. There was a substantial variation in the uptake and export of 109Cd among and within wheat species. On average, diploid wheats (AA) absorbed and translocated more 109Cd than other wheats. The largest variation in 109Cd uptake was found within tetraploid wheats (BBAA). Primitive tetraploid wheats (ssp. dicoccum) had a greater uptake capacity for 109Cd than modern tetraploid wheats (ssp. durum). In all wheats studied, the amount of the 109Cd exported from the treated leaf into the roots and the remainder of the shoots was poorly related to the total absorption. For example, bread wheat cultivars were more or less similar in total absorption, but differed greatly in the amount of 109Cd retranslocated. The diploid wheat genotype 'FAL-43' absorbed the lowest amount of 109Cd, but retranslocated the greatest amount of 109Cd in roots and remainder of shoots. The results indicate the existence of substantial genotypic variation in the uptake and retranslocation of leaf-applied 109Cd. This variation is discussed in terms of potential genotypic differences in binding of Cd to cell walls and the composition of phloem sap ligands possibly affecting Cd transport into sink organs. PMID:10938828

Cakmak, I; Welch, R M; Hart, J; Norvell, W A; Oztürk, L; Kochian, L V

2000-02-01

38

Evidence for a direct relationship between mitochondrial genome organization and regeneration ability in hexaploid wheat somatic tissue cultures  

Microsoft Academic Search

Embryogenic and non-embryogenic long-term callus cultures of hexaploid wheat exhibit differences in the organization of their mitochondrial genome. Embryogenic and non-embryogenic fractions of callus cultures initiated from immature embryos of the wheat cultivar “Chinese Spring” have been isolated and subsequently subcultured. DNA-DNA hybridization experiments using labelled cloned wheat mitochondrial DNA fragments have shown that the mitochondrial DNA organization of embryogenic

A. Rode; C. Hartmann; J. Buyser; Y. Henry

1988-01-01

39

Nitrate reductases in hexaploid and tetraploid wheats and Aegilops.  

PubMed

Nitrate reductase activity (NR activity), protein content (NR protein) and polypeptides were compared in shoots of Triticum aestivum ssp. vulgare (L.) cv Fidel (bread wheat, AABBDD genome), Triticum dicoccum cv Vernal (AABB genome), Aegilops squarrosa var. strangulata (DD genome) and the amphiploid 365 (AABBDD genome), produced by crossing T. dicoccum cv Vernal and Ae. squarrosa var. strangulata. Constitutive NR protein and activity were found in shoots of all seedlings grown without nitrate, with the highest activity in the bread wheat. The inducible NR protein and activity developed upon the addition of nitrate. A 116-K polypeptide was identified as the main component of the NR from the bread wheat, while a faint, sometimes discernable 94-K band appeared on Western blots. Only one NR polypeptide could be identified in Ae. squarrosa -the 94 K. An intermediary situation was observed with the tetraploid T. dicoccum and the amphiploid: The 94-K polypeptide was the only one separated from NR of seedlings grown in the absence of nitrate. The 116-K polypeptide appeared after the addition of nitrate. The intensity of its band on the gel increased with the duration of the nitrate treatment. When comparing Ae. squarrosa and T. dicoccum, the constitutive isozyme (94-K polypeptide) was found in the D as well as in the AB genomes, while the inducible NR (116-K polypeptide) was absent from the D genome. Addition of the D genome into the AB genome slightly reinforced the expression of the inducible form (AB genome expression) in the amphiploid wheat. We postulate that the inducible form of NR in the bread wheat resulted from an evolutionary selection pressure favoured by cultivation. PMID:24226112

Ouhmidou, B; Cauderon, Y; Cherel, I; Champigny, M L

1990-01-01

40

Diversity of Starch Pasting Properties in Iranian Hexaploid Wheat Landraces  

Microsoft Academic Search

1,3 ABSTRACT Cereal Chem. 74(4):417-423 Wheat landraces possess a wide diversity in starch physical properties that could be useful in breeding for improved quality of specific prod- ucts, such as various types of Asian noodles. The pasting properties (using a Rapid Visco-Analyser (RVA)) and flour swelling volume (FSV, using silver nitrate to inactivate ?-amylase activity) of wholemeal, were measured for

Monisha Bhattacharya; Jamshid Jafari-Shabestari; Calvin O. Qualset; Harold Corke

1997-01-01

41

Heterochronic development of the floret meristem determines grain number per spikelet in diploid, tetraploid and hexaploid wheats  

PubMed Central

Background and Aims The inflorescence of grass species such as wheat, rice and maize consists of a unique reproductive structure called the spikelet, which is comprised of one, a few, or several florets (individual flowers). When reproductive growth is initiated, the inflorescence meristem differentiates a spikelet meristem as a lateral branch; the spikelet meristem then produces a floret meristem as a lateral branch. Interestingly, in wheat, the number of fertile florets per spikelet is associated with ploidy level: one or two florets in diploid, two or three in tetraploid, and more than three in hexaploid wheats. The objective of this study was to identify the mechanisms that regulate the architecture of the inflorescence in wheat and its relationship to ploidy level. Methods The floral anatomy of diploid (Triticum monococcum), tetraploid (T. turgidum ssp. durum) and hexaploid (T. aestivum) wheat species were investigated by light and scanning electron microscopy to describe floret development and to clarify the timing of the initiation of the floret primordia. In situ hybridization analysis using Wknox1, a wheat knotted1 orthologue, was performed to determine the patterning of meristem formation in the inflorescence. Key Results The recessive natural mutation of tetraploid (T. turgidum ssp. turgidum) wheat, branching head (bh), which produces branched inflorescences, was used to demonstrate the utility of Wknox1 as a molecular marker for meristematic tissue. Then an analysis of Wknox1 expression was performed in diploid, tetraploid and hexaploid wheats and heterochronic development of the floret meristems was found among these wheat species. Conclusions It is shown that the difference in the number of floret primordia in diploid, tetraploid and hexaploid wheats is caused by the heterochronic initiation of floret meristem development from the spikelet meristem. PMID:19491089

Shitsukawa, Naoki; Kinjo, Hiroko; Takumi, Shigeo; Murai, Koji

2009-01-01

42

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

43

TYPES AND RATES OF SEQUENCE EVOLUTION AT HMW-GLUTENIN LOCUS IN HEXAPLOID WHEAT AND ITS ANCESTRAL GENOMES  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

44

New broad-spectrum resistance to septoria tritici blotch derived from synthetic hexaploid wheat.  

PubMed

Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola, is one of the most devastating foliar diseases of wheat. We screened five synthetic hexaploid wheats (SHs), 13 wheat varieties that represent the differential set of cultivars and two susceptible checks with a global set of 20 isolates and discovered exceptionally broad STB resistance in SHs. Subsequent development and analyses of recombinant inbred lines (RILs) from a cross between the SH M3 and the highly susceptible bread wheat cv. Kulm revealed two novel resistance loci on chromosomes 3D and 5A. The 3D resistance was expressed in the seedling and adult plant stages, and it controlled necrosis (N) and pycnidia (P) development as well as the latency periods of these parameters. This locus, which is closely linked to the microsatellite marker Xgwm494, was tentatively designated Stb16q and explained from 41 to 71% of the phenotypic variation at seedling stage and 28-31% in mature plants. The resistance locus on chromosome 5A was specifically expressed in the adult plant stage, associated with SSR marker Xhbg247, explained 12-32% of the variation in disease, was designated Stb17, and is the first unambiguously identified and named QTL for adult plant resistance to M. graminicola. Our results confirm that common wheat progenitors might be a rich source of new Stb resistance genes/QTLs that can be deployed in commercial breeding programs. PMID:21912855

Tabib Ghaffary, S Mahmod; Faris, Justin D; Friesen, Timothy L; Visser, Richard G F; van der Lee, Theo A J; Robert, Olivier; Kema, Gert H J

2012-01-01

45

Molecular characterization of Rht-1 dwarfing genes in hexaploid wheat.  

PubMed

The introduction of the Reduced height (Rht)-B1b and Rht-D1b semidwarfing genes led to impressive increases in wheat (Triticum aestivum) yields during the Green Revolution. The reduction in stem elongation in varieties containing these alleles is caused by a limited response to the phytohormone gibberellin (GA), resulting in improved resistance to stem lodging and yield benefits through an increase in grain number. Rht-B1 and Rht-D1 encode DELLA proteins, which act to repress GA-responsive growth, and their mutant alleles Rht-B1b and Rht-D1b are thought to confer dwarfism by producing more active forms of these growth repressors. While no semidwarfing alleles of Rht-A1 have been identified, we show that this gene is expressed at comparable levels to the other homeologs and represents a potential target for producing novel dwarfing alleles. In this study, we have characterized additional dwarfing mutations in Rht-B1 and Rht-D1. We show that the severe dwarfism conferred by Rht-B1c is caused by an intragenic insertion, which results in an in-frame 90-bp insertion in the transcript and a predicted 30-amino acid insertion within the highly conserved amino-terminal DELLA domain. In contrast, the extreme dwarfism of Rht-D1c is due to overexpression of the semidwarfing Rht-D1b allele, caused by an increase in gene copy number. We show also that the semidwarfing alleles Rht-B1d and Rht-B1e introduce premature stop codons within the amino-terminal coding region. Yeast two-hybrid assays indicate that these newly characterized mutations in Rht-B1 and Rht-D1 confer "GA-insensitive" dwarfism by producing DELLA proteins that do not bind the GA receptor GA INSENSITIVE DWARF1, potentially compromising their targeted degradation. PMID:22013218

Pearce, Stephen; Saville, Robert; Vaughan, Simon P; Chandler, Peter M; Wilhelm, Edward P; Sparks, Caroline A; Al-Kaff, Nadia; Korolev, Andrey; Boulton, Margaret I; Phillips, Andrew L; Hedden, Peter; Nicholson, Paul; Thomas, Stephen G

2011-12-01

46

Molecular characterization and genomic organization of low molecular weight glutenin subunit genes at the Glu3 loci in hexaploid wheat ( Triticum aestivum L.)  

Microsoft Academic Search

In this study, we report on the molecular characterization and genomic organization of the low molecular weight glutenin subunit\\u000a (LMW-GS) gene family in hexaploid wheat (Triticum aestivum L.). Eighty-two positive BAC clones were identified to contain LMW-GS genes from the hexaploid wheat ‘Glenlea’ BAC library\\u000a via filter hybridization and PCR validation. Twelve unique LMW glutenin genes and seven pseudogenes were

Xiu-Qiang Huang; Sylvie Cloutier

2008-01-01

47

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

PubMed

The feasibility of exploiting non-gridded bacterial artificial chromosome (BAC) libraries and some major factors affecting the efficiency of handling such libraries were studied in hexaploid wheat. Even for a bacterial culture containing only 55% recombinants, some 2000 BAC clones with inserts ranging from 45 to 245 kb could be pooled. The pooled BAC clones could be amplified by culturing for up to 6 h without losing any target clones. These results imply that even for hexaploid wheat, which has an extremely large genome, some 250 pools are sufficient for a BAC library that should satisfy many research objectives. This non-gridded strategy would dramatically reduce the cost and make robotic equipment non-essential in exploiting BAC technology. To construct a representative library and to minimise clone competition, thawing and re-freezing ligation mixtures and bacterial cultures should be avoided in BAC library construction and application. PMID:11121493

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

2000-12-15

48

Genetic transfer of resistance to powdery mildew and of an associated biochemical marker from Aegilops ventricosa to hexaploid wheat  

Microsoft Academic Search

Resistance to powdery mildew, caused by the fungus Erysiphe graminis f.sp. tritici, has been transferred from Aegilops ventricosa (genomes DvMv) to hexaploid wheat (Triticum aestivum, ABD). In two transfer lines, H-93-8 and H-93-35, the resistance gene was linked to a gene encoding protein U-1, whereas one line, H-93-33, was resistant but lacked the molecular marker, and another line, H-93-1, was

A. Delibes; I. Lopez-Brafia; M. Mena; F. García-Olmedo

1987-01-01

49

The effect of the crossability loci Kr1 and Kr2 on fertilization frequency in hexaploid wheat x maize crosses.  

PubMed

Dominant alleles of the Kr1 and Kr2 genes reduce the crossability of hexaploid wheat with many alien species, including rye and Hordeum bulbosum, with Kr1 having the greater effect. However, a cytological study of wheat ovaries fixed 48 h after pollination showed that the wheat genotypes 'Highbury' (kr1, Kr2) and 'Chinese Spring (Hope 5B)' (kr1, kr2) were crossable with 'Seneca 60' maize, fertilization occurring in 14.4 and 30.7% of embryo sacs respectively. The latter figure was similar to the 29.7% fertilization found in 'Chinese Spring' (kr1, kr2). Most embryo sacs in which fertilization occurred contained an embryo but lacked an endosperm and where an endosperm was formed it was usually highly aberrant. All three wheat x maize combinations were karyotypically unstable and rapidly eliminated maize chromosomes to produce haploid wheat embryos. PMID:24241002

Laurie, D A; Bennett, M D

1987-01-01

50

A high-density genetic map of hexaploid wheat ( Triticum aestivum L.) from the cross Chinese Spring × SQ1 and its use to compare QTLs for grain yield across a range of environments  

Microsoft Academic Search

A population of 96 doubled haploid lines (DHLs) was prepared from F1 plants of the hexaploid wheat cross Chinese Spring × SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the

S. A. Quarrie; A. Steed; C. Calestani; A. Semikhodskii; C. Lebreton; C. Chinoy; N. Steele; D. Pljevljakusi?; E. Waterman; J. Weyen; J. Schondelmaier; D. Z. Habash; P. Farmer; L. Saker; D. T. Clarkson; A. Abugalieva; M. Yessimbekova; Y. Turuspekov; S. Abugalieva; R. Tuberosa; M. C. Sanguineti; P. A. Hollington; R. Aragués; A. Royo; D. Dodig

2005-01-01

51

Meiotic behaviour of tetraploid wheats (Triticum turgidum L.) and their synthetic hexaploid wheat derivates influenced by meiotic restitution and heat stress.  

PubMed

Meiotic restitution is considered to be a common mechanism of polyploidization in plants and hence is one of the most important processes in plant speciation. Meiotic behaviour of plant chromosomes is influenced by both genetic and environmental factors. In this study, the meiotic behaviour of cereal crops was investigated, which includes tetraploid wheat genotypes (with and without the meiotic restitution trait) and their derivates (synthetic hexaploid wheats and a doubled haploid (DH) line), grown at two planting dates in the field. In addition, two local landraces of emmer wheat (Triticum turgidum ssp. dicoccum), one wheat cultivar (Chinese spring), one DH triticale cultivar (Eleanor) and one rye accession were included. Immature spikes of mid-autumn and end-winter sowing plants were collected in April and May 2008, respectively, fixed in Carnoy's solution and stained with hematoxylin. Pollen mother cells (PMCs) from anthers at different stages of meiotic process were analysed for their chromosomal behaviour and irregularities. Meiotic aberrations such as laggards, chromosome bridges, micronuclei, abnormal cytokines, chromatin pulling and meiotic restitution were observed and the studied genotypes were accordingly ranked as follows: triticale > synthetic hexaploid wheats > tetraploid wheats possessing meiotic restitution > tetraploid wheats lacking meiotic restitution > rye. The results indicated that the samples that had been planted in the autumn, thus experiencing an optimum temperature level at the flowering stage, exhibited less meiotic irregularities than winter planting samples that encountered heat stress at the flowering period. PMID:21273690

Rezaei, Masoumeh; Arzani, Ahmad; Sayed-Tabatabaei, Badraldin Ebrahim

2010-12-01

52

Population divergence in the wheat leaf rust fungus Puccinia triticina is correlated with wheat evolution.  

PubMed

Co-evolution of fungal pathogens with their host species during the domestication of modern crop varieties has likely affected the current genetic divergence of pathogen populations. The objective of this study was to determine if the evolutionary history of the obligate rust pathogen on wheat, Puccinia triticina, is correlated with adaptation to hosts with different ploidy levels. Sequence data from 15 loci with different levels of polymorphism were generated. Phylogenetic analyses (parsimony, Bayesian, maximum likelihood) showed the clear initial divergence of P. triticina isolates collected from Aegilops speltoides (the likely B genome donor of modern wheat) in Israel from the other isolates that were collected from tetraploid (AB genomes) durum wheat and hexaploid (ABD genomes) common wheat. Coalescence-based genealogy samplers also indicated that P. triticina on A. speltoides, diverged initially, followed by P. triticina isolates from durum wheat in Ethiopia and then by isolates from common wheat. Isolates of P. triticina found worldwide on cultivated durum wheat were the most recently coalesced and formed a clade nested within the isolates from common wheat. By a relative time scale, the divergence of P. triticinia as delimited by host specificity appears very recent. Significant reciprocal gene flow between isolates from common wheat and isolates from durum wheat that are found worldwide was detected, in addition to gene flow from isolates on common wheat to isolates on durum wheat in Ethiopia. PMID:24301080

Liu, M; Rodrigue, N; Kolmer, J

2014-04-01

53

Identification of Novel QTL for Seeding and Adult Plant Leaf Rust Resistance in a Wheat Doubled Haploid Population  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pyramiding of genes that confer partial resistance is a method for developing wheat (Triticum aestivum L.) cultivars with durable resistance to leaf rust caused by Puccinia triticina. In this research, a doubled haploid (DH) population derived from the cross between the synthetic hexaploid wheat (S...

54

Expression and suppression of resistance to greenbug (Homoptera: Aphididae) in synthetic hexaploid wheats derived from Triticum dicoccum x Aegilops tauschii crosses.  

PubMed

Fifty-eight synthetic hexaploid wheats, developed by crossing Triticum dicoccum Schrank. and Aegilops tauschii (Coss.) Schmal., were evaluated at the seedling stage, together with their parents, for resistance to greenbug (Schizaphis graminum Rondani) under greenhouse conditions. Seedlings of different synthetic hexaploids showed large phenotypic differences for resistance. All the T. dicoccum parents were susceptible, while high levels of resistance were observed in some of the Ae. tauschii parents. Of the synthetic hexaploids derived from resistant Ae. tauschii parents, a high proportion (76%) showed levels of resistance to the greenbug biotype used that were comparable to those of the resistant parent. While there were clear indications of the presence of suppressor genes for greenbug resistance in the A and/or B genomes of T. dicoccum in some synthetics, positive epistatic interaction was also found in synthetic hexaploids with higher levels of resistance than that of either parent. Resistance from different Ae. tauschii accessions was expressed differently when crossed with the same T. dicoccum, indicating diversity among the resistance genes present in the test synthetic hexaploid wheats. Based on resistance reactions, the genes conferring greenbug resistance in these synthetic hexaploids are probably different from resistance genes previously transferred to wheat from Ae. tauschii. PMID:12650363

Lage, J; Skovmand, B; Andersen, S B

2003-02-01

55

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

56

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

57

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

PubMed

The allelic compositions of high- and low-molecular-weight subunits of glutenins (HMW-GS and LMW-GS) among European spelt ( Triticum spelta L.) and related hexaploid and tetraploid Triticum species were investigated by one- and two-dimensional polyacrylamide-gel electrophoresis (PAGE) and capillary electrophoresis (CE). A total of seven novel glutenin alleles (designated A1a*, B1d*, B1g*, B1f*, B1j*, D1a* at Glu-1 and A3h at the Glu-3 loci, respectively) in European spelt wheat were detected by SDS-PAGE, which were confirmed further by employing A-PAGE and CE methods. Particularly, two HMW-GS alleles, Glu-B1d* coding the subunits 6.1 and 22.1, and Glu-B1f* coding the subunits 13 and 22*, were found to occur in European spelt with frequencies of 32.34% and 5.11%, respectively. These two alleles were present in cultivated emmer (Triticum dicoccum), but they were not observed in bread wheat (Triticum aestivum L.). The allele Glu-B1g* coding for 13* and 19* subunits found in spelt wheat was also detected in club wheat (Triticum compactum L.). Additionally, two alleles coding for LMW-GS, Glu-A3h and Glu-B3d, occurred with high frequencies in spelt, club and cultivated emmer wheat, whereas these were not found or present with very low frequencies in bread wheat. Our results strongly support the secondary origin hypothesis, namely European spelt wheat originated from hybridization between cultivated emmer and club wheat. This is also confirmed experimentally by the artificial synthesis of spelt through crossing between old European emmer wheat, T. dicoccum and club wheat, T. compactum. PMID:13679994

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

2003-11-01

58

Identification and independent validation of a stable yield and thousand grain weight QTL on chromosome 6A of hexaploid wheat (Triticum aestivum L.)  

PubMed Central

Background Grain yield in wheat is a polygenic trait that is influenced by environmental and genetic interactions at all stages of the plant’s growth. Yield is usually broken down into three components; number of spikes per area, grain number per spike, and grain weight (TGW). In polyploid wheat, studies have identified quantitative trait loci (QTL) which affect TGW, yet few have been validated and fine-mapped using independent germplasm, thereby having limited impact in breeding. Results In this study we identified a major QTL for TGW, yield and green canopy duration on wheat chromosome 6A of the Spark x Rialto population, across 12 North European environments. Using independent germplasm in the form of BC2 and BC4 near isogenic lines (NILs), we validated the three QTL effects across environments. In four of the five experiments the Rialto 6A introgression gave significant improvements in yield (5.5%) and TGW (5.1%), with morphometric measurements showing that the increased grain weight was a result of wider grains. The extended green canopy duration associated with the high yielding/TGW Rialto allele was comprised of two independent effects; earlier flowering and delayed final maturity, and was expressed stably across the five environments. The wheat homologue (TaGW2) of a rice gene associated with increased TGW and grain width was mapped within the QTL interval. However, no polymorphisms were identified in the coding sequence between the parents. Conclusion The discovery and validation through near-isogenic lines of robust QTL which affect yield, green canopy duration, thousand grain weight, and grain width on chromosome 6A of hexaploid wheat provide an important first step to advance our understanding of the genetic mechanisms regulating the complex processes governing grain size and yield in polyploid wheat. PMID:25034643

2014-01-01

59

Resistance to the cereal cyst nematode (Heterodera avenae Woll.) transferred from the wild grassAegilops ventricosa to hexaploid wheat by a "stepping-stone" procedure.  

PubMed

Transfer of resistance toHeterodera avenae, the cereal cyst nematode (CCN), by a "stepping-stone" procedure from the wild grassAegilops ventricosa to hexaploid wheat has been demonstrated. The number of nematodes per plant was lower, and reached a plateau much earlier, in the resistant introgression line H93-8 (1-2 nematodes per plant) than in the recipient H10-15 wheat (14-16 nematodes per plant). Necrosis (hypersensitive reaction) near the nematode, little cell fusion, and few, often degraded syncytia were observed in infested H93-8 roots, while abundant, well-formed syncytia were present in the susceptible H10-15 wheat. Line H93-8 was highly resistant to the two Spanish populations tested, as well as the four French races (Fr1-Fr4), and the British pathotype Hall, but was susceptible to the Swedish pathotypes HgI and HgIII. Resistance was inherited as though determined by a single quasi-dominant factor in the F2 generations resulting from crosses of H93-8 with H10-15 and with Loros, a resistant wheat carrying the geneCre1 (syn.Ccn1). The resistance gene in H93-8 (Cre2 orCcn2) is not allelic with respect to that in Loros. RFLPs and other markers, together with the cytogenetical evidence, indicate that theCre2 gene has been integrated into a wheat chromosome without affecting its meiotic pairing ability. Introduction ofCre2 by backcrossing into a commercial wheat backgroud increases grain yield when under challenge by the nematode and is not detrimental in the absence of infestation. PMID:24190269

Delibes, A; Romero, D; Aguaded, S; Duce, A; Mena, M; Lopez-Braña, I; Andrés, M F; Martin-Sanchez, J A; García-Olmedo, F

1993-11-01

60

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

61

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

62

mRNA and Small RNA Transcriptomes Reveal Insights into Dynamic Homoeolog Regulation of Allopolyploid Heterosis in Nascent Hexaploid Wheat.  

PubMed

Nascent allohexaploid wheat may represent the initial genetic state of common wheat (Triticum aestivum), which arose as a hybrid between Triticum turgidum (AABB) and Aegilops tauschii (DD) and by chromosome doubling and outcompeted its parents in growth vigor and adaptability. To better understand the molecular basis for this success, we performed mRNA and small RNA transcriptome analyses in nascent allohexaploid wheat and its following generations, their progenitors, and the natural allohexaploid cultivar Chinese Spring, with the assistance of recently published A and D genome sequences. We found that nonadditively expressed protein-coding genes were rare but relevant to growth vigor. Moreover, a high proportion of protein-coding genes exhibited parental expression level dominance, with genes for which the total homoeolog expression level in the progeny was similar to that in T. turgidum potentially participating in development and those with similar expression to that in Ae. tauschii involved in adaptation. In addition, a high proportion of microRNAs showed nonadditive expression upon polyploidization, potentially leading to differential expression of important target genes. Furthermore, increased small interfering RNA density was observed for transposable element-associated D homoeologs in the allohexaploid progeny, which may account for biased repression of D homoeologs. Together, our data provide insights into small RNA-mediated dynamic homoeolog regulation mechanisms that may contribute to heterosis in nascent hexaploid wheat. PMID:24838975

Li, Aili; Liu, Dengcai; Wu, Jun; Zhao, Xubo; Hao, Ming; Geng, Shuaifeng; Yan, Jun; Jiang, Xiaoxue; Zhang, Lianquan; Wu, Junyan; Yin, Lingjie; Zhang, Rongzhi; Wu, Liang; Zheng, Youliang; Mao, Long

2014-05-16

63

Mixed Model Association Mapping for Fusarium Head Blight Resistance in Tunisian-Derived Durum Wheat Populations  

PubMed Central

Sources of resistance to Fusarium head blight (FHB) in wheat are mostly restricted to Chinese hexaploid genotypes. The effort to incorporate the resistance from hexaploid wheat or wild relatives to cultivated durum wheat (Triticum turgidum L. var. durum Desf.) have not been successful in providing resistance to the level of the donor parents. In this study, we used 171 BC1F6 and 169 BC1F7 lines derived from crossing of four Tunisian tetraploid sources of resistance (Tun7, Tun18, Tun34, Tun36) with durum cultivars ‘Ben,’ ‘Maier,’ ‘Lebsock,’ and ‘Mountrail’ for association studies. The Tun18 and Tun7 FHB resistances were found to be comparable to the best hexaploid wheat sources. A new significant QTL for FHB resistance was identified on the long arm of chromosome 5B (Qfhs.ndsu-5BL) with both association and classical QTL mapping analysis. Linkage disequilibrium (LD) blocks extending up to 40 cM were evident in these populations. The linear mixed model considering the structure (Q or P) and the kinship matrix (KT) estimated by restricted maximum likelihood (REML) was identified as the best for association studies in a mixture of wheat populations from a breeding program. The results of association mapping analysis also demonstrated a region on the short arm of chromosome 3B as potentially linked to FHB resistance. This region is in proximity of major FHB resistance gene fhb1 reported in hexaploid wheat. A possibility of having susceptibility or suppressor of resistance gene(s) on durum wheat chromosome 2A was further confirmed in this material, explaining the problem in developing resistant genotypes without counter selection against this region. PMID:22384332

Ghavami, Farhad; Elias, Elias M.; Mamidi, Sujan; Ansari, Omid; Sargolzaei, Mehdi; Adhikari, Tika; Mergoum, Mohamed; Kianian, Shahryar F.

2011-01-01

64

Lr34 multi-pathogen resistance ABC transporter: molecular analysis of homoeologous and orthologous genes in hexaploid wheat and other grass species.  

