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1

The genetic study utility of a hexaploid wheat DH population with non-recombinant A- and B-genomes.  

PubMed

To study the D-genome of the wild wheat relative Aegilops tauschii Cosson at the hexaploid level, we developed a synthetic doubled-haploid (DH) hexaploid wheat population, SynDH3. This population was derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from a cross between Triticum turgidum ssp. dicoccon PI377655 and A. tauschii ssp. strangulata AS66 × ssp. tauschii AS87. SynDH3 is a diploidization-hexaploid DH population containing recombinant D chromosomes from two different A. tauschii genotypes, with A and B chromosomes from T. turgidum being homogenous across the entire population. Using this population, we constructed a genetic map. Of the 440 markers used to construct the map, 421 (96%) were assigned to 12 linkage groups; these included 346 Diversity Arrays Technology (DArT) and 75 simple sequence repeat (SSR) markers. The total map length of the seven D chromosomes spanned 916.27 cM, with an average length of 130.90 cM per chromosome and an average distance between markers of 3.47 cM. Seven segregation distortion regions were detected on seven linkage groups. Out of 50 markers shared with those on a common wheat map, 37 showed a consistent order. The utility of the diploidization-hexaploid DH population for mapping qualitative trait genes was confirmed using the dominant glaucousness-inhibiting gene W2 (I) as an example. PMID:23577301

Hao, Ming; Chen, Jixiang; Zhang, Lianquan; Luo, Jiangtao; Yuan, Zhongwei; Yan, Zehong; Zhang, Bo; Chen, Wenjie; Wei, Yuming; Zhang, Huaigang; Zheng, Youliang; Liu, Dengcai

2013-12-01

2

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

3

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

4

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

5

Evolution of physiological responses to salt stress in hexaploid wheat  

PubMed Central

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

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

2014-01-01

6

[Analysis of intraspecific divergence of hexaploid wheat Triticum spelta L. by chromosome C-banding].  

PubMed

Intraspecific divergence of hexaploid wheat Triticum spelta was studied by chromosome C-banding in 41 accessions of different geographic origins. The spelt accessions did not differ in karyotype structure or heterochromatin distribution from common wheat, but showed greater intraspecific polymorphism for chromosome rearrangements (translocations, inversions) and banding patterns. On evidence of C-banding patterns, spelt was assumed to occupy an intermediate position between tetraploid and hexaploid wheat species. Accessions of the Asian spelt subspecies had more diverse banding patterns than European accessions. A relatively high frequency of chromosome rearrangements was observed in Iranian accessions. Visual analysis revealed high uniformity of chromosome banding patterns in T. spelta populations of Afghanistan, Spain, and Germany (Bavarian group), suggesting a significant role of the founder effect in their evolution. PMID:15575503

Dedkova, O S; Badaeva, E D; Mitrofanova, O P; Zelenin, A V; Pukhal'ski?, V A

2004-10-01

7

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

8

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat  

Microsoft Academic Search

Hexaploid wheat (Triticum aestivum) accumulates benzoxazinones (Bxs) as defensive compounds. Previously, we found that five Bx biosynthetic genes, TaBx1-TaBx5, are located on each of the three genomes (A, B, and D) of hexaploid wheat. In this study, we isolated three homoeologous cDNAs of each TaBx gene to estimate the contribution of individual homoeologous TaBx genes to the biosynthesis of Bxs

Taiji Nomura; Atsushi Ishihara; Ryo C. Yanagita; Takashi R. Endo; Hajime Iwamura

2005-01-01

9

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat.  

PubMed

Hexaploid wheat (Triticum aestivum) accumulates benzoxazinones (Bxs) as defensive compounds. Previously, we found that five Bx biosynthetic genes, TaBx1-TaBx5, are located on each of the three genomes (A, B, and D) of hexaploid wheat. In this study, we isolated three homoeologous cDNAs of each TaBx gene to estimate the contribution of individual homoeologous TaBx genes to the biosynthesis of Bxs in hexaploid wheat. We analyzed their transcript levels by homoeolog- or genome-specific quantitative RT-PCR and the catalytic properties of their translation products by kinetic analyses using recombinant TaBX enzymes. The three homoeologs were transcribed differentially, and the ratio of the individual homoeologous transcripts to total homoeologous transcripts also varied with the tissue, i.e., shoots or roots, as well as with the developmental stage. Moreover, the translation products of the three homoeologs had different catalytic properties. Some TaBx homoeologs were efficiently transcribed, but the translation products showed only weak enzymatic activities, which inferred their weak contribution to Bx biosynthesis. Considering the transcript levels and the catalytic properties collectively, we concluded that the homoeologs on the B genome generally contributed the most to the Bx biosynthesis in hexaploid wheat, especially in shoots. In tetraploid wheat and the three diploid progenitors of hexaploid wheat, the respective transcript levels of the TaBx homoeologs were similar in ratio to those observed in hexaploid wheat. This result indicates that the genomic bias in the transcription of the TaBx genes in hexaploid wheat originated in the diploid progenitors and has been retained through the polyploidization. PMID:16260753

Nomura, Taiji; Ishihara, Atsushi; Yanagita, Ryo C; Endo, Takashi R; Iwamura, Hajime

2005-11-01

10

Three genomes differentially contribute to the biosynthesis of benzoxazinones in hexaploid wheat  

PubMed Central

Hexaploid wheat (Triticum aestivum) accumulates benzoxazinones (Bxs) as defensive compounds. Previously, we found that five Bx biosynthetic genes, TaBx1-TaBx5, are located on each of the three genomes (A, B, and D) of hexaploid wheat. In this study, we isolated three homoeologous cDNAs of each TaBx gene to estimate the contribution of individual homoeologous TaBx genes to the biosynthesis of Bxs in hexaploid wheat. We analyzed their transcript levels by homoeolog- or genome-specific quantitative RT-PCR and the catalytic properties of their translation products by kinetic analyses using recombinant TaBX enzymes. The three homoeologs were transcribed differentially, and the ratio of the individual homoeologous transcripts to total homoeologous transcripts also varied with the tissue, i.e., shoots or roots, as well as with the developmental stage. Moreover, the translation products of the three homoeologs had different catalytic properties. Some TaBx homoeologs were efficiently transcribed, but the translation products showed only weak enzymatic activities, which inferred their weak contribution to Bx biosynthesis. Considering the transcript levels and the catalytic properties collectively, we concluded that the homoeologs on the B genome generally contributed the most to the Bx biosynthesis in hexaploid wheat, especially in shoots. In tetraploid wheat and the three diploid progenitors of hexaploid wheat, the respective transcript levels of the TaBx homoeologs were similar in ratio to those observed in hexaploid wheat. This result indicates that the genomic bias in the transcription of the TaBx genes in hexaploid wheat originated in the diploid progenitors and has been retained through the polyploidization. PMID:16260753

Nomura, Taiji; Ishihara, Atsushi; Yanagita, Ryo C.; Endo, Takashi R.; Iwamura, Hajime

2005-01-01

11

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

12

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 (...

13

Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat D-genome genetic diversity and pinpoint the geographic origin of hexaploid wheat.  

PubMed

Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes. PMID:23374069

Wang, Jirui; Luo, Ming-Cheng; Chen, Zhongxu; You, Frank M; Wei, Yuming; Zheng, Youliang; Dvorak, Jan

2013-05-01

14

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

PubMed

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

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

2014-06-15

15

Identification of multiple highly similar XIP-type xylanase inhibitor genes in hexaploid wheat  

Microsoft Academic Search

In hexaploid wheat, Xip-I is the only XIP-type xylanase inhibitor gene whose expression and function have been characterized in detail. Here we demonstrate the existence of new XIP-type genes with the identification of Xip-R1 and Xip-R2 in the root cDNAs. Southern blot analysis with the Xip-R1 probe revealed that XIP-type genes comprised a significantly greater gene family than previously speculated

Naoko Takahashi-Ando; Makiko Inaba; Shuichi Ohsato; Tomoko Igawa; Ron Usami; Makoto Kimura

2007-01-01

16

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

17

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

18

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

PubMed

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

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

2012-12-01

19

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

E-print Network

of this research was to evaluate the potential and performance of synthetic wheat in Texas. Ten elite primary synthetics from the International Maize and Wheat Improvement Center (CIMMYT), screened for desirable traits, were backcrossed to two Texas cultivars, TAM...

Cooper, Jessica Kay

2012-02-14

20

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

21

Quality of synthetic hexaploid wheat containing null alleles at Glu-A1 and Glu-B1 loci.  

PubMed

Triticum turgidum ssp. dicoccon PI94668 and PI349045 were identified as containing null alleles at Glu-A1 and Glu-B1 loci in previous investigation. Sequencing of the respective HMW-GS genes Ax, Bx, Ay and By in both accessions indicated equal DNA lengths with gene silencing caused by 1 to 4 in-frame stop codon(s) in the open reading frames. Six synthetic hexaploid wheat lines were produced by crossing PI94668 or PI349045 with six Aegilops tauschii by spontaneous chromosome doubling of unreduced gametes. As expected, these amphiploids had three different HMW-GS: Dx 3.1(t) + Dy11(*t), Dx2.1(t) +10(t) and Dx2(t) +Dy12(t) in Glu-D1 but double nulls in Glu-A1 and Glu-B1. Quality tests showed that most quality parameters in two T. turgidum ssp. dicoccon parents were very low due to the lack of HMW-GSs. However, incorporation of HMW-GS from Ae. tauschii in six synthetic hexaploid wheat lines significantly increased most quality related parameters. The potential values of these wheat lines in improving the quality of wheat are discussed. PMID:23970079

Hu, Xinkun; Dai, Shoufen; Pu, Zhien; Liu, Dengcai; Pu, Zongjun; Jiang, Jiaqi; Wei, Yuming; Wu, Bihua; Lan, Xiujin; Zheng, Youliang; Yan, Zehong

2013-01-01

22

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

E-print Network

DETERNINATION OF THE 3' INKAGE RELATIONSHIPS AND THE GENE-CENTBQYZRZ GENETIC DISTANCES FOR ENDOPEPTIDASE STRUCTU~& GENES IN HEXAPLOID WHEAT A Thesis by DAVID EDWIN NcNILLIN Submitted to the Graduate College of Texas A6K University iri... partial fulfillrr~ent of the requirement for the degree of :PASTER OF SCIE'ACR Nay 1977 Hajor Sub-je" t: Gea, ties DETERMINATION OF THE LD'KACE kEM'). '. ~'OBBHZPS AND THi?: GENE-CENTF''ONEM GENETIC DIS'L&NCES FOR ENDOPEPTIDASE STRUCTURAL GENES IN H...

McMillin, David Edwin

2012-06-07

23

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

24

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, Frederic; Yen, Yang; Zhang, Lianquan; Liu, Dengcai

2014-01-01

25

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

PubMed

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

26

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

27

Construction and Characterization of a Bacterial Artificial Chromosome Library for the Hexaploid Wheat Line 92R137  

PubMed Central

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

Yuan, Fengping; Xu, Xin; Shi, Xue; Zhuang, Hua; Wang, Zhonghua; Huang, Lili; Han, Dejun; Kang, Zhensheng

2014-01-01

28

Cloning and comparative analysis of carotenoid ?-hydroxylase genes provides new insights into carotenoid metabolism in tetraploid (Triticum turgidum ssp. durum) and hexaploid (Triticum aestivum) wheat grains.  

PubMed

Carotenoid ?-hydroxylases attach hydroxyl groups to the ?-ionone rings (?-rings) of carotenoid substrates, resulting in modified structures and functions of carotenoid molecules. We cloned and characterized two genes (each with three homeologs), HYD1 and HYD2, which encode ?-hydroxylases in wheat. The results from bioinformatic and nested degenerate PCR analyses collectively suggest that HYD1 and HYD2 may represent the entire complement of non-heme di-iron ?-hydroxylases in wheat. The homeologs of wheat HYDs exhibited major ?-ring and minor ?-ring hydroxylation activities in carotenoid-accumulating E. coli strains. Distinct expression patterns were observed for different HYD genes and homeologs in vegetative tissues and developing grains of tetraploid and hexaploid wheat, suggesting their functional divergence and differential regulatory control in tissue-, grain development-, and ploidy-specific manners. An intriguing observation was that the expression of HYD1, particularly HYD-B1, reached highest levels at the last stage of tetraploid and hexaploid grain development, suggesting that carotenoids (at least xanthophylls) were still actively synthesized in mature grains. This result challenges the common perception that carotenoids are simply being turned over during wheat grain development after their initial biosynthesis at the early grain development stages. Overall, this improved understanding of carotenoid biosynthetic gene expression and carotenoid metabolism in wheat grains will contribute to the improvement of the nutritional value of wheat grains for human consumption. PMID:23015203

Qin, Xiaoqiong; Zhang, Wenjun; Dubcovsky, Jorge; Tian, Li

2012-12-01

29

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

Microsoft Academic Search

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

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

2009-01-01

30

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) ...

31

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

PubMed Central

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

2013-01-01

32

Overexpression of Three TaEXPA1 Homoeologous Genes with Distinct Expression Divergence in Hexaploid Wheat Exhibit Functional Retention in Arabidopsis  

PubMed Central

Common wheat is a hexaploid species with most of the genes present as triplicate homoeologs. Expression divergences of homoeologs are frequently observed in wheat as well as in other polyploid plants. However, little is known about functional variances among homologous genes arising from polyploidy. Expansins play diverse roles in plant developmental processes related to the action of cell wall loosening. Expression of the three TaEXPA1 homoeologs varied dynamically at different stages and organs, and epigenetic modifications contribute to the expression divergence of three TaEXPA1 homoeologs during wheat development. Nevertheless, their functions remain to be clarified. We found that over expression of TaEXPA1-A, -B and -D produced similar morphological changes in transgenic Arabidopsis plants, including increased germination and growth rate during seedling and adult stages, indicating that the proteins encoded by these three wheat TaEXPA1 homoeologs have similar (or conserved) functions in Arabidopsis. Collectively, our present study provided an example of a set of homoeologous genes expression divergence in different developmental stages and organs in hexaploid wheat but functional retention in transgenic Arabidopsis plants. PMID:23696842

Xing, Jiewen; Chen, Yanhong; Han, Zongfu; Yao, Yingyin; Peng, Huiru; Ni, Zhongfu; Sun, Qixin

2013-01-01

33

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

34

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

35

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

36

Hemi-nested touchdown PCR combined with primer-template mismatch PCR for rapid isolation and sequencing of low molecular weight glutenin subunit gene family from a hexaploid wheat BAC library  

Microsoft Academic Search

BACKGROUND: Hexaploid wheat (Triticum aestivum L.) possesses a large genome that contains 1.6 × 1010 bp of DNA. Isolation of a large number of gene sequences from complex gene families with a high level of gene sequence identity from genomic DNA is therefore difficult and time-consuming. Bacterial artificial chromosome (BAC) libraries can be useful for such work. Here we report

Xiu-Qiang Huang; Sylvie Cloutier

2007-01-01

37

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

38

Alteration of the embryo transcriptome of hexaploid winter wheat ( Triticum aestivum cv. Mercia) during maturation and germination  

Microsoft Academic Search

Grain dormancy and germination are areas of biology that are of considerable interest to the cereal community. We have used a 9,155-feature wheat unigene cDNA microarray resource to investigate changes in the wheat embryo transcriptome during late grain development and maturation and during the first 48 h of postimbibition germination. In the embryo 392 mRNAs accumulated by twofold or greater over

Ian D. Wilson; Gary L. A. Barker; Chungui Lu; Jane A. Coghill; Richard W. Beswick; John R. Lenton; Keith J. Edwards

2005-01-01

39

Frequency and fidelity of alien chromosome transmission in Gossypium hexaploid bridging populations.  

PubMed

The Australian diploid Gossypium species possess traits of potential agronomical value, such as gossypol-free seeds and Fusarium wilt resistance. However, they belong to the tertiary germplasm pool, which is the most difficult group of species from which to introgress genes into G. barbadense L. and G. hirsutum L. Interspecific triploid hybrids can be generated but they are sterile. The sterility barrier can be overcome using synthetic polyploids as introgression bridges, but whether there is sufficient homoeologous chromosome interaction at meiosis to allow recombination is still an open question. To ascertain, genetically, observable levels of homoeologous introgression, 2 synthetic hexaploid lines (2x G. hirsutum x G. australe and 2x G. hirsutum x G. sturtianum) were crossed to G. hirsutum to generate pentaploid F1 plants that, in turn, were backcrossed to G. hirsutum to generate BC1 and BC2 multiple alien chromosome addition lines (MACALs). Gossypium australe F. Muell. and G. sturtianum Willis chromosome-specific markers were used to track the frequency and fidelity of chromosome transmission to the BC1 and BC2 MACALs. The chromosomal location of the AFLP markers was determined by their distribution among the MACALs and confirmed in parental F2 families. Roughly half the available chromosomes were transmitted to the G. hirsutum x G. australe (54%) and G. hirsutum x G. sturtianum (52%) BC1 MACALs. The BC2 MACAL families again inherited about half of the available chromosomes. There were, however, notable exceptions for specific chromosomes. Some chromosomes were preferentially eliminated, while others were preferentially transmitted. Consistent with the genomic stability of Gossypium synthetic polyploids, the de novo loss or gain of AFLP fragments was rarely observed. While restructuring of the donor G. australe and G. sturtianum chromosomes was observed, this is more likely the result of chromatin loss, and no clear cases of introgression of donor chromatin into the recipient G. hirsutum genome were observed. PMID:17612617

Becerra Lopez-Lavalle, L Augusto; Brubaker, Curt L

2007-05-01

40

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

41

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

42

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

43

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

44

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

45

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

46

Spring Wheat Breeding  

Microsoft Academic Search

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

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

47

Identification of transposons, retroelements, and a gene family predominantly expressed in floral tissues in chromosome 3DS of the hexaploid wheat progenitor Aegilops tauschii  

Microsoft Academic Search

A multigene family expressed during early floral development was identified on the short arm of wheat chromosome 3D in the region of the Ph2 locus, a locus controlling homoeologous chromosome pairing in allohexaploid wheat. Physical, genetic and molecular characterisation of the Wheat\\u000a Meiosis 1 (WM1) gene family identified seven members that localised within a region of 173-kb. WM1 gene family

Ryan Whitford; Ute Baumann; Tim Sutton; Luke Gumaelius; Petra Wolters; Scott Tingey; Jason A. Able; Peter Langridge

2007-01-01

48

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

49

A highly conserved gene island of three genes on chromosome 3B of hexaploid wheat: diverse gene function and genomic structure maintained in a tightly linked block  

Microsoft Academic Search

BACKGROUND: The complexity of the wheat genome has resulted from waves of retrotransposable element insertions. Gene deletions and disruptions generated by the fast replacement of repetitive elements in wheat have resulted in disruption of colinearity at a micro (sub-megabase) level among the cereals. In view of genomic changes that are possible within a given time span, conservation of genes between

James M Breen; Thomas Wicker; Xiuying Kong; Juncheng Zhang; Wujun Ma; Etienne Paux; Catherine Feuillet; Rudi Appels; Matthew Bellgard

2010-01-01

50

Genetic and physiological architecture of early vigor in Aegilops tauschii, the D-genome of hexaploid wheat. A quantitative trait loci analysis  

Microsoft Academic Search

Plant growth can be studied at different organizational levels, varying from cell, leaf, and shoot to the whole plant. The early growth of seedlings is important for the plant's establishment and its eventual success. Wheat (Triticum aestivum, genome AABBDD) seedlings exhibit a low early growth rate or early vigor. The germplasm of wheat is limited. Wild relatives constitute a source

Steege ter M. W; Ouden den F. M; H. Lambers; P. Stam; A. J. M. Peeters

2005-01-01

51

Genetic and Physiological Architecture of Early Vigor in Aegilops tauschii, the D-Genome Donor of Hexaploid Wheat. A Quantitative Trait Loci Analysis1(w)  

Microsoft Academic Search

Plant growth can be studied at different organizational levels, varying from cell, leaf, and shoot to the whole plant. The early growth of seedlings is important for the plant's establishment and its eventual success. Wheat (Triticum aestivum, genome AABBDD) seedlings exhibit a low early growth rate or early vigor. The germplasm of wheat is limited. Wild relatives constitute a source

Franka M. den Ouden; Hans Lambers; Piet Stam; Anton J. M. Peeters

52

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

53

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

PubMed Central

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

2013-01-01

54

Screening for zinc efficiency among wheat relatives and their utilisation for alien gene transfer  

Microsoft Academic Search

Genetic diversity for micronutrient efficiency among the most highly adapted and advanced hexaploid and tetraploid wheat cultivars\\u000a in the world is limited compared with alien species of wheat or rye. Therefore, screening for zinc efficiency was conducted\\u000a in greenhouse experiments under controlled conditions, and in field trials. Different varieties of hexaploid wheat, hexaploid\\u000a oats and diploid rye, together with hexaploid

R. Schlegel; I. Cakmak; B. Torun; S. Eker; I. Tolay; H. Ekiz; M. Kalayci; H. J. Braun

1998-01-01

55

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

56

An analysis of dormancy, ABA responsiveness, after-ripening and pre-harvest sprouting in hexaploid wheat (Triticum aestivum L.) caryopses  

Microsoft Academic Search

Embryo and caryopsis dormancy, abscisic acid (ABA) responsiveness, after-ripening (AR), and the disorder pre- harvest sprouting (PHS) were investigated in six genetically related wheat varieties previously characterized as resistant, intermediate, or susceptible to PHS. Timing of caryopsis AR differed between varieties; AR occurred before harvest ripeness in the most PHS-susceptible, whereas AR was slowest in the most PHS-resistant. Whole caryopses

Tanja Gerjets; Duncan Scholefield; M. John Foulkes; John R. Lenton; Michael J. Holdsworth

2010-01-01

57

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; Gordun, Elena

2013-01-01

58

An analysis of dormancy, ABA responsiveness, after-ripening and pre-harvest sprouting in hexaploid wheat (Triticum aestivum L.) caryopses.  