PubMed

The Triticum aestivum (bread wheat) disease resistance gene Lr34 confers durable, race non-specific protection against three fungal pathogens, and has been a highly relevant gene for wheat breeding since the green revolution. Lr34, located on chromosome 7D, encodes an ATP-binding cassette (ABC) transporter. Both wheat cultivars with and without Lr34-based resistance encode a putatively functional protein that differ by only two amino acid polymorphisms. In this study, we focused on the identification and characterization of homoeologous and orthologous Lr34 genes in hexaploid wheat and other grasses. In hexaploid wheat we found an expressed and putatively functional Lr34 homoeolog located on chromosome 4A, designated Lr34-B. Another homoeologous Lr34 copy, located on chromosome 7A, was disrupted by the insertion of repetitive elements. Protein sequences of LR34-B and LR34 were 97% identical. Orthologous Lr34 genes were detected in the genomes of Oryza sativa (rice) and Sorghum bicolor (sorghum). Zea mays (maize), Brachypodium distachyon and Hordeum vulgare (barley) lacked Lr34 orthologs, indicating independent deletion of this particular ABC transporter. Lr34 was part of a gene-rich island on the wheat D genome. We found gene colinearity on the homoeologous A and B genomes of hexaploid wheat, but little microcolinearity in other grasses. The homoeologous LR34-B protein and the orthologs from rice and sorghum have the susceptible haplotype for the two critical polymorphisms distinguishing the LR34 proteins from susceptible and resistant wheat cultivars. We conclude that the particular Lr34-haplotype found in resistant wheat cultivars is unique. It probably resulted from functional gene diversification that occurred after the polyploidization event that was at the origin of cultivated bread wheat. PMID:21265893

Krattinger, Simon G; Lagudah, Evans S; Wicker, Thomas; Risk, Joanna M; Ashton, Anthony R; Selter, Liselotte L; Matsumoto, Takashi; Keller, Beat

2011-02-01

65

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

66

Genetic and Epigenetic Alteration among Three Homoeologous Genes of a Class E MADS Box Gene in Hexaploid Wheat[W][OA  

PubMed Central

Bread wheat (Triticum aestivum) is a hexaploid species with A, B, and D ancestral genomes. Most bread wheat genes are present in the genome as triplicated homoeologous genes (homoeologs) derived from the ancestral species. Here, we report that both genetic and epigenetic alterations have occurred in the homoeologs of a wheat class E MADS box gene. Two class E genes are identified in wheat, wheat SEPALLATA (WSEP) and wheat LEAFY HULL STERILE1 (WLHS1), which are homologs of Os MADS45 and Os MADS1 in rice (Oryza sativa), respectively. The three wheat homoeologs of WSEP showed similar genomic structures and expression profiles. By contrast, the three homoeologs of WLHS1 showed genetic and epigenetic alterations. The A genome WLHS1 homoeolog (WLHS1-A) had a structural alteration that contained a large novel sequence in place of the K domain sequence. A yeast two-hybrid analysis and a transgenic experiment indicated that the WLHS1-A protein had no apparent function. The B and D genome homoeologs, WLHS1-B and WLHS1-D, respectively, had an intact MADS box gene structure, but WLHS1-B was predominantly silenced by cytosine methylation. Consequently, of the three WLHS1 homoeologs, only WLHS1-D functions in hexaploid wheat. This is a situation where three homoeologs are differentially regulated by genetic and epigenetic mechanisms. PMID:17586655

Shitsukawa, Naoki; Tahira, Chikako; Kassai, Ken-ichiro; Hirabayashi, Chizuru; Shimizu, Tomoaki; Takumi, Shigeo; Mochida, Keiichi; Kawaura, Kanako; Ogihara, Yasunari; Murai, Koji

2007-01-01

67

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

68

Subgenome chromosome walking in wheat: a 450-kb physical contig in Triticum monococcum L. spans the Lr10 resistance locus in hexaploid wheat (Triticum aestivum L.).  

PubMed

For many agronomically important plant genes, only their position on a genetic map is known. In the absence of an efficient transposon tagging system, such genes have to be isolated by map-based cloning. In bread wheat Triticum aestivum, the genome is hexaploid, has a size of 1.6 x 10(10) bp, and contains more than 80% of repetitive sequences. So far, this genome complexity has not allowed chromosome walking and positional cloning. Here, we demonstrate that chromosome walking using bacterial artificial chromosome (BAC) clones is possible in the diploid wheat Triticum monococcum (A(m) genome). BAC end sequences were mostly repetitive and could not be used for the first walking step. New probes corresponding to rare low-copy sequences were efficiently identified by low-pass DNA sequencing of the BACs. Two walking steps resulted in a physical contig of 450 kb on chromosome 1A(m)S. Genetic mapping of the probes derived from the BAC contig demonstrated perfect colinearity between the physical map of T. monococcum and the genetic map of bread wheat on chromosome 1AS. The contig genetically spans the Lr10 leaf rust disease resistance locus in bread wheat, with 0.13 centimorgans corresponding to 300 kb between the closest flanking markers. Comparison of the genetic to physical distances has shown large variations within 350 kb of the contig. The physical contig can now be used for the isolation of the orthologous regions in bread wheat. Thus, subgenome chromosome walking in wheat can produce large physical contigs and saturate genomic regions to support positional cloning. PMID:11078510

Stein, N; Feuillet, C; Wicker, T; Schlagenhauf, E; Keller, B

2000-11-21

69

Two different CC-NBS-LRR genes are required for Lr10-mediated leaf rust resistance in tetraploid and hexaploid wheat.  

PubMed

Comparative study of disease resistance genes in crop plants and their relatives provides insight on resistance gene function, evolution and diversity. Here, we studied the allelic diversity of the Lr10 leaf rust resistance gene, a CC-NBS-LRR coding gene originally isolated from hexaploid wheat, in 20 diploid and tetraploid wheat lines. Besides a gene in the tetraploid wheat variety 'Altar' that is identical to the hexaploid wheat Lr10, two additional, functional resistance alleles showing sequence diversity were identified by virus-induced gene silencing in tetraploid wheat lines. In contrast to most described NBS-LRR proteins, the N-terminal CC domain of LR10 was found to be under strong diversifying selection. A second NBS-LRR gene at the Lr10 locus, RGA2, was shown through silencing to be essential for Lr10 function. Interestingly, RGA2 showed much less sequence diversity than Lr10. These data demonstrate allelic diversity of functional genes at the Lr10 locus in tetraploid wheat, and these new genes can now be analyzed for agronomic relevance. Lr10-based resistance is highly unusual both in its dependence on two, only distantly, related CC-NBS-LRR proteins, as well as in the pattern of diversifying selection in the N-terminal domain. This indicates a new and complex molecular mechanism of pathogen detection and signal transduction. PMID:19769576

Loutre, Caroline; Wicker, Thomas; Travella, Silvia; Galli, Paolo; Scofield, Steve; Fahima, Tzion; Feuillet, Catherine; Keller, Beat

2009-12-01

70

Molecular Evolution of Receptor-Like Kinase Genes in Hexaploid Wheat. Independent Evolution of Orthologs after Polyploidization and Mechanisms of Local Rearrangements at Paralogous Loci1  

PubMed Central

Hexaploid wheat is a young polyploid species and represents a good model to study mechanisms of gene evolution after polyploidization. Recent studies at the scale of the whole genome have suggested rapid genomic changes after polyploidization but so far the rearrangements that have occurred in terms of gene content and organization have not been analyzed at the microlevel in wheat. Here, we have isolated members of a receptor kinase (Lrk) gene family in hexaploid and diploid wheat, Aegilops tauschii, and barley (Hordeum vulgare). Phylogenetic analysis has allowed us to establish evolutionary relationships (orthology versus paralogy) between the different members of this gene family in wheat as well as with Lrk genes from barley. It also demonstrated that the sequences of the homoeologous Lrk genes evolved independently after polyploidization. In addition, we found evidence for gene loss during the evolution of wheat and barley. Analysis of large genomic fragments isolated from nonorthologous Lrk loci showed a high conservation of the gene content and gene organization at these loci on the homoeologous group 1 chromosomes of wheat and barley. Finally, sequence comparison of two paralogous fragments of chromosome 1B showed a large number of local events (sequence duplications, deletions, and insertions), which reveal rearrangements and mechanisms for genome enlargement at the microlevel. PMID:11244111

Feuillet, Catherine; Penger, Anja; Gellner, Klaus; Mast, Austin; Keller, Beat

2001-01-01

71

Marker Development and Saturation Mapping of the Tan Spot Ptr ToxB Sensitivity locus Tsc2 in Hexaploid Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ptr ToxB is a host-selective toxin produced by the tan spot fungus that induces chlorosis in wheat lines harboring the Tsc2 gene, which was previously located to chromosome arm 2BS in tetraploid wheat. In this study, molecular mapping in a recombinant inbred (RI) population derived from a cross betw...

72

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

73

ANEUPLOIDY DETECTION WITH A SHORT-TERM HEXAPLOID WHEAT ASSAY (JOURNAL VERSION)  

EPA Science Inventory

A novel assay for the identification of agents causing aneuploidy is described. This assay takes advantage of allohexaploid wheat in which monosomic and nullisomic cell lineages can be genetically detected. The wheat strain used is homozygous for a pair of recissive alleles (v1) ...

74

Microarray expression analysis of meiosis and microsporogenesis in hexaploid bread wheat  

PubMed Central

Background Our understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of wild wheat relatives in breeding programs has prompted many years of cytogenetic and genetic research to develop an understanding of the control of chromosome pairing and recombination. The rapid advance of biochemical and molecular information on meiosis in model organisms such as yeast provides new opportunities to investigate the molecular basis of chromosome pairing control in wheat. However, building the link between the model and wheat requires points of data contact. Results We report here a large-scale transcriptomics study using the Affymetrix wheat GeneChip® aimed at providing this link between wheat and model systems and at identifying early meiotic genes. Analysis of the microarray data identified 1,350 transcripts temporally-regulated during the early stages of meiosis. Expression profiles with annotated transcript functions including chromatin condensation, synaptonemal complex formation, recombination and fertility were identified. From the 1,350 transcripts, 30 displayed at least an eight-fold expression change between and including pre-meiosis and telophase II, with more than 50% of these having no similarities to known sequences in NCBI and TIGR databases. Conclusion This resource is now available to support research into the molecular basis of pairing and recombination control in the complex polyploid, wheat. PMID:17052357

Crismani, Wayne; Baumann, Ute; Sutton, Tim; Shirley, Neil; Webster, Tracie; Spangenberg, German; Langridge, Peter; Able, Jason A

2006-01-01

75

The Ph1 Locus Suppresses Cdk2-Type Activity during Premeiosis and Meiosis in Wheat W OA  

E-print Network

of related (homoeologous) chromosomes, hexaploid wheat (Triticum aestivum) restricts pairing to just true in hexaploid wheat (Triticum aestivum) and tetraploid wheat (Triticum turgidum) is under the genetic control

Shaw, Peter

76

Revealing the genetic architecture of FHB resistance in hexaploid wheat ( Triticum aestivum L.) by QTL meta-analysis  

Microsoft Academic Search

Fusarium head blight (FHB) in wheat results in reduced yield and quality and in accumulation of mycotoxins. The objective of this\\u000a study was to identify genomic regions in wheat involved in the control of FHB resistance applying a QTL meta-analysis approach\\u000a by combining QTL of 30 mapping populations to propose independent meta-QTL (MQTL). A consensus map was created on which

Martin Löffler; Chris-Carolin Schön; Thomas Miedaner

2009-01-01

77

Molecular characterization and genomic organization of low molecular weight glutenin subunit genes at the Glu-3 loci in hexaploid wheat (Triticum aestivum L.).  

PubMed

In this study, we report on the molecular characterization and genomic organization of the low molecular weight glutenin subunit (LMW-GS) gene family in hexaploid wheat (Triticum aestivum L.). Eighty-two positive BAC clones were identified to contain LMW-GS genes from the hexaploid wheat 'Glenlea' BAC library via filter hybridization and PCR validation. Twelve unique LMW glutenin genes and seven pseudogenes were isolated from these positive BAC clones by primer-template mismatch PCR and subsequent primer walking using hemi-nested touchdown PCR. These genes were sequenced and each consisted of a single-open reading frame (ORF) and untranslated 5' and 3' flanking regions. All 12 LMW glutenin subunits contained eight cysteine residues. The LMW-m-type subunits are the most abundant in hexaploid wheat. Of the 12 LMW-GS, 1, 2 and 9 are i-type, s-type and m-type, respectively. The phylogenetic analysis suggested that the LMW-i type gene showed greater differences to LMW-s and LMW-m-type genes, which, in turn, were more closely related to one another. On the basis of their N-terminal sequences, they were classified into nine groups. Fingerprinting of the 82 BAC clones indicated 30 BAC clones assembled into eight contigs, while the remaining clones were singletons. BAC end sequencing of the 82 clones revealed that long terminal repeat (LTR) retrotransposons were abundant in the Glu-3 regions. The average physical distance between two adjacent LMW-GS genes was estimated to be 81 kb. Most of LMW-GS genes are located in the D: -genome, suggesting that the Glu-D3 locus is much larger than the Glu-B3 locus and Glu-A3 locus. Alignments of sequences indicated that the same type (starting with the same N-terminal sequence) LMW-GS genes were highly conserved in the homologous genomes between hexaploid wheat and its donors such as durum wheat and T. tauschii. PMID:18305921

Huang, Xiu-Qiang; Cloutier, Sylvie

2008-05-01

78

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...

79

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

80

A genetic basis for the origin of six different isolectins in hexaploid wheat.  

PubMed

Wheat (Triticum aestivum) germ agglutinin represents a complex mixture of multiple isolectin forms. Upon ion exchange chromatography at pH 3.8, three isolectins can be separated, each of which is composed of two identical subunits. At pH 5.0, however, three additional isolectins can be distinguished, which are built up of two different subunits (heteromeric lectins). Evidence is presented that these heterodimers are normal constituents of the wheat embryo cells. Analyses of the isolectin patterns in extracts from Triticum monococcum, Triticum turgidum dicoccum and Triticum aestivum, provide evidence that each genome, either in simple or complex (polyploid) genomes, directs the synthesis of a single lectin subunit species. In addition, a comparison of the isolectin pattern in these wheat species of increasing ploidy level, made it possible to determine unequivocally the genome by which the individual lectin subunits in polyploid species are coded for. The possible use of lectins in studies on the origin of individual genoms in polyploid species is discussed. PMID:24276352

Peumans, W J; Stinissen, H M; Carlier, A R

1982-06-01

81

Mapping and proteomic analysis of albumin and globulin proteins in hexaploid wheat kernels ( Triticum aestivum L.)  

Microsoft Academic Search

Albumins and globulins of wheat endosperm represent 20% of total kernel protein. They are soluble proteins, mainly enzymes\\u000a and proteins involved in cell functions. Two-dimensional gel immobiline electrophoresis (2DE) (pH 4-7) × SDS-Page revealed\\u000a around 2,250 spots. Ninety percent of the spots were common between the very distantly related cultivars ‘Opata 85’ and ‘Synthetic\\u000a W7984’, the two parents of the International Triticeae

Marielle Merlino; Philippe Leroy; Christophe Chambon; Gérard Branlard

2009-01-01

82

Preferential elimination of chromosome 1D from homoeologous group-1 alien addition lines in hexaploid wheat.  

PubMed

Alien chromosome addition lines are useful genetic material for studying the effect of an individual chromosome in the same genetic background. However, addition lines are sometimes unstable and tend to lose the alien chromosome in subsequent generations. In this study, we report preferential removal of chromosome 1D rather than the alien chromosome from homoeologous group-1 addition lines. The Agropyron intermedium chromosome 1Agi (1E) addition line, created in the background of 'Vilmorin 27', showed loss of a part of chromosome 1D, thereby losing its HMW glutenin locus. Even in the case of Aegilops longissima and Ae. peregrina, the genomes of which are closer to the B genome than D genome, chromosome 1D was lost from chromosome 1Sl and 1Sv addition lines in cv. 'Chinese Spring' rather than chromosome 1B during transfer from one generation to another. A similar observation was also observed in the case of a chromosome 1E disomic addition line of Ag. elongatum and alloplasmic common wheat line with Ag. intermedium ssp. trichophorum cytoplasm. The reason for this strange observation is thought to lie in the history of wheat evolution, the size of chromosome 1D compared to 1A and 1B, or differing pollen competition abilities. PMID:17991995

Garg, Monika; Elamein, Hala M M; Tanaka, Hiroyuki; Tsujimoto, Hisashi

2007-10-01

83

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

84

Effect of 5-azacytidine and trichostatin A on somatic centromere association in wheat  

E-print Network

Allopolyploids like hexaploid wheat (Triticum aestivum) not only possess pairs of identical chromosomes (homo hexaploid and tetraploid (Triticum durum) wheat, has a major controlling effect on the pairing

Shaw, Peter

85

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

PubMed

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 locus on chromosome 5B had a more pronounced affect on both rye and H. bulbosum crossability than the Kr2 locus on chromosome 5A and that the effects of both loci were cumulative. The Kr alleles affected both rye and H. bulbosum crossability in a linear, or additive, fashion. The Kr 2 allele was shown to have little effect on H. bulbosum crossability compared to a significant effect on rye crossability. Tests with tetrasomic and nulli-tetrasomic lines of 'Chinese Spring' indicated that the kr allele is 'null' or inactive in promoting crossability while the Kr allele is active in reducing crossability to both rye and H. bulbosum. Thus, extra doses of the kr allele do not increase rye or H. bulbosum crossability in the presence of the corresponding Kr allele. PMID:24265078

Falk, D E; Kasha, K J

1983-03-01

86

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

PubMed

Most elite wheat varieties cannot be crossed with related species thereby restricting greatly the germplasm that can be used for alien introgression in breeding programs. Inhibition to crossability is controlled genetically and a number of QTL have been identified to date, including the major gene Kr1 on 5BL and SKr, a strong QTL affecting crossability between wheat and rye on chromosome 5BS. In this study, we used a recombinant SSD population originating from a cross between the poorly crossable cultivar Courtot (Ct) and the crossable line MP98 to characterize the major dominant effect of SKr and map the gene at the distal end of the chromosome near the 5B homeologous GSP locus. Colinearity with barley and rice was used to saturate the SKr region with new markers and establish orthologous relationships with a 54-kb region on rice chromosome 12. In total, five markers were mapped within a genetic interval of 0.3 cM and 400 kb of BAC contigs were established on both sides of the gene to lay the foundation for map-based cloning of SKr. Two SSR markers completely linked to SKr were used to evaluate a collection of crossable wheat progenies originating from primary triticale breeding programs. The results confirm the major effect of SKr on crossability and the usefulness of the two markers for the efficient introgression of crossability in elite wheat varieties. PMID:19652174

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

2009-10-01

87

Mapping of quantitative trait loci determining agronomic important characters in hexaploid wheat ( Triticum aestivum L.)  

Microsoft Academic Search

A set of 114 recombinant inbred lines of the 'International Triticeae Mapping Initiative' mapping population was grown during the seasons 1997, 1998, 1999 and 2000 under several environments. Twenty morphological (glume colour, awn colour, waxiness, leaf erectness, peduncle length), agronomical (ear emergence time, flowering time, grain filling time, ear length, plant height, lodging, grain number, thousand-grain-weight, grain weight per ear,

A. Börner; E. Schumann; A. Fürste; H. Cöster; B. Leithold; M. Röder; W. Weber

2002-01-01

88

mRNA and Small RNA Transcriptomes Reveal Insights into Dynamic Homoeolog Regulation of Allopolyploid Heterosis in Nascent Hexaploid Wheat[W][OPEN  

PubMed Central

Nascent allohexaploid wheat may represent the initial genetic state of common wheat (Triticum aestivum), which arose as a hybrid between Triticum turgidum (AABB) and Aegilops tauschii (DD) and by chromosome doubling and outcompeted its parents in growth vigor and adaptability. To better understand the molecular basis for this success, we performed mRNA and small RNA transcriptome analyses in nascent allohexaploid wheat and its following generations, their progenitors, and the natural allohexaploid cultivar Chinese Spring, with the assistance of recently published A and D genome sequences. We found that nonadditively expressed protein-coding genes were rare but relevant to growth vigor. Moreover, a high proportion of protein-coding genes exhibited parental expression level dominance, with genes for which the total homoeolog expression level in the progeny was similar to that in T. turgidum potentially participating in development and those with similar expression to that in Ae. tauschii involved in adaptation. In addition, a high proportion of microRNAs showed nonadditive expression upon polyploidization, potentially leading to differential expression of important target genes. Furthermore, increased small interfering RNA density was observed for transposable element–associated D homoeologs in the allohexaploid progeny, which may account for biased repression of D homoeologs. Together, our data provide insights into small RNA–mediated dynamic homoeolog regulation mechanisms that may contribute to heterosis in nascent hexaploid wheat. PMID:24838975

Li, Aili; Liu, Dengcai; Wu, Jun; Zhao, Xubo; Hao, Ming; Geng, Shuaifeng; Yan, Jun; Jiang, Xiaoxue; Zhang, Lianquan; Wu, Junyan; Yin, Lingjie; Zhang, Rongzhi; Wu, Liang; Zheng, Youliang; Mao, Long

2014-01-01

89

Line differences in Cor/Lea and fructan biosynthesis-related gene transcript accumulation are related to distinct freezing tolerance levels in synthetic wheat hexaploids.  

PubMed

In common wheat, cultivar differences in freezing tolerance are considered to be mainly due to allelic differences at two major loci controlling freezing tolerance. One of the two loci, Fr-2, is coincident with a cluster of genes encoding C-repeat binding factors (CBFs), which induce downstream Cor/Lea genes during cold acclimation. Here, we conducted microarray analysis to study comprehensive changes in gene expression profile under long-term low-temperature (LT) treatment and to identify other LT-responsive genes related to cold acclimation in leaves of seedlings and crown tissues of a synthetic hexaploid wheat line. The microarray analysis revealed marked up-regulation of a number of Cor/Lea genes and fructan biosynthesis-related genes under the long-term LT treatment. For validation of the microarray data, we selected four synthetic wheat lines that contain the A and B genomes from the tetraploid wheat cultivar Langdon and the diverse D genomes originating from different Aegilops tauschii accessions with distinct levels of freezing tolerance after cold acclimation. Quantitative RT-PCR showed increased transcript levels of the Cor/Lea, CBF, and fructan biosynthesis-related genes in more freezing-tolerant lines than in sensitive lines. After a 14-day LT treatment, a significant difference in fructan accumulation was observed among the four lines. Therefore, the fructan biosynthetic pathway is associated with cold acclimation in development of wheat freezing tolerance and is another pathway related to diversity in freezing tolerance, in addition to the CBF-mediated Cor/Lea expression pathway. PMID:25577733

Yokota, Hirokazu; Iehisa, Julio C M; Shimosaka, Etsuo; Takumi, Shigeo

2015-03-15

90

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

Microsoft Academic Search

The allelic compositions of high- and low-molecular-weight subunits of glutenins (HMW-GS and LMW-GS) among European spelt ( Triticum spelta L.) and related hexaploid and tetraploid Triticum species were investigated by one- and two-dimensional polyacrylamide-gel electrophoresis (PAGE) and capillary electrophoresis (CE). A total of seven novel glutenin alleles (designated A1a*, B1d*, B1g*, B1f*, B1j*, D1a* at Glu-1 and A3h at the

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

2003-01-01

91

Linkage mapping and transcriptional profiling of resistance to soil- borne viruses in hexaploid wheat (Triticum vulgare ssp. aestivum)  

Microsoft Academic Search

Summary Soil-borne viruses, i.e. Soil-borne wheat mosaic virus (SBWMV), Soil-borne cereal mosaic virus (SBCMV) and Wheat spindle streak mosaic virus (WSSMV) are a serious threat to winter wheat cultivation in Europe. In previous screening programmes cultivars resistant to SBCMV and WSSMV were identified and preliminary results on the genetics of resistance to SBCMV based on the analyses of doubled haploid

D. PEROVIC; J. WEYEN; J. SCHONDELMAIER; J. FÖRSTER; P. DEVAUX; D. HARIRI; D. FEUERHELM; N. STEIN; A. GRANER; F. ORDON

92

Molecular characterization of the AP2-like Q gene homoeoallele on chromosome 5D in hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Q gene of wheat is responsible for many morphological traits associated with domestication. Q is located on wheat chromosome 5A and it is a member of the AP2 class of transcription factors. Genotypes harboring the q allele on chromosome 5A have speltoid spikes, which include non free-threshing...

93

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

Technology Transfer Automated Retrieval System (TEKTRAN)

The Hessian fly 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 the insect resistance pathway in higher plants, but little is known about genes controlling the insect in wheat. In this study, 154...

94

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

95

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

96

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

97

Identification of novel QTL for resistance to Fusarium head blight in a tetraploid wheat population.  

PubMed

Most tetraploid durum wheat (Triticum turgidum L var. durum) cultivars are susceptible to Fusarium head blight (FHB). This study reports novel quantitative trait loci (QTL) associated with FHB resistance. A backcross recombinant inbred line (BCRIL) population was developed from the cross BGRC3487/2*DT735, and 160 lines were evaluated for resistance to Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schwein. Petch) in field trials over 3 years (2008-2010) and to a F. graminearum 3-acetyl-deoxynivalenol (3-ADON) chemotype in greenhouse trials. The population was genotyped with 948 polymorphic loci using DArT and microsatellite markers. Eleven QTL were associated with FHB resistance under field conditions on chromosomes 2A, 3B, 5A, 5B, 7A, and 7B. Two of these, QFhb.usw-3B from BGRC3487 and QFhb.usw-7A2, were consistently detected over environments. The QFhb.usw-3B QTL was in a similar position to a resistance QTL in hexaploid wheat. The combination of the two QTL reduced field index by 53.5%-86.2%. Two QTL for resistance to the 3-ADON chemotype were detected on chromosomes 1B and 4B. Both BGRC3487 and DT735 could provide new sources of FHB resistance and the combination of QTL reported here could be valuable tools in breeding FHB-resistant durum wheat. PMID:23231604

Ruan, Yuefeng; Comeau, André; Langevin, François; Hucl, Pierre; Clarke, John M; Brule-Babel, Anita; Pozniak, Curtis J

2012-12-01

98

Integration of mate pair sequences to improve shotgun assemblies of flow-sorted chromosome arms of hexaploid wheat  

PubMed Central

Background The assembly of the bread wheat genome sequence is challenging due to allohexaploidy and extreme repeat content (>80%). Isolation of single chromosome arms by flow sorting can be used to overcome the polyploidy problem, but the repeat content cause extreme assembly fragmentation even at a single chromosome level. Long jump paired sequencing data (mate pairs) can help reduce assembly fragmentation by joining multiple contigs into single scaffolds. The aim of this work was to assess how mate pair data generated from multiple displacement amplified DNA of flow-sorted chromosomes affect assembly fragmentation of shotgun assemblies of the wheat chromosomes. Results Three mate pair (MP) libraries (2 Kb, 3 Kb, and 5 Kb) were sequenced to a total coverage of 89x and 64x for the short and long arm of chromosome 7B, respectively. Scaffolding using SSPACE improved the 7B assembly contiguity and decreased gene space fragmentation, but the degree of improvement was greatly affected by scaffolding stringency applied. At the lowest stringency the assembly N50 increased by ~7 fold, while at the highest stringency N50 was only increased by ~1.5 fold. Furthermore, a strong positive correlation between estimated scaffold reliability and scaffold assembly stringency was observed. A 7BS scaffold assembly with reduced MP coverage proved that assembly contiguity was affected only to a small degree down to ~50% of the original coverage. Conclusion The effect of MP data integration into pair end shotgun assemblies of wheat chromosome was moderate; possibly due to poor contig assembly contiguity, the extreme repeat content of wheat, and the use of amplified chromosomal DNA for MP library construction. PMID:23557231

2013-01-01

99

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....

100

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

101

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

PubMed Central

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-?9 and Glia-?20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-?9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-?20 was included as a technical reference. Overall, the presence of the Glia-?9 epitope was higher in the modern varieties, whereas the presence of the Glia-?20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of ‘low CD toxic’ as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD. PMID:20664999

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

2010-01-01

102

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

PubMed

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades, a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness and to improved diagnostic techniques, but increased wheat and gluten consumption is also considered a major cause. To analyze whether wheat breeding contributed to the increase of the prevalence of CD, we have compared the genetic diversity of gluten proteins for the presence of two CD epitopes (Glia-?9 and Glia-?20) in 36 modern European wheat varieties and in 50 landraces representing the wheat varieties grown up to around a century ago. Glia-?9 is a major (immunodominant) epitope that is recognized by the majority of CD patients. The minor Glia-?20 was included as a technical reference. Overall, the presence of the Glia-?9 epitope was higher in the modern varieties, whereas the presence of the Glia-?20 epitope was lower, as compared to the landraces. This suggests that modern wheat breeding practices may have led to an increased exposure to CD epitopes. On the other hand, some modern varieties and landraces have been identified that have relatively low contents of both epitopes. Such selected lines may serve as a start to breed wheat for the introduction of 'low CD toxic' as a new breeding trait. Large-scale culture and consumption of such varieties would considerably aid in decreasing the prevalence of CD. PMID:20664999

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

2010-11-01

103

Identification of seed dormancy for four populations derived from synthetic hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seed dormancy is a key adaptive trait for wild species and is also a major domestication-related trait for crop species. Cereal cultivars have been selected for rapid, uniform germination during domestication and breeding and consequently, they generally have an insufficient degree of seed dormancy ...