PubMed

Embryo and caryopsis dormancy, abscisic acid (ABA) responsiveness, after-ripening (AR), and the disorder pre-harvest sprouting (PHS) were investigated in six genetically related wheat varieties previously characterized as resistant, intermediate, or susceptible to PHS. Timing of caryopsis AR differed between varieties; AR occurred before harvest ripeness in the most PHS-susceptible, whereas AR was slowest in the most PHS-resistant. Whole caryopses of all varieties showed little ABA-responsiveness during AR; PHS-susceptible varieties were responsive at the beginning of the AR period whereas PHS-resistant showed some responsiveness throughout. Isolated embryos showed relatively little dormancy during grain-filling and most varieties exhibited a window of decreased ABA-responsiveness around the period of maximum dry matter accumulation (physiological maturity). Susceptibility to PHS was assessed by overhead misting of either isolated ears or whole plants during AR; varieties were clearly distinguished using both methods. These analyses allowed an investigation of the interactions between the different components of seed development, compartments, and environment for the six varieties. There was no direct relationship between speed of caryopsis AR and embryo dormancy or ABA-responsiveness during seed maturation. However, the velocity of AR of a variety was closely associated with the degree of susceptibility to PHS during AR suggesting that these characters are developmentally linked. Investigation of genetic components of AR may therefore aid breeding approaches to reduce susceptibility to PHS. PMID:19923197

Gerjets, Tanja; Scholefield, Duncan; Foulkes, M John; Lenton, John R; Holdsworth, Michael J

2010-01-01

59

Genetic diversity of wheat storage proteins and bread wheat quality  

Microsoft Academic Search

To understand the genetic and biochemical basis of the bread makingquality of wheat varieties, a large experiment was carried out with a set of162 hexaploid bread wheat varieties registered in the French or EuropeanWheat Catalogue. This material was used to analyse their allelic compositionat the twelve main storage protein loci. A large genetic and biochemicaldiversity of the gluten proteins was

G. Branlard; M. Dardevet; R. Saccomano; F. Lagoutte; J. Gourdon

2001-01-01

60

[Effects of wheat-oilseed rape or wheat-garlic intercropping on the population dynamics of Sitobion avenae and its main natural enemies].  

PubMed

Sitobion avenae (Fabricius) is one of the most important pests of winter wheat in China. An investigation was conducted at the experimental farm of Shandong Agricultural University to study the effects of intercropping oilseed rape or garlic with winter wheat on the population dynamics of S. avenae and its main natural enemies. The results showed that in most cases, the population density of S. avenae apterae was significantly lower in wheat-oilseed rape and wheat-garlic intercropping fields than in wheat monoculture field. The population density of ladybeetle and the ratio of ladybeetle to S. avenae were higher in wheat-oilseed rape intercropping field. Before May 2, the population density of aphid parasitoids in wheat-oilseed rape intercropping field was higher than that in wheat-garlic intercropping field and wheat monoculture field; and after May 5, the mummy rate of aphid parasitoids and the ratio of aphid parasitoids to S. avenae in wheat-oilseed rape intercropping field were significantly higher than those in the other two fields. In wheat-garlic intercropping field, S. avenae alatae had a higher population amount, but no significant change was observed in the population amounts of ladybeetle and aphid parasitoids. It was concluded that wheat-oilseed rape or wheat-garlic intercropping could control S. avenae in wheat fields. PMID:18808028

Wang, Wan-Lei; Liu, Yong; Ji, Xiang-Long; Wang, Guang; Zhou, Hai-Bo

2008-06-01

61

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.; Prochazka, T.; Munzbergova, Z.

2012-01-01

62

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

63

Development of near-isogenic lines of wheat carrying different null Wx alleles and their starch properties  

Microsoft Academic Search

The granule-bound starch synthase (GBSS I) encoded by the Wxgenes, is involved in amylose synthesis. For analyses of mechanisms of amylose synthesis and associated starch properties\\u000a in hexaploid wheat, eight possible genotypes having different combinations of the three null alleles at the Wx loci with a common genetic background are a prerequisite. A near-isogenic population of doubled haploid (DH) lines

H. Miura; M. H. A. Wickramasinghe; R. M. Subasinghe; E. Araki; K. Komae

2002-01-01

64

Reproductive allocation patterns in different density populations of spring wheat.  

PubMed

The effects of increased intraspecific competition on size hierarchies (size inequality) and reproductive allocation were investigated in populations of the annual plant, spring wheat (Triticum aestivum). A series of densities (100, 300, 1000, 3000 and 10,000 plants/m(2)) along a gradient of competition intensity were designed in this experiment. The results showed that average shoot biomass decreased with increased density. Reproductive allocation was negatively correlated to Gini coefficient (R(2) = 0.927), which suggested that reproductive allocation is inclined to decrease as size inequality increases. These results suggest that both vegetative and reproductive structures were significantly affected by intensive competition. However, results also indicated that there were different relationships between plant size and reproductive allocation pattern in different densities. In the lowest density population, lacking competition (100 plants/m(2)), individual reproductive allocation was size independent but, in high density populations (300, 1000, 3000 and 10,000 plants/m(2)), where competition occurred, individual reproductive allocation was size dependent: the small proportion of larger individuals were winners in competition and got higher reproductive allocation (lower marginal reproductive allocation; MRA), and the larger proportion of smaller individuals were suppressed and got lower reproductive allocation (higher MRA). In conclusion, our results support the prediction that elevated intraspecific competition would result in higher levels of size inequality and decreased reproductive allocation (with a negative relationship between them). However, deeper analysis indicated that these frequency- and size-dependent reproductive strategies were not evolutionarily stable strategies. PMID:18713435

Liu, Jing; Wang, Gen-Xuan; Wei, Liang; Wang, Chun-Ming

2008-02-01

65

[Effects of plant hedgerow on population dynamics of wheat aphid and its natural enemies].  

PubMed

This paper studied the effects of planting different kinds of plant hedgerow (Amorpha fruticosa, Vetiveria zizanioides, Eulaliopsis binata, and Medicago sativa) on the population dynamics of wheat aphid and its natural enemies in the hillside wheat fields in Ziyang City of Sichuan Province, Southwest China. On the 20 degrees hillside, A. fruticosa hedgerow inhibited the occurrence of wheat aphid in the wheat field significantly, and the parasitoid densities were equal to or significantly lower than those in the wheat field with V. zizanioides hedgerow. On the 12 degrees hillside, M. sativa and E. binata hedgerows delayed the peak time of wheat aphid occurrence, and E. binata hedgerow suppressed the wheat aphid population density significantly. In the wheat field with M. sativa hedgerow, the parasitoid densities were significantly higher than those with no hedgerow. An equal or significantly higher ladybird density was observed in the field with M. sativa hedgerow. The olfactory responses showed that E. binata volatiles had repellent effect on both Sitobion avenae and Rhopalosiphum padi, but attracted a spider species of oxyopidae. M. sativa volatiles attracted S. avenae, whereas neither M. sativa nor E. binata volatiles caused obvious behavior response of ladybird adults. Therefore, planting A. fruticosa and E. binata as the hedgerows in hillside wheat fields could not only prevent the soil erosion from seasonal rainfall, but also benefit the control of pest insects. PMID:22384596

Shi, Guo-Qing; Lin, Chao-Wen; Liu, Zhang-Yong; Li, Chuan-Ren; Chen, Yi-Bing; Ma, Tao; Wang, Qi-Feng; Liu, Zhi-Long; Cai, Qing-Nian

2011-12-01

66

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

PubMed Central

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. PMID:23047200

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

2013-01-01

67

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

68

Inheritance of resistance to Fusarium head blight in three European winter wheat populations  

Microsoft Academic Search

Fusarium head blight (FHB) resistance is of particular importance in wheat breeding programmes due to the detrimental effects\\u000a of this fungal disease on human and animal health, yield and grain quality. Segregation for FHB resistance in three European\\u000a winter wheat populations enabled the identification of resistance loci in well-adapted germplasm. Populations obtained from\\u000a crosses of resistant cultivars Apache, History and

Josef Holzapfel; Hans-Henning Voss; Thomas Miedaner; Viktor Korzun; Jennifer Häberle; Günther Schweizer; Volker Mohler; Gerhard Zimmermann; Lorenz Hartl

2008-01-01

69

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

70

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

71

Population Analysis of Fusarium graminearum from Wheat Fields in Eastern China  

Microsoft Academic Search

Gale, L. R., Chen, L.-F., Hernick, C. A., Takamura, K., and Kistler, H. C. 2002. Population analysis of Fusarium graminearum from wheat fields in eastern China. Phytopathology 92:1315-1322. Wheat heads showing symptoms of Fusarium head blight were col- lected from four commercial fields in Zhejiang Province, China, an area where epidemics occur regularly. A total of 225 isolates were subjected

L. Rosewich Gale; L.-F. Chen; C. A. Hernick; K. Takamura; H. C. Kistler

2002-01-01

72

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

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer, is a polyphagous eriophyoid mite and the primary vector of wheat streak mosaic virus (WSMV) and five other viral pathogens in cereals. Previous research using molecular markers and a series of laboratory experiments found A. tosichella in Australia to consist of two genetically distinct lineages, which have broad overlapping distributions and differ in their ability to transmit WSMV under controlled conditions. This pattern of transmission also appears to be apparent in the field, whereby a strong association between WSMV detection and a single WCM lineage has been detected. In this study, we conduct a population genetic analysis and provide information on the genetic structure of the Australian viruliferous WCM lineage. We assessed genetic differentiation of 16 WCM populations using nine microsatellite markers. Strong evidence for extensive gene flow and low genetic structuring throughout the Australian wheatbelt was evident, with an exception for Western Australian and far north Queensland populations that appear to be genetically isolated. The data also indicate genetic patterns consistent with an arrhenotokous parthenogenetic mode of reproduction. Implications of these findings are discussed with reference to the management of WCM and associated cereal pathogens in Australia and overseas. PMID:22030277

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

2012-04-01

73

Registration of Steele-ND\\/ND 735 Wheat Recombinant Inbred Lines Mapping Population  

Microsoft Academic Search

Steele-ND\\/ND 735 (Reg. No. MP-1, NSL 462030), a hard red spring wheat (Triticum aestivum L.) (HRSW) recombinant inbred lines (RILs) population, was developed and released by the North Dakota State University (NDSU), Fargo, ND, in 2008. This mapping population is composed of 129 F2:9 RILs. The Steele-ND\\/ND 735 RILs population has been used extensively to study the genetics of resistance

Mohamed Mergoum; Pawan K. Singh; Richard C. Frohberg; Shahryar F. Kianian; Farhad Ghavami; Khwaja Hossain; Tika B. Adhikari; Vibin E. Harilal; Senay Simsek

2009-01-01

74

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

75

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

Microsoft Academic Search

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

S. Asakawa; K. Hayano

1995-01-01

76

A multiparent advanced generation inter-cross population for genetic analysis in wheat.  

PubMed

We present the first results from a novel multiparent advanced generation inter-cross (MAGIC) population derived from four elite wheat cultivars. The large size of this MAGIC population (1579 progeny), its diverse genetic composition and high levels of recombination all contribute to its value as a genetic resource. Applications of this resource include interrogation of the wheat genome and the analysis of gene-trait association in agronomically important wheat phenotypes. Here, we report the utilization of a MAGIC population for the first time for linkage map construction. We have constructed a linkage map with 1162 DArT, single nucleotide polymorphism and simple sequence repeat markers distributed across all 21 chromosomes. We benchmark this map against a high-density DArT consensus map created by integrating more than 100 biparental populations. The linkage map forms the basis for further exploration of the genetic architecture within the population, including characterization of linkage disequilibrium, founder contribution and inclusion of an alien introgression into the genetic map. Finally, we demonstrate the application of the resource for quantitative trait loci mapping using the complex traits plant height and hectolitre weight as a proof of principle. PMID:22594629

Huang, Bevan E; George, Andrew W; Forrest, Kerrie L; Kilian, Andrzej; Hayden, Matthew J; Morell, Matthew K; Cavanagh, Colin R

2012-09-01

77

Wheat Polyphenol Oxidase: Distribution and Genetic Mapping in Three Inbred Line Populations  

Microsoft Academic Search

strates for PPO, are endogenous to the wheat plant and grain (Hatcher and Kruger, 1997). PPO is believed to be The enzyme polyphenol oxidase (PPO) has been implicated in involved in oxidation of such phenolic acids to quinones, discoloration of Asian noodles. The recombinant inbred line (RIL) populations, M6\\/'Opata 85', NY18\\/CC, and ND2603\\/'Butte 86' were and the quinones in turn

Tigst Demeke; Craig F. Morris; Kimberly G. Campbell; Garrison E. King; James A. Anderson; Hak-Gil Chang

78

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

PubMed Central

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

Enjalbert, J; David, J L

2000-01-01

79

N-terminal amino acid sequence homology of storage protein components from barley and a diploid wheat  

Microsoft Academic Search

Wild barley (Hordeum spontaneum) and the wild diploid wheat Triticum boeoticum were possibly the first plants cultivated by early man1, giving rise to the domesticated forms Hordeum vulgare L. and Triticum monococcum L. In addition, T. boeoticum may have contributed the A genome to polyploid wheats, including common bread wheat (Triticum aestivum)2 which is a hexaploid with genome composition ABD.

Peter R. Shewry; Jean-Claude Autran; Charles C. Nimmo; Ellen J.-L. Lew; Donald D. Kasarda

1980-01-01

80

Effect of bacterial population density on germination wheat seeds and dynamics of simple artificial ecosystems  

NASA Astrophysics Data System (ADS)

Effect of the size of rhizospheric bacterial populations on germination of seeds and development of simple terrestrial "wheat plants - rhizospheric microorganisms - artificial soil" and "wheat plants - artificial soil" systems has been studied. Experiments demonstrated that within specify ranges in the inoculate, the rhizospheric bacteria are capable of increasing the yield of germinated seeds and stimulate the growth of plantlets. Germination of seeds inoculated with bacteria was either stimulated, or inhibited or remained at control levels depending on the amount of bacteria. Plant biomass growth and total photoassimilation has been found to depend on the amount of bacteria on the plant roots: the higher the amount of bacteria on plant roots, the smaller is the biomass of plants but the total photoassimilation is, higher. Thus, depending on the amount of bacteria on the roots of plants the system either increases the biomass of plants or increases the total photoassimilation, i.e. "pumps" carbon through itself involving bacteria.

Somova, L. A.; Pechurkin, N. S.; Sarangova, A. B.; Pisman, T. I.

81

Rapid Elimination of Low-Copy DNA Sequences in Polyploid Wheat: A Possible Mechanism for Differentiation of Homoeologous Chromosomes  

PubMed Central

To study genome evolution in allopolyploid plants, we analyzed polyploid wheats and their diploid progenitors for the occurrence of 16 low-copy chromosome- or genome-specific sequences isolated from hexaploid wheat. Based on their occurrence in the diploid species, we classified the sequences into two groups: group I, found in only one of the three diploid progenitors of hexaploid wheat, and group II, found in all three diploid progenitors. The absence of group II sequences from one genome of tetraploid wheat and from two genomes of hexaploid wheat indicates their specific elimination from these genomes at the polyploid level. Analysis of a newly synthesized amphiploid, having a genomic constitution analogous to that of hexaploid wheat, revealed a pattern of sequence elimination similar to the one found in hexaploid wheat. Apparently, speciation through allopolyploidy is accompanied by a rapid, nonrandom elimination of specific, low-copy, probably noncoding DNA sequences at the early stages of allopolyploidization, resulting in further divergence of homoeologous chromosomes (partially homologous chromosomes of different genomes carrying the same order of gene loci). We suggest that such genomic changes may provide the physical basis for the diploid-like meiotic behavior of polyploid wheat. PMID:9383078

Feldman, M.; Liu, B.; Segal, G.; Abbo, S.; Levy, A. A.; Vega, J. M.

1997-01-01

82

Evolution of resistance against powdery mildew in winter wheat populations conducted under dynamic management. II. Adult plant resistance  

Microsoft Academic Search

The evolution of adult plant resistance towards powdery mildew (caused by Blumeria graminis f. sp. tritici) was investigated in 11 wheat populations cultivated for 10 years in a French network for dynamic management (DM) of wheat\\u000a genetic resources. The aims of the study were to compare the evolution of resistance in sites submitted to different powdery\\u000a mildew pressure and to

S. Paillard; I. Goldringer; J. Enjalbert; M. Trottet; J. David; C. de Vallavieille-Pope; P. Brabant

2000-01-01

83

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

84

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

85

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

86

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

87

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

PubMed

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

Qiu, Jianbo; Shi, Jianrong

2014-08-01

88

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

89

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

90

Fungicide resistance status in French populations of the wheat eyespot fungi Oculimacula acuformis and Oculimacula yallundae.  

PubMed

Eyespot, caused by Oculimacula acuformis and Oculimacula yallundae, is the major foot disease of winter wheat in several European countries, including France. It can be controlled by chemical treatment between tillering and the second node stage. The fungicides used include antimicrotubule toxicants (benzimidazoles), inhibitors of sterol 14?-demethylation (DMIs) or of succinate dehydrogenase (SDHIs), the anilinopyrimidines cyprodinil and the benzophenone metrafenone. Since the early 1980s, a long-term survey has been set up in France to monitor changes in the sensitivity of eyespot populations to fungicides. Resistance to benzimidazoles has become generalised since the early 1990s, in spite of the withdrawal of this class of fungicides. In the DMI group, resistance to triazoles is generalised, whereas no resistance to the triazolinethione prothioconazole has yet developed. Resistance to the imidazole prochloraz evolved successively in O. acuformis and O. yallundae and is now well established. Specific resistance to cyprodinil has also been detected, but its frequency has generally remained low. Finally, since the early 2000s, a few strains of O. yallundae displaying multidrug resistance (MDR) have been detected. These strains display low levels of resistance to prothioconazole and SDHIs, such as boscalid. Knowledge of the spatiotemporal distribution in France of O. acuformis and O. yallundae field strains resistant to fungicides allows resistance management strategies for eyespot fungi in winter wheat to be proposed. PMID:23073993

Leroux, Pierre; Gredt, Michel; Remuson, Florent; Micoud, Annie; Walker, Anne-Sophie

2013-01-01

91

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

PubMed

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

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

2014-01-01

92

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

93

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

PubMed

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

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

2009-10-01

94

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

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

2013-01-01

95

Moving Waves of Bacterial Populations and Total Organic Carbon along Roots of Wheat.  

PubMed

> Abstract To determine if spatial variation in soluble carbon sources along the root coincides with different trophic groups of bacteria, copiotrophic and oligotrophic bacteria were enumerated from bulk soil and rhizosphere samples at 2 cm intervals along wheat roots 2, 3, and 4 weeks after planting. There was a moderate rhizosphere effect in one experiment with soil rich in fresh plant debris, and a very pronounced rhizosphere effect in the second experiment with soil low in organic matter. We obtained wavelike patterns of both trophic groups of bacteria as well as water-soluble total organic carbon (TOC) along the whole root length (60 or 90 cm). TOC concentrations were maximal at the root tip and base and minimal in the middle part of the roots. Oscillations in populations of copiotrophic and oligotrophic bacteria had two maxima close to the root tip and at the root base, or three maxima close to the tip, in the middle section, and at the root base. The location and pattern of the waves in bacterial populations changed progressively from week to week and was not consistently correlated with TOC concentrations or the location of lateral root formation. Thus, the traditional view that patterns in bacterial numbers along the root directly reflect patterns in exudation and rhizodeposition from several fixed sources along the root may not be true. We attributed the observed wavelike patterns in bacterial populations to bacterial growth and death cycles (due to autolysis or grazing by predators). Considering the root tip as a moving nutrient source, temporal oscillations in bacterial populations at any location where the root tip passed would result in moving waves along the root. This change in concept about bacterial populations in the rhizosphere could have significant implications for plant growth promotion and bioremediation. PMID:9929400

Semenov; van Bruggen AHC; Zelenev

1999-02-01

96

Effects of metsulfuron-methyl on the microbial population and enzyme activities in wheat rhizosphere soil.  

PubMed

The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 microg x g(-1) metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but the effects on common fungi and common actinomycete were not evident. In the meantime, the number of tolerant fungi increased greatly in the rhizosphere after the application of metsulfuron-methyl in contrast to the significant decrease of the amount of tolerant actinomycete. It indicates that fungi might turn into the dominant microbial type and actinomycete is the sensitive factor in the soil polluted by sulfonylurea residues. The population of aromatic compounds-decomposing bacteria, aerobic azotobacter, and nitrite bacteria all increased in the earlier period, but the aerobic azotobacter decreased rapidly in number 30 days later, and the amount of nitrite bacteria also showed a temporary decrease with time 15 days later. However, the denitrifying bacteria just began to increase significantly after the crops had grown for 50 days. The amount of sulfur-oxidizing bacteria gradually decreased with the growth of crops, and so were the sulfate-reducing bacteria after metsulfuron-methyl application. To all types of microorganisms, there were more microbes in rhizosphere samples than those in nonrhizosphere except aerobic azotobacter. It means the growth of wheat root system can stimulate the growth of most microorganisms. The activities of hydrogen peroxidase and polyphenol oxidase in soil samples after metsulfuron-methyl application were notably lower than those in the control, and the difference of the activities between the samples of rhizosphere and nonrhizosphere was evident. On the contrary, the activity of dehydrogenase was not inhibited by the application of metsulfuron-methyl, and the rhizosphere effect was not obvious either. PMID:16484087

He, Yong Hua; Shen, Dong Sheng; Fang, Cheng Ran; He, Ruo; Zhu, Yin Mei

2006-01-01

97

An efficient transient gene expression system using aleurones of diploid wheat seeds  

Microsoft Academic Search

To establish a transient gene expression system for investigating the molecular function of genes in mature wheat seeds, we bombarded embryos or aleurones of three hexaploid wheat (Triticum aestivum L.) varieties Chinese Spring, RL4137 and OS21-5, two diploid wheat (T. monococcum L.) varieties KT3-1 and KT3-5 and a barley (Hordeum vulgare, L.) variety Himalaya with fusion constructs containing the GUS

Shigeko Utsugi; Masahiko Maekawa; Kazuhiko Noda

2006-01-01

98

Weed populations and agronomic practices at wheat farms on the Hanang plains in Tanzania  

Microsoft Academic Search

Weed species and densities of weeds present on the wheat farms at the Hanang plains in northern Tanzania were surveyed just before wheat harvest in May, 1986. The dominant weed was Setaria spp. mainly, Setaria verticillata (L.) Beauv., which occurred at an average density of 58 shoots\\/m. Additional weed species which occurred at average densities of greater than 1 plant\\/m

J. R. Moyer; Z. J. Owenya; S. P. Kibuwa

1989-01-01

99

Population dynamics and within field distribution of the greenbug, Schizaphis graminum (Rondani), and its parasitoids in Central Texas winter wheat  

E-print Network

the population dynamics and h' I ld d'* 'I?' I H hb'R ph' R (R d 'I d parasttoids, and to develop a sampling methodology for these insects in Central Texas wtnter wheat. Aphid densities remained below recommended treatment levels in all three sample locations... ?y (~ pl The primary parasitoid L. testaceipes was the most abundant parasitozd species, representing over 80/. of the total parasitoids collected. The parasitoid densities remained far below aphid densities on all sample dates. Collectively...