104

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

PubMed Central

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

2014-01-01

105

New insights into the origin of the B genome of hexaploid wheat: Evolutionary relationships at the SPA genomic region with the S genome of the diploid relative Aegilops speltoides  

PubMed Central

Background Several studies suggested that the diploid ancestor of the B genome of tetraploid and hexaploid wheat species belongs to the Sitopsis section, having Aegilops speltoides (SS, 2n = 14) as the closest identified relative. However molecular relationships based on genomic sequence comparison, including both coding and non-coding DNA, have never been investigated. In an attempt to clarify these relationships, we compared, in this study, sequences of the Storage Protein Activator (SPA) locus region of the S genome of Ae. speltoides (2n = 14) to that of the A, B and D genomes co-resident in the hexaploid wheat species (Triticum aestivum, AABBDD, 2n = 42). Results Four BAC clones, spanning the SPA locus of respectively the A, B, D and S genomes, were isolated and sequenced. Orthologous genomic regions were identified as delimited by shared non-transposable elements and non-coding sequences surrounding the SPA gene and correspond to 35 268, 22 739, 43 397 and 53 919 bp for the A, B, D and S genomes, respectively. Sequence length discrepancies within and outside the SPA orthologous regions are the result of non-shared transposable elements (TE) insertions, all of which inserted after the progenitors of the four genomes divergence. Conclusion On the basis of conserved sequence length as well as identity of the shared non-TE regions and the SPA coding sequence, Ae speltoides appears to be more evolutionary related to the B genome of T. aestivum than the A and D genomes. However, the differential insertions of TEs, none of which are conserved between the two genomes led to the conclusion that the S genome of Ae. speltoides has diverged very early from the progenitor of the B genome which remains to be identified. PMID:19032732

Salse, Jérome; Chagué, Véronique; Bolot, Stéphanie; Magdelenat, Ghislaine; Huneau, Cécile; Pont, Caroline; Belcram, Harry; Couloux, Arnaud; Gardais, Soazic; Evrard, Aurélie; Segurens, Béatrice; Charles, Mathieu; Ravel, Catherine; Samain, Sylvie; Charmet, Gilles; Boudet, Nathalie; Chalhoub, Boulos

2008-01-01

106

Development of a Virus-Induced Gene-Silencing System for Hexaploid Wheat and Its Use in Functional Analysis of the Lr21-Mediated Leaf Rust Resistance Pathway1  

PubMed Central

Virus-induced gene silencing (VIGS) is an important tool for the analysis of gene function in plants. In VIGS, viruses engineered to carry sequences derived from plant gene transcripts activate the host's sequence-specific RNA degradation system. This mechanism targets the RNAs of the viral genome for degradation, and as the virus contains transcribed plant sequence, homologous host mRNAs are also targeted for destruction. While routinely used in some dicots, no VIGS system was known for monocot plants until the recent report of silencing in barley (Hordeum vulgare) by barley stripe mosaic virus (BSMV). Here, we report development of protocols for use of BSMV to efficiently silence genes in hexaploid wheat (Triticum aestivum). The VIGS system was first optimized in studies silencing phytoene desaturase expression. Next, we used it to assay genes functioning in leaf rust resistance mediated by Lr21, which encodes a nucleotide binding site-leucine-rich repeat class resistance gene product. We demonstrated that infection with BSMV constructs carrying a 150-bp fragment of Lr21 caused conversion of incompatible interactions to compatible, whereas infection with a control construct or one that silences phytoene desaturase had no effect on resistance or susceptibility. Additionally, silencing the RAR1, SGT1, and HSP90 genes, known to be required in many but not all nucleotide binding site-leucine-rich repeat resistance pathways in diverse plant species, resulted in conversion to compatibility, indicating that these genes are essential in Lr21-mediated resistance. These studies indicate that BSMV-VIGS is a powerful tool for dissecting the genetic pathways of disease resistance in hexaploid wheat. PMID:16024691

Scofield, Steven R.; Huang, Li; Brandt, Amanda S.; Gill, Bikram S.

2005-01-01

107

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

108

Systematic Spatial Analysis of Gene Expression during Wheat Caryopsis Development W  

E-print Network

but coordinated developmental programs. Because of the hexaploid genome in wheat (Triticum aestivum endosperm is derived from the fertilized polar nuclei. In wheat (Triticum aestivum), the endosperm nuclei

Shaw, Peter

109

Agronomic and Quality Performance of Progeny Lines Derived from Spring Wheat by Durum Wheat Crosses  

Microsoft Academic Search

Cereal Chem. 80(6):717-721 Hard red spring wheat (Triticum aestivum L. subsp. aestivum) and durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) have both been selected for dryland yield potential and high grain protein, although end uses of flour are different. For this study, 14 tetraploid and 10 hexaploid lines were derived from crosses between tetraploid durum wheat and hexaploid

S. P. Lanning; D. Habernicht; J. M. Martin; J. D. Sherman; A. Fischer; L. E. Talbert

2003-01-01

110

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

PubMed Central

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

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

2013-01-01

111

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

PubMed

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

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

2013-01-01

112

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

PubMed

The presence of 5S rDNA units on chromosome 1A of Triticum aestivum was shown by the development of a specific PCR test, using head-to-head oriented primers. This primer set allowed the amplification of complete 5S DNA units and was used to isolate SS-Rrna-A1 sequences from polyploid and diploid wheat species. Multiple-alignment and parsimony analyses of the 132 sequences divided the sequences into four types. The isolates from T. aestivum and the tetraploid species (T. dicoccoides, T. dicoccum, T durum, T. araraticum, and T timopheevi) were all of one type, which was shown to be closely related to the type mainly characteristic for T. urartu. The other two types were isolated exclusively from the diploid species T. monococcum, T aegilopoides, T. thaoudar, and T. sinskajae and the hexaploid species T. zhukovski. Triticum monococcum was the only species for which representatives of each of the four sequence types were found to be present. Further, we discuss the possible multicluster arrangement of the 5S-Rrna-A1 array. PMID:11550886

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

2001-08-01

113

Evolution and Balanced Gene Expression of Homoeologs in Polyploid Wheat  

E-print Network

Evolution and Balanced Gene Expression of Homoeologs in Polyploid Wheat ABSTRACT . RESULTS AND DISCUSSION Hexaploid wheat is a relatively young polyploid with its evolution from diploid to tetraploid ~ .5 MYA and from tetraploid to hexaploid only ~10,000 years ago. The wheat genome is large of which only

Gill, Kulvinder

114

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

115

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

116

Map-based isolation of the leaf rust disease resistance gene Lr10 from the hexaploid wheat (Triticum aestivum L.) genome  

Microsoft Academic Search

More than 50 leaf rust resistance (Lr) genes against the fungal pathogen Puccinia triticina have been identified in the wheat gene pool, and a large number of them have been extensively used in breeding. Of the 50 Lr genes, all are known only from their phenotype and\\/or map position except for Lr21, which was cloned recently. For many years, the

Catherine Feuillet; Silvia Travella; Nils Stein; Laurence Albar; Aurélie Nublat; Beat Keller

2003-01-01

117

Quantitative Trait Loci Identified for Resistance to Stagonospora Glume Blotch in Wheat in the USA and Australia  

Microsoft Academic Search

Resistance to stagonospora nodorum blotch (SNB) in glumes of hexaploid wheat (Triticum aes- tivum L.), caused by Phaeosphaeria (Stagonos- pora anamorph) nodorum was investigated in a recombinant-inbred (RI) population. The Purdue University winter wheat breeding lines P91193D1 and P92201D5, unrelated by parentage but both exhibiting partial SNB resistance, were crossed to develop 254 RI lines by single-seed descent (SSD) from

J. Uphaus; E. Walker; M. Shankar; H. Golzar; R. Loughman; M. Francki; H. Ohm

2007-01-01

118

Development of a Recombinant Inbred Line (RIL) Population in Soft White Winter Wheat  

Microsoft Academic Search

Recombinant inbred line (RIL) populations are very useful to develop molecular markers in wheat. One market class that has been under-represented in RIL populations has been soft white winter wheat. A RIL population of 314 individuals was developed using a cross between Brundage and Coda. Brundage is an awnless, common, soft white winter wheat. Coda is an awned, club, soft

Arron Carter; Jenny Hansen; Thomas Koehler; Xianming M. Chen; Robert Zemetra

119

Genetic relationships and diversity among Tibetan wheat, common wheat and European spelt wheat revealed by RAPD markers  

Microsoft Academic Search

An endemic hexaploid wheat found in Tibet, China was taxonomically classified as a subspecies in common wheat, i.e. Triticum\\u000a aestivum ssp. tibetanum. Seven accessions of the Tibetan wheat, 22 cultivars of common wheat and 17 lines of spelt wheat were\\u000a used for RAPD analysis to study the genetic relationships of the Tibetan wheat with common wheat and spelt wheat, and

Qixin Sun; Zhongfu Ni; Zhiyong Liu; Jianwei Gao; Tiecheng Huang

1998-01-01

120

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

PubMed Central

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

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

2015-01-01

121

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

PubMed

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

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

2015-01-01

122

Retention of D genome chromosomes in pentaploid wheat crosses  

PubMed Central

The transfer of genes between Triticum aestivum (hexaploid bread wheat) and T. turgidum (tetraploid durum wheat) holds considerable potential for genetic improvement of both these closely related species. Five different T. aestivum/T. turgidum ssp. durum crosses were investigated using Diversity Arrays Technology (DArT) markers to determine the inheritance of parental A, B and D genome material in subsequent generations derived from these crosses. The proportions of A, B and D chromosomal segments inherited from the hexaploid parent were found to vary significantly among individual crosses. F2 populations retained widely varying quantities of D genome material, ranging from 99% to none. The relative inheritance of bread wheat and durum alleles in the A and B genomes of derived lines also varied among the crosses. Within any one cross, progeny without D chromosomes in general had significantly more A and B genome durum alleles than lines retaining D chromosomes. The ability to select for and manipulate this non-random segregation in bread wheat/durum crosses will assist in efficient backcrossing of selected characters into the recurrent durum or hexaploid genotype of choice. This study illustrates the utility of DArT markers in the study of inter-specific crosses to commercial crop species. PMID:21427754

Martin, A; Simpfendorfer, S; Hare, R A; Eberhard, F S; Sutherland, M W

2011-01-01

123

A Microsatellite Map of Wheat  

Microsoft Academic Search

Hexaploid bread wheat (Triticum aestivum L. em. Thell) is one of the world's most important crop plants and displays a very low level of intraspecific polymorphism. We report the development of highly polymorphic microsatellite markers using procedures optimized for the large wheat genome. The isolation of microsatellite-containing clones from hypomethylated regions of the wheat genome increased the proportion of useful

Marion S. Roder; Victor Korzun; Katja Wendehake; Jens Plaschke; Marie-Helene Tixier; Philippe Leroy; Martin W. Ganal

124

Genetic analysis of prolamins synthesised by the Hch genome and their effects on gluten strength in hexaploid tritordeum  

Microsoft Academic Search

Hexaploid tritordeum is an amphiploid derived from the cross between Hordeum chilense and durum wheat. This amphiploid has\\u000a shown potential for bread making, which has been associated to the prolamins from H. chilense. The role of each prolamin subunit\\u000a on the gluten strength in tritordeum has been evaluated. Advanced progenies from two hexaploid tritordeum crosses were analysed\\u000a for prolamins composition

J. B. Alvarez; L. A. C. Campos; A. Martín; J. A. Sillero; L. M. Martín

1999-01-01

125

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

PubMed

Plant pathogens emerge in agro-ecosystems following different evolutionary mechanisms over different time scales. Previous analyses based on sequence variation at six nuclear loci indicated that Mycosphaerella graminicola diverged from an ancestral population adapted to wild grasses during the process of wheat domestication approximately 10,500 years ago. We tested this hypothesis by conducting coalescence analyses based on four mitochondrial loci using 143 isolates that included four closely related pathogen species originating from four continents. Pathogen isolates from bread and durum wheat were included to evaluate the emergence of specificity towards these hosts in M. graminicola. Although mitochondrial and nuclear genomes differed greatly in degree of genetic variability, their coalescence was remarkably congruent, supporting the proposed origin of M. graminicola through host tracking. The coalescence analysis was unable to trace M. graminicola host specificity through recent evolutionary time, indicating that the specificity towards durum or bread wheat emerged following the domestication of the pathogen on wheat. PMID:21145978

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

2011-02-01

126

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...

127

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

128

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

PubMed Central

Background and Aims The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. Methods Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4?,6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. Key Results The diploid–hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. Conclusions The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus. PMID:22887024

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

2012-01-01

129

Original article Divergent evolution of wheat populations conducted  

E-print Network

selection / dynamic management / Triticum aestivum / genetic variability / local adaptation / wheat pop.) sélection récurrente / gestion dynamique / Triticum aestivum / variabilité génétique / adaptation locale 1

Paris-Sud XI, Université de

130

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

Technology Transfer Automated Retrieval System (TEKTRAN)

The biotypic diversity of the Russian wheat aphid, Diuraphis noxia (Kurdjumov), was assessed in five isolates collected in Colorado. Three isolates, RWA 1, RWA 2, and an isolate from Montezuma County, CO designated RWA6, were originally collected from cultivated wheat, Triticum aestivum L. The fou...

131

Genetic Diversity, Population Structure and Linkage Disequilibrium in Elite Chinese Winter Wheat Investigated with SSR Markers  

PubMed Central

To ascertain genetic diversity, population structure and linkage disequilibrium (LD) among a representative collection of Chinese winter wheat cultivars and lines, 90 winter wheat accessions were analyzed with 269 SSR markers distributed throughout the wheat genome. A total of 1,358 alleles were detected, with 2 to 10 alleles per locus and a mean genetic richness of 5.05. The average genetic diversity index was 0.60, with values ranging from 0.05 to 0.86. Of the three genomes of wheat, ANOVA revealed that the B genome had the highest genetic diversity (0.63) and the D genome the lowest (0.56); significant differences were observed between these two genomes (P<0.01). The 90 Chinese winter wheat accessions could be divided into three subgroups based on STRUCTURE, UPGMA cluster and principal coordinate analyses. The population structure derived from STRUCTURE clustering was positively correlated to some extent with geographic eco-type. LD analysis revealed that there was a shorter LD decay distance in Chinese winter wheat compared with other wheat germplasm collections. The maximum LD decay distance, estimated by curvilinear regression, was 17.4 cM (r2>0.1), with a whole genome LD decay distance of approximately 2.2 cM (r2>0.1, P<0.001). Evidence from genetic diversity analyses suggest that wheat germplasm from other countries should be introduced into Chinese winter wheat and distant hybridization should be adopted to create new wheat germplasm with increased genetic diversity. The results of this study should provide valuable information for future association mapping using this Chinese winter wheat collection. PMID:22957076

Chen, Xiaojie; Min, Donghong; Yasir, Tauqeer Ahmad; Hu, Yin-Gang

2012-01-01

132

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

PubMed

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz(+)) and 2,4-diacetylphloroglucinol (Phl(+)) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz(+) and Phl(+) Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz(+) bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g(-1) of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl(+) and Phz(+) Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl(+) bacteria whereas only 8 to 50% of plants harbored Phz(+) bacteria. In addition, Phz(+) Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat. PMID:22389379

Mavrodi, Olga V; Mavrodi, Dmitri V; Parejko, James A; Thomashow, Linda S; Weller, David M

2012-05-01

133

Irrigation Differentially Impacts Populations of Indigenous Antibiotic-Producing Pseudomonas spp. in the Rhizosphere of Wheat  

PubMed Central

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz+) and 2,4-diacetylphloroglucinol (Phl+) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz+ and Phl+ Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz+ bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g?1 of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl+ and Phz+ Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl+ bacteria whereas only 8 to 50% of plants harbored Phz+ bacteria. In addition, Phz+ Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat. PMID:22389379

Mavrodi, Olga V.; Mavrodi, Dmitri V.; Parejko, James A.; Thomashow, Linda S.

2012-01-01

134

Niche differentiation between diploid and hexaploid Aster amellus  

Microsoft Academic Search

The maintenance of separated diploid and polyploid populations within a contact zone is possible due to both prezygotic and\\u000a postzygotic isolation mechanisms. Niche differentiation between two cytotypes may be an important prezygotic isolating mechanism\\u000a and can be studied using reciprocal transplant experiments. We investigated niche differentiation between diploid and hexaploid\\u000a Aster amellus in their contact zone in the Czech Republic.

Jana Raabová; Markus Fischer; Zuzana Münzbergová

2008-01-01

135

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

136

Chromosome constitution of polyploid wheats: Introduction of diploid wheat chromosome 4  

PubMed Central

Chromosome 4 of diploid wheat (chromosome d4) is not present in hexaploid wheat. This chromosome has been added to hexaploid wheat and observed not to pair meiotically with its 21 chromosomes. Also, chromosome d4 compensates for Cornerstone male sterility, which involves a recessive mutation in chromosome arm 4AS. Chromosome d4 has been separately substituted for chromosomes 4A and 4B. These two substituted hexaploid chromotypes have the entire genome of diploid wheat and may have agricultural significance. An alternative hypothesis of the evolution of polyploid wheats is proposed that involves the loss of chromosome d4 and the retention of two versions of chromosome 4B at the early tetraploid stage. Images PMID:16593705

Wazuddin, M.; Driscoll, C. J.

1986-01-01

137

GLIADIN ALLELES IN WHEAT: IDENTIFICATION AND APPLICATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid or common bread wheat (2n=42) is a self-pollinated crop, with three genomes designated A, B and D, each composed of seven chromosome pairs. Each Gli locus encodes a group (or block) of gliadin electrophoretic components. Analysis of progenies from crosses between different wheat cultivar...

138

Chapter 6: Floral Transformation of Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid wheat is one of the world’s most important staple crops but genetic transformation is still challenging. We are developing a floral transformation protocol for wheat that does not require tissue culture. Several T-DNA transformants have been produced in the high quality, hard red germpla...

139

IMPACT OF IRRIGATION ON POPULATIONS OF ANTIBIOTIC-PRODUCING PSEUDOMONAS SPP. IN RHIZOSPHERE OF WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

This work studied the impact of irrigation on seasonal dynamics of populations of phenazine (Phz+) and 2,4-diacetylphloroglucinol (Phl+) Pseudomonas spp. in the rhizosphere of wheat grown in the low-precipitation zone (<400 mm) of the Columbia Plateau of the Inland Pacific Northwest, WA. Population...

140

Population divergence in the wheat leaf rust fungus Puccinia triticina is correlated with wheat evolution  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to determine if the evolutionary history of the obligate pathogen on wheat, Puccinia triticina, is correlated with adaptation to hosts with different ploidy levels. Sequence data from 15 loci with different levels of polymorphism were generated. Phylogenetic analyses ...

141

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...

142

Fertility of a spontaneous hexaploid male Siberian sturgeon, Acipenser baerii  

PubMed Central

Background Evolution of sturgeons and paddlefishes (order Acipenseriformes) is inherently connected with polyploidization events which resulted in differentiation of ploidy levels and chromosome numbers of present acipenseriform species. Moreover, allopolyploidization as well as autopolyploidization seems to be an ongoing process in these fishes and individuals with abnormal ploidy levels were occasionally observed within sturgeon populations. Here, we reported occurrence of Siberian sturgeon (Acipenser baerii) male with abnormal ploidy level for this species, accessed its ploidy level and chromosome number and investigate its potential sterility or fertility in comparison with normal individuals of sterlet (A. ruthenus), Russian sturgeon (A. gueldenstaedtii) and Siberian sturgeon (A. baerii). Results Acipenser ruthenus possessed 120 chromosomes, exhibiting recent diploidy (2n), A. gueldenstaedtii and A. baerii had ~245 chromosomes representing recent tetraploidy (4n), and A. baerii male with abnormal ploidy level had?~?368 chromosomes, indicating recent hexaploidy (6n). Genealogy assessed from the mtDNA control region did not reveal genome markers of other sturgeon species and this individual was supposed to originate from spontaneous 1.5 fold increment in number of chromosome sets with respect to the number most frequently found in nature for this species. Following hormone stimulation, the spontaneous hexaploid male produced normal sperm with ability for fertilization. Fertilization of A. baerii and A. gueldenstaedtii ova from normal 4n level females with sperm of the hexaploid male produced viable, non-malformed pentaploid (5n) progeny with a ploidy level intermediate to those of the parents. Conclusion This study firstly described occurrence of hexaploid individual of A. baerii and confirmed its autopolyploid origin. In addition to that, the first detailed evidence about fertility of spontaneous hexaploid sturgeon was provided. If 1.5 fold increment in number of chromosome sets occurring in diploids, resulted triploids possess odd number of chromosome sets causing their sterility or subfertility due to interference of gametogenesis. In contrast, 1.5 fold increment in number of chromosome sets in naturally tetraploid A. baerii resulted in even number of chromosome sets and therefore in fertility of the hexaploid specimen under study. PMID:24410899

2014-01-01

143

Epidemiology and simulation of population development of Sitobion avenae in winter wheat  

Microsoft Academic Search

The epidemiology ofSitobion avenae and its natural enemies in winter wheat was studied in 1975, 1976 and 1977. Immigration was important until the end of flowering. The alate immigrants had apterous offspring. These became the driving force in population growth. Their offspring were mostly alatae which usually left the field. A model of the epidemic was developed. Quantitative relations between

R. Rabbinge; G. W. Ankersmit; G. A. Pak

1979-01-01

144

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

145

Molecular Characterization of Durable Yellow and Leaf Rust Resistance in Two Wheat Populations  

E-print Network

potential wheat lines 'Quaiu 3' and 'TAM 111', and 2) map the putative Quantitative Trait Loci (QTL) associated with YR and LR resistance using DNA-based molecular markers. Two Recombinant Inbred Line (RIL) populations were subjected to YR and LR disease...

Basnet, Bhoja

2012-07-16

146

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...

147

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

148

Domestication evolution, genetics and genomics in wheat  

Microsoft Academic Search

Domestication of plants and animals is the major factor underlying human civilization and is a gigantic evolutionary experiment\\u000a of adaptation and speciation, generating incipient species. Wheat is one of the most important grain crops in the world, and\\u000a consists mainly of two types: the hexaploid bread wheat (Triticum aestivum) accounting for about 95% of world wheat production, and the tetraploid

Junhua H. Peng; Dongfa Sun; Eviatar Nevo

149

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

150

Low crop plant population densities promote pollen-mediated gene flow in spring wheat (Triticum aestivum L.).  

PubMed

Transgenic wheat is currently being field tested with the intent of eventual commercialization. The development of wheat genotypes with novel traits has raised concerns regarding the presence of volunteer wheat populations and the role they may play in facilitating transgene movement. Here, we report the results of a field experiment that investigated the potential of spring wheat plant population density and crop height to minimize gene flow from a herbicide-resistant (HR) volunteer population to a non-HR crop. Pollen-mediated gene flow (PMGF) between the HR volunteer wheat population and four conventional spring wheat genotypes varying in height was assessed over a range of plant population densities. Natural hybridization events between the two cultivars were detected by phenotypically scoring plants in F(1) populations followed by verification with Mendelian segregation ratios in the F(1:2) families. PMGF was strongly associated with crop yield components, but showed no association with flowering synchrony. Maximum observed PMGF was always less than 0.6%, regardless of crop height and density. The frequency of PMGF in spring wheat decreased exponentially with increasing plant population density, but showed no dependence on either crop genotype or height. However, increasing plant densities beyond the recommended planting rate of 300 cropped wheat plants m(-2) provided no obvious benefit to reducing PMGF. Nevertheless, our results demonstrate a critical plant density of 175-200 cropped wheat plants m(-2) below which PMGF frequencies rise exponentially with decreasing plant density. These results will be useful in the development of mechanistic models and best management practices that collectively facilitate the coexistence of transgenic and nontransgenic wheat crops. PMID:19387859

Willenborg, Christian J; Brûlé-Babel, Anita L; Van Acker, Rene C

2009-12-01

151

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

152

Selecting and Sorting Waxy Wheat Kernels Using Near-Infrared Spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

An automated single kernel near-infrared (NIR) sorting system was used to separate single wheat (Triticum aestivum L.) kernels with amylose-free (waxy) starch from reduced-amylose (partial waxy) or wild-type wheat kernels. Waxy kernels of hexaploid wheat are null for the granule-bound starch syntha...

153

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.)...

154

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

155

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...

156

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...

157

A major gene for powdery mildew resistance transferred to common wheat from wild einkorn wheat.  

PubMed

ABSTRACT A major gene for resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici = Erysiphe graminis f. sp. tritici) has been successfully transferred into hexaploid common wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) from wild einkorn wheat (Triticum monococcum subsp. aegilopoides, 2n = 2x = 14, AA). NC96BGTA5 is a germ plasm line with the pedigree Saluda x 3/PI427662. The response patterns for powdery mildew resistance in NC96BGTA5 were tested with 30 differential isolates of B. graminis f. sp. tritici, and the line was resistant to all tested isolates. The analyses of P(1), P(2), F(1), F(2), and BC(1)F(1) populations derived from NC96BGTA5 revealed two genes for wheat powdery mildew resistance in the NC96BGTA5 line. One gene, Pm3a, was from its recurrent parent Saluda, and the second was a new gene introgressed from wild einkorn wheat. The gene was determined to be different from Pm1 to Pm21 by gene-for-gene and pedigree analyses. The new gene was identified as linked to the Pm3a gene based on the F(2) and BC(1)F(1) populations derived from a cross between NC96BGTA5 and a susceptible cultivar NK-Coker 68-15, and the data indicated that the gene was located on chromosome 1A. It is proposed that this new gene be designated Pm25 for wheat powdery mildew resistance in NC96BGTA5. Three random amplified polymorphic DNA markers, OPX06(1050), OPAG04(950), and OPAI14(600), were found to be linked to this new gene. PMID:18944983

Shi, A N; Leath, S; Murphy, J P

1998-02-01

158

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

159

Phenotypic assessment and mapped markers for H31, a new wheat gene conferring resistance to Hessian fly (Diptera: Cecidomyiidae)  

Microsoft Academic Search

A new source of resistance to the highly virulent and widespread biotype L of the Hessian fly, Mayetiola destructor (Say), was identified in an accession of tetraploid durum wheat, Triticum turgidum Desf., and was introgressed into hexaploid common wheat, Triticum aestivum L. Genetic analysis and deletion mapping revealed that the common wheat line contained a single locus for resistance, H31,

C. E. Williams; C. C. Collier; N. Sardesai; H. W. Ohm; S. E. Cambron

2003-01-01

160

Chlorophyll fluorescence parameters and drought tolerance in a mapping population of winter bread wheat in the highlands of Iran  

Microsoft Academic Search

The usefulness of fluorescence parameters as drought tolerance selection criteria for winter bread wheat in the highlands\\u000a of Iran was studied. A population of 142 recombinant inbred lines, derived from a cross between two common wheat varieties,\\u000a Azar2 (winter type) and 87Zhong291 (facultative type), was used to analyze the correlation between grain yield and chlorophyll\\u000a fluorescence parameters at the grain-filling

M. Roostaei; S. A. Mohammadi; A. Amri; E. Majidi; M. Nachit; R. Haghparast

2011-01-01

161

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

162

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

163

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

164

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...