Kring, T. J

2012-06-07

100

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

PubMed Central

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

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

2011-01-01

101

Development of genome-specific primers for homoeologous genes in allopolyploid species: the waxy and starch synthase II genes in allohexaploid wheat (Triticum aestivum L.) as examples  

PubMed Central

Background In allopolypoid crops, homoeologous genes in different genomes exhibit a very high sequence similarity, especially in the coding regions of genes. This makes it difficult to design genome-specific primers to amplify individual genes from different genomes. Development of genome-specific primers for agronomically important genes in allopolypoid crops is very important and useful not only for the study of sequence diversity and association mapping of genes in natural populations, but also for the development of gene-based functional markers for marker-assisted breeding. Here we report on a useful approach for the development of genome-specific primers in allohexaploid wheat. Findings In the present study, three genome-specific primer sets for the waxy (Wx) genes and four genome-specific primer sets for the starch synthase II (SSII) genes were developed mainly from single nucleotide polymorphisms (SNPs) and/or insertions or deletions (Indels) in introns and intron-exon junctions. The size of a single PCR product ranged from 750 bp to 1657 bp. The total length of amplified PCR products by these genome-specific primer sets accounted for 72.6%-87.0% of the Wx genes and 59.5%-61.6% of the SSII genes. Five genome-specific primer sets for the Wx genes (one for Wx-7A, three for Wx-4A and one for Wx-7D) could distinguish the wild type wheat and partial waxy wheat lines. These genome-specific primer sets for the Wx and SSII genes produced amplifications in hexaploid wheat, cultivated durum wheat, and Aegilops tauschii accessions, but failed to generate amplification in the majority of wild diploid and tetraploid accessions. Conclusions For the first time, we report on the development of genome-specific primers from three homoeologous Wx and SSII genes covering the majority of the genes in allohexaploid wheat. These genome-specific primers are being used for the study of sequence diversity and association mapping of the three homoeologous Wx and SSII genes in natural populations of both hexaploid wheat and cultivated tetraploid wheat. The strategies used in this paper can be used to develop genome-specific primers for homoeologous genes in any allopolypoid species. They may be also suitable for (i) the development of gene-specific primers for duplicated paralogous genes in any diploid species, and (ii) the development of allele-specific primers at the same gene locus. PMID:20497560

2010-01-01

102

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

PubMed

Simulation studies were conducted to determine temperature accumulations below defined thresholds and to show the impact of controlled aeration on populations of the rusty grain beetle, Cryptolestes ferrigineus (Stephens), a major secondary pest of stored wheat, Triticum aestivum (L.). Recorded data from weather stations in Texas, Oklahoma, Kansas, eastern New Mexico, and eastern Colorado (356 total) were used to determine hours of temperature accumulation below 23.9 degrees C in June and July, 15.6 degrees C in September and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m3/s/m3 (0.1 cubic ft3/min/bu), which requires 120 h of temperatures below the specified threshold to complete an aeration cycle, summer cooling at 23.9 degrees C in bulk-stored wheat could be completed throughout the hard red winter wheat zone except for extreme southern Texas. An early-autumn cooling cycle at 15.6 degrees C could not be completed throughout most of Texas and Oklahoma before the end of September. The late-autumn cooling cycle could be completed in all states except Texas by the end of November. Five geographic regions were delineated and the times required for completion of the summer, early-autumn, and late-autumn cooling cycles within each region were estimated. Population growth of the rusty grain beetle was modeled for San Antonio, TX; Abilene, TX; Tulsa, OK; Topeka KS; and Goodland, KS, by predicting the numbers of adults in the top, outer middle, outer periphery, and the center of the bin during a 1-yr storage season. Populations of C. ferrugineus in San Antonio and Austin were predicted to exceed the Federal Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during the winter, and increase the following spring. In Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the top and outer middle of the bin, whereas populations in the Kansas locations were not predicted to exceed the threshold at any time. PMID:10985054

Arthur, F H; Flinn, P W

2000-08-01

103

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

104

Investigation of genetic diversity and population structure of common wheat cultivars in northern China using DArT markers  

PubMed Central

Background In order to help establish heterotic groups of Chinese northern wheat cultivars (lines), Diversity arrays technology (DArT) markers were used to investigate the genetic diversity and population structure of Chinese common wheat (Triticum aestivum L.). Results In total, 1637 of 7000 DArT markers were polymorphic and scored with high confidence among a collection of 111 lines composed mostly of cultivars and breeding lines from northern China. The polymorphism information content (PIC) of DArT markers ranged from 0.03 to 0.50, with an average of 0.40, with P > 80 (reliable markers). With principal-coordinates analysis (PCoA) of DArT data either from the whole genome or from the B-genome alone, all lines fell into one of two major groups reflecting 1RS/1BL type (1RS/1BL and non-1RS/1BL). Evidence of geographic clustering of genotypes was also observed using DArT markers from the A genome. Cluster analysis based on the unweighted pair-group method with algorithmic mean suggested the existence of two subgroups within the non-1RS/1BL group and four subgroups within the 1RS/1BL group. Furthermore, analysis of molecular variance (AMOVA) revealed highly significant (P < 0.001) genetic variance within and among subgroups and among groups. Conclusion These results provide valuable information for selecting crossing parents and establishing heterotic groups in the Chinese wheat-breeding program. PMID:21569312

2011-01-01

105

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

106

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

107

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

108

Gossypol content of C X (AD)1 and G X (AD)1 hexaploids and parents  

E-print Network

). This trait has been observed in C and G genome diploids. Three hexaploids, developed from crosses of C and G genome diploids with upland-type cottons (G. hirsutum L.), were used for this study: two C genome hexaploids, G. australe x Hancock and G. sturtianum...

White, Linn Elizabeth

2012-06-07

109

Establishing an Efficient Way to Utilize the Drought Resistance Germplasm Population in Wheat  

PubMed Central

Drought resistance breeding provides a hopeful way to improve yield and quality of wheat in arid and semiarid regions. Constructing core collection is an efficient way to evaluate and utilize drought-resistant germplasm resources in wheat. In the present research, 1,683 wheat varieties were divided into five germplasm groups (high resistant, HR; resistant, R; moderate resistant, MR; susceptible, S; and high susceptible, HS). The least distance stepwise sampling (LDSS) method was adopted to select core accessions. Six commonly used genetic distances (Euclidean distance, Euclid; Standardized Euclidean distance, Seuclid; Mahalanobis distance, Mahal; Manhattan distance, Manhat; Cosine distance, Cosine; and Correlation distance, Correlation) were used to assess genetic distances among accessions. Unweighted pair-group average (UPGMA) method was used to perform hierarchical cluster analysis. Coincidence rate of range (CR) and variable rate of coefficient of variation (VR) were adopted to evaluate the representativeness of the core collection. A method for selecting the ideal constructing strategy was suggested in the present research. A wheat core collection for the drought resistance breeding programs was constructed by the strategy selected in the present research. The principal component analysis showed that the genetic diversity was well preserved in that core collection. PMID:23737717

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

2013-01-01

110

Microsatellite markers in the hexaploid Prunus domestica species and parentage lineage of three European plum cultivars using nuclear and chloroplast simple-sequence repeats  

Microsoft Academic Search

In a previous study, cDNA microsatellite markers were described in apricot (Prunus armeniaca L.). Specific PCR primers were designed to amplify the microsatellite-containing regions from genomic DNA in different Prunus species. In the present work, cDNA microsatellite markers were developed in the hexaploid Prunus domestica L. species and polymorphism was ascertained in a segregating plum population. Co-dominant mendelian segregation of

V. Decroocq; L. S. Hagen; M.-G. Favé; J.-P. Eyquard; A. Pierronnet

2004-01-01

111

Identification of new mitochondrial genome organizations in wheat plants regenerated from somatic tissue cultures  

Microsoft Academic Search

Plants have been regenerated from short-and long-term in vitro somatic tissue cultures made from immature embryos of the hexaploid wheat cultivar “Chinese Spring”. The mitochondrial genome organization of each regenerated plantlet was studied, after one selfing, by probing Sal I-restricted total DNA with cloned Sal I fragments of wheat mitochondrial DNA derived from a segment of the genome, which displays

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

1989-01-01

112

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

PubMed

The polyploid nature of hexaploid wheat (T. aestivum, AABBDD) often represents a great challenge in various aspects of research including genetic mapping, map-based cloning of important genes, and sequencing and accurately assembly of its genome. To explore the utility of ancestral diploid species of polyploid wheat, sequence variation of T. urartu (A(u)A(u)) was analyzed by comparing its 277-kb large genomic region carrying the important Glu-1 locus with the homologous regions from the A genomes of the diploid T. monococcum (A(m)A(m)), tetraploid T. turgidum (AABB), and hexaploid T. aestivum (AABBDD). Our results revealed that in addition to a high degree of the gene collinearity, nested retroelement structures were also considerably conserved among the A(u) genome and the A genomes in polyploid wheats, suggesting that the majority of the repetitive sequences in the A genomes of polyploid wheats originated from the diploid A(u) genome. The difference in the compared region between A(u) and A is mainly caused by four differential TE insertion and two deletion events between these genomes. The estimated divergence time of A genomes calculated on nucleotide substitution rate in both shared TEs and collinear genes further supports the closer evolutionary relationship of A to A(u) than to A(m). The structure conservation in the repetitive regions promoted us to develop repeat junction markers based on the A(u) sequence for mapping the A genome in hexaploid wheat. Eighty percent of these repeat junction markers were successfully mapped to the corresponding region in hexaploid wheat, suggesting that T. urartu could serve as a useful resource for developing molecular markers for genetic and breeding studies in hexaploid wheat. PMID:23052831

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

2012-12-01

113

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

114

Quackgrass- and ryegrass-adapted populations of the cereal rust mite, Abacarus hystrix (Acari: Eriophyidae), differ in their potential for wheat, Triticum aestivum, colonization.  

PubMed

The cereal rust mite, Abacarus hystrix, is one of the most notable among mites causing losses in cultivated grasslands. It is one of a few eriophyoid species for which a broad host range has been reported. Recent studies, however, have shown that host specialization is very likely in this species. For two populations of A. hystrix (one inhabiting perennial ryegrass, the second inhabiting quackgrass), host-associated differences correlated with strong host fidelity, distinct phenotypes and reproductive barriers have been found. In the present study, the ability of wheat colonization by quackgrass- and ryegrass-adapted cereal rust mite was studied. The hypothesis that the potential for wheat colonization by the quackgrass strain is more likely was tested by comparing the colonization performance (assessed by female survival and fecundity) of quackgrass- and ryegrass-associated A. hystrix on their familiar hosts and on wheat. The ryegrass population had no success in wheat colonization (expressed by extremely low fecundity and female survival). Fecundity and survival of quackgrass strain were similar on wheat and the familiar host, or even higher on wheat. Phylogenetic similarity of quackgrass and wheat is discussed as a possible factor that might influence such patterns of host colonization. Since A. hystrix is the only vector of the ryegrass mosaic virus (RgMV), the presented results may be helpful in explaining the inability of RgMV to successfully infest wheat. The conclusions are that (i) quackgrass- and ryegrass-adapted strains of the cereal rust mite have different physiological host ranges and (ii) phylogenetic relationships between host plant species appear to be drivers for host specialization in this mite species. PMID:18590598

Skoracka, A

2009-02-01

115

DNA markers for Fusarium head blight resistance QTLs in two wheat populations  

Microsoft Academic Search

Genetic resistance to Fusarium head blight (FHB), caused by Fusarium graminearum, is necessary to reduce the wheat grain yield and quality losses caused by this disease. Development of resistant cultivars\\u000a has been slowed by poorly adapted and incomplete resistance sources and confounding environmental effects that make screening\\u000a of germplasm difficult. DNA markers for FHB resistance QTLs have been identified and

J. A. Anderson; R. W. Stack; S. Liu; B. L. Waldron; A. D. Fjeld; C. Coyne; B. Moreno-Sevilla; J. Mitchell Fetch; Q. J. Song; P. B. Cregan; R. C. Frohberg

2001-01-01

116

High-density mapping and marker development for the powdery mildew resistance gene PmAS846 derived from wild emmer wheat (Triticum turgidum var. dicoccoides).  

PubMed

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important foliar disease of wheat worldwide. The dominant powdery mildew resistance gene PmAS846 was transferred to the hexaploid wheat lines N9134 and N9738 from wild emmer wheat (Triticum dicoccoides) in 1995, and it is still one of the most effective resistance genes in China. A high resolution genetic map for PmAS846 locus was constructed using two F(2) populations and corresponding F(2:3) families developed from the crosses of N9134/Shaanyou 225 and N9738/Huixianhong. Synteny between wheat and Brachypodium distachyon and rice was used to develop closely linked molecular markers to reduce the genetic interval around PmAS846. Twenty-six expressed sequence tag-derived markers were mapped to the PmAS846 locus. Five markers co-segregated with PmAS846 in the F(2) population of N9134/Shaanyou 225. PmAS846 was physically located to wheat chromosome 5BL bin 0.75-0.76 within a gene-rich region. The markers order is conserved between wheat and Brachypodium distachyon, but rearrangements are present in rice. Two markers, BJ261635 and CJ840011 flanked PmAS846 and narrowed PmAS846 to a region that is collinear with 197 and 112 kb genomic regions on Brachypodium chromosome 4 and rice chromosome 9, respectively. The genes located on the corresponding homologous regions in Brachypodium, rice and barley could be considered for further marker saturation and identification of potential candidate genes for PmAS846. The markers co-segregating with PmAS846 provide a potential target site for positional cloning of PmAS846, and can be used for marker-assisted selection of this gene. PMID:22350087

Xue, Fei; Ji, Wanquan; Wang, Changyou; Zhang, Hong; Yang, Baoju

2012-05-01

117

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

PubMed Central

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

Araya, Alemu; Belay, Tesfay; Hussein, Temam

2014-01-01

118

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

119

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

120

Wheat Allergy  

MedlinePLUS

Wheat Allergy Wheat allergy is most common in children, and is usually outgrown before reaching adulthood, often by age ... you are trying to achieve. Differences between Wheat Allergy and Celiac Disease or Gluten Intolerance A wheat ...

121

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

Microsoft Academic Search

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

Fernando Álvarez-Alfageme; Simone von Burg; Jörg Romeis

2011-01-01

122

Co-ordinate regulation of cytokinin gene family members during flag leaf and reproductive development in wheat  

PubMed Central

Background As the global population continues to expand, increasing yield in bread wheat is of critical importance as 20% of the world’s food supply is sourced from this cereal. Several recent studies of the molecular basis of grain yield indicate that the cytokinins are a key factor in determining grain yield. In this study, cytokinin gene family members in bread wheat were isolated from four multigene families which regulate cytokinin synthesis and metabolism, the isopentenyl transferases (IPT), cytokinin oxidases (CKX), zeatin O-glucosyltransferases (ZOG), and ?-glucosidases (GLU). As bread wheat is hexaploid, each gene family is also likely to be represented on the A, B and D genomes. By using a novel strategy of qRT-PCR with locus-specific primers shared among the three homoeologues of each family member, detailed expression profiles are provided of family members of these multigene families expressed during leaf, spike and seed development. Results The expression patterns of individual members of the IPT, CKX, ZOG, and GLU multigene families in wheat are shown to be tissue- and developmentally-specific. For instance, TaIPT2 and TaCKX1 were the most highly expressed family members during early seed development, with relative expression levels of up to 90- and 900-fold higher, respectively, than those in the lowest expressed samples. The expression of two cis-ZOG genes was sharply increased in older leaves, while an extremely high mRNA level of TaGLU1-1 was detected in young leaves. Conclusions Key genes with tissue- and developmentally-specific expression have been identified which would be prime targets for genetic manipulation towards yield improvement in bread wheat breeding programmes, utilising TILLING and MAS strategies. PMID:22672647

2012-01-01

123

Molecular and comparative mapping of genes governing spike compactness from wild emmer wheat.  

PubMed

The development and morphology of the wheat spike is important because the spike is where reproduction occurs and it holds the grains until harvest. Therefore, genes that influence spike morphology are of interest from both theoretical and practical stand points. When substituted for the native chromosome 2A in the tetraploid Langdon (LDN) durum wheat background, the Triticum turgidum ssp. dicoccoides chromosome 2A from accession IsraelA confers a short, compact spike with fewer spikelets per spike compared to LDN. Molecular mapping and quantitative trait loci (QTL) analysis of these traits in a homozygous recombinant population derived from LDN × the chromosome 2A substitution line (LDNIsA-2A) indicated that the number of spikelets per spike and spike length were controlled by linked, but different, loci on the long arm of 2A. A QTL explaining most of the variation for spike compactness coincided with the QTL for spike length. Comparative mapping indicated that the QTL for number of spikelets per spike overlapped with a previously mapped QTL for Fusarium head blight susceptibility. The genes governing spike length and compactness were not orthologous to either sog or C, genes known to confer compact spikes in diploid and hexaploid wheat, respectively. Mapping and sequence analysis indicated that the gene governing spike length and compactness derived from wild emmer could be an ortholog of the barley Cly1/Zeo gene, which research indicates is an AP2-like gene pleiotropically affecting cleistogamy, flowering time, and rachis internode length. This work provides researchers with knowledge of new genetic loci and associated markers that may be useful for manipulating spike morphology in durum wheat. PMID:24652470

Faris, Justin D; Zhang, Zengcui; Garvin, David F; Xu, Steven S

2014-08-01

124

Inheritance of resistance to stem rust (race 15B) and several other characters in wheat  

E-print Network

associations exist between these characters and genes for stem rust resistance. REV IT]?./ OF LIT'TUTURE Inheritance of resistance of wheats to race 15B of stem rust in the mature plant stage has not been reported. A need for this knowledge exists in Texas...Fadden (37) concluded that it is possible to transfer genes for desirable character from tetraploid wheats to hexaploid wheats by means of crossing, followed, by rigid selection. Hynes (25) confirmed McFadden?s (37) results in a cross between Federation...

Shamma, Wifki Shakir El

2013-10-04

125

Discrimination of the closely related A and D genomes of the hexaploid oat Avena sativa L.  

PubMed Central

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 the genome of diploid (A and C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) Avena species. In contrast, sequences homologous to As120a were found in two A-genome species (A. strigosa and Avena longiglumis) and in the hexaploid A. sativa whereas this sequence was little amplified in the tetraploid Avena murphyi and was absent in the remaining A- and C-genome diploid species. In situ hybridization of pAs120a to hexaploid oat species revealed the distribution of elements of the As120a repeated family over both arms of 14 of 42 chromosomes of this species. By using double in situ hybridization with pAs120a and a C genome-specific probe, three sets of 14 chromosomes were revealed corresponding to the A, C, and D genomes of the hexaploid species. Simultaneous in situ hybridizations with pAs120a and ribosomal probes were used to assign the SAT chromosomes of hexaploid species to their correct genomes. This work reports a sequence able to distinguish between the closely related A and D genomes of hexaploid oats. This sequence offers new opportunities to analyze the relationships of Avena species and to explore the possible evolution of various polyploid oat species. PMID:9770506

Linares, Concha; Ferrer, Esther; Fominaya, Araceli

1998-01-01

126

Long-term consequences of tillage, residue management, and crop rotation on maize\\/wheat root rot and nematode populations in subtropical highlands  

Microsoft Academic Search

Densely populated and intensively cropped, the subtropical highlands of the world have severe agricultural sustainability problems resulting from soil erosion and fertility decline. In 1991, the International Maize and Wheat Improvement Center (CIMMYT) initiated a long-term field experiment with zero tillage under rainfed conditions at its semi-arid highland experiment station in Mexico (2240m asl; 19.31°N, 98.50°W; Cumulic Phaeozem) to evaluate

Bram Govaerts; Monica Mezzalama; Ken D. Sayre; Jose Crossa; Julie M. Nicol; Jozef Deckers

2006-01-01

127

Genome-wide gene expression analysis supports a developmental model of low temperature tolerance gene regulation in wheat ( Triticum aestivum L .)  

Microsoft Academic Search

Background  To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global\\u000a changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome\\u000a microarray. We compared the expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring\\u000a Manitou and spring Norstar))

Debbie Laudencia-Chingcuanco; Seedhabadee Ganeshan; Frank You; Brian Fowler; Ravindra Chibbar; Olin Anderson

2011-01-01

128

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

Microsoft Academic Search

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

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

2009-01-01

129

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

E-print Network

lines, namely, 1SI, ZSI, 3SI, 4/7SI, 5SI, 6SI, and 7/4SI (Feldman, 1975; Hart and Tuleen, 1983c), and the amphiploid were examined. The ADK phenotypes of T. monococcum and T. tauschii were also analyzed. Also, the ditelo-3S S and -3S L addition lines... lines, namely, 1SI, ZSI, 3SI, 4/7SI, 5SI, 6SI, and 7/4SI (Feldman, 1975; Hart and Tuleen, 1983c), and the amphiploid were examined. The ADK phenotypes of T. monococcum and T. tauschii were also analyzed. Also, the ditelo-3S S and -3S L addition lines...

Yang, Yaw-Ching

2012-06-07

130

Analysis and annotation of the hexaploid oat seed transcriptome  

PubMed Central

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

2013-01-01

131

Acc homoeoloci and the evolution of wheat genomes  

PubMed Central

The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3–2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. PMID:18599450

Chalupska, D.; Lee, H. Y.; Faris, J. D.; Evrard, A.; Chalhoub, B.; Haselkorn, R.; Gornicki, P.

2008-01-01

132

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 Garcia, Pedro; Rauchova, Jana; Suda, Jan; Schneeweiss, Gerald M.; Hulber, Karl; Schonswetter, Peter

2010-01-01

133

Genetic Analysis of Bread Making Quality Stability in Wheat using a Halberd X Len Recombinant Inbred Line Population  

E-print Network

of this study were to 1) analyze the different wheat quality parameters in Recombinant Inbred Lines (RILs) grown under different environments, and 2) to identify Quantitative Trait Loci (QTLs) associated with quality stability in RILs grown under different...

Poudel, Ashima

2012-07-16

134

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

Microsoft Academic Search

Variation in photoperiod response plays an important role in adapting crops to agricultural environments. In hexaploid wheat,\\u000a mutations conferring photoperiod insensitivity (flowering after a similar time in short or long days) have been mapped on\\u000a the 2B (Ppd-B1) and 2D (Ppd-D1) chromosomes in colinear positions to the 2H Ppd-H1 gene of barley. No A genome mutation is known. On the

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

2009-01-01

135

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

PubMed Central

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

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

2013-01-01

136

Heat and drought adaptive QTL in a wheat population designed to minimize confounding agronomic effects  

PubMed Central

A restricted range in height and phenology of the elite Seri/Babax recombinant inbred line (RIL) population makes it ideal for physiological and genetic studies. Previous research has shown differential expression for yield under water deficit associated with canopy temperature (CT). In the current study, 167 RILs plus parents were phenotyped under drought (DRT), hot irrigated (HOT), and temperate irrigated (IRR) environments to identify the genomic regions associated with stress-adaptive traits. In total, 104 QTL were identified across a combination of 115 traits × 3 environments × 2 years, of which 14, 16, and 10 QTL were associated exclusively with DRT, HOT, and IRR, respectively. Six genomic regions were related to a large number of traits, namely 1B-a, 2B-a, 3B-b, 4A-a, 4A-b, and 5A-a. A yield QTL located on 4A-a explained 27 and 17% of variation under drought and heat stress, respectively. At the same location, a QTL explained 28% of the variation in CT under heat, while 14% of CT variation under drought was explained by a QTL on 3B-b. The T1BL.1RS (rye) translocation donated by the Seri parent was associated with decreased yield in this population. There was no co-location of consistent yield and phenology or height-related QTL, highlighting the utility of using a population with a restricted range in anthesis to facilitate QTL studies. Common QTL for drought and heat stress traits were identified on 1B-a, 2B-a, 3B-b, 4A-a, 4B-b, and 7A-a confirming their generic value across stresses. Yield QTL were shown to be associated with components of other traits, supporting the prospects for dissecting crop performance into its physiological and genetic components in order to facilitate a more strategic approach to breeding. Electronic supplementary material The online version of this article (doi:10.1007/s00122-010-1351-4) contains supplementary material, which is available to authorized users. PMID:20523964

Pinto, R. Suzuky; Mathews, Ky L.; McIntyre, C. Lynne; Olivares-Villegas, Juan-Jose; Chapman, Scott C.