165

Impact of Field Release of Genetically Modified Pseudomonas fluorescens on Indigenous Microbial Populations of Wheat  

PubMed Central

In a field release experiment, an isolate of Pseudomonas fluorescens, which was chromosomally modified with two reporter gene cassettes (lacZY and Kan(supr)-xylE), was applied to spring wheat as a seed coating and subsequently as a foliar spray. The wild-type strain was isolated from the phylloplane of sugar beet but was found to be a common colonizer of both the rizosphere and phylloplane of wheat as well. The impact on the indigenous microbial populations resulting from release of this genetically modified microorganism (GMM) was compared with the impact of the unmodified, wild-type strain and a nontreated control until 1 month after harvest of the crop. The release of the P. fluorescens GMM and the unmodified, wild-type strain resulted in significant but transient perturbations of some of the culturable components of the indigenous microbial communities that inhabited the rhizosphere and phylloplane of wheat, but no significant perturbations of the indigenous culturable microbial populations in nonrhizosphere soil were found. Fast-growing organisms that did not produce resting structures (for example, fluorescent pseudomonads and yeasts) seemed to be most sensitive to perturbation. In terms of hazard and risk to the environment, the observed microbial perturbations that resulted from this GMM release may be considered minor for several reasons. First, the recombinant P. fluorescens strain caused changes that were, in general, not significantly different from those caused by the unmodified wild-type strain; second, perturbations resulting from bacterial inoculations were mainly small; and third, the release of bacteria had no obvious effects on plant growth and plant health. PMID:16535129

De Leij, F.; Sutton, E. J.; Whipps, J. M.; Fenlon, J. S.; Lynch, J. M.

1995-01-01

166

Alpha-gliadin genes from the A, B, and D genomes of wheat contain different sets of celiac disease epitopes  

PubMed Central

Background Bread wheat (Triticum aestivum) is an important staple food. However, wheat gluten proteins cause celiac disease (CD) in 0.5 to 1% of the general population. Among these proteins, the ?-gliadins contain several peptides that are associated to the disease. Results We obtained 230 distinct ?-gliadin gene sequences from severaldiploid wheat species representing the ancestral A, B, and D genomes of the hexaploid bread wheat. The large majority of these sequences (87%) contained an internal stop codon. All ?-gliadin sequences could be distinguished according to the genome of origin on the basis of sequence similarity, of the average length of the polyglutamine repeats, and of the differences in the presence of four peptides that have been identified as T cell stimulatory epitopes in CD patients through binding to HLA-DQ2/8. By sequence similarity, ?-gliadins from the public database of hexaploid T. aestivum could be assigned directly to chromosome 6A, 6B, or 6D. T. monococcum (A genome) sequences, as well as those from chromosome 6A of bread wheat, almost invariably contained epitope glia-?9 and glia-?20, but never the intact epitopes glia-? and glia-?2. A number of sequences from T. speltoides, as well as a number of sequences fromchromosome 6B of bread wheat, did not contain any of the four T cell epitopes screened for. The sequences from T. tauschii (D genome), as well as those from chromosome 6D of bread wheat, were found to contain all of these T cell epitopes in variable combinations per gene. The differences in epitope composition resulted mainly from point mutations. These substitutions appeared to be genome specific. Conclusion Our analysis shows that ?-gliadin sequences from the three genomes of bread wheat form distinct groups. The four known T cell stimulatory epitopes are distributed non-randomly across the sequences, indicating that the three genomes contribute differently to epitope content. A systematic analysis of all known epitopes in gliadins and glutenins will lead to better understanding of the differences in toxicity among wheat varieties. On the basis of such insight, breeding strategies can be designed to generate less toxic varieties of wheat which may be tolerated by at least part of the CD patient population. PMID:16403227

van Herpen, Teun WJM; Goryunova, Svetlana V; van der Schoot, Johanna; Mitreva, Makedonka; Salentijn, Elma; Vorst, Oscar; Schenk, Martijn F; van Veelen, Peter A; Koning, Frits; van Soest, Loek JM; Vosman, Ben; Bosch, Dirk; Hamer, Rob J; Gilissen, Luud JWJ; Smulders, Marinus JM

2006-01-01

167

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

168

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...

169

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

170

A Comparative Analysis of Free, Bound and Total Lipid Content on Spelt and Winter Wheat Wholemeal  

Microsoft Academic Search

Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method in whole ground spelt (Triticum aestivum ssp. spelta L.) and hexaploid winter wheat (T. aestivum) samples. Ninety-one samples of spelt and 78 samples of winter wheat were analysed in the present study. The available material is representative of the wide variability found in spelt

Nike L. Ruibal-Mendieta; Dominique L. Delacroix; Marc Meurens

2002-01-01

171

Evidence for stable transformation of wheat by floraldip in Agrobacterium tumefaciens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid wheat is one of the world’s most important staple crops but genetic transformation is still challenging. We have developed a floral transformation protocol that does not utilize tissue culture. Three T-DNA wheat transformants have been produced in the germplasm line, Crocus, using this p...

172

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

173

Rapid development of PCR-based genome-specific repetitive DNA junction markers in wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

In hexaploid wheat (Triticum aestivum L.) (AABBDD, C=17,000Mb), repeat DNA accounts for ~ 90% of the genome of which transposable elements (TEs) constitute 60-80 %. Despite the dynamic evolution of TEs, our previous study indicated that the majority of TEs between the homologous wheat genomes are co...

174

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

175

Synteny perturbations between wheat homoeologous chromosomes caused by locus duplications and  

E-print Network

of chromosomes. Hexaploid wheat Triticum aestivum L. (2n 42, genome formula AABBDD) evolved by hybridization of three dip- loid (2n 14) species: Triticum urartu Thum ex Gand. (the source of the A genome), Aegilops are related by descent from a chromosome of the ancestor of the Triticum­ Aegilops alliance. Most wheat

Gill, Kulvinder

176

Using genic sequence capture in combination with a syntenic pseudo genome to map a deletion mutant in a wheat species.  

PubMed

Mapping-by-sequencing analyses have largely required a complete reference sequence and employed whole genome re-sequencing. In species such as wheat, no finished genome reference sequence is available. Additionally, because of its large genome size (17 Gb), re-sequencing at sufficient depth of coverage is not practical. Here, we extend the utility of mapping by sequencing, developing a bespoke pipeline and algorithm to map an early-flowering locus in einkorn wheat (Triticum monococcum L.) that is closely related to the bread wheat genome A progenitor. We have developed a genomic enrichment approach using the gene-rich regions of hexaploid bread wheat to design a 110-Mbp NimbleGen SeqCap EZ in solution capture probe set, representing the majority of genes in wheat. Here, we use the capture probe set to enrich and sequence an F2 mapping population of the mutant. The mutant locus was identified in T. monococcum, which lacks a complete genome reference sequence, by mapping the enriched data set onto pseudo-chromosomes derived from the capture probe target sequence, with a long-range order of genes based on synteny of wheat with Brachypodium distachyon. Using this approach we are able to map the region and identify a set of deleted genes within the interval. PMID:25205592

Gardiner, Laura-Jayne; Gawro?ski, Piotr; Olohan, Lisa; Schnurbusch, Thorsten; Hall, Neil; Hall, Anthony

2014-12-01

177

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

178

Quantitative trait loci for adult-plant resistance to Mycosphaerella graminicola in two winter wheat populations.  

PubMed

Septoria tritici blotch (STB) is one of the most important leaf spot diseases in wheat worldwide. The goal of this study was to detect chromosomal regions for adult-plant resistance in large winter wheat populations to STB. Inoculation by two isolates with virulence to Stb6 and Stb15, both present in the parents, was performed and STB severity was visually scored plotwise as percent coverage of flag leaves with pycnidia-bearing lesions. 'Florett'/'Biscay' and 'Tuareg'/'Biscay', each comprising a cross of a resistant and a susceptible cultivar, with population sizes of 316 and 269 F(7:8) recombinant inbred lines, respectively, were phenotyped across four and five environments and mapped with amplified fragment length polymorphism, diversity array technology, and simple sequence repeat markers covering polymorphic regions of ?1,340 centimorgans. Phenotypic data revealed significant (P < 0.01) genotypic differentiation for STB, heading date, and plant height. Entry-mean heritabilities (h(2)) for STB were 0.73 for 'Florett'/'Biscay' and 0.38 for 'Tuareg'/'Biscay'. All correlations between STB and heading date as well as between STB and plant height were low (r = -0.13 to -0.20). In quantitative trait loci (QTL) analysis, nine and six QTL were found for STB ratings explaining, together, 55 and 51% of phenotypic variation in 'Florett'/'Biscay' and 'Tuareg'/'Biscay', respectively. Genotype-environment and QTL-environment interactions had a large impact. Two major QTL were detected consistently across environments on chromosomes 3B and 6D from 'Florett' and chromosomes 4B and 6B from 'Tuareg', each explaining 12 to 17% of normalized adjusted phenotypic variance. These results indicate that adult-plant resistance to STB in both mapping populations was of a quantitative nature. PMID:21635143

Risser, P; Ebmeyer, E; Korzun, V; Hartl, L; Miedaner, T

2011-10-01

179

[Effects of population distribution pattern and irrigation schedule on radiation utilization in winter wheat farmland].  

PubMed

A field experiment was conducted in 2006-2008 to study the effects of different population distribution pattern and irrigation schedule on the radiation utilization in a winter wheat farmland at the same population density (2.04 x 10(6) plant x hm(-2)). Four population distribution patterns were designed, i.e., row spacing (cm) x plant spacing (cm) 7 x 7 (A), 14 x 3.5 (B), 24.5 x 2 (C), and 49 x 1 (D), and each pattern had four irrigation schedules, i. e., no-irrigation, irrigation at jointing stage, irrigation at jointing and heading stages, and irrigation at jointing, heading and filling stages. The irrigation amount was 0.60 m3 each time. In the patterns A and B, the tiller number and leaf area index (LIA) were significantly higher than those in C and D (P< 0.05). With the increase of row spacing, the photosynthetically active radiation (PAR) transmittance ratio increased gradually, while the PAR capture ratio had a decreasing trend. Increasing irrigation times increased the tiller number and LAI, but decreased the transmittance ratio of PAR, resulting in a significant increase of PAR capture ratio (P<0.05). The PAR capture ratio in the crop canopy was higher in upper layers, compared with that in lower layers. Relatively uniform population distribution and irrigation increased the PAR capture ratio in the upper 40 cm canopy layers significantly. The radiation use efficiency (RUE) decreased with increasing row spacing, with the two year's average total RUE in A, B, C, and D being 1.24%, 1.27%, 1.21% and 1.06%, respectively, and that in B was 5.21% and 19.56% higher than that in C and D, respectively, with the difference being significant. It was suggested that relatively uniform population distribution improved the winter wheat population structure and PAR capture, being beneficial to the fully use of radiation, and irrigation also had positive effects on the population structure, being helpful to the increase of crop RUE. PMID:19947205

Yang, Guo-Min; Sun, Shu-Juan; Zhou, Xun-Bo; Chen, Yu-Hai; Qi, Lin; Gao, Hui-Jun; Liu, Yan

2009-08-01

180

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

181

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

PubMed

The domestication of wheat was instrumental in spawning the civilization of humankind, and it occurred through genetic mutations that gave rise to types with non-fragile rachises, soft glumes, and free-threshing seed. Wild emmer (Triticum turgidum ssp. dicoccoides), the tetraploid AB-genome progenitor of domesticated wheat has genes that confer tenacious glumes (Tg) that underwent genetic mutations to give rise to free-threshing wheat. Here, we evaluated disomic substitution lines involving chromosomes 2A and 2B of wild emmer accessions substituted for homologous chromosomes in tetraploid and hexaploid backgrounds. The results suggested that both chromosomes 2A and 2B of wild emmer possess genes that inhibit threshability. A population of recombinant inbred lines derived from the tetraploid durum wheat variety Langdon crossed with a Langdon - T. turgidum ssp. dicoccoides accession PI 481521 chromosome 2B disomic substitution line was used to develop a genetic linkage map of 2B, evaluate the genetics of threshability, and map the gene derived from PI 481521 that inhibited threshability. A 2BS linkage map comprised of 58 markers was developed, and markers delineated the gene to a 2.3 cM interval. Comparative analysis with maps containing the tenacious glume gene Tg-D1 on chromosome arm 2 DS from Aegilops tauschii, the D genome progenitor of hexaploid wheat, revealed that the gene inhibiting threshability in wild emmer was homoeologous to Tg-D1 and therefore designated Tg-B1. Comparative analysis with rice and Brachypodium distachyon indicated a high level of divergence and poorly conserved colinearity, particularly near the Tg-B1 locus. These results provide a foundation for further studies involving Tg-B1, which, together with Tg-D1, had profound influences on wheat domestication. PMID:24657062

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

2014-06-01

182

Detection of a 4DL chromosome segment translocated to rye chromosome 5R in an advanced hexaploid triticale line Bronco 90  

Microsoft Academic Search

Bronco 90 is an advanced line of hexaploid triticale and was reported to be a 2D(2R) chromosome substitution type. In F1 hybrids of this triticale with bread wheat, however, a meiotic configuration of 16 bivalents and 10 univalents was frequently\\u000a observed indicating the presence of an additional D(R) chromosome substitution or D\\/R translocation. To determine the chromosome\\u000a constitution of Bronco

Shin Taketa; Tetsuya Nakazaki; Trude Schwarzacher; John S. Heslop-Harrison

1997-01-01

183

Evolutionary Genomics of Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is the world’s largest and most important food crop for direct human consumption, therefore, continued wheat improvement is paramount for feeding an ever-increasing human population. Wheat improvement is tightly associated with the characterization and understanding of wheat evolution and gene...

184

POPULATIONS OF 2,4-DIACETYLPHLOROGLUCINOL (DAPG)-PRODUCING PSEUDOMONAS FLUORESCENS IN THE RHIZOSPHERE OF PYTHIUM-INFECTED WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Root infections by soilborne pathogens can either positively or negatively affect root colonization and antibiotic production by beneficial bacteria. We tested the impact of four Pythium spp. on colonization of wheat roots by indigenous populations of 2,4-diacetylphloroglucinol (DAPG)-producing Pse...

185

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...

186

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...

187

POPULATION DYNAMICS IN THE FIELD OF A BIOCONTROL AGENT FOR FUSARIUM HEAD BLIGHT OF WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Gibberella zeae (anamorph Fusarium graminearum) is the major causal organism of Fusarium head blight (FHB) on wheat and barley. Wheat anthers are an important site of infection. Application of Crytococcus nodaensis OH 182.9 to wheat heads at the time of flowering reduces FHB. The goal of this res...

188

Mapping Stripe Rust Resistance in a BrundageXCoda Winter Wheat Recombinant Inbred Line Population  

PubMed Central

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

189

Experimental Estimation of Mutation Rates in a Wheat Population With a Gene Genealogy Approach  

PubMed Central

Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 × 10?3 per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues. PMID:18689900

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

2008-01-01

190

An Eight-Parent Multiparent Advanced Generation Inter-Cross Population for Winter-Sown Wheat: Creation, Properties, and Validation  

PubMed Central

MAGIC populations represent one of a new generation of crop genetic mapping resources combining high genetic recombination and diversity. We describe the creation and validation of an eight-parent MAGIC population consisting of 1091 F7 lines of winter-sown wheat (Triticum aestivum L.). Analyses based on genotypes from a 90,000-single nucleotide polymorphism (SNP) array find the population to be well-suited as a platform for fine-mapping quantitative trait loci (QTL) and gene isolation. Patterns of linkage disequilibrium (LD) show the population to be highly recombined; genetic marker diversity among the founders was 74% of that captured in a larger set of 64 wheat varieties, and 54% of SNPs segregating among the 64 lines also segregated among the eight founder lines. In contrast, a commonly used reference bi-parental population had only 54% of the diversity of the 64 varieties with 27% of SNPs segregating. We demonstrate the potential of this MAGIC resource by identifying a highly diagnostic marker for the morphological character "awn presence/absence" and independently validate it in an association-mapping panel. These analyses show this large, diverse, and highly recombined MAGIC population to be a powerful resource for the genetic dissection of target traits in wheat, and it is well-placed to efficiently exploit ongoing advances in phenomics and genomics. Genetic marker and trait data, together with instructions for access to seed, are available at http://www.niab.com/MAGIC/. PMID:25237112

Mackay, Ian J.; Bansept-Basler, Pauline; Barber, Toby; Bentley, Alison R.; Cockram, James; Gosman, Nick; Greenland, Andy J.; Horsnell, Richard; Howells, Rhian; O’Sullivan, Donal M.; Rose, Gemma A.; Howell, Phil J.

2014-01-01

191

An eight-parent multiparent advanced generation inter-cross population for winter-sown wheat: creation, properties, and validation.  

PubMed

MAGIC populations represent one of a new generation of crop genetic mapping resources combining high genetic recombination and diversity. We describe the creation and validation of an eight-parent MAGIC population consisting of 1091 F7 lines of winter-sown wheat (Triticum aestivum L.). Analyses based on genotypes from a 90,000-single nucleotide polymorphism (SNP) array find the population to be well-suited as a platform for fine-mapping quantitative trait loci (QTL) and gene isolation. Patterns of linkage disequilibrium (LD) show the population to be highly recombined; genetic marker diversity among the founders was 74% of that captured in a larger set of 64 wheat varieties, and 54% of SNPs segregating among the 64 lines also segregated among the eight founder lines. In contrast, a commonly used reference bi-parental population had only 54% of the diversity of the 64 varieties with 27% of SNPs segregating. We demonstrate the potential of this MAGIC resource by identifying a highly diagnostic marker for the morphological character "awn presence/absence" and independently validate it in an association-mapping panel. These analyses show this large, diverse, and highly recombined MAGIC population to be a powerful resource for the genetic dissection of target traits in wheat, and it is well-placed to efficiently exploit ongoing advances in phenomics and genomics. Genetic marker and trait data, together with instructions for access to seed, are available at http://www.niab.com/MAGIC/. PMID:25237112

Mackay, Ian J; Bansept-Basler, Pauline; Barber, Toby; Bentley, Alison R; Cockram, James; Gosman, Nick; Greenland, Andy J; Horsnell, Richard; Howells, Rhian; O'Sullivan, Donal M; Rose, Gemma A; Howell, Phil J

2014-09-01

192

Genetic Diversity and Population Structure of Tetraploid Wheats (Triticum turgidum L.) Estimated by SSR, DArT and Pedigree Data  

PubMed Central

Levels of genetic diversity and population genetic structure of a collection of 230 accessions of seven tetraploid Triticum turgidum L. subspecies were investigated using six morphological, nine seed storage protein loci, 26 SSRs and 970 DArT markers. The genetic diversity of the morphological traits and seed storage proteins was always lower in the durum wheat compared to the wild and domesticated emmer. Using Bayesian clustering (K?=?2), both of the sets of molecular markers distinguished the durum wheat cultivars from the other tetraploid subspecies, and two distinct subgroups were detected within the durum wheat subspecies, which is in agreement with their origin and year of release. The genetic diversity of morphological traits and seed storage proteins was always lower in the improved durum cultivars registered after 1990, than in the intermediate and older ones. This marked effect on diversity was not observed for molecular markers, where there was only a weak reduction. At K >2, the SSR markers showed a greater degree of resolution than for DArT, with their identification of a greater number of groups within each subspecies. Analysis of DArT marker differentiation between the wheat subspecies indicated outlier loci that are potentially linked to genes controlling some important agronomic traits. Among the 211 loci identified under selection, 109 markers were recently mapped, and some of these markers were clustered into specific regions on chromosome arms 2BL, 3BS and 4AL, where several genes/quantitative trait loci (QTLs) are involved in the domestication of tetraploid wheats, such as the tenacious glumes (Tg) and brittle rachis (Br) characteristics. On the basis of these results, it can be assumed that the population structure of the tetraploid wheat collection partially reflects the evolutionary history of Triticum turgidum L. subspecies and the genetic potential of landraces and wild accessions for the detection of unexplored alleles. PMID:23826256

Laidò, Giovanni; Mangini, Giacomo; Taranto, Francesca; Gadaleta, Agata; Blanco, Antonio; Cattivelli, Luigi; Marone, Daniela; Mastrangelo, Anna M.; Papa, Roberto; De Vita, Pasquale

2013-01-01

193

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

194

GENETIC CHARACTERIZATION AND MOLECULAR MAPPING OF HESSIAN FLY RESISTANCE GENES DERIVED FROM TRITICUM TAUSCHII IN SYNTHETIC WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two synthetic hexaploid wheat lines (×Aegilotriticum spp., 2n=6x=42, genomes AABBDD), SW8 and SW34, developed from the crosses of the durum wheat cultivar Langdon (Triticum turgidum L. var. durum, 2n=4x=28, genomes AABB) with two T. tauschii (Coss.) Schmal accessions (2n=2x=14, genome DD), were dete...

195

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

196

PHENOTYPIC ASSESSMENT AND MAPPED MARKERS FOR H31, A NEW WHEAT GENE CONFERRING RESISTANCE TO HESSIAN FLY (DIPTERA: CECIDOMYIIDAE)  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new source of resistance to the highly virulent and widespread biotype L of the Hessian fly, Mayetiola destructor (Say), was identified in an accession of tetraploid durum wheat, Triticum turgidum Desf., and was introgressed into hexaploid common wheat, T. aestivum L. Genetic analysis revealed th...

197

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

PubMed

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

198

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

199

Selecting and Sorting Waxy Wheat Kernels Using Near-Infrared Spectroscopy  

Microsoft Academic Search

Cereal Chem. 86(3):251-255 An automated single kernel near-infrared (NIR) sorting system was used to separate single wheat (Triticum aestivum L.) kernels with amylose-free (waxy) starch from reduced-amylose (partial waxy) or wild- type wheat kernels. Waxy kernels of hexaploid wheat are null for the granule-bound starch synthase alleles at all three Wx gene loci; partial waxy kernels have at least one

F. E. Dowell; E. B. Maghirang; R. A. Graybosch; W. A. Berzonsky; S. R. Delwiche

2009-01-01

200

Production of waxy (amylose-free) wheats  

Microsoft Academic Search

The Waxy (Wx) protein has been identified as granule-bound starch synthase (GBSS; EC 24.1.21), which is involved in amylose synthesis in plants. Although common wheat (Triticum aestivum L.) has three Wx proteins, “partial waxy mutants” lacking one or two of the three proteins have been found. Using such partial waxy mutants, tetra- and hexaploid waxy mutants with endosperms that are

Toshiki Nakamura; Makoto Yamamori; Hisashi Hirano; Soh Hidaka; Tukasa Nagamine

1995-01-01

201

Estimation of Long-Term Effective Population Sizes Through the History of Durum Wheat Using Microsatellite Data  

PubMed Central

Estimation of long-term effective population size (Ne) from polymorphism data alone requires an independent knowledge of mutation rate. Microsatellites provide the opportunity to estimate Ne because their high mutation rate can be estimated from observed mutations. We used this property to estimate Ne in allotetraploid wheat Triticum turgidum at four stages of its history since its domestication. We estimated the mutation rate of 30 microsatellite loci. Allele-specific mutation rates ? were predicted from the number of repeats of the alleles. Effective population sizes were calculated from the diversity parameter ? = 4Ne?. We demonstrated from simulations that the unbiased estimator of ? based on Nei's heterozygosity is the most appropriate for estimating Ne because of a small variance and a relative robustness to variations in the mutation model compared to other estimators. We found a Ne of 32,500 individuals with a 95% confidence interval of [20,739; 45,991] in the wild ancestor of wheat, 12,000 ([5790; 19,300]) in the domesticated form, 6000 ([2831; 9556]) in landraces, and 1300 ([689; 2031]) in recent improved varieties. This decrease illustrates the successive bottlenecks in durum wheat. No selective effect was detected on our loci, despite a complete loss of polymorphism for two of them. PMID:15545658

Thuillet, A.-C.; Bataillon, T.; Poirier, S.; Santoni, S.; David, J. L.

2005-01-01

202

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

203

Comparison of the genetic structure of populations of wild emmer wheat, Triticum turgidum ssp. dicoccoides , from Israel and Turkey revealed by AFLP analysis  

Microsoft Academic Search

The aim of the present study was to assess the genetic variation in several Israeli and Turkish populations of wild emmer\\u000a wheat, Triticum turgidum ssp. dicoccoides, the progenitor of most domesticated wheat. Single spikes were collected in 2002 from 60 plants that grew in six different\\u000a habitats in Ammiad, northeastern Israel (8–12 plants from each habitat), and in 1998 from 56

O. Ozbek; E. Millet; Y. Anikster; O. Arslan; M. Feldman

2007-01-01

204

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

205

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

PubMed Central

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

2014-01-01

206

Wheat domestication: lessons for the future.  

PubMed

Wheat was one of the first crops to be domesticated more than 10,000 years ago in the Middle East. Molecular genetics and archaeological data have allowed the reconstruction of plausible domestication scenarios leading to modern cultivars. For diploid einkorn and tetraploid durum wheat, a single domestication event has likely occurred in the Karacadag Mountains, Turkey. Following a cross between tetraploid durum and diploid T. tauschii, the resultant hexaploid bread wheat was domesticated and disseminated around the Caucasian region. These polyploidisation events facilitated wheat domestication and created genetic bottlenecks, which excluded potentially adaptive alleles. With the urgent need to accelerate genetic progress to confront the challenges of climate change and sustainable agriculture, wild ancestors and old landraces represent a reservoir of underexploited genetic diversity that may be utilized through modern breeding methods. Understanding domestication processes may thus help identifying new strategies. PMID:21377616

Charmet, Gilles

2011-03-01

207

Comparative growth and development of hexaploid and tetraploid reed canarygrass  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

208

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...

209

A SNP genotyping array for hexaploid oat (Avena sativa L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

210

Cytoplasmic effects on the tissue culture response of wheat ( Triticum aestivum ) callus  

Microsoft Academic Search

Calli were initiated from immature embryos of eight lines of hexaploid wheat (Triticum aestivum L. em. Thell) with different cytoplasms, the euplasmic nuclear donor ‘Chinese Spring’ and seven alloplasmic lines derived from wild relative species of the genera Triticum and Aegilops. The calli were found to differ in their initial growth rates, their sensitivity to 2,4-D and their ability to

R. J. Mathias; K. Fukui; C. N. Law

1986-01-01

211

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

212

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...

213

Effects of tillage on microbial populations associated to soil aggregates under dryland spring wheat system  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tillage may influence the proportions of microorganisms involved in soil aggregation. We evaluated the effects of no till (NT) and conventional tillage (CT, tillage depth about 7 cm) continuous spring wheat system on bacterial communities predominant in microaggregates (0.25-0.05 mm) and on saprophy...

214

MARKER ASSISTED SELECTION FOR FUSARIUM RESISTANCE IN WHEAT FROM DOUBLE HAPLOID POPULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is caused by Fusarium graminearum Schwabe. The fungus can degenerate the wheat grain tissue and produce deoxynivalenol (DON) which is toxic to both human and animals. Epidemics of FHB can result in severe loss of yield and grain quality. Cultural or/and chemical control of...

215

MARKER ASSISTED SELECTION FOR FHB RESISTANCE IN SOFT RED WHEAT FROM DOUBLE HAPLOID POPULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is caused by Fusarium graminearum Schwabe. The fungus can degenerate the wheat grain tissue and produce deoxynivalenol (DON) which is toxic to both human and animals. Epidemics of FHB can result in severe loss of yield and grain quality. Cultural or/and chemical control of...

216

QTLS FOR YIELD AND RELATED TRAITS IN THE WHEAT POPULATION, NING 7840 X CLARK  

Technology Transfer Automated Retrieval System (TEKTRAN)

Grain yield and associated agronomic traits are important factors in wheat (Triticum aestivum L.) improvement. Knowledge regarding the number, genomic location, and effect of quantitative trait loci (QTL) would facilitate marker-assisted selection and the development of cultivars with desirable cha...

217

Mapping of QTL for Fusarium head blight resistance and morphological and developmental traits in three backcross populations derived from Triticum dicoccum × Triticum durum.  

PubMed

Breeding for resistance to Fusarium head blight (FHB) in durum wheat continues to be hindered by the lack of effective resistance sources. Only limited information is available on resistance QTL for FHB in tetraploid wheat. In this study, resistance to FHB of a Triticum dicoccum line in the background of three Austrian T. durum cultivars was genetically characterized. Three populations of BC(1)F(4)-derived RILs were developed from crosses between the resistant donor line T. dicoccum-161 and the Austrian T. durum recipient varieties DS-131621, Floradur and Helidur. About 130 BC(1)F(4)-derived lines per population were evaluated for FHB response using artificial spray inoculation in four field experiments during two seasons. Lines were genetically fingerprinted using SSR and AFLP markers. Genomic regions on chromosomes 3B, 4B, 6A, 6B and 7B were significantly associated with FHB severity. FHB resistance QTL on 6B and 7B were identified in two populations and a resistance QTL on 4B appeared in three populations. The alleles that enhanced FHB resistance were derived from the T. dicoccum parent, except for the QTL on chromosome 3B. All QTL except the QTL on 6A mapped to genomic regions where QTL for FHB have previously been reported in hexaploid wheat. QTL on 3B and 6B coincided with Fhb1 and Fhb2, respectively. This implies that tetraploid and hexaploid wheat share common genomic regions associated with FHB resistance. QTL for FHB resistance on 4B co-located with a major QTL for plant height and mapped at the position of the Rht-B1 gene, while QTL on 7B overlapped with QTL for flowering time. PMID:22926291

Buerstmayr, Maria; Huber, Karin; Heckmann, Johannes; Steiner, Barbara; Nelson, James C; Buerstmayr, Hermann

2012-12-01

218

Chromosomal rearrangements in the rye genome relative to that of wheat  

Microsoft Academic Search

An RFLP-based genetic map of Secale Cereale has provided evidence for multiple evolutionary translocations in the rye genome relative to that of hexaploid wheat. DNA clones which have previously been mapped in wheat indicated that chromosome arms 2RS, 3RL, 4RL, 5RL, 6RS, 6RL, 7RS and 7RL have all been involved in at least one translocation. A possible evolutionary pathway, which

Katrien M. Devos; M. D. Atkinson; C. N. Chinoy; H. A. Francis; R. L. Harcourt; R. M. D. Koebner; C. J. Liu; P. Masoj?; D. X. Xie; M. D. Gale

1993-01-01

219

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

220

Development of isohomoeoallelic lines within the wheat cv. Courtot for high molecular weight glutenin subunits: transfer of the Glu-D1 locus to chromosome 1A  

Microsoft Academic Search

Wheat quality depends on protein composition and grain protein content. High molecular weight glutenin subunits (HMW-GS) play\\u000a an important role in determining the viscoelastic properties of gluten. In an attempt to improve the bread-making quality\\u000a of hexaploid wheat by elaborating novel HMW-GS combinations, a fragment of wheat chromosome 1D containing the Glu-D1 locus encoding the Dx2+Dy12 subunits was translocated to

J. Dumur; G. Branlard; A.-M. Tanguy; M. Dardevet; O. Coriton; V. Huteau; J. Lemoine; Joseph Jahier

2009-01-01

221

Quantification of genetic relationships among A genomes of wheats.  

PubMed

The genetic relationships of A genomes of Triticum urartu (Au) and Triticum monococcum (Am) in polyploid wheats are explored and quantified by AFLP fingerprinting. Forty-one accessions of A-genome diploid wheats, 3 of AG-genome wheats, 19 of AB-genome wheats, 15 of ABD-genome wheats, and 1 of the D-genome donor Ae. tauschii have been analysed. Based on 7 AFLP primer combinations, 423 bands were identified as potentially A genome specific. The bands were reduced to 239 by eliminating those present in autoradiograms of Ae. tauschii, bands interpreted as common to all wheat genomes. Neighbour-joining analysis separates T. urartu from T. monococcum. Triticum urartu has the closest relationship to polyploid wheats. Triticum turgidum subsp. dicoccum and T. turgidum subsp. durum lines are included in tightly linked clusters. The hexaploid spelts occupy positions in the phylogenetic tree intermediate between bread wheats and T. turgidum. The AG-genome accessions cluster in a position quite distant from both diploid and other polyploid wheats. The estimates of similarity between A genomes of diploid and polyploid wheats indicate that, compared with Am, Au has around 20% higher similarity to the genomes of polyploid wheats. Triticum timo pheevii AG genome is molecularly equidistant from those of Au and Am wheats. PMID:16699549

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

2006-04-01

222

The wheat ribosomal DNA spacer region: Its structure and variation in populations and among species  

Microsoft Academic Search

The wheat rDNA clone pTA250 was examined in detail to provide a restriction enzyme map and the nucleotide sequence of two of the eleven, 130 bp repeating units found within the spacer region. The 130 bp units showed some sequence heterogeneity. The sequence difference between the two 130 bp units analysed (130.6 and 130.8) was at 7 positions and could

R. Appels; J. Dvo?ák

1982-01-01

223

Abundance, variability and chromosomal location of microsatellites in wheat  

Microsoft Academic Search

The potential of microsatellite sequences as genetic markers in hexaploid wheat (Triticum aestivum) was investigated with respect to their abundance, variability, chromosomal location and usefulness in related species. By screening a lambda phage library, the total number of (GA)n blocks was estimated to be 3.6 x 104 and the number of (GT)n blocks to be 2.3 x 104 per haploid

Marion S. Röder; Jens Plaschke; Susanne U. König; Andreas Börner; Mark E. Sorrells; Steven D. Tanksley; Martin W. Ganal

1995-01-01

224

Composition and phylogenetic analysis of wheat cryptochrome gene family  

Microsoft Academic Search

Cryptochrome (CRY) gene family encodes photoreceptors mediating developmental responses to blue light throughout the life\\u000a of plants. We report here the characterization of CRY gene family in hexaploid wheat. Degenerate PCR amplification of the regions encoding the conserved flavin-binding domain\\u000a of CRY proteins yielded seven bands, resulting from amplification of CRY1a, CRY1b and CRY2 homologous genes. Assignment of individual amplicons

Pei Xu; Hui Lan Zhu; Hai Bin Xu; Zheng Zhi Zhang; Cai Qin Zhang; Li Xia Zhang; Zheng Qiang Ma

2010-01-01

225

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

226

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

227

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...

228

Exploring the diploid wheat ancestral A genome through sequence comparison at the High-Molecular-Weight glutenin locus region  

Technology Transfer Automated Retrieval System (TEKTRAN)

The polyploid nature of hexaploid wheat (T. aestivum, AABBDD) often represents a great challenge in various aspects of research including genetic mapping, map-based cloning of important genes, and sequencing and accurate assembly of its genome. To explore the utility of ancestral diploid species o...

229

The interaction of genotype and culture medium on the tissue culture responses of wheat (Triticum aestivum L. em. thell) callus  

Microsoft Academic Search

The effect of the interaction of genotype and culture medium on the initiation of callus from immature embryos and subsequent plant regeneration was investigated in eight hexaploid wheat lines. Intervarietal differences in culture response and interaction of the genotype with coconut milk are reported. The relative contributions of media and genotype effects to culture performance are assessed. The observation that

Raymond J. Mathias; Eric S. Simpson

1986-01-01

230

The effect of specific chromosome and cytoplasm substitutions on the tissue culture response of wheat ( Triticum aestivum ) callus  

Microsoft Academic Search

Calli were initiated from immature embryos of four lines of hexaploid wheat (Triticum aestivum L. em. Thell), the euplasmic nuclear donor ‘Chinese Spring’, ‘Chinese Spring’ in which both 4B chromosomes were substituted by those of the variety ‘Cappelle-Desprez’ and two alloplasmic lines in which these nuclei were substituted into the cytoplasm of Aegilops ovata. The calli were found to differ

R. J. Mathias; K. Fukui

1986-01-01

231

Variation in virulence to wheat in Pyrenophora tritici-repentis population from Saskatchewan, Canada, from 2000 to 2002  

Microsoft Academic Search

Tan spot, caused by Pyrenophora tritici-repentis, is an economically important disease of wheat worldwide. Isolates of P. tritici-repentis are presently classified into eight races on the basis of their virulence (ability to induce necrosis and (or) chlorosis) on a set of wheat differential cultivars. A total of 337 isolates of P. tritici-repentis from leaves of common wheat (Triticum aestivum), durum

P. K. Singh; M. Mergoum; G. R. Hughes

2007-01-01

232

Reconstruction of the synthetic W9784 x Opata85 wheat reference population  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

233

EVIDENCE FOR FREQUENT RECOMBINATION IN A WHEAT STREAK MOSAIC VIRUS POPULATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

There are two types of recombination events of interest in RNA viruses. One is between divergent virus populations or virus species. The other is between members of the same population. The former is perhaps important for long-term virus evolution while the latter could serve as a mechanism to preve...

234

The production of haploid wheat plants from wheat x maize crosses.  

PubMed

Hybrid embryos from hexaploid wheat x maize crosses rapidly lose the maize chromosomes to produce haploid wheat embryos. Such embryos almost always aborted when left to develop on the plant, and only 1 was recovered from 2440 florets (0.17% of the expected number). Embryos had greater viability in spikelet culture, 47 (26.5% of the expected number) being recovered from 706 ovaries. Thirty-two of these embryos germinated to give green plants, 31 of which were haploid (21 wheat chromosomes) and 1 of which was euploid (42 wheat chromosomes). Spikelet culture enabled 17.1% of the expected number of embryos to be recovered as haploid plants, a 100-fold improvement on allowing embryos to develop in vivo. Ten haploid plants of 'Chinese Spring' (kr1, kr2), 13 plants of 'Chinese Spring (Hope 5A)' (kr1, Kr2), and 8 of 'Hope' (Kr1, Kr2) were recovered. The potential of wheat x maize crosses for wheat haploid production and for gene transfer from maize to wheat is discussed. PMID:24232203

Laurie, D A; Bennett, M D

1988-09-01

235

Conditional QTL mapping for plant height with respect to the length of the spike and internode in two mapping populations of wheat  

Microsoft Academic Search

Plant height (PH) in wheat is a complex trait; its components include spike length (SL) and internode lengths. To precisely\\u000a analyze the factors affecting PH, two F8:9 recombinant inbred line (RIL) populations comprising 485 and 229 lines were generated. Crosses were performed between Weimai\\u000a 8 and Jimai 20 (WJ) and between Weimai 8 and Yannong 19 (WY). Possible genetic relationships

Fa CuiJun; Jun Li; Anming Ding; Chunhua Zhao; Lin Wang; Xiuqin Wang; Sishen Li; Yinguang Bao; Xingfeng Li; Deshun Feng; Lingrang Kong; Honggang Wang

2011-01-01

236

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

237

A NEW HOST SELECTIVE TOXIN PRODUCED BY STAGONOSPORA NODORUM AND ITS SIGNIFICANCE IN DISEASE USING A SEGREGATING WHEAT MAPPING POPULATION.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stagonospora nodorum blotch is a devastating disease of wheat and durum throughout the world. We have recently identified a new host selective toxin (SnTox2) from culture filtrates of Stagonospora nodorum. The toxin shows selective action on several different wheat genotypes indicating that it is...

238

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...

239

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

240

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...

241

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

242

Tracking costs of virulence in natural populations of the wheat pathogen, Puccinia striiformis f.sp.tritici  

PubMed Central

Background Costs of adaptation play an important role in host-parasite coevolution. For parasites, evolving the ability to circumvent host resistance may trade off with subsequent growth or transmission. Such costs of virulence (sensu plant pathology) limit the spread of all-infectious genotypes and thus facilitate the maintenance of genetic polymorphism in both host and parasite. We investigated costs of three virulence factors in Puccinia striiformis f.sp.tritici, a fungal pathogen of wheat (Triticum aestivum). Results In pairwise competition experiments, we compared the fitness of near-isogenic genotypes that differed by a single virulence factor. Two virulence factors (vir4, vir6) imposed substantial fitness costs in the absence of the corresponding resistance genes. In contrast, the vir9 virulence factor conferred a strong competitive advantage to several isolates, and this for different host cultivars and growing seasons. In part, the experimentally derived fitness costs and benefits are consistent with frequency changes of these virulence factors in the French pathogen population. Conclusion Our results illustrate the variation in the evolutionary trajectories of virulence mutations and the potential role of compensatory mutations. Anticipation of such variable evolutionary outcomes represents a major challenge for plant breeding strategies. More generally, we believe that agro-patho-systems can provide valuable insight in (co)evolutionary processes in host-parasite systems. PMID:19183485

Bahri, Bochra; Kaltz, Oliver; Leconte, Marc; de Vallavieille-Pope, Claude; Enjalbert, Jérôme

2009-01-01

243

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

244

Applicability of inter-simple sequence repeat polymorphisms in wheat for use as DNA markers in comparison to RFLP and RAPD markers  

Microsoft Academic Search

Inter-simple sequence repeat polymorphic DNA (ISSR) was evaluated for its applicability as a genetic marker system in wheat.\\u000a PCR was carried out with primers that annealed to simple sequence repeats. The resultant products were subjected to agarose-gel\\u000a electrophoresis, and the banding patterns were compared among six wheat accessions containing diploid, tetraploid, and hexaploid\\u000a members. Out of 100 examined, 33 primers

T. Nagaoka; Y. Ogihara

1997-01-01

245

Microsatellite markers associated with two Aegilops tauschii-derived greenbug resistance loci in wheat.  

PubMed

A new source of greenbug (Schizaphis graminum Rondani) resistance derived from Aegilops tauschii (Coss.) Schmal was identified in W7984, a synthetic hexaploid wheat line and one parent of the International Triticeae Mapping Initiative (ITMI) mapping population. Segregation analysis of responses to greenbug feeding in a set of recombinant inbred lines (RILs) identified a single, dominant gene governing the greenbug resistance in W7984, which was placed in chromosome arm 7DL by linkage analysis with molecular markers in the ITMI population. Allelism tests based on the segregation of responses to greenbug feeding in F2 and testcross plants revealed that the greenbug resistance in W7984 and Largo, another synthetic line carrying the greenbug resistance gene Gb3, was controlled by different but linked loci. Using the ITMI reference map and a target mapping strategy, we have constructed a microsatellite map of Gb3 in a mapping population of 130 F7 RILs from Largo x TAM 107 and identified one marker (Xwmc634) co-segregating with Gb3 and four markers (Xbarc76, Xgwm037, Xgwm428 and Xwmc824) closely linked with Gb3. Deletion mapping of selected microsatellite markers flanking the Gb3 locus placed this resistance gene into the distal 18% region of 7DL. Comparative mapping in the ITMI and Largo x TAM 107 populations using the same set of microsatellite markers provided further evidence that greenbug resistance in W7984 and Largo is conditioned by two different loci. We suggest that the greenbug resistance gene in W7984 be designated Gb7. The microsatellite map of Gb3 constructed from this study should be a valuable tool for marker-assisted selection of Gb3-conferred greenbug resistance in wheat breeding. PMID:15592809

Weng, Y; Li, W; Devkota, R N; Rudd, J C

2005-02-01

246

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

247

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

PubMed

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

2011-12-01

248

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

SciTech Connect

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

French, Roy [Agricultural Research Service, United States Department of Agriculture and Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583 (United States); Stenger, Drake C. [Agricultural Research Service, United States Department of Agriculture and Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583 (United States)]. E-mail: dstenger@unlnotes.unl.edu

2005-12-20

249

Estimation of genetic parameters of a DH wheat population grown at different N stress levels characterized by probe genotypes.  

PubMed

Low market prices and environmental concerns in Europe favor lower input wheat production systems. To efficiently breed for new varieties adapted to low input management while maintaining high yield levels, our objective was to characterize the heritability and its components for yield and nitrogen traits under different nitrogen levels. Two hundred and twenty-two doubled-haploid (DH) lines from the cross between Arche (tolerant) and Récital (sensitive) were tested in France at four locations in 2000, and three in 2001, under high (N+) and low (N-) nitrogen supplies. The response of yield to the environment of four probe genotypes, the parents and two controls, were tested and used as descriptors of these environments. Grain yield (GY), its components, and grain and straw nitrogen, called nitrogen traits, were studied. A factorial regression was performed to assess the sensitivity (slope) of the DH lines to nitrogen stress and their performance to low nitrogen supply. An index based on the nitrogen nutrition index at flowering of the probe genotype Récital was the best descriptor of the environment stress. Heritabilities of yield and nitrogen traits for both nitrogen supplies were always above 0.6. When nitrogen stress increased, heritabilities decreased and genotype x nitrogen interaction variances increased. The decrease in heritability was mainly explained by a decrease in genetic variance. Genetic variation for sensitivity to nitrogen stress and performance under low nitrogen supply were shown in the population. GY decreased from 278 to 760 g/m2 per unit of nitrogen stress index increase and GY under moderate nitrogen stress varied from 340 to 613 g/m2. Those contrasted reactions revealed specific lines to include in breeding programs for improving GY under low nitrogen supply. PMID:16432739

Laperche, Anne; Brancourt-Hulmel, Maryse; Heumez, Emmanuel; Gardet, Olivier; Le Gouis, Jacques

2006-03-01

250

Characterization of ?-secalin genes from rye, triticale, and a wheat 1BL\\/1RS translocation line  

Microsoft Academic Search

Sixty-two DNA sequences for the coding regions of omega-secalin (?-secalin) genes have been characterized from rye (Secale cereale L.), hexaploid and octoploid triticale (×Triticosecale Wittmack), and wheat (Triticum aestivum L.) 1BL\\/1RS translocation line. Only 19 out of the 62 ?-secalin gene sequences were full-length open reading frames (ORFs),\\u000a which can be expressed into functional proteins. The other 43 DNA sequences

Q. T. Jiang; Y. M. Wei; L. Andre; Z. X. Lu; Z. E. Pu; Y. Y. Peng; Y. L. Zheng

2010-01-01

251

Wheat Improvement Programs WHEAT PROGRAM  

E-print Network

Wheat Improvement Programs WHEAT PROGRAM The small grains improvement effort at Texas Agri techniques. The College Station center focuses on wheat and oats for the South Texas and Blacklands regions of Texas, while the Amarillo center develops wheat and triticale lines for the Texas High Plains

252

Genotype-specific SNP map based on whole chromosome 3B sequence information from wheat cultivars Arina and Forno.  

PubMed

Agronomically important traits are frequently controlled by rare, genotype-specific alleles. Such genes can only be mapped in a population derived from the donor genotype. This requires the development of a specific genetic map, which is difficult in wheat because of the low level of polymorphism among elite cultivars. The absence of sufficient polymorphism, the complexity of the hexaploid wheat genome as well as the lack of complete sequence information make the construction of genetic maps with a high density of reproducible and polymorphic markers challenging. We developed a genotype-specific genetic map of chromosome 3B from winter wheat cultivars Arina and Forno. Chromosome 3B was isolated from the two cultivars and then sequenced to 10-fold coverage. This resulted in a single-nucleotide polymorphisms (SNP) database of the complete chromosome. Based on proposed synteny with the Brachypodium model genome and gene annotation, sequences close to coding regions were used for the development of 70 SNP-based markers. They were mapped on a Arina × Forno Recombinant Inbred Lines population and found to be spread over the complete chromosome 3B. While overall synteny was well maintained, numerous exceptions and inversions of syntenic gene order were identified. Additionally, we found that the majority of recombination events occurred in distal parts of chromosome 3B, particularly in hot-spot regions. Compared with the earlier map based on SSR and RFLP markers, the number of markers increased fourfold. The approach presented here allows fast development of genotype-specific polymorphic markers that can be used for mapping and marker-assisted selection. PMID:23046423

Shatalina, Margarita; Wicker, Thomas; Buchmann, Jan P; Oberhaensli, Simone; Simková, Hana; Doležel, Jaroslav; Keller, Beat

2013-01-01

253

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

254

Performance of wheat crops with different chromosome ploidy: root-sourced signals, drought tolerance, and yield performance.  

PubMed

Pot-culture experiments were carried out to estimate the role of non-hydraulic root signals (nHRS) and the relation of these signals to drought tolerance and grain yield formation under drought stress in six wheat varieties. These were two modern hexaploid wheat (Triticum aestivum L., AABBDD) Plateau602 and Longchun8139-2, two diploid wheat (Triticum monococcum L., AB) MO1 and MO4, and two tetraploid wheat (Triticum dicoccum Schuebl L., AABB) DM22 and DM31. In the two diploid relatives, the nHRS was switched on and off at a soil water content (SWC) of approximately 53-45% field water capacity (FWC). In contrast, in the modern hexaploid varieties, Longchun8139-2 and Plateau602 the nHRS occurred between a SWC of about 71 and 35% FWC, a much wider soil moisture range. The two tetraploid relatives, DM22 and DM31, were generally intermediate. The nHRS threshold range in SWC also narrowed as all six varieties went through successive developmental stages from shooting to grain filling. The two hexaploid wheat varieties had the longest duration of survival after the water supply ceased, and the best yield stability under drought stress, similar to with tetraploid wheat varieties; the diploid wheat varieties were least robust. These two parameters were both significantly correlated with the nHRS soil moisture threshold range (r=0.9456** and 0.8608*, respectively). Based on these patterns, we propose a "triple Z" model to describe the features of non-hydraulic stomatal sensitivity versus soil drought in wheat growth. PMID:16506063

Xiong, You-Cai; Li, Feng-Min; Zhang, Ting

2006-08-01

255

High molecular weight glutenin subunit in durum wheat (T. durum).  

PubMed

The diversity of high molecular weight (HMW) glutenin subunits of 502 varieties of durum wheat (Triticum durum) from 23 countries was studied using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Twenty-nine types of patterns were observed with 18 mobility bands. A total of 18 alleles were identified by comparing the mobilities of their subunits to those previously found in hexaploid wheat (T. aestivum) and in Triticum turgidum var. dicoccum. Five new alleles were detected: two on the Glu A1 and three on the Glu B1 locus. Comparison of the frequency of alleles in the three species T. aestivum, T. dicoccum and T. durum was investigated. Significant differences exist between each of these species on the basis of the frequency distributions of their three and four common alleles at the Glu A1 and Glu B1 locus, respectively. The Glu B1c allele occuring very frequently in hexaploid wheats was not found in the two tetraploid species. More than 83% of the T. durum analysed were found to have the Glu A1c (null) allele. PMID:24227241

Branlard, G; Autran, J C; Monneveux, P

1989-09-01

256

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

257

Identification of three Wx proteins in wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Nullisomic analysis of waxy (Wx) protein of hexaploid wheat (Triticum aestivum L.) cv. “Chinese Spring” using two-dimensional polyacrylamide gel electrophoresis revealed that threeWx loci,Wx-A1, Wx-B1, andWx-D1, located on chromosome arms 7AS, 4AL, and 7DS, produce three distinct Wx subunit groups, subunit group-A (SGA), SGB, and\\u000a SGD, respectively. SGA has a higher molecular weight and a more basic isoelectric point (pI)

T. Nakamura; M. Yamamori; H. Hirano; S. Hidaka

1993-01-01

258

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs  

Microsoft Academic Search

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination

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

2007-01-01

259

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

260

Wheat Allergy  

MedlinePLUS

... Wheat Soy Fish Shellfish Other Symptoms Diagnosis & Testing Proven Methods Skin Prick Tests Blood Tests Oral Food ... Wheat Soy Fish Shellfish Other Symptoms Diagnosis & Testing Proven Methods Skin Prick Tests Blood Tests Oral Food ...

261

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

PubMed

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

2011-12-01

262

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

263

Distribution and habitat segregation on different spatial scales among diploid, tetraploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps  

PubMed Central

Background and Aims The spatial distribution of cytotypes can provide valuable insights into evolutionary patterns of polyploid complexes. In a previous study the macro-scale distribution of the three main cytotypes in Senecio carniolicus (Asteraceae) within the Eastern Alps was characterized. Employing a roughly 12-fold extended sampling, the present study focuses on unravelling patterns of cytotype distribution on the meso- and microscale and on correlating those with ecological properties of the growing sites. Methods DAPI flow cytometry of dried samples was used to determine DNA ploidy level in 5033 individuals from 100 populations spread over the entire Eastern Alpine distribution area of S. carniolicus. Descriptors of microhabitats as well as spatial data were recorded in the field, and analysed with a mixed-effects ANOVA. Key Results Extensive variation in DNA ploidy levels (2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x) was detected. Of the main cytotypes, diploids and hexaploids were widespread and had strongly overlapping distributions resulting in the frequent occurrence of cytotype mixtures (half of the investigated populations), whereas tetraploids were disjunctly distributed and occurred in the south-west and the east of the species' distribution area. In spite of the frequent co-occurrence of cytotypes, only 1 % of the samples belonged to secondary cytotypes (3x, 5x, 7x, 8x, 9x). Diploids, tetraploids and hexaploids were altitudinally segregated, but with broad overlap. Similarly, highly significant differences in vegetation and rock cover as well as microhabitat exposure were found between the main cytotypes. Conclusions Senecio carniolicus shows a remarkable diversity of cytotypes. The distribution of the three main cytotypes (2x, 4x, 6x) has been shaped by Pleistocene glaciations to different extents. Whereas tetraploids are nearly entirely restricted to refugia, hexaploids colonized areas that were extensively glaciated. Diploid and hexaploid individuals often co-occur in mixed populations, where they are spatially and ecologically segregated at both the meso-scale (altitudinal differentiation, exposure of the growing site) and the micro-scale (cover of vegetation and bare rock). With regard to the ecological parameters investigated, the tetraploid cytotype occupies an intermediate position. The rareness of secondary cytotypes suggests the presence of strong pre- or post-zygotic mating barriers. PMID:20880930

Sonnleitner, Michaela; Flatscher, Ruth; Escobar García, Pedro; Rauchová, Jana; Suda, Jan; Schneeweiss, Gerald M.; Hülber, Karl; Schönswetter, Peter

2010-01-01

264

Quality (End-Use) Improvement in Wheat  

Microsoft Academic Search

Wheat provides nutrients and the raw materials for industrialized food production. Recent global economic trends and increases in urban population growth have led to an increased demand for wheat-based convenience foods (fast, ready-to-eat, frozen foods, etc.) and for new wheat-based products. These factors have resulted in a greater emphasis than ever on the end-use quality of wheat. This paper reviews

R. J. Peña; R. Trethowan; W. H. Pfeiffer; M. Van Ginkel

2002-01-01

265

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

266

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...

267

Isolation of full-length candidate CBF genes from hexaploid wheat (Triticum aestivum L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cold temperature is a serious abiotic stress to cereals in areas with severe winters. CBF (C-repeat binding factor) is a transcription factor that regulates Cold regulated (COR) genes in Arabidopsis and it is an important component of the CBF cold acclimation pathway. The CBF gene family is hypothes...

268

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

269

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

PubMed

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. PMID:3840588

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

1985-10-11

270

Effect of Introduced Pseudomonas fluorescens Strains on Soil Nematode and Protozoan Populations in the Rhizosphere of Wheat and Pea  

Microsoft Academic Search

Previous studies have shown that inoculation of pea seeds with Pseudomonas fluorescens strains F113lacZY or F113G22 increased mineralization of organic nitrogen in the rhizosphere. In contrast, inoculation of the same strains\\u000a onto wheat seeds reduced mineralization of N from organic residues incorporated into soil. In the present study, we report\\u000a on a likely explanation of this phenomenon, which appears to

M. J. Brimecombe; F. A. A. M. De Leij; J. M. Lynch

1999-01-01

271

Genome-Wide Quantitative Trait Locus Mapping Identifies Multiple Major Loci for Brittle Rachis and Threshability in Tibetan Semi-Wild Wheat (Triticum aestivum ssp. tibetanum Shao)  

PubMed Central

Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) is a semi-wild hexaploid wheat resource that is only naturally distributed in the Qinghai-Tibet Plateau. Brittle rachis and hard threshing are two important characters of Tibetan semi-wild wheat. A whole-genome linkage map of T. aestivum ssp. tibetanum was constructed using a recombinant inbred line population (Q1028×ZM9023) with 186 lines, 564 diversity array technology markers, and 117 simple sequence repeat markers. Phenotypic data on brittle rachis and threshability, as two quantitative traits, were evaluated on the basis of the number of average spike rachis fragments per spike and percent threshability in 2012 and 2013, respectively. Quantitative trait locus (QTL) mapping performed using inclusive composite interval mapping analysis clearly identified four QTLs for brittle rachis and three QTLs for threshability. However, three loci on 2DS, 2DL, and 5AL showed pleiotropism for brittle rachis and threshability; they respectively explained 5.3%, 18.6%, and 18.6% of phenotypic variation for brittle rachis and 17.4%, 13.2%, and 35.2% of phenotypic variation for threshability. A locus on 3DS showed an independent effect on brittle rachis, which explained 38.7% of the phenotypic variation. The loci on 2DS and 3DS probably represented the effect of Tg and Br1, respectively. The locus on 5AL was in very close proximity to the Q gene, but was different from the predicted q in Tibetan semi-wild wheat. To our knowledge, the locus on 2DL has never been reported in common wheat but was prominent in T. aestivum ssp. tibetanum accession Q1028. It remarkably interacted with the locus on 5AL to affect brittle rachis. Several major loci for brittle rachis and threshability were identified in Tibetan semi-wild wheat, improving the understanding of these two characters and suggesting the occurrence of special evolution in Tibetan semi-wild wheat. PMID:25474652

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

2014-01-01

272

Construction of an integrative linkage map and QTL mapping of grain yield-related traits using three related wheat RIL populations.  