2010-01-01

137

Selection pressure and founder effects constrain genetic variation in differentiated populations of soilborne bymovirus Wheat yellow mosaic virus (Potyviridae) in China.  

PubMed

To study the population genetic structure and forces driving the evolution of Wheat yellow mosaic virus (WYMV), the nucleotide sequences encoding the coat protein (CP) (297 sequences) or the genome-linked virion protein (VPg) (87 sequences) were determined from wheat plants growing at 11 different locations distributed in five provinces in China. There were close phylogenetic relationships between all sequences but clustering on the phylogenetic trees was congruent with their provenance, suggesting an origin-dependent population genetic structure. There were low levels of genetic diversity, ranging from 0.00035 ± 0.00019 to 0.01536 ± 0.00043 (CP), and 0.00086 ± 0.00039 to 0.00573 ± 0.00111 (VPg), indicating genetic stability or recent emergence of WYMV in China. The results may suggest that founder effects play a role in shaping the genetic structure of WYMV. Between-population diversity was consistently higher than within-population diversity, suggesting limited gene flow between subpopulations (average FST 0.6241 for the CP and 0.7981 for the VPg). Consistent amino acid substitutions correlated with the provenance of the sequences were observed at nine positions in the CP (but none in the VPg), indicating an advanced stage in population structuring. Strong negative (purifying) selection was implicated on both the CP and VPg but positive selection on a few codons in the CP, indicating an ongoing molecular adaptation. PMID:23550972

Sun, B-J; Sun, L-Y; Tugume, A K; Adams, M J; Yang, J; Xie, L-H; Chen, J-P

2013-09-01

138

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

PubMed

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

Haider, N

2013-03-01

139

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.  

PubMed

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 approximately 5.0 x 10(-4)/nt across all populations and ranged from 2.4 to 11.6 x 10(-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. PMID:16181653

French, Roy; Stenger, Drake C

2005-12-20

140

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

141

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

142

Mapping QTLs with epistatic effects and QTL x environment interactions for plant height using a doubled haploid population in cultivated wheat.  

PubMed

Quantitative trait loci (QTLs) for plant height in wheat (Triticum aestivum L.) were studied using a set of 168 doubled haploid (DH) lines, which were derived from the cross Huapei 3/Yumai 57. A genetic linkage map was constructed using 283 SSR and 22 EST-SSR markers. The DH population and the parents were evaluated for wheat plant height in 2005 and 2006 in Tai'an and 2006 in Suzhou. QTL analyses were performed using the software of QTLNetwork version 2.0 based on the mixed linear model. Four additive QTLs and five pairs of epistatic effects were detected, which were distributed on chromosomes 3A, 4B, 4D, 5A, 6A, 7B, and 7D. Among them, three additive QTLs and three pairs of epistatic QTLs showed QTL x environment interactions (QEs). Two major QTLs, Qph4B and Qph4D, which accounted for 14.51% and 20.22% of the phenotypic variation, were located similar to the reported locations of the dwarfing genes Rht1 and Rht2, respectively. The Qph3A-2 with additive effect was not reported in previous linkage mapping studies. The total QTL effects detected for the plant height explained 85.04% of the phenotypic variation, with additive effects 46.07%, epistatic effects 19.89%, and QEs 19.09%. The results showed that both additive effects and epistatic effects were important genetic bases of wheat plant height, which were subjected to environmental modifications, and caused dramatic changes in phenotypic effects. The information obtained in this study will be useful for manipulating the QTLs for wheat plant height by molecular marker-assisted selection (MAS). PMID:18407059

Zhang, Kunpu; Tian, Jichun; Zhao, Liang; Wang, Shanshan

2008-02-01

143

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

144

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

145

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

146

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

Microsoft Academic Search

Changes in ascorbate peroxidase (APX) enzyme activity in response to nematode (Heterodera avenae) attack were studied in roots of three hexaploid wheat lines carrying Cre2, Cre5, or Cre7 nematode resistance genes and the susceptible Triticum aestivum cv. Anza. A spectrophotometric analysis was carried out with root extracts of infected plants 4, 7, 11, and 14 days after\\u000a nematode inoculation using uninfected

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

2010-01-01

147

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

PubMed Central

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

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

2011-01-01

148

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

149

Genetic characterisation of dough rheological properties in a wheat doubled haploid population: additive genetic effects and epistatic interactions  

Microsoft Academic Search

Doubled haploid lines (n=160) from a cross between wheat cultivars ‘Cranbrook’ (high dough extensibility) and ‘Halberd’ (low dough extensibility) were grown at three Australian locations. The parents differ at all high- and low-molecular-weight glutenin loci. Dough rheological parameters were measured using small-scale testing procedures, and quantitative trait locus (QTL) mapping procedures were carried out using an existing well-saturated genetic linkage

W. Ma; R. Appels; F. Bekes; O. Larroque; M. K. Morell; K. R. Gale

2005-01-01

150

Prevalence of gene expression additivity in genetically stable wheat allohexaploids.  

PubMed

The reprogramming of gene expression appears as the major trend in synthetic and natural allopolyploids where expression of an important proportion of genes was shown to deviate from that of the parents or the average of the parents. In this study, we analyzed gene expression changes in previously reported, highly stable synthetic wheat allohexaploids that combine the D genome of Aegilops tauschii and the AB genome extracted from the natural hexaploid wheat Triticum aestivum. A comprehensive genome-wide analysis of transcriptional changes using the Affymetrix GeneChip Wheat Genome Array was conducted. Prevalence of gene expression additivity was observed where expression does not deviate from the average of the parents for 99.3% of 34,820 expressed transcripts. Moreover, nearly similar expression was observed (for 99.5% of genes) when comparing these synthetic and natural wheat allohexaploids. Such near-complete additivity has never been reported for other allopolyploids and, more interestingly, for other synthetic wheat allohexaploids that differ from the ones studied here by having the natural tetraploid Triticum turgidum as the AB genome progenitor. Our study gave insights into the dynamics of additive gene expression in the highly stable wheat allohexaploids. PMID:23278496

Chelaifa, Houda; Chagué, Véronique; Chalabi, Smahane; Mestiri, Imen; Arnaud, Dominique; Deffains, Denise; Lu, Yunhai; Belcram, Harry; Huteau, Virginie; Chiquet, Julien; Coriton, Olivier; Just, Jérémy; Jahier, Joseph; Chalhoub, Boulos

2013-02-01

151

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

152

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

153

Next-Generation Survey Sequencing and the Molecular Organization of Wheat Chromosome 6B¶  

PubMed Central

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

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

2014-01-01

154

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

PubMed

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

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

2013-06-01

155

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

156

Structural and functional partitioning of bread wheat chromosome 3B.  

PubMed

We produced a reference sequence of the 1-gigabase chromosome 3B of hexaploid bread wheat. By sequencing 8452 bacterial artificial chromosomes in pools, we assembled a sequence of 774 megabases carrying 5326 protein-coding genes, 1938 pseudogenes, and 85% of transposable elements. The distribution of structural and functional features along the chromosome revealed partitioning correlated with meiotic recombination. Comparative analyses indicated high wheat-specific inter- and intrachromosomal gene duplication activities that are potential sources of variability for adaption. In addition to providing a better understanding of the organization, function, and evolution of a large and polyploid genome, the availability of a high-quality sequence anchored to genetic maps will accelerate the identification of genes underlying important agronomic traits. PMID:25035497

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

2014-07-18

157

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

158

Survival analysis approach to insect life table analysis and hypothesis testing: with particular reference to Russian wheat aphid (Diuraphis noxia (Mordvilko)) populations.  

PubMed

The goal of this paper is to examine and demonstrate that survival analysis, which has been a de facto standard in biomedical research since the 1990s but has not been widely adopted in entomology yet, should possess similar potential in entomological research. The following three objectives are set to achieve this goal: (i) addressing a fundamental issue - censoring or incomplete observations; (ii) demonstrating the application of survival analysis to analyze insect life tables; and (iii) applying survival analysis for hypothesis testing. The data used to demonstrate the applications is from our laboratory experiments, which recorded the development, survival and reproduction of 1800 Russian wheat aphids (Diuraphis noxia (Mordvilko), RWA) under 25 treatments of temperature and plant-growth stage. With regard to the first two objectives, besides examining the near ubiquitous existence of censoring in insect population research, we constructed and analyzed life tables of 1800 RWA individuals with survival analysis. We further demonstrate that there could be very significant differences in life table parameters, such as median development times with and without considering censoring. To the best of our knowledge, this is the first recognition in entomology that censoring, which is hardly avoidable, can cause significant systematical bias (ranging between 4-25%; table 1) in insect development data analysis. As for the third objective, the study shows that four statistics from survival analysis can be applied to testing the effects of covariates, such as temperature and plant-growth stage, on development and survival of the Russian wheat aphid. The advantages of survival analysis include the handling of censored observations, survival probabilities in the form of rigorous survivor function vs. simple survival rates, dynamic modeling of covariates effects on development and survival with a unified model structure, etc. The methods demonstrated in this article should also be useful for entomological research beyond insect demography, such as bioassay, assessment of natural enemies, the studies of insect behaviors, etc. PMID:19941673

Ma, Z S

2010-06-01

159

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, Angelique; Justesen, Annemarie F.; Hovm?ller, Mogens S.; Enjalbert, Jerome; de Vallavieille-Pope, Claude

2014-01-01

160

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

PubMed

Amphiplasty in hexaploid triticale, the artificial amphiploid of tetraploid wheat and diploid rye, is analyzed for the first time using a modified, highly reproducible, silver-staining procedure. A comparative analysis of metaphase somatic cells by phase contrast, C-banding and silver-staining of the hexaploid triticale cv. 'Cachirulo' and its parents, namely, the tetraploid durum wheat cv. 'Enano de Andujar' and the diploid rye cv. 'Petkus' has been made. Two silver-stained nucleolar organizer regions (Ag-NORs) (the chromosome pair 1 R) are observed in all rye plants analyzed, whereas four Ag-NORs (chromosome pairs 1 B and 6 B) are found both in the tetraploid wheat parent and in the triticale. The rye Ag-NORs are absent in the triticale. Since the Agstaining reaction of NORs can be considered as an indication for genetic activity, the silver procedure can be used to visualize gene functionality at the rDNA sites with conventional light microscopy and, consequently, the modified Ag-staining method described can be very useful in analyzing the amphiplasty phenomenon in natural or artificial hybrid combinations and derivatives in the Triticum group and its relatives. PMID:24258550