PubMed

A novel high-density consensus wheat genetic map was obtained based on three related RIL populations, and the important chromosomal regions affecting yield and related traits were specified. A prerequisite for mapping quantitative trait locus (QTL) is to build a genetic linkage map. In this study, three recombinant inbred line populations (represented by WL, WY, and WJ) sharing one common parental line were used for map construction and subsequently for QTL detection of yield-related traits. PCR-based and diversity arrays technology markers were screened in the three populations. The integrated genetic map contains 1,127 marker loci, which span 2,976.75 cM for the whole genome, 985.93 cM for the A genome, 922.16 cM for the B genome, and 1,068.65 cM for the D genome. Phenotypic values were evaluated in four environments for populations WY and WJ, but three environments for population WL. Individual and combined phenotypic values across environments were used for QTL detection. A total of 165 putative additive QTL were identified, 22 of which showed significant additive-by-environment interaction effects. A total of 65 QTL (51.5%) were stable across environments, and 23 of these (35.4%) were common stable QTL that were identified in at least two populations. Notably, QTkw-5B.1, QTkw-6A.2, and QTkw-7B.1 were common major stable QTL in at least two populations, exhibiting 11.28-16.06, 5.64-18.69, and 6.76-21.16% of the phenotypic variance, respectively. Genetic relationships between kernel dimensions and kernel weight and between yield components and yield were evaluated. Moreover, QTL or regions that commonly interact across genetic backgrounds were discussed by comparing the results of the present study with those of previous similar studies. The present study provides useful information for marker-assisted selection in breeding wheat varieties with high yield. PMID:24326459

Cui, Fa; Zhao, Chunhua; Ding, Anming; Li, Jun; Wang, Lin; Li, Xingfeng; Bao, Yinguang; Li, Junming; Wang, Honggang

2014-03-01

273

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

274

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...

275

Monitoring Population Size, Activity, and Distribution of gfp-luxAB-Tagged Pseudomonas fluorescens SBW25 during Colonization of Wheat.  

PubMed

Increasingly, focus has been directed towards the use of microorganisms as biological control agents to combat fungal disease, as an alternative to chemical fungicides. Pseudomonas fluorescens SBW25 is one bacterial strain that has been demonstrated to promote plant growth by biocontrol of pathogenic fungi. To understand the mode of action of this bacterium, information regarding its localization and metabolic activity on plants is important. In this study, a gfp/luxAB-tagged derivative of P. fluorescens SBW25, expressing the green fluorescent protein (GFP) and bacterial luciferase, was monitored during colonization of wheat starting from seed inoculation. Since bacterial luciferase is dependent on cellular energy reserves for phenotypic expression, metabolically active cells were detected using this marker. In contrast, the stable GFP fluorescence phenotype was used to detect the cells independently of their metabolic status. The combination of these two markers enabled P. fluorescens SBW25 cells to be monitored on wheat plants to determine their specific location and metabolic activity. Studies on homogenized wheat plant parts demonstrated that the seed was the preferred location of P. fluorescens SBW25 during the 65-day time period studied, but the leaves and roots were also colonized. Interestingly, the bacteria were also found to be metabolically active on all plant parts examined. In situ localization of P. fluorescens SBW25 using a combination of different microscopic techniques confirmed the preference for the cells to colonize specific regions of the seed. We speculate that the colonization pattern of P. fluorescens SBW25 can be linked to the mechanism of protection of plants from fungal infection. PMID:12032602

Unge, A.; Jansson, J.

2001-02-01

276

Analysis of the bread wheat genome using whole genome shotgun sequencing  

PubMed Central

Summary Bread wheat (Triticum aestivum) is a globally important crop, accounting for 20% of the calories consumed by mankind. We sequenced its large and challenging 17 Gb hexaploid genome using 454 pyrosequencing and compared this with the sequences of diploid ancestral and progenitor genomes. Between 94,000-96,000 genes were identified, and two-thirds were assigned to the A, B and D genomes. High-resolution synteny maps identified many small disruptions to conserved gene order. We show the hexaploid genome is highly dynamic, with significant loss of gene family members upon polyploidization and domestication, and an abundance of gene fragments. Several classes of genes involved in energy harvesting, metabolism and growth are among expanded gene families that could be associated with crop productivity. Our analyses, coupled with the identification of extensive genetic variation, provide a new resource for accelerating gene discovery and improving this major crop. PMID:23192148

Brenchley, Rachel; Spannagl, Manuel; Pfeifer, Matthias; Barker, Gary L.A.; D’Amore, Rosalinda; Allen, Alexandra M.; McKenzie, Neil; Kramer, Melissa; Kerhornou, Arnaud; Bolser, Dan; Kay, Suzanne; Waite, Darren; Trick, Martin; Bancroft, Ian; Gu, Yong; Huo, Naxin; Luo, Ming-Cheng; Sehgal, Sunish; Kianian, Sharyar; Gill, Bikram; Anderson, Olin; Kersey, Paul; Dvorak, Jan; McCombie, Richard; Hall, Anthony; Mayer, Klaus F.X.; Edwards, Keith J.; Bevan, Michael W.; Hall, Neil

2012-01-01

277

Identification of three wheat globulin genes by screening a Triticum aestivum BAC genomic library with cDNA from a diabetes-associated globulin  

PubMed Central

Background Exposure to dietary wheat proteins in genetically susceptible individuals has been associated with increased risk for the development of Type 1 diabetes (T1D). Recently, a wheat protein encoded by cDNA WP5212 has been shown to be antigenic in mice, rats and humans with autoimmune T1D. To investigate the genomic origin of the identified wheat protein cDNA, a hexaploid wheat genomic library from Glenlea cultivar was screened. Results Three unique wheat globulin genes, Glo-3A, Glo3-B and Glo-3C, were identified. We describe the genomic structure of these genes and their expression pattern in wheat seeds. The Glo-3A gene shared 99% identity with the cDNA of WP5212 at the nucleotide and deduced amino acid level, indicating that we have identified the gene(s) encoding wheat protein WP5212. Southern analysis revealed the presence of multiple copies of Glo-3-like sequences in all wheat samples, including hexaploid, tetraploid and diploid species wheat seed. Aleurone and embryo tissue specificity of WP5212 gene expression, suggested by promoter region analysis, which demonstrated an absence of endosperm specific cis elements, was confirmed by immunofluorescence microscopy using anti-WP5212 antibodies. Conclusion Taken together, the results indicate that a diverse group of globulins exists in wheat, some of which could be associated with the pathogenesis of T1D in some susceptible individuals. These data expand our knowledge of specific wheat globulins and will enable further elucidation of their role in wheat biology and human health. PMID:19615078

Loit, Evelin; Melnyk, Charles W; MacFarlane, Amanda J; Scott, Fraser W; Altosaar, Illimar

2009-01-01

278

Mating type idiomorphs from a French population of the wheat pathogen Mycosphaerella graminicola: widespread equal distribution and low but distinct levels of molecular polymorphism.  

PubMed

Septoria tritici blotch caused by the heterothallic ascomycete Mycosphaerella graminicola is currently the most frequent and the most economically damaging disease on wheat worldwide. Five hundred and ten strains of this fungus were sampled from 16 geographical locations representing the major wheat producing areas in France. Multiplex PCR amplification, PCR-RFLP-SSCP screening and sequencing of parts of mating type encoding sequences were performed in order to assess the distribution and molecular polymorphism of the mating type idiomorphs. The two idiomorphs were scored at similar frequencies within all sampled locations. Both mating types were also identified at the leaf spatial scale, on 42% of leaves from which two or three strains were isolated. No correlation was found between distribution of mating types and either host cultivars from which the sampling was carried out or in vitro colony phenotypes observed during the culture of strains on potato dextrose agar (PDA) medium. PCR-RFLP-SSCP assay highlighted only one MAT1-1 strain exhibiting a profile distinct from all other MAT1-1 strains, whereas ten MAT1-2 strains (among which two and four with same profiles, respectively) showed profiles differing from the other MAT1-2 strains. Sequencing revealed that all polymorphisms corresponded to single nucleotide variations and all strains displaying the same single strand conformation polymorphism (SSCP) profiles showed identical nucleotide sequences, thereby confirming the high sensitivity of SSCP. Only two out of the disclosed nucleotide variations were nonsynonymous. This study strongly suggests a large potential for sexual reproduction in the French population of M. graminicola and reports a high conservation of mating type sequences in the fungus at both nucleotide and population levels, with a great difference in molecular variability between the two idiomorphs. PMID:21036342

Siah, Ali; Tisserant, Benoit; El Chartouni, Léa; Duyme, Florent; Deweer, Caroline; Roisin-Fichter, Céline; Sanssené, Jean; Durand, Roger; Reignault, Philippe; Halama, Patrice

2010-01-01

279

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

280

Population Diversity of Yeasts and Lactic Acid Bacteria in Pig Feed Fermented with Whey, Wet Wheat Distillers' Grains, or Water at Different Temperatures?  

PubMed Central

The diversity of populations of yeast and lactic acid bacteria (LAB) in pig feeds fermented at 10, 15, or 20°C was characterized by rRNA gene sequencing of isolates. The feeds consisted of a cereal grain mix blended with wet wheat distillers' grains (WWDG feed), whey (W feed), or tap water (WAT feed). Fermentation proceeded for 5 days without disturbance, followed by 14 days of daily simulated feed outtakes, in which 80% of the contents were replaced with fresh feed mixtures. In WWDG feed, Pichia galeiformis became the dominant yeast species, independent of the fermentation temperature and feed change. The LAB population was dominated by Pediococcus pentosaceus at the start of the fermentation period. After 3 days, the Lactobacillus plantarum population started to increase in feeds at all temperatures. The diversity of LAB increased after the addition of fresh feed components. In W feed, Kluyveromyces marxianus dominated, but after the feed change, the population diversity increased. With increasing fermentation temperatures, there was a shift toward Pichia membranifaciens as the dominant species. L. plantarum was the most prevalent LAB in W feed. The WAT feed had a diverse microbial flora, and the yeast population changed throughout the whole fermentation period. Pichia anomala was the most prevalent yeast species, with increasing occurrence at higher fermentation temperatures. Pediococcus pentosaceus was the most prevalent LAB, but after the feed change, L. plantarum started to proliferate. The present study demonstrates that the species composition in fermented pig feed may vary considerably, even if viable cell counts indicate stable microbial populations. PMID:18223110

Olstorpe, Matilda; Lyberg, Karin; Lindberg, Jan Erik; Schnürer, Johan; Passoth, Volkmar

2008-01-01

281

Leaf rust resistance gene Lr1, isolated from bread wheat (Triticum aestivum L.) is a member of the large psr567 gene family.  

PubMed

In hexaploid wheat, leaf rust resistance gene Lr1 is located at the distal end of the long arm of chromosome 5D. To clone this gene, an F(1)-derived doubled haploid population and a recombinant inbred line population from a cross between the susceptible cultivar AC Karma and the resistant line 87E03-S2B1 were phenotyped for resistance to Puccinia triticina race 1-1 BBB that carries the avirulence gene Avr1. A high-resolution genetic map of the Lr1 locus was constructed using microsatellite, resistance gene analog (RGA), BAC end (BE), and low pass (LP) markers. A physical map of the locus was constructed by screening a hexaploid wheat BAC library from cultivar Glenlea that is known to have Lr1. The locus comprised three RGAs from a gene family related to RFLP marker Xpsr567. Markers specific to each paralog were developed. Lr1 segregated with RGA567-5 while recombinants were observed for the other two RGAs. Transformation of the susceptible cultivar Fielder with RGA567-5 demonstrated that it corresponds to the Lr1 resistance gene. In addition, the candidate gene was also confirmed by virus-induced gene silencing. Twenty T (1) lines from resistant transgenic line T (0)-938 segregated for resistance, partial resistance and susceptibility to Avr1 corresponding to a 1:2:1 ratio for a single hemizygous insertion. Transgene presence and expression correlated with the phenotype. The resistance phenotype expressed by Lr1 seemed therefore to be dependant on the zygosity status. T (3)-938 sister lines with and without the transgene were further tested with 16 virulent and avirulent rust isolates. Rust reactions were all as expected for Lr1 thereby providing additional evidence toward the Lr1 identity of RGA567-5. Sequence analysis of Lr1 indicated that it is not related to the previously isolated Lr10 and Lr21 genes and unlike these genes, it is part of a large gene family. PMID:17611798

Cloutier, Sylvie; McCallum, Brent D; Loutre, Caroline; Banks, Travis W; Wicker, Thomas; Feuillet, Catherine; Keller, Beat; Jordan, Mark C

2007-09-01

282

Eat Wheat!  

ERIC Educational Resources Information Center

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

Idaho Wheat Commission, Boise.

283

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 ...

284

Physical Mapping Integrated with Syntenic Analysis to Characterize the Gene Space of the Long Arm of Wheat Chromosome 1A  

PubMed Central

Background Bread wheat (Triticum aestivum L.) is one of the most important crops worldwide and its production faces pressing challenges, the solution of which demands genome information. However, the large, highly repetitive hexaploid wheat genome has been considered intractable to standard sequencing approaches. Therefore the International Wheat Genome Sequencing Consortium (IWGSC) proposes to map and sequence the genome on a chromosome-by-chromosome basis. Methodology/Principal Findings We have constructed a physical map of the long arm of bread wheat chromosome 1A using chromosome-specific BAC libraries by High Information Content Fingerprinting (HICF). Two alternative methods (FPC and LTC) were used to assemble the fingerprints into a high-resolution physical map of the chromosome arm. A total of 365 molecular markers were added to the map, in addition to 1122 putative unique transcripts that were identified by microarray hybridization. The final map consists of 1180 FPC-based or 583 LTC-based contigs. Conclusions/Significance The physical map presented here marks an important step forward in mapping of hexaploid bread wheat. The map is orders of magnitude more detailed than previously available maps of this chromosome, and the assignment of over a thousand putative expressed gene sequences to specific map locations will greatly assist future functional studies. This map will be an essential tool for future sequencing of and positional cloning within chromosome 1A. PMID:23613713

Lucas, Stuart J.; Akp?nar, Bala An?; Kantar, Melda; Weinstein, Zohar; Ayd?no?lu, Fatma; Šafá?, Jan; Šimková, Hana; Frenkel, Zeev; Korol, Abraham; Magni, Federica; Cattonaro, Federica; Vautrin, Sonia; Bellec, Arnaud; Bergès, Hélène; Doležel, Jaroslav; Budak, Hikmet

2013-01-01

285

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

PubMed

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem. PMID:17557853

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

2007-08-01

286

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs?  

PubMed Central

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem. PMID:17557853

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

2007-01-01

287

Variability in wheat based on low-copy DNA sequence comparisons.  

PubMed

The chromosomes of the B genome of hexaploid wheat (AABBDD) do not pair completely with those of any of the diploid species with genomes similar to B. Various biochemical and molecular analyses have suggested that each of the five diploid species in section Sitopsis of Triticum are ancestral to B. These observations have led to the hypothesis that the B genome may be polyphyletic, descending from more than one diploid ancestor. This hypothesis may account for differences between the wheat B genome and the diploids and also for variability that currently exists among different wheat accessions. In this study, we cloned and compared nucleotide sequences for three low-copy DNA fragments from the B and D genomes of several wheat accessions and from diploid relatives of the B and D genomes. Our results suggested that the amount of DNA sequence variability in wheat is low, although somewhat more variability existed in the B genome than in the D genome. The B genome of wheat was significantly diverged from all the Sitopsis diploid species, and Triticum speltoides was closer to B than to other members of this section. The D genome of wheat was very similar to that of its progenitor, Triticum tauschii. No evidence for a polyphyletic origin of the B genome was found. A more parsimonious hypothesis is that the wheat B genome diverged from its diploid ancestor after the original hybridization event occurred. PMID:8537004

Talbert, L E; Blake, N K; Storlie, E W; Lavin, M

1995-10-01

288

Self-Transmissible Mercury Resistance Plasmids with Gene-Mobilizing Capacity in Soil Bacterial Populations: Influence of Wheat Roots and Mercury Addition  

PubMed Central

A set of mercury resistance plasmids was obtained from wheat rhizosphere soil amended or not amended with mercuric chloride via exogenous plasmid isolation by using Pseudomonas fluorescens R2f, Pseudomonas putida UWC1, and Enterobacter cloacae BE1 as recipient strains. The isolation frequencies were highest from soil amended with high levels of mercury, and the isolation frequencies from unamended soil were low. With P. putida UWC1 as the recipient, the isolation frequency was significantly enhanced in wheat rhizosphere compared to bulk soil. Twenty transconjugants were analyzed per recipient strain. All of the transconjugants contained plasmids which were between 40 and 50 kb long. Eight selected plasmids were distributed among five groups, as shown by restriction digestion coupled with a similarity matrix analysis. However, all of the plasmids formed a tight group, as judged by hybridization with two whole-plasmid probes and comparisons with other plasmids in dot blot hybridization analyses. The results of replicon typing and broad-host-range incompatibility (Inc) group-specific PCR suggested that the plasmid isolates were not related to any previously described Inc group. Although resistance to copper, resistance to streptomycin, and/or resistance to chloramphenicol was found in several plasmids, catabolic sequences were generally not identified. One plasmid, pEC10, transferred into a variety of bacteria belonging to the ? and ? subdivisions of the class Proteobacteria and mobilized as well as retromobilized the IncQ plasmid pSUP104. A PCR method for detection of pEC10-like replicons was used, in conjunction with other methods, to monitor pEC10-homologous sequences in mercury-polluted and unpolluted soils. The presence of mercury enhanced the prevalence of pEC10-like replicons in soil and rhizosphere bacterial populations. PMID:9546155

Smit, Eric; Wolters, Anneke; van Elsas, Jan Dirk

1998-01-01

289

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

PubMed Central

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

290

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

PubMed

Bread wheat (Triticum aestivum) is one of the most important crop plants, globally providing staple food for a large proportion of the human population. However, improvement of this crop has been limited due to its large and complex genome. Advances in genomics are supporting wheat crop improvement. We provide a variety of web-based systems hosting wheat genome and genomic data to support wheat research and crop improvement. WheatGenome.info is an integrated database resource which includes multiple web-based applications. These include a GBrowse2-based wheat genome viewer with BLAST search portal, TAGdb for searching wheat second-generation genome sequence data, wheat autoSNPdb, links to wheat genetic maps using CMap and CMap3D, and a wheat genome Wiki to allow interaction between diverse wheat genome sequencing activities. This system includes links to a variety of wheat genome resources hosted at other research organizations. This integrated database aims to accelerate wheat genome research and is freely accessible via the web interface at http://www.wheatgenome.info/. PMID:22009731

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

2012-02-01

291

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.

292

Absence of mitochondrial DNA sequence variation in Russian wheat aphid (Hemiptera: Aphididae) populations consistent with a single introduction into the United States  

Technology Transfer Automated Retrieval System (TEKTRAN)

Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), was introduced into North America in Mexico during 1980 and by 1988 had spread north across the Western US into Southern Canada. South Africa has been suspected as the source of the introduction. RWA is the major insect pest of wheat and barl...

293

NITROGEN USE AND BIOMASS DISTRIBUTION IN CULMS OF WINTER WHEAT POPULATIONS SELECTED FROM GRAIN-ONLY AND DUAL-PURPOSE SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Beginning in late fall and ending at jointing in early spring winter wheat (Triticum aestivum L.) crops in the southern Great Plains are often grazed by stocker cattle (Bos tarus L.) and then harvested for grain. Traditionally, dual-purpose (grazing plus grain) wheat cultivars are developed from a g...

294

Breeding barriers at a diploid–hexaploid contact zone in Aster amellus  

Microsoft Academic Search

Polyploidization is an important mechanism of sympatric speciation, but few studies have addressed breeding barriers between\\u000a polyploids and their diploid progenitors in the field, and the available data have been mainly obtained from diploid-tetraploid\\u000a contact zones. In contrast to diploid-tetraploid complexes, hybridization between diploid and hexaploid individuals may lead\\u000a to viable fertile tetraploid offspring, and thus the interactions between these

Sílvia Castro; Zuzana Münzbergová; Jana Raabová; João Loureiro

2011-01-01

295

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

296

[Use of the common winter wheat homozygous population for genetic analysis of beta-amylase and evaluation of its aggregation ability].  

PubMed

We investigated a self-pollinated homozygous population of common winter wheat, F(-> ?) 24/04 x Odesskaya krasnokolosaya, for variants of beta-amylase and the aggregation ability of the protein complex of weevil via disulfide bonds. It was found that variation in the electrophoretic types of this enzyme was due to four isoenzymes. Two of them (a and b) are doubled and controlled by separate loci with independent inheritance. Isoenzyme c was due to three dominant factors, and four loci were responsible for d. Analysis of the number of -S-S-bonds of five genotypes, which were harvested in 2013 and differed in the types of beta-amylase, showed that some of them were significantly different from others in this indicator. In general, the samples were grouped by the type of this enzyme, forming the following continuous series with respect to aggregation ability: I ? B ? F ? D ? G or 59.13 ± 3.18 ? 56.65 ± 2.46 ? 52.54 ± 2.24 ? 50.16 ± 1.67 ? 48.63 ± 6.25 of cond. units. Significant differences were observed for this property between groups B > D and I > D. Therefore, genotypes having types I and B have a positive influence on the rheological properties of dough. PMID:25739283

Netsvetaev, V P; Akinshina, O V; Bondarenko, L S

2014-11-01

297

The usefulness of fungicide mixtures and alternation for delaying the selection for resistance in populations of Mycosphaerella graminicola on winter wheat: a modeling analysis.  

PubMed

A fungicide resistance model (reported and tested previously) was amended to describe the development of resistance in Mycosphaerella graminicola populations in winter wheat (Triticum aestivum) crops in two sets of fields, connected by spore dispersal. The model was used to evaluate the usefulness of concurrent, alternating, or mixture use of two high-resistance-risk fungicides as resistance management strategies. We determined the effect on the usefulness of each strategy of (i) fitness costs of resistance, (ii) partial resistance to fungicides, (iii) differences in the dose-response curves and decay rates between fungicides, and (iv) different frequencies of the double-resistant strain at the start of a treatment strategy. Parameter values for the quinine outside inhibitor pyraclostrobin were used to represent two fungicides with differing modes of action. The effectiveness of each strategy was quantified as the maximum number of growing seasons that disease was effectively controlled in both sets of fields. For all scenarios, the maximum effective lives achieved by the use of the strategies were in the order mixtures ? alternation ? concurrent use. Mixtures were of particular benefit where the pathogen strain resistant to both modes of action incurred a fitness penalty or was present at a low initial frequency. PMID:23384858

Hobbelen, P H F; Paveley, N D; Oliver, R P; van den Bosch, F

2013-07-01

298

Molecular linkage map of Einkorn wheat: mapping of storage-protein and soft-glume genes and bread-making quality QTLs.  

PubMed

Two molecular maps of Triticum monococcum L were produced and integrated. The integrated map includes a total of 477 markers, 32 RFLPs, 438 AFLPs, one morphological (soft glume (Sog)) and six storage-protein markers, and covers 856 cM. The trait Sog with the recessive allele sog maps to linkage group 2S. Probably, this is the T. monococcum homologue of Tg and Tg2 in hexaploid and tetraploid wheats, respectively. Loci coding for seed storage proteins were allocated to chromosomes 1L (HMW GLU1,2 and Glu1), 1S (LMW GLU6,7, LMW GLU1-4, omega GLI1-4, gamma GLI5 and Gli-1) and 6L (alpha/beta GLI7-14). Parameters related to bread-making quality (SDS sedimentation volume, specific sedimentation volume (SSV) and total protein content) were studied in one of the two populations. A QTL that is consistently present across environments was detected for SDS sedimentation volume and for SSV. The position of the QTL on chromosome 1S was in close agreement with the map positions of storage-protein loci. A second QTL was mapped on chromosome 5. For protein content, two significant QTLs were mapped to linkage groups 1 and 5. PMID:12534216

Taenzler, B; Esposti, R F; Vaccino, P; Brandolini, A; Effgen, S; Heun, M; Schäfer-Pregl, R; Borghi, B; Salamini, F

2002-10-01

299

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

PubMed Central

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

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

2015-01-01

300

Ancient haplotypes resulting from extensive molecular rearrangements in the wheat A genome have been maintained in species of three different ploidy levels  

PubMed Central

Plant genomes, in particular grass genomes, evolve very rapidly. The closely related A genomes of diploid, tetraploid, and hexaploid wheat are derived from a common ancestor that lived <3 million years ago and represent a good model to study molecular mechanisms involved in such rapid evolution. We have sequenced and compared physical contigs at the Lr10 locus on chromosome 1AS from diploid (211 kb), tetraploid (187 kb), and hexaploid wheat (154 kb). A maximum of 33% of the sequences were conserved between two species. The sequences from diploid and tetraploid wheat shared all of the genes, including Lr10 and RGA2 and define a first haplotype (H1). The 130-kb intergenic region between Lr10 and RGA2 was conserved in size despite its activity as a hot spot for transposon insertion, which resulted in >70% of sequence divergence. The hexaploid wheat sequence lacks both Lr10 and RGA2 genes and defines a second haplotype, H2, which originated from ancient and extensive rearrangements. These rearrangements included insertions of retroelements and transposons deletions, as well as unequal recombination within elements. Gene disruption in haplotype H2 was caused by a deletion and subsequent large inversion. Gene conservation between H1 haplotypes, as well as conservation of rearrangements at the origin of the H2 haplotype at three different ploidy levels indicate that the two haplotypes are ancient and had a stable gene content during evolution, whereas the intergenic regions evolved rapidly. Polyploidization during wheat evolution had no detectable consequences on the structure and evolution of the two haplotypes. PMID:15805493

Isidore, Edwige; Scherrer, Beatrice; Chalhoub, Boulos; Feuillet, Catherine; Keller, Beat

2005-01-01

301

Ecological and molecular investigation of wheat bulb fly (Delia coarctata, Fallén, Diptera: Anthomyiidae) for the advancement of population monitoring and control methodologies   

E-print Network

Wheat bulb fly (WBF) (Delia coarctata, Fallén, Diptera: Anthomyiidae) is a pest of commercial importance in cereal crops. Control is dependent on organophosphates some of which are restricted in the UK, while current ...

Rogers, Craig David

2012-06-22

302

Winter and Specialty Wheat  

Microsoft Academic Search

Wheat is the most widely grown crop in the world. Winter wheat is primarily common wheat (2n = 6x = 42) which has extensive germplasm resources that are used in breeding, often for disease and insect resistance. Though\\u000a wheat can be used as a forage crop and its grain for animal feed, the primary uses of common wheat are to

P. Baenziger; R. Graybosch; D. Van Sanford; W. Berzonsky

303

The localization and expression of the class II starch synthases of wheat.  

PubMed

The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat. PMID:10444098

Li, Z; Chu, X; Mouille, G; Yan, L; Kosar-Hashemi, B; Hey, S; Napier, J; Shewry, P; Clarke, B; Appels, R; Morell, M K; Rahman, S

1999-08-01

304

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

305

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

306

Morphological features and physicochemical properties of waxy wheat starch.  

PubMed

Morphological features, granule composition, and physicochemical properties of waxy wheat starch were compared with those of normal wheat starch. The morphologies and granule populations were found to be similar for the two starches. However, waxy wheat starch contained a smaller proportion of B-type granules, had a larger average granule diameter, and a higher degree of crystallinity than normal wheat starch, as measured by particle size analysis and differential scanning calorimetry. These differences resulted in a higher gelatinization temperature, transition enthalpy, peak viscosity, breakdown, swelling power, lower peak viscosity temperature and final viscosity in waxy wheat starch. These points suggest that waxy wheat starch should have greater resistance to retrogradation during cooling and higher water-holding capacity under dry conditions. Highlighting the differences in physicochemical properties of waxy and normal wheat starches should help point toward effective applications of waxy wheat starch in the food industry. PMID:24076202

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

2013-11-01

307

Duplication and partitioning in evolution and function of homoeologous Q loci governing domestication characters in polyploid wheat  

PubMed Central

The Q gene encodes an AP2-like transcription factor that played an important role in domestication of polyploid wheat. The chromosome 5A Q alleles (5AQ and 5Aq) have been well studied, but much less is known about the q alleles on wheat homoeologous chromosomes 5B (5Bq) and 5D (5Dq). We investigated the organization, evolution, and function of the Q/q homoeoalleles in hexaploid wheat (Triticum aestivum L.). Q/q gene sequences are highly conserved within and among the A, B, and D genomes of hexaploid wheat, the A and B genomes of tetraploid wheat, and the A, S, and D genomes of the diploid progenitors, but the intergenic regions of the Q/q locus are highly divergent among homoeologous genomes. Duplication of the q gene 5.8 Mya was likely followed by selective loss of one of the copies from the A genome progenitor and the other copy from the B, D, and S genomes. A recent V329-to-I mutation in the A lineage is correlated with the Q phenotype. The 5Bq homoeoalleles became a pseudogene after allotetraploidization. Expression analysis indicated that the homoeoalleles are coregulated in a complex manner. Combined phenotypic and expression analysis indicated that, whereas 5AQ plays a major role in conferring domestication-related traits, 5Dq contributes directly and 5Bq indirectly to suppression of the speltoid phenotype. The evolution of the Q/q loci in polyploid wheat resulted in the hyperfunctionalization of 5AQ, pseudogenization of 5Bq, and subfunctionalization of 5Dq, all contributing to the domestication traits. PMID:22042872

Zhang, Zengcui; Belcram, Harry; Gornicki, Piotr; Charles, Mathieu; Just, Jérémy; Huneau, Cécile; Magdelenat, Ghislaine; Couloux, Arnaud; Samain, Sylvie; Gill, Bikram S.; Rasmussen, Jack B.; Barbe, Valérie; Faris, Justin D.; Chalhoub, Boulos

2011-01-01

308

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

PubMed Central

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

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

2012-01-01

309

Nucleotide diversity and molecular evolution of the WAG-2 gene in common wheat (Triticum aestivum L) and its relatives  

PubMed Central

In this work, we examined the genetic diversity and evolution of the WAG-2 gene based on new WAG-2 alleles isolated from wheat and its relatives. Only single nucleotide polymorphisms (SNP) and no insertions and deletions (indels) were found in exon sequences of WAG-2 from different species. More SNPs and indels occurred in introns than in exons. For exons, exons+introns and introns, the nucleotide polymorphism ? decreased from diploid and tetraploid genotypes to hexaploid genotypes. This finding indicated that the diversity of WAG-2 in diploids was greater than in hexaploids because of the strong selection pressure on the latter. All dn/ds ratios were < 1.0, indicating that WAG-2 belongs to a conserved gene affected by negative selection. Thirty-nine of the 57 particular SNPs and eight of the 10 indels were detected in diploid species. The degree of divergence in intron length among WAG-2 clones and phylogenetic tree topology suggested the existence of three homoeologs in the A, B or D genome of common wheat. Wheat AG-like genes were divided into WAG-1 and WAG-2 clades. The latter clade contained WAG-2, OsMADS3 and ZMM2 genes, indicating functional homoeology among them. PMID:22215965

Wei, Shuhong; Peng, Zhengsong; Zhou, Yonghong; Yang, Zaijun; Wu, Kai; Ouyang, Zhongming

2011-01-01

310

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

311

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

PubMed

The objectives of this study were to develop a high-density chromosome bin map of homoeologous group 7 in hexaploid wheat (Triticum aestivum L.), to identify gene distribution in these chromosomes, and to perform comparative studies of wheat with rice and barley. We mapped 2148 loci from 919 EST clones onto group 7 chromosomes of wheat. In the majority of cases the numbers of loci were significantly lower in the centromeric regions and tended to increase in the distal regions. The level of duplicated loci in this group was 24% with most of these loci being localized toward the distal regions. One hundred nineteen EST probes that hybridized to three fragments and mapped to the three group 7 chromosomes were designated landmark probes and were used to construct a consensus homoeologous group 7 map. An additional 49 probes that mapped to 7AS, 7DS, and the ancestral translocated segment involving 7BS also were designated landmarks. Landmark probe orders and comparative maps of wheat, rice, and barley were produced on the basis of corresponding rice BAC/PAC and genetic markers that mapped on chromosomes 6 and 8 of rice. Identification of landmark ESTs and development of consensus maps may provide a framework of conserved coding regions predating the evolution of wheat genomes. PMID:15514045

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

2004-10-01

312

A Chromosome Bin Map of 2148 Expressed Sequence Tag Loci of Wheat Homoeologous Group 7  

PubMed Central

The objectives of this study were to develop a high-density chromosome bin map of homoeologous group 7 in hexaploid wheat (Triticum aestivum L.), to identify gene distribution in these chromosomes, and to perform comparative studies of wheat with rice and barley. We mapped 2148 loci from 919 EST clones onto group 7 chromosomes of wheat. In the majority of cases the numbers of loci were significantly lower in the centromeric regions and tended to increase in the distal regions. The level of duplicated loci in this group was 24% with most of these loci being localized toward the distal regions. One hundred nineteen EST probes that hybridized to three fragments and mapped to the three group 7 chromosomes were designated landmark probes and were used to construct a consensus homoeologous group 7 map. An additional 49 probes that mapped to 7AS, 7DS, and the ancestral translocated segment involving 7BS also were designated landmarks. Landmark probe orders and comparative maps of wheat, rice, and barley were produced on the basis of corresponding rice BAC/PAC and genetic markers that mapped on chromosomes 6 and 8 of rice. Identification of landmark ESTs and development of consensus maps may provide a framework of conserved coding regions predating the evolution of wheat genomes. PMID:15514045

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

2004-01-01

313

Aegilops tauschii draft genome sequence reveals a gene repertoire for wheat adaptation.  

PubMed

About 8,000 years ago in the Fertile Crescent, a spontaneous hybridization of the wild diploid grass Aegilops tauschii (2n = 14; DD) with the cultivated tetraploid wheat Triticum turgidum (2n = 4x = 28; AABB) resulted in hexaploid wheat (T. aestivum; 2n = 6x = 42; AABBDD). Wheat has since become a primary staple crop worldwide as a result of its enhanced adaptability to a wide range of climates and improved grain quality for the production of baker's flour. Here we describe sequencing the Ae. tauschii genome and obtaining a roughly 90-fold depth of short reads from libraries with various insert sizes, to gain a better understanding of this genetically complex plant. The assembled scaffolds represented 83.4% of the genome, of which 65.9% comprised transposable elements. We generated comprehensive RNA-Seq data and used it to identify 43,150 protein-coding genes, of which 30,697 (71.1%) were uniquely anchored to chromosomes with an integrated high-density genetic map. Whole-genome analysis revealed gene family expansion in Ae.?tauschii of agronomically relevant gene families that were associated with disease resistance, abiotic stress tolerance and grain quality. This draft genome sequence provides insight into the environmental adaptation of bread wheat and can aid in defining the large and complicated genomes of wheat species. PMID:23535592

Jia, Jizeng; Zhao, Shancen; Kong, Xiuying; Li, Yingrui; Zhao, Guangyao; He, Weiming; Appels, Rudi; Pfeifer, Matthias; Tao, Yong; Zhang, Xueyong; Jing, Ruilian; Zhang, Chi; Ma, Youzhi; Gao, Lifeng; Gao, Chuan; Spannagl, Manuel; Mayer, Klaus F X; Li, Dong; Pan, Shengkai; Zheng, Fengya; Hu, Qun; Xia, Xianchun; Li, Jianwen; Liang, Qinsi; Chen, Jie; Wicker, Thomas; Gou, Caiyun; Kuang, Hanhui; He, Genyun; Luo, Yadan; Keller, Beat; Xia, Qiuju; Lu, Peng; Wang, Junyi; Zou, Hongfeng; Zhang, Rongzhi; Xu, Junyang; Gao, Jinlong; Middleton, Christopher; Quan, Zhiwu; Liu, Guangming; Wang, Jian; Yang, Huanming; Liu, Xu; He, Zhonghu; Mao, Long; Wang, Jun

2013-04-01

314

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

315

Sequencing of chloroplast genomes from wheat, barley, rye and their relatives provides a detailed insight into the evolution of the Triticeae tribe.  

PubMed

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; Wicker, Thomas; Kilian, Benjamin

2014-01-01

316

Quanah Wheat.  

E-print Network

is sufficiently winter-hardy for the recommended area of the Roll- ing Plains and Central Texas, but should not be grown outsick these areas. Quanah is similar to Comanche in milling and baking charac- t eristics. Tests by commercial and institutional... in other states. Development Quanah wheat was developed from a complex cross in which the first generations of two hybrids were crossed. The parentage was (Comanche x Honor-Forward, Cornell 501e-1-28, F,) x (Med- iterranean-Hope, 41-33-1-513 x Comanche...

Atkins, Irvin Milburn

1951-01-01

317

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

318

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

E-print Network

into four pheno- types based solely on the presence or absence of bands 2 and 4 (Fj gure 6) In this hypothesis, a structural gene on 7AL would e~press the isozyme band 2 or 4 while a endopeptidase structural gene on 7BL would express the other isozyme... IV Observed 40 Expected 20. 75 [ o-e ? . 5] 10. 48 2 e x (corrected) 2 54. 68 20. 75 20. 75 11. 21 20. 75 16. 05 P ? . 001 Conclusion: Genes contributing to band 2 and 4 are linked. It was assumed that all isozymes expressed in this plant...

McMillin, David Edwin

1977-01-01

319

No evidence for a role of competitive capabilities of adults in causing habitat segregation of diploid and hexaploid Senecio carniolicus (Asteracaeae)  

PubMed Central

Hexaploid individuals of Senecio carniolicus (Asteraceae) predominantly occur in dense swards while diploids prevail in open vegetation. We test whether this habitat segregation is due to differential responses to competition. Linear regression models were used to relate biomass and maximum leaf length of adults to vegetation cover within radii of 20 cm around target individuals. Biomass differed between ploidy levels, but was independent from vegetation cover in both cytotypes. Maximum leaf length of diploids increased with vegetation cover, but remained constant in hexaploids. This suggests that at the adult stage diploids respond to increasing competition by changes in plant architecture rather than changes in resource utilization, while hexaploids are unaffected by competition. Consequently, other factors, such as competitive interactions at earlier life stages, likely are responsible for habitat segregation of diploid and hexaploid S. carniolicus. PMID:24348456

Hülber, Karl; Berger, Andreas; Gilli, Christian; Hofbauer, Markus; Patek, Monika; Schneeweiss, Gerald M.

2013-01-01

320

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

321

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

322

Effect of 7H(ch) Hordeum chilense Chromosome Introgressions on the Wheat Endosperm Proteomic Profile.  

PubMed

Hordeum chilense is an excellent genetic resource for wheat breeding due to its potential to improve breadmaking quality and nutritional value and provide resistance to some biotic and abiotic stresses. Hexaploid wheat lines carrying chromosome 7H(ch) introgressions, namely, chromosome additions of the whole chromosome 7H(ch) or the 7H(ch)? or the 7H(ch)? chromosome arms, and chromosome substitutions of the homeologous chromosomes 7A, 7B, or 7D by chromosome 7H(ch) were compared by 2D-PAGE analysis to study the effect of these alien introgressions on the wheat endosperm proteome. The addition of the 7H(ch)? chromosome arm did not alter the profile of most glutenins and gliadins, but showed higher quantities of puroindolines and lower xylanase inhibitors, which might improve also resistance to plant pathogens. On the other hand, (7A)7H(ch) or (7D)7H(ch) substitution lines showed enhanced avenin-like b proteins and triticin levels but reduced puroindolines, which could be desirable to improve dough properties and nutritional value and increase kernel hardness in wheat. PMID:25824108

Collado-Romero, Melania; Alós, Enriqueta; Prieto, Pilar

2015-04-15

323

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

PubMed

Variation at eight storage protein loci was analyzed in the collection of T. spelta accessions from the National Centre of Plant Genetic Resources of Ukraine, most of which are European spelts. The analysis allowed identification of seven alleles at the Gli-B1 locus, five alleles at the Gli-A1 and Glu-B1 loci, three alleles at the Gli-A3 locus, two at the Gli-D1, Gli-B5, Glu-A1, and Glu-D1 loci. The majority of alleles are encountered among common wheat cultivars, only five alleles were specific for spelts. The high frequency of the alleles Gli-B1hs* and h encoding the 45-type gamma-gliadin in European spelts and durum wheat cultivars, as well as the occurrence of these alleles in T. dicoccum, in particular, in accessions from Switzerland and Germany, supports von Büren's hypothesis that European spelt resulted from hybridization between a tetraploid wheat with the 45-type y-gliadin and a hexaploid wheat. Analysis of genetic distances based on the genotypes at eight storage protein loci permitted differentiation of the Asian spelt accession from European spelts. PMID:24791472

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

2014-01-01

324

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

325

Estimation of economically optimum seed rates for winter wheat from series of trials  

E-print Network

Estimation of economically optimum seed rates for winter wheat from series of trials C. M. THEOBALD of recent trials for winter wheat (Triticum aestivum L.) have influenced farming practice in the UK early, wheat can compensate for reduced plant populations by increased tiller production. Results from

Theobald, Chris

326

Plant Protect. Sci. Vol. 39, No. 2: 6164 Cereal aphids are a serious problem in wheat  

E-print Network

growths of three cereal aphid species on winter wheat. Plant Protect. Sci., 39: 61­64. Population growths61 Plant Protect. Sci. Vol. 39, No. 2: 61­64 Cereal aphids are a serious problem in wheat growing (e.g. D 1987). In Central Europe, three species are serious pests of winter wheat: Metopolo- phium

Kratochvíl, Lukas

327

Wheat Diseases Atlas.  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . I4 OTHER WHEAT PROBLEMS . . . . . . . . . . . . . . . I4 Frost and Winter Injury . . . . . . . . . . . . . . . . . . . . I4 Cold Wind Scorch . . . . . . . . . . . . . . . . . . . . . . . . I5 Color Banding... to wheat producers over the state on whose farms demonstrations have been conducted and pic tures for this publication were made. WhEAT DisEASES ATLAs Norman L. McCoy and Robert W Berry* INTRODUCTION Wheat diseases have caused untold human suffer ing...

McCoy, Norman L.; Berry, Robert W.

1982-01-01

328

Processing Wheat for Food  

NSDL National Science Digital Library

Teachers' Domain presents this interactive lesson on wheat processing, including an introduction to the five kinds of wheat grown in the US and the anatomy of wheat. The module then moves through the six steps in wheat processing: cleaning, conditioning, blending, breaking, sieving, and reducing. Each step is animated to help students visualize the process. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

329

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.

Janet R. Galle

2005-01-01

330

QUANTITATIVE TRAIT LOCI FOR ALUMINUM RESISTANCE IN WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Quantitative trait loci (QTLs) for wheat resistance to aluminum (Al) toxicity were analyzed using simple sequence repeats (SSRs) in a population of 192 F6 recombinant inbred lines (RILs) derived from a cross between an Al-resistant cultivar, Atlas 66 and an Al-sensitive cultivar, Chisholm. Wheat rea...

331

Molecular Characterization of wheat stem rust races in Kenya  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stem or black rust caused by Puccinia graminis f. sp. tritici (Pgt) Erikss. & Henning causes severe losses to wheat (Triticum aestivum L.), historically threatening global wheat production. Characterizing prevalent isolates of Pgt would enhance the knowledge of population dynamics and evolution of t...

332

Characterization of Diploid, Tetraploid and Hexaploid Helianthus Species by Chromosome Banding and FISH with 45S rDNA Probe  

Microsoft Academic Search

Comparative karyotype analyses of five diploid, two tetraploid, and three hexaploid species of Helianthuswere performed using Feulgen staining, Giemsa C and CMA3 (C-CMA) staining, and FISH with 45S rDNA probe. The karyotypes are composed by a basic number of x?=?17 with a predominance of meta- and submetacentric chromosome types. A polyploid series is associated with the basic number. Giemsa C-

André L. L. Vanzela; Claudete F. Ruas; Marcelo F. Oliveira; Paulo M. Ruas

2002-01-01

333

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

334

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...

335

Extensive Pericentric Rearrangements in the Bread Wheat (Triticum aestivum L.) Genotype “Chinese Spring” Revealed from Chromosome Shotgun Sequence Data  

PubMed Central

The bread wheat (Triticum aestivum L.) genotype “Chinese Spring” (“CS”) is the reference base in wheat genetics and genomics. Pericentric rearrangements in this genotype were systematically assessed by analyzing homoeoloci for a set of nonredundant genes from Brachypodium distachyon, Triticum urartu, and Aegilops tauschii in the CS chromosome shotgun sequence obtained from individual chromosome arms flow-sorted from CS aneuploid lines. Based on patterns of their homoeologous arm locations, 551 genes indicated the presence of pericentric inversions in at least 10 of the 21 chromosomes. Available data from deletion bin-mapped expressed sequence tags and genetic mapping in wheat indicated that all inversions had breakpoints in the low-recombinant gene-poor pericentromeric regions. The large number of putative intrachromosomal rearrangements suggests the presence of extensive structural differences among the three subgenomes, at least some of which likely occurred during the production of the aneuploid lines of this hexaploid wheat genotype. These differences could have significant implications in wheat genome research where comparative approaches are used such as in ordering and orientating sequence contigs and in gene cloning. PMID:25349265

Ma, Jian; Stiller, Jiri; Wei, Yuming; Zheng, You-Liang; Devos, Katrien M.; Doležel, Jaroslav; Liu, Chunji

2014-01-01

336

Extensive pericentric rearrangements in the bread wheat (Triticum aestivum L.) genotype "Chinese Spring" revealed from chromosome shotgun sequence data.  

PubMed

The bread wheat (Triticum aestivum L.) genotype "Chinese Spring" ("CS") is the reference base in wheat genetics and genomics. Pericentric rearrangements in this genotype were systematically assessed by analyzing homoeoloci for a set of nonredundant genes from Brachypodium distachyon, Triticum urartu, and Aegilops tauschii in the CS chromosome shotgun sequence obtained from individual chromosome arms flow-sorted from CS aneuploid lines. Based on patterns of their homoeologous arm locations, 551 genes indicated the presence of pericentric inversions in at least 10 of the 21 chromosomes. Available data from deletion bin-mapped expressed sequence tags and genetic mapping in wheat indicated that all inversions had breakpoints in the low-recombinant gene-poor pericentromeric regions. The large number of putative intrachromosomal rearrangements suggests the presence of extensive structural differences among the three subgenomes, at least some of which likely occurred during the production of the aneuploid lines of this hexaploid wheat genotype. These differences could have significant implications in wheat genome research where comparative approaches are used such as in ordering and orientating sequence contigs and in gene cloning. PMID:25349265

Ma, Jian; Stiller, Jiri; Wei, Yuming; Zheng, You-Liang; Devos, Katrien M; Doležel, Jaroslav; Liu, Chunji

2014-01-01

337

Relationship between kernel color and protein content of hard red x hard white winter wheat progeny  

Microsoft Academic Search

Utilization of high-protein hard red wheat germplasm in breeding high-protein hard white winter wheats for the U.S. Great Plains raised concern regarding possible genetic relationships between kernel color and protein content. Segregating F3 and F4 populations from reciprocal crosses and backcrosses involving high-protein hard red winter wheat cultivar Plainsman V and normal-protein hard white winter wheat line KS75216 were examined.

L. M. Corpuz; G. M. Paulsen; E. G. Heyne

1983-01-01

338

High-Density Genetic Linkage Map Construction and QTL Mapping of Grain Shape and Size in the Wheat Population Yanda1817 × Beinong6.  

PubMed

High-density genetic linkage maps are necessary for precisely mapping quantitative trait loci (QTLs) controlling grain shape and size in wheat. By applying the Infinium iSelect 9K SNP assay, we have constructed a high-density genetic linkage map with 269 F 8 recombinant inbred lines (RILs) developed between a Chinese cornerstone wheat breeding parental line Yanda1817 and a high-yielding line Beinong6. The map contains 2431 SNPs and 128 SSR & EST-SSR markers in a total coverage of 3213.2 cM with an average interval of 1.26 cM per marker. Eighty-eight QTLs for thousand-grain weight (TGW), grain length (GL), grain width (GW) and grain thickness (GT) were detected in nine ecological environments (Beijing, Shijiazhuang and Kaifeng) during five years between 2010-2014 by inclusive composite interval mapping (ICIM) (LOD?2.5). Among which, 17 QTLs for TGW were mapped on chromosomes 1A, 1B, 2A, 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6B with phenotypic variations ranging from 2.62% to 12.08%. Four stable QTLs for TGW could be detected in five and seven environments, respectively. Thirty-two QTLs for GL were mapped on chromosomes 1B, 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4B, 4D, 5A, 5B, 6B, 7A and 7B, with phenotypic variations ranging from 2.62% to 44.39%. QGl.cau-2A.2 can be detected in all the environments with the largest phenotypic variations, indicating that it is a major and stable QTL. For GW, 12 QTLs were identified with phenotypic variations range from 3.69% to 12.30%. We found 27 QTLs for GT with phenotypic variations ranged from 2.55% to 36.42%. In particular, QTL QGt.cau-5A.1 with phenotypic variations of 6.82-23.59% was detected in all the nine environments. Moreover, pleiotropic effects were detected for several QTL loci responsible for grain shape and size that could serve as target regions for fine mapping and marker assisted selection in wheat breeding programs. PMID:25675376

Wu, Qiu-Hong; Chen, Yong-Xing; Zhou, Sheng-Hui; Fu, Lin; Chen, Jiao-Jiao; Xiao, Yao; Zhang, Dong; Ouyang, Shu-Hong; Zhao, Xiao-Jie; Cui, Yu; Zhang, De-Yun; Liang, Yong; Wang, Zhen-Zhong; Xie, Jing-Zhong; Qin, Jin-Xia; Wang, Guo-Xin; Li, De-Lin; Huang, Yin-Lian; Yu, Mei-Hua; Lu, Ping; Wang, Li-Li; Wang, Ling; Wang, Hao; Dang, Chen; Li, Jie; Zhang, Yan; Peng, Hui-Ru; Yuan, Cheng-Guo; You, Ming-Shan; Sun, Qi-Xin; Wang, Ji-Rui; Wang, Li-Xin; Luo, Ming-Cheng; Han, Jun; Liu, Zhi-Yong

2015-01-01

339

High-Density Genetic Linkage Map Construction and QTL Mapping of Grain Shape and Size in the Wheat Population Yanda1817 × Beinong6  

PubMed Central

High-density genetic linkage maps are necessary for precisely mapping quantitative trait loci (QTLs) controlling grain shape and size in wheat. By applying the Infinium iSelect 9K SNP assay, we have constructed a high-density genetic linkage map with 269 F 8 recombinant inbred lines (RILs) developed between a Chinese cornerstone wheat breeding parental line Yanda1817 and a high-yielding line Beinong6. The map contains 2431 SNPs and 128 SSR & EST-SSR markers in a total coverage of 3213.2 cM with an average interval of 1.26 cM per marker. Eighty-eight QTLs for thousand-grain weight (TGW), grain length (GL), grain width (GW) and grain thickness (GT) were detected in nine ecological environments (Beijing, Shijiazhuang and Kaifeng) during five years between 2010–2014 by inclusive composite interval mapping (ICIM) (LOD?2.5). Among which, 17 QTLs for TGW were mapped on chromosomes 1A, 1B, 2A, 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6B with phenotypic variations ranging from 2.62% to 12.08%. Four stable QTLs for TGW could be detected in five and seven environments, respectively. Thirty-two QTLs for GL were mapped on chromosomes 1B, 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4B, 4D, 5A, 5B, 6B, 7A and 7B, with phenotypic variations ranging from 2.62% to 44.39%. QGl.cau-2A.2 can be detected in all the environments with the largest phenotypic variations, indicating that it is a major and stable QTL. For GW, 12 QTLs were identified with phenotypic variations range from 3.69% to 12.30%. We found 27 QTLs for GT with phenotypic variations ranged from 2.55% to 36.42%. In particular, QTL QGt.cau-5A.1 with phenotypic variations of 6.82–23.59% was detected in all the nine environments. Moreover, pleiotropic effects were detected for several QTL loci responsible for grain shape and size that could serve as target regions for fine mapping and marker assisted selection in wheat breeding programs. PMID:25675376

Wu, Qiu-Hong; Chen, Yong-Xing; Zhou, Sheng-Hui; Fu, Lin; Chen, Jiao-Jiao; Xiao, Yao; Zhang, Dong; Ouyang, Shu-Hong; Zhao, Xiao-Jie; Cui, Yu; Zhang, De-Yun; Liang, Yong; Wang, Zhen-Zhong; Xie, Jing-Zhong; Qin, Jin-Xia; Wang, Guo-Xin; Li, De-Lin; Huang, Yin-Lian; Yu, Mei-Hua; Lu, Ping; Wang, Li-Li; Wang, Ling; Wang, Hao; Dang, Chen; Li, Jie; Zhang, Yan; Peng, Hui-Ru; Yuan, Cheng-Guo; You, Ming-Shan; Sun, Qi-Xin; Wang, Ji-Rui; Wang, Li-Xin; Luo, Ming-Cheng; Han, Jun; Liu, Zhi-Yong

2015-01-01

340

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

341

Molecular, physicochemical and rheological characteristics of introgressive Triticale/Triticum monococcum ssp. monococcum lines with wheat 1D/1A chromosome substitution.  

PubMed

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

342

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

343

Nucleotide diversity maps reveal variation in diversity among wheat genomes and chromosomes  

PubMed Central

Background A genome-wide assessment of nucleotide diversity in a polyploid species must minimize the inclusion of homoeologous sequences into diversity estimates and reliably allocate individual haplotypes into their respective genomes. The same requirements complicate the development and deployment of single nucleotide polymorphism (SNP) markers in polyploid species. We report here a strategy that satisfies these requirements and deploy it in the sequencing of genes in cultivated hexaploid wheat (Triticum aestivum, genomes AABBDD) and wild tetraploid wheat (Triticum turgidum ssp. dicoccoides, genomes AABB) from the putative site of wheat domestication in Turkey. Data are used to assess the distribution of diversity among and within wheat genomes and to develop a panel of SNP markers for polyploid wheat. Results Nucleotide diversity was estimated in 2114 wheat genes and was similar between the A and B genomes and reduced in the D genome. Within a genome, diversity was diminished on some chromosomes. Low diversity was always accompanied by an excess of rare alleles. A total of 5,471 SNPs was discovered in 1791 wheat genes. Totals of 1,271, 1,218, and 2,203 SNPs were discovered in 488, 463, and 641 genes of wheat putative diploid ancestors, T. urartu, Aegilops speltoides, and Ae. tauschii, respectively. A public database containing genome-specific primers, SNPs, and other information was constructed. A total of 987 genes with nucleotide diversity estimated in one or more of the wheat genomes was placed on an Ae. tauschii genetic map, and the map was superimposed on wheat deletion-bin maps. The agreement between the maps was assessed. Conclusions In a young polyploid, exemplified by T. aestivum, ancestral species are the primary source of genetic diversity. Low effective recombination due to self-pollination and a genetic mechanism precluding homoeologous chromosome pairing during polyploid meiosis can lead to the loss of diversity from large chromosomal regions. The net effect of these factors in T. aestivum is large variation in diversity among genomes and chromosomes, which impacts the development of SNP markers and their practical utility. Accumulation of new mutations in older polyploid species, such as wild emmer, results in increased diversity and its more uniform distribution across the genome. PMID:21156062

2010-01-01

344

How diverse a farmer-managed wheat landrace can be?  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

345

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).

346

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

347

Introgression of Elymus trachycaulus chromatin into common wheat.  

PubMed

A number of wheat-Elymus trachycaulus (2n = 4x = 28, genomically StStHtHt) chromosome addition, substitution, and translocation lines were isolated from the derivatives of an E. trachycaulus x wheat hybrid. Eighteen out of a total of 28 chromosome arms of E. trachycaulus were recovered in the addition lines. The genomic affinity of individual E. trachycaulus chromosomes was analysed by comparative chromosome banding and in situ hybridization using genome-specific repetitive DNA sequences as probes. The homoeology of the E. trachycaulus chromosomes added to wheat was determined by storage protein, isozyme, and restriction fragment length polymorphism analysis. Alloplasmic wheat-E. trachycaulus chromosome additions were isolated which only involved chromosome 1Ht and 1St that carry fertility restoration gene Rf-Ht1 and Rf-St1, respectively. Based on the results of production and characterization of a wheat-E. trachycaulus 5Ht(5B) substitution line, it is likely that some wheat chromosomes can be well compensated genetically by E. trachycaulus chromosomes. Several spontaneous wheat-E. trachycaulus chromosome translocation lines were detected. All the translocation lines involved either 1Ht or 1St. To estimate the potential of recombination between wheat and E. trachycaulus chromosomes, a backcross population derived from a plant which was double monosomic for chromosomes 7A and 7AL.7AS-1StS and a ph1b gene was developed. The plants from this population were analysed for 1St-specific genetic markers and no recombinant was recovered. PMID:8162318

Jiang, J; Morris, K L; Gill, B S

1994-01-01

348

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

349

A high density physical map of chromosome 1BL supports evolutionary studies, map-based cloning and sequencing in wheat  

PubMed Central

Background As for other major crops, achieving a complete wheat genome sequence is essential for the application of genomics to breeding new and improved varieties. To overcome the complexities of the large, highly repetitive and hexaploid wheat genome, the International Wheat Genome Sequencing Consortium established a chromosome-based strategy that was validated by the construction of the physical map of chromosome 3B. Here, we present improved strategies for the construction of highly integrated and ordered wheat physical maps, using chromosome 1BL as a template, and illustrate their potential for evolutionary studies and map-based cloning. Results Using a combination of novel high throughput marker assays and an assembly program, we developed a high quality physical map representing 93% of wheat chromosome 1BL, anchored and ordered with 5,489 markers including 1,161 genes. Analysis of the gene space organization and evolution revealed that gene distribution and conservation along the chromosome results from the superimposition of the ancestral grass and recent wheat evolutionary patterns, leading to a peak of synteny in the central part of the chromosome arm and an increased density of non-collinear genes towards the telomere. With a density of about 11 markers per Mb, the 1BL physical map provides 916 markers, including 193 genes, for fine mapping the 40 QTLs mapped on this chromosome. Conclusions Here, we demonstrate that high marker density physical maps can be developed in complex genomes such as wheat to accelerate map-based cloning, gain new insights into genome evolution, and provide a foundation for reference sequencing. PMID:23800011

2013-01-01

350

Wheat Streak Mosaic Virus  

E-print Network

Figure 1. Leaves infected with Wheat Streak Mosaic Virus. Picture from KSU Department of Plant Pathology web-site. Figure 2. Wheat plant infected with Wheat Streak Mosaic Virus and High Plains Virus. Picture was provided by Dr. Charlie Rush, Plant....edu/Agriculture/Entomology/entfacts/fldcrops/ef117. htm ? Compendium of Wheat Diseases, Wiese. American Phy- topathological Society. 1987. Produced by AgriLife Communications and Marketing, Texas A&M System Extension publications can be found on the Web at: http://AgriLifebookstore.org Visit...

Morgan, Gaylon

2005-01-26

351

Highly recombinogenic regions at seed storage protein loci on chromosome 1DS of Aegilops tauschii, the D-genome donor of wheat.  

PubMed Central

A detailed RFLP map was constructed of the distal end of the short arm of chromosome 1D of Aegilops tauschii, the diploid D-genome donor species of hexaploid wheat. Ae. tauschii was used to overcome some of the limitations commonly associated with molecular studies of wheat such as low levels of DNA polymorphism. Detection of multiple loci by most RFLP probes suggests that gene duplication events have occurred throughout this chromosomal region. Large DNA fragments isolated from a BAC library of Ae. tauschii were used to determine the relationship between physical and genetic distance at seed storage protein loci located at the distal end of chromosome 1DS. Highly recombinogenic regions were identified where the ratio of physical to genetic distance was estimated to be <20 kb/cM. These results are discussed in relation to the genome-wide estimate of the relationship between physical and genetic distance. PMID:10790409

Spielmeyer, W; Moullet, O; Laroche, A; Lagudah, E S

2000-01-01

352

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

353

Response of Spring Wheat Yield and Protein to Row Spacing, Plant Density, and Nitrogen Application in Central Montana  

E-print Network

Response of Spring Wheat Yield and Protein to Row Spacing, Plant Density, and Nitrogen Application and agronomic management practices must maximize the efficient use of these resources. Spring wheat development was to investigate effects of plant population, row spacing, and split-application of N on spring wheat yield

Lawrence, Rick L.

354

Comparison of conventional, flood irrigated, flat planting with furrow irrigated, raised bed planting for winter wheat in China  

Microsoft Academic Search

China is the most populous nation and largest food producer and consumer in the world. In terms of planted area and output, wheat (Triticum aestivum L.) (including both winter and spring habit wheat) is the number one crop in northern China, and currently almost all irrigated wheat is conventionally planted in narrow spaced rows on the flat and is irrigated

Wang Fahong; Wang Xuqing; Ken Sayre

2004-01-01

355

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

356

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

357

Effects of herbicide applications in wheat fields  

PubMed Central

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

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

2012-01-01

358

Global migration patterns in the fungal wheat pathogen Phaeosphaeria nodorum  

Microsoft Academic Search

The global migration patterns of the fungal wheat pathogen Phaeosphaeria nodorum were analysed using 12 microsatellite loci. Analysis of 693 isolates from nine populations indi- cated that the population structure of P. nodorum is characterized by high levels of genetic diversity and a low degree of subdivision between continents. To determine whether genetic similarity of populations was a result of

EVA H. STUKENBROCK; SØREN BANKE; BRUCE A. M

359

Consumption of aphid honeydew, a wheat yield reduction factor, by phyllosphere yeasts under field conditions  

Microsoft Academic Search

Aphid honeydew on wheat leaves can affect host physiology directly and can stimulate infection by necrotrophic pathogens. The role of naturally occurring saprophytes on wheat flag leaves in removing aphid honeydew was examined in five field experiments at different locations in the Netherlands in 1987 and 1988. Aphid populations, saprophyte populations and aphid honeydew were measured weekly. Diseases were monitored

A. J. Dik; N. J. Fokkema; J. A. Van Pelt

1991-01-01

360

Registration of "Brick" Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) [caused by Fusarium graminearum Schwabe; telomorph Gibberella zeae (Schwein.) Petch, is a major constraint to spring wheat (Triticum aestivum L.) production. The objective of this research was to release a hard red spring wheat (HRSW) cultivar with enhanced FHB resistance....

361

Registration of "Select" Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB), caused by Fusarium graminearum, Schwabe [telomorph Gibberella zeae (Schwein.) Petch]), is a major constraint on the production of spring wheat (Triticum aestivum L.). The objective of this research was to release a hard red spring wheat (HRSW) cultivar with enhanced level...

362

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...

363

Registration of 'Snowmass' wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Snowmass’ (Reg. No. CV-1050, PI 658597) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in July 2009 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State Uni...

364

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...

365

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 ...

366

Registration of 'Antero' Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

367

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...

368

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...

369

REGISTRATION OF 'HALLAM' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Hallam’ (PI 638790) 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 2005 by the developing institutions. Hallam was released primarily for its superior adaptation to rainfed wheat pr...

370

Transcriptome analysis of an mvp mutant reveals important changes in global gene expression and a role for methyl jasmonate in vernalization and flowering in wheat  

PubMed Central

The einkorn wheat mutant mvp-1 (maintained vegetative phase 1) has a non-flowering phenotype caused by deletions including, but not limited to, the genes CYS, PHYC, and VRN1. However, the impact of these deletions on global gene expression is still unknown. Transcriptome analysis showed that these deletions caused the upregulation of several pathogenesis-related (PR) and jasmonate-responsive genes. These results suggest that jasmonates may be involved in flowering and vernalization in wheat. To test this hypothesis, jasmonic acid (JA) and methyl jasmonate (MeJA) content in mvp and wild-type plants was measured. The content of JA was comparable in all plants, whereas the content of MeJA was higher by more than 6-fold in mvp plants. The accumulation of MeJA was also observed in vernalization-sensitive hexaploid winter wheat during cold exposure. This accumulation declined rapidly once plants were deacclimated under floral-inductive growth conditions. This suggests that MeJA may have a role in floral transition. To confirm this result, we treated vernalization-insensitive spring wheat with MeJA. The treatment delayed flowering with significant downregulation of both TaVRN1 and TaFT1 genes. These data suggest a role for MeJA in modulating vernalization and flowering time in wheat. PMID:24683181

Diallo, Amadou Oury; Agharbaoui, Zahra; Sarhan, Fathey

2014-01-01

371

Transcriptome analysis of an mvp mutant reveals important changes in global gene expression and a role for methyl jasmonate in vernalization and flowering in wheat.  

PubMed

The einkorn wheat mutant mvp-1 (maintained vegetative phase 1) has a non-flowering phenotype caused by deletions including, but not limited to, the genes CYS, PHYC, and VRN1. However, the impact of these deletions on global gene expression is still unknown. Transcriptome analysis showed that these deletions caused the upregulation of several pathogenesis-related (PR) and jasmonate-responsive genes. These results suggest that jasmonates may be involved in flowering and vernalization in wheat. To test this hypothesis, jasmonic acid (JA) and methyl jasmonate (MeJA) content in mvp and wild-type plants was measured. The content of JA was comparable in all plants, whereas the content of MeJA was higher by more than 6-fold in mvp plants. The accumulation of MeJA was also observed in vernalization-sensitive hexaploid winter wheat during cold exposure. This accumulation declined rapidly once plants were deacclimated under floral-inductive growth conditions. This suggests that MeJA may have a role in floral transition. To confirm this result, we treated vernalization-insensitive spring wheat with MeJA. The treatment delayed flowering with significant downregulation of both TaVRN1 and TaFT1 genes. These data suggest a role for MeJA in modulating vernalization and flowering time in wheat. PMID:24683181

Diallo, Amadou Oury; Agharbaoui, Zahra; Badawi, Mohamed A; Ali-Benali, Mohamed Ali; Moheb, Amira; Houde, Mario; Sarhan, Fathey

2014-06-01

372

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

PubMed Central

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

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

2009-01-01

373

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

374

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

375

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

376

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 ...

377

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...

378

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

379

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

380

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

PubMed

The effect of salinity on mitochondrial properties was investigated by comparing the reference wheat variety Chinese Spring (CS) to a salt-tolerant amphiploid (AMP). The octoploid AMP genotype was previously generated by combining hexaploid bread wheat (CS) with the diploid wild wheatgrass adapted to salt marshes, Lophopyrum elongatum. Here we used a combination of physiological, biochemical, and proteomic analyses to explore the mitochondrial and respiratory response to salinity in these two genotypes. The AMP showed greater growth tolerance to salinity treatments and altered respiration rate in both roots and shoots. A proteomic workflow of 2D-DIGE and MALDI TOF/TOF mass spectrometry was used to compare the protein composition of isolated mitochondrial samples from roots and shoots of both genotypes, following control or salt treatment. A large set of mitochondrial proteins were identified as responsive to salinity in both genotypes, notably enzymes involved in detoxification of reactive oxygen species. Genotypic differences in mitochondrial composition were also identified, with AMP exhibiting a higher abundance of manganese superoxide dismutase, serine hydroxymethyltransferase, aconitase, malate dehydrogenase, and ?-cyanoalanine synthase compared to CS. We present peptide fragmentation spectra derived from some of these AMP-specific protein spots, which could serve as biomarkers to track superior protein variants. PMID:23895732

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

2013-11-01

381

Infestation of Transgenic Powdery Mildew-Resistant Wheat by Naturally Occurring Insect Herbivores under Different Environmental Conditions  

PubMed Central

A concern associated with the growing of genetically modified (GM) crops is that they could adversely affect non-target organisms. We assessed the impact of several transgenic powdery mildew-resistant spring wheat lines on insect herbivores. The GM lines carried either the Pm3b gene from hexaploid wheat, which confers race-specific resistance to powdery mildew, or the less specific anti-fungal barley seed chitinase and ?-1,3-glucanase. In addition to the non-transformed control lines, several conventional spring wheat varieties and barley and triticale were included for comparison. During two consecutive growing seasons, powdery mildew infection and the abundance of and damage by naturally occurring herbivores were estimated under semi-field conditions in a convertible glasshouse and in the field. Mildew was reduced on the Pm3b-transgenic lines but not on the chitinase/glucanase-expressing lines. Abundance of aphids was negatively correlated with powdery mildew in the convertible glasshouse, with Pm3b wheat plants hosting significantly more aphids than their mildew-susceptible controls. In contrast, aphid densities did not differ between GM plants and their non-transformed controls in the field, probably because of low mildew and aphid pressure at this location. Likewise, the GM wheat lines did not affect the abundance of or damage by the herbivores Oulema melanopus (L.) and Chlorops pumilionis Bjerk. Although a previous study has revealed that some of the GM wheat lines show pleiotropic effects under field conditions, their effect on herbivorous insects appears to be low. PMID:21829479

Álvarez-Alfageme, Fernando; von Burg, Simone; Romeis, Jörg

2011-01-01

382

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

383

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

384

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.

Biotechnology and Biological Sciences Research Council

2012-01-01

385

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

386

Supplementary Materials for Reckoning wheat yield trends  

E-print Network

Supplementary Materials for Reckoning wheat yield trends Marena Lin and Peter Huybers Department decomposition of wheat yields 5 4.1 U.S. county-level wheat yields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.2 French departmental wheat yields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5

Huybers, Peter

387

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...

388

Wheat Pasture Poisoning.  

E-print Network

the time the first symptoms develop until the animal passes into the comatose condi- ;ion. If treatment is not begun before coma, there ir little chance of recovery. While wheat pasture poisoning has been re- yrted in dry cows, heifers and sheep, we... used gave definite positive tests. It is felt, however, that further work of this nature might be of value. TREATMENT OF CASES During the period covered by these studies, the basic treatment for wheat pasture poisoning has been the intravenous...

Crookshank, H. R.; Sims, Frank H.

1956-01-01

389

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

ERIC Educational Resources Information Center

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

Idaho Wheat Commission, Boise.

390

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

2015-04-01

391

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

392

High-throughput single nucleotide polymorphism genotyping in wheat (Triticum spp.).  

PubMed

Over the past few years, considerable progress has been made in high-throughput single nucleotide polymorphism (SNP) genotyping technologies, largely through the investment of the human genetics community. These technologies are well adapted to diploid species. For plant breeding purposes, it is important to determine whether these genotyping methods are adapted to polyploidy, as most major crops are former or recent polyploids. To address this problem, we tested the capacity of the multiplex technology SNPlex with a set of 47 wheat SNPs to genotype DNAs of 1314 lines that were organized in four 384-well plates. These lines represented different taxa of tetra- and hexaploid Triticum species and their wild diploid relatives. We observed 40 markers which gave less than 20% missing data. Different methods, based on either Sanger sequencing or the MassARRAY genotyping technology, were then used to validate the genotypes obtained by SNPlex for 11 markers. The concordance of the genotypes obtained by SNPlex with the results obtained by the different validation methods was 96%, except for one discarded marker. Furthermore, a mapping study on six markers showed the expected genetic positions previously described. To conclude, this study showed that high-throughput genotyping technologies developed for diploid species can be used successfully in polyploids, although there is a need for manual reading. For the first time in wheat species, a core of 39 SNPs is available that can serve as the basis for the development of a complete SNPlex set of 48 markers. PMID:19379285

Bérard, Aurélie; Le Paslier, Marie Christine; Dardevet, Mireille; Exbrayat-Vinson, Florence; Bonnin, Isabelle; Cenci, Alberto; Haudry, Annabelle; Brunel, Dominique; Ravel, Catherine

2009-05-01

393

The wheat-Septoria conflict: a new front opening up?  

PubMed

In the utopic absence of abiotic and/or biotic stressors, attaining the predicted increase (up to 70%) in wheat demand by 2050 in response to global population trends is a challenge. This objective becomes daunting, however, when one factors in the continuous constraint on global wheat production posed by Septoria tritici blotch (STB) disease. This is because, despite resistant loci being identified, a deficit of commercially relevant STB-resistant wheat germplasm remains. The issue is further compounded for growers by the emergence and prevalence of fungicide-resistant/insensitive strains of the causative pathogen Zymoseptoria tritici (formerly known as Mycosphaerella graminicola/Septoria tritici). However, biotechnology-based research is providing new opportunities in this struggle. As the exome response of wheat to STB attack begins to be deciphered, genes intrinsic to resistant and susceptible phenotypes will be identified. Combined with the application of genome-editing techniques and a growing appreciation of the complexity of wheat's and the dynamism of Z. tritici's genome, the generation of resulting STB-resistant wheat varieties will counter the prevalent threat of STB disease in wheat-production systems. PMID:24957882

O'Driscoll, Aoife; Kildea, Steven; Doohan, Fiona; Spink, John; Mullins, Ewen

2014-09-01

394

Next-generation sequencing and syntenic integration of flow-sorted arms of wheat chromosome 4A exposes the chromosome structure and gene content.  

PubMed

Wheat is the third most important crop for human nutrition in the world. The availability of high-resolution genetic and physical maps and ultimately a complete genome sequence holds great promise for breeding improved varieties to cope with increasing food demand under the conditions of changing global climate. However, the large size of the bread wheat (Triticum aestivum) genome (approximately 17 Gb/1C) and the triplication of genic sequence resulting from its hexaploid status have impeded genome sequencing of this important crop species. Here we describe the use of mitotic chromosome flow sorting to separately purify and then shotgun-sequence a pair of telocentric chromosomes that together form chromosome 4A (856 Mb/1C) of wheat. The isolation of this much reduced template and the consequent avoidance of the problem of sequence duplication, in conjunction with synteny-based comparisons with other grass genomes, have facilitated construction of an ordered gene map of chromosome 4A, embracing ?85% of its total gene content, and have enabled precise localization of the various translocation and inversion breakpoints on chromosome 4A that differentiate it from its progenitor chromosome in the A genome diploid donor. The gene map of chromosome 4A, together with the emerging sequences of homoeologous wheat chromosome groups 4, 5 and 7, represent unique resources that will allow us to obtain new insights into the evolutionary dynamics between homoeologous chromosomes and syntenic chromosomal regions. PMID:21974774

Hernandez, Pilar; Martis, Mihaela; Dorado, Gabriel; Pfeifer, Matthias; Gálvez, Sergio; Schaaf, Sebastian; Jouve, Nicolás; Šimková, Hana; Valárik, Miroslav; Doležel, Jaroslav; Mayer, Klaus F X

2012-02-01

395

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

PubMed Central

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

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

2012-01-01

396

New Uses for Wheat and Modified Wheat Products  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard wheat from the Great Plains historically has been used as a source of flour for the production of leavened bakery products. However, potentially applications of wheat in both new markets and new products has necessitated the need to develop wheats with novel processing attributes. The most lo...

397

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...

398

A high-density microsatellite consensus map for bread wheat ( Triticum aestivum L.)  

Microsoft Academic Search

A microsatellite consensus map was constructed by joining four independent genetic maps of bread wheat. Three of the maps were F1-derived, doubled-haploid line populations and the fourth population was ‘Synthetic’ × ‘Opata’, an F6-derived, recombinant-inbred line population. Microsatellite markers from different research groups including the Wheat Microsatellite Consortium, GWM, GDM, CFA, CFD, and BARC were used in the mapping. A

Daryl J. Somers; Peter Isaac; Keith Edwards

2004-01-01

399

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

400

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...

401

Identification and mapping of H32 , a new wheat gene conferring resistance to Hessian fly  

Microsoft Academic Search

H32 is a newly identified gene that confers resistance to the highly pervasive Biotype L of the Hessian fly [ Mayetiola destructor (Say)]. The gene was identified in a synthetic amphihexaploid wheat, W-7984, that was constructed from the durum ‘Altar 84’ and Aegilops tauschii. This synthetic wheat is one of the parents of the marker-rich ITMI population, which consists of

N. Sardesai; J. A. Nemacheck; S. Subramanyam; C. E. Williams

2005-01-01

402

Directional Flow of Summer Aeration to Manage Insect Pests in Stored Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field trials were conducted in metal wheat storage bins to determine whether pressure aeration, pushing ambient air from the bottom, or suction aeration, pulling air down from the top, would be more efficient at cooling the wheat mass and thereby limiting insect population growth. Aeration was accom...

403

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

404

Quantitative trait loci and epistasis for crown freezing tolerance in the Kanota x Ogle hexaploid oat mapping population.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter hardiness is a complex trait, and poor winter hardiness limits commercial production of winter oat. Crown freeze tolerance is the most important factor conferring winter hardiness, and controlled crown freeze tests correlate well with field winter hardiness. The objective of this study was ...

405

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.

406

Quantitative trait loci for resistance to pre-harvest sprouting in US hard white winter wheat Rio Blanco  

Microsoft Academic Search

Pre-harvest sprouting (PHS) of wheat is a major problem that severely limits the end-use quality of flour in many wheat-growing\\u000a areas worldwide. To identify quantitative trait loci (QTLs) for PHS resistance, a population of 171 recombinant inbred lines\\u000a (RILs) was developed from the cross between PHS-resistant white wheat cultivar Rio Blanco and PHS-susceptible white wheat\\u000a breeding line NW97S186. The population

Shubing Liu; Shibin Cai; Robert Graybosch; Cuixia Chen; Guihua Bai

2008-01-01

407

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

408

Intraspecific sequence comparisons reveal similar rates of non-collinear gene insertion in the B and D genomes of bread wheat  

PubMed Central

Background Polyploidization is considered one of the main mechanisms of plant genome evolution. The presence of multiple copies of the same gene reduces selection pressure and permits sub-functionalization and neo-functionalization leading to plant diversification, adaptation and speciation. In bread wheat, polyploidization and the prevalence of transposable elements resulted in massive gene duplication and movement. As a result, the number of genes which are non-collinear to genomes of related species seems markedly increased in wheat. Results We used new-generation sequencing (NGS) to generate sequence of a Mb-sized region from wheat chromosome arm 3DS. Sequence assembly of 24 BAC clones resulted in two scaffolds of 1,264,820 and 333,768 bases. The sequence was annotated and compared to the homoeologous region on wheat chromosome 3B and orthologous loci of Brachypodium distachyon and rice. Among 39 coding sequences in the 3DS scaffolds, 32 have a homoeolog on chromosome 3B. In contrast, only fifteen and fourteen orthologs were identified in the corresponding regions in rice and Brachypodium, respectively. Interestingly, five pseudogenes were identified among the non-collinear coding sequences at the 3B locus, while none was found at the 3DS locus. Conclusion Direct comparison of two Mb-sized regions of the B and D genomes of bread wheat revealed similar rates of non-collinear gene insertion in both genomes with a majority of gene duplications occurring before their divergence. Relatively low proportion of pseudogenes was identified among non-collinear coding sequences. Our data suggest that the pseudogenes did not originate from insertion of non-functional copies, but were formed later during the evolution of hexaploid wheat. Some evidence was found for gene erosion along the B genome locus. PMID:22935214

2012-01-01

409

New wheats and social progress.  

PubMed

Will the upward trend in all food production, so dramatically exemplified by the new wheats, be adequate to meet the needs of the growing population? Yes, for a while. No one knows for how long (14). The prophets of doom will undeniably be proved right in the long run unless their basic assumptions are nullified by concrete acts, and soon. At some point in time, either a zero population growth must be achieved or vast new sources of food must be developed, and purchasing power increased. There is nothing on the research horizon to reject "a prodigious need for mankind to practice human husbandry" (12). Our waste products have reached levels that cause major concern, and it may well be that both agricultural and social advancement will be halted by the demands dictated by population growth and the by-products of what now passes for progress but also brings environmental unbalance (15). At least, life will be different, and it may be catastrophic (16, 28). The "Three Ancients" (29) who helped plan and then, after a quarter of a century, reviewed the agricultural research and development work of the Rockefeller Foundation in developing nations concluded: PMID:5432698

Reitz, L P

1970-09-01

410

Characteristics of spelt wheat products and nutritional value of spelt wheat-based bread  

Microsoft Academic Search

Spelt wheat cultivars (cv.) Hercule, Rouquin and Ostro, grown in the Alpine region of Italy, were compared to the common wheat cv. Manital and durum wheat Grazia for protein, ash and dietary fibre contents. The spelt wheat cultivars studied had higher contents of soluble dietary fibre and protein than the standard wheat or the durum wheat. In the bread of

G. Bonafaccia; V. Galli; R. Francisci; V. Mair; V. Skrabanja; I. Kreft

2000-01-01

411

DERIVED DEMAND FOR WHEAT BY CLASS  

Microsoft Academic Search

To quantify price responsiveness and economic substitutability among wheat classes, derived demand functions were specified from a normalized quadratic profit function. Own-price and cross-price elasticities were estimated for hard red winter, hard red spring, soft wheat (combined red and white), and durum wheat. In general, soft wheat varieties were less responsive to their own price than were hard wheat varieties.

Justin J. Terry; Thomas L. Marsh

2000-01-01

412

REGISTRATION OF ‘LOUISE’ WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Louise’ soft white spring wheat (Triticum aestivum L.) (Reg. No. CV-987, PI 634865) was developed and jointly released in August 2005 by the Agricultural Research Center of Washington State University in cooperation with the Agricultural Experiment Stations (AESs) of the University of Idaho and Ore...

413

Wheat Breeding Activity  

NSDL National Science Digital Library

This interactive activity goes through the basic process used in a wheat breeding program. Crossing, genetic variation, selection and elements of DNA technology are discussed within this activity. The material is aimed towards high school or introductory life science undergraduate students.

414

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 ...

415

REGISTRATION OF 'GLENN' WHEAT.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Glenn (Reg. no. CV- , PI 639273), is a hard red spring wheat (Triticum aestivum L.) developed at North Dakota State university and released by the North Dakota Agricultural Experiment Station in July 2005. Glenn was released because it combines a very high level of resistance to Fusarium head bli...

416

Wheat Production in Texas.  

E-print Network

............-- .......................................................... Stem Rust ?I: ......................................................... Stripe Rust 2 I Q ..... .............................................. Septoria .. 1:) ............................................... Powdery Mildew 2,) n - - I Smuts... AREA I11 : The Blackland Prairie, Grand Prairie, East and West Cross Timbers and Northeast Texas Timberlands are all included in this reasearch area, Extension Districts 4 and 5, where about 8 percent of the state wheat acre- age is grown...

Atkins, I. M.; Porter, K. B.; Merkle, O. G.; Lahr, K. A.; Gilmore, E. C.

1970-01-01

417

REGISTRATION OF 'EDNURANCE' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Endurance’ is a hard red winter wheat (Triticum aestivum L.) that 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 intensive grazing in a...

418

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...

419

Registration of ‘Ambassador’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

"Ambassador" soft white winter wheat (Triticum aestivum L.) was developed by the Michigan Agricultural Experiment Station and released August 20, 2007, in an exclusive licensing agreement through Michigan State University (MSU) Technologies. Ambassador was selected from the cross of Pioneer Brand 27...

420

Modelling Wheat Production  

Technology Transfer Automated Retrieval System (TEKTRAN)

In wheat, a shorter pre-anthesis phase is often associated with increased grain protein content (GPC) but decreased grain yield. Cultivar differences in pre-anthesis development are mainly determined by vernalization requirement, photoperiod sensitivity and earliness per se. This research examines w...

421

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...

422

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...

423

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...

424

REGISTRATION OF 'INTRADA' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Intrada' is a hard white winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station, Kansas Agricultural Experiment Station, and the USDA-ARS, and released in September, 2000, in cooperation with the USDA-ARS. Intrada was released for its high yield...

425

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 ...

426

Registration of ‘MDM’ wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘MDM’ (J980628, WA007936) hard white winter wheat (HWW) (Triticum aestivum L.) (Reg. No. CV-XXX, PI 634716) was released in 2005 by the Agricultural Research Center of Washington State University (WSU) in cooperation with the USDA-ARS. MDM is a semi dwarf cultivar adapted to the low- to intermediat...

427

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- ...

428

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...

429

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...

430

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...

431

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...

432

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’ ...

433

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, ...

434

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...

435

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

436

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...

437

Registration of ‘Bearpaw’ wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Bearpaw’ (Reg. No. CV-1083, PI 665228) hard red winter (HRW) wheat (Triticum aestivum L.) was developed and released by the Montana Agricultural Experiment Station in September 2011. Bearpaw is of unknown pedigree, derived from a composite of five crosses made to the same F1 male sterile parent in ...

438

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...

439

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...

440

Registration of ‘Shirley’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Shirley’ (Reg. No. CV-1039, PI 656753) soft red winter (SRW)