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

1984-01-01

161

Chromosome Sorting in Tetraploid Wheat and Its Potential for Genome Analysis  

PubMed Central

This study evaluates the potential of flow cytometry for chromosome sorting in durum wheat (Triticum turgidum Desf. var. durum, 2n = 4x = 28). Histograms of fluorescence intensity (flow karyotypes) obtained after the analysis of DAPI-stained chromosomes consisted of three peaks. Of these, one represented chromosome 3B, a small peak corresponded to chromosomes 1A and 6A, and a large peak represented the remaining 11 chromosomes. Chromosomes sorted onto microscope slides were identified after fluorescence in situ hybridization (FISH) with probes for GAA microsatellite, pSc119.2, and Afa repeats. Genomic distribution of these sequences was determined for the first time in durum wheat and a molecular karyotype has been developed for this crop. Flow karyotyping in double-ditelosomic lines of durum wheat revealed that the lines facilitated sorting of any arm of the wheat A- and B-genome chromosomes. Compared to hexaploid wheat, flow karyotype of durum wheat is less complex. This property results in better discrimination of telosomes and high purities in sorted fractions, ranging from 90 to 98%. We have demonstrated that large insert libraries can be created from DNA purified using flow cytometry. This study considerably expands the potential of flow cytogenetics for use in wheat genomics and opens the possibility of sequencing the genome of this important crop one chromosome arm at a time. PMID:15802508

Kubalakova, Marie; Kovarova, Pavlina; Suchankova, Pavla; Cihalikova, Jarmila; Bartos, Jan; Lucretti, Sergio; Watanabe, Nobuyoshi; Kianian, Shahryar F.; Dolezel, Jaroslav

2005-01-01

162

The role of selection on the genetic structure of pathogen populations: Evidence from field experiments with Mycosphaerella graminicola on wheat  

Microsoft Academic Search

Coevolution refers to reciprocal genetic changes that occur in two or more ecologically interacting species. In agricultural ecosystems, we are especially concerned with the genetic response of pathogen populations to resistant cultivars produced by plant breeding programs. It would be useful to be able to predict whether disease resistance is likely to be durable or ephemeral before a cultivar is

Bruce A. McDonald; Christopher C. Mundt; Ruey-Shyang Chen

1996-01-01

163

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

164

The Protein Disulfide Isomerase gene family in bread wheat (T. aestivum L.)  

PubMed Central

Background The Protein Disulfide Isomerase (PDI) gene family encodes several PDI and PDI-like proteins containing thioredoxin domains and controlling diversified metabolic functions, including disulfide bond formation and isomerisation during protein folding. Genomic, cDNA and promoter sequences of the three homoeologous wheat genes encoding the "typical" PDI had been cloned and characterized in a previous work. The purpose of present research was the cloning and characterization of the complete set of genes encoding PDI and PDI like proteins in bread wheat (Triticum aestivum cv Chinese Spring) and the comparison of their sequence, structure and expression with homologous genes from other plant species. Results Eight new non-homoeologous wheat genes were cloned and characterized. The nine PDI and PDI-like sequences of wheat were located in chromosome regions syntenic to those in rice and assigned to eight plant phylogenetic groups. The nine wheat genes differed in their sequences, genomic organization as well as in the domain composition and architecture of their deduced proteins; conversely each of them showed high structural conservation with genes from other plant species in the same phylogenetic group. The extensive quantitative RT-PCR analysis of the nine genes in a set of 23 wheat samples, including tissues and developmental stages, showed their constitutive, even though highly variable expression. Conclusions The nine wheat genes showed high diversity, while the members of each phylogenetic group were highly conserved even between taxonomically distant plant species like the moss Physcomitrella patens. Although constitutively expressed the nine wheat genes were characterized by different expression profiles reflecting their different genomic organization, protein domain architecture and probably promoter sequences; the high conservation among species indicated the ancient origin and diversification of the still evolving gene family. The comprehensive structural and expression characterization of the complete set of PDI and PDI-like wheat genes represents a basis for the functional characterization of this gene family in the hexaploid context of bread wheat. PMID:20525253

2010-01-01

165

C-banding pattern and meiotic pairing in five rye chromosomes of hexaploid triticale.  

PubMed

The meiotic behaviour of rye chromosomes 1R, 2R, 3R, 6R and 7R/4R of hexaploid triticale 'Cachirulo' is analyzed using the C-banding technique. These chromosomes show different C-banding patterns and present different pairing levels at metaphase I. A decreasing effect of large telomeric heterochromatin bands on pairing is deduced from the following two main facts: i) The chromosome 7R/4R shows the highest pairing associated with the smallest amount of heterochromatin, ii) pairing levels of 2 R short arm and 3 R long arm which carry large telomeric bands are less than their respective long and short arms lacking telomeric heterochromatin. Possible desynaptic effects of heterochromatin are discussed although an asynaptic effect cannot be rejected. PMID:24270434

Naranjo, T; Lacadena, J R

1982-09-01

166

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny.  

PubMed

The dynamics of rye chromosomes during mitosis and meiosis was analyzed in a subset comprising 33 F3 lines from the cross of wheat, Psathyrostachys huashanica amphiploid (AABBDDNsNs) and hexaploid triticale (AABBRR), as visualized by genomic in situ hybridization. The results indicated that 31 of the total lines contained 4-14 rye chromosomes. Twenty-eight combinations had more rye chromosomes than the F1 hybrids, suggesting the occurrence of spontaneous quantitative increment. No P. huashanica chromosomes were detected in all of the combinations tested. Mitotic analysis showed that rye chromosomes progressed normally with the wheat counterparts without loss. However, abnormal meiosis was found in almost all lines. Similar progression between wheat and rye genomes appeared from interphase to metaphase I. It was at anaphase I that many rye univalents lagged behind those of wheat, followed by equational division. This resulted in the formation of chromosomal segments and micronuclei at telophase I or II. Micronuclei could also be generated from the immobilized univalents in the periphery of cells. Synapsis and translocations between wheat and rye genomes, chromosome bridges, and unreduced gametes were detected. Therefore, it is proposed that rye chromosome elimination may involve chromatid lagging, fragmentation and micronucleation, or the immobilization of certain univalents during meiosis instead of mitosis in the relatively advanced generations. This mechanism, together with spontaneous incremental increase of rye chromosome number, permitted the generation of various germplasms for wheat improvement. PMID:23315875

Xie, Q; Kang, H; Sparkes, D L; Tao, S; Fan, X M; Xu, L; Fan, X; Sha, L; Zhang, H; Wang, Y; Zeng, J; Zhou, Y

2013-01-01

167

Rationalising germplasm collections: a case study for wheat.  

PubMed

In total 70 genebank accessions comprising 50 hexaploid, 12 tetraploid and 8 diploid wheats of the Gatersleben collection were selected based on the screening of the passport data for identical cultivar names or accession numbers of the donor genebanks. Twelve potential duplicate groups consisting of three to nine accessions with identical names/numbers were selected and analysed with DNA markers (microsatellites). A bootstrap approach based on re-sampling of both microsatellite markers and alleles within marker loci was used to test for homogeneity. Although several homogeneous groups were identified it became clear that cultivar name identity alone did not allow the determination of duplicates. A combination of SSR-analysis followed by the bootstrap method and database survey considering the botanical classification and other data (origin, growth habit and donor) available is recommended in order to determine duplicates. A procedure for the identification of duplicates and their further handling in ex situ genebanks is discussed. PMID:16133307

Dobrovolskaya, O; Saleh, U; Malysheva-Otto, L; Röder, M S; Börner, A

2005-11-01

168

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

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

2013-01-01

169

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

Guzman, Carlos; Caballero, Leonor; Martin, Luis M.; Alvarez, Juan B.

2012-01-01

170

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

Microsoft Academic Search

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

M. YOUSOFI; Payam Noor

171

Expression and localisation analysis of the wheat sucrose transporter TaSUT1 in vegetative tissues.  

PubMed

Previously we reported the isolation of three sucrose transporter genes, TaSUT1A, 1B and 1D, all expressed at high levels in the developing grains of hexaploid wheat ( Triticum aestivum L.), but also in a variety of other tissues. In order to further characterise the expression of the TaSUT1 genes in wheat plants, we have analysed TaSUT1 expression in their vegetative tissues using semi-quantitative reverse transcription-polymerase chain reaction, in situ hybridisation and immunolocalisation. The three TaSUT1 genes, which encode 98% identical SUT proteins, all appeared to be expressed at the same level in leaf blades, leaf sheaths and internodes, as well as developing grains, of hexaploid wheat. In mature leaf blades, TaSUT1 protein localised to the plasma membrane of phloem sieve elements in all classes of veins. In contrast, TaSUT1 mRNA was found to be localised to phloem companion cells. A similar localisation pattern for TaSUT1 protein was observed in veins of leaf sheaths and internodes. These results suggest that the wheat SUT1 has a transport function in enucleate sieve elements, in both veins responsible for loading photoassimilates, and in veins for axial transport. Furthermore, transport of the fluorescent dye carboxyfluorescein was used to investigate symplasmic connectivity between sieve element-companion cell complexes and non-phloem cells. Observations in source leaves indicated that sieve element-companion cell complexes of minor veins were symplasmically restricted, suggesting a role of TaSUT1 in apoplasmic phloem loading. In contrast, the dye was able to move symplasmically out of the phloem in internodes. In these circumstances TaSUT1 may also have a role in retrieving sucrose leaked to the phloem apoplasm. PMID:15014993

Aoki, N; Scofield, G N; Wang, X-D; Patrick, J W; Offler, C E; Furbank, R T

2004-05-01

172

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

173

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

PubMed

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

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

2013-11-01

174

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

175

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

176

Relationship between cereal leaf beetle (Coleoptera: Chrysomelidae) egg and fourth-instar populations and impact of fourth-instar defoliation of winter wheat yields in North Carolina and Virginia.  

PubMed

Cereal leaf beetle, Oulema melanopus (L.), has become a serious pest of small grains in the mid-Atlantic region of the United States. Existing thresholds for implementing control measures allowed too much leaf damage and consequent yield loss to occur before recommending treatment. Information on beetle biology and crop response to injury, both prerequisites for developing new management strategies, was lacking for this region. A 3-yr project was initiated to generate an area wide cereal leaf beetle biological and yield impact database for winter wheat, and to evaluate the injury and yield loss potential of different population densities. Over the study period, beetle populations were evaluated at 26 winter wheat field locations in Virginia and North Carolina. Eggs and larvae, classified to instar, were counted twice each week from February to June. Replicated insecticide versus noninsecticide treatments were conducted at each location where leaf defoliation and yield were documented. Results showed that the relationship between 50th percentile egg and fourth-instar population estimates were in strong agreement (y = 0.36x - 0.01; r2 = 0.79). Potentially detrimental larval infestations were forecast before appearance of foliage injury from egg populations present during the stem elongation to flag leaf emergence developmental stages. A significant positive linear relationship between total fourth instar per stem population estimates and percent flag leaf defoliation was detected (y = 20.29x + 1.34; r2 = 0.60). A weaker but still significant relationship between the total fourth-instar population estimates and percent yield loss was found (y = 11.74x + 6.51; r2 = 0.26), indicating that factors in addition to flag leaf injury, primarily by fourth instars, also contributed to reduced yields. PMID:11425017

Ihrig, R A; Herbert, D A; Van Duyn, J W; Bradley, J R

2001-06-01

177

Mapping of main and epistatic effect QTLs associated to grain protein and gluten strength using a RIL population of durum wheat  

Microsoft Academic Search

Quality, specifically protein content and gluten strength are among the main objectives of a durum wheat breeding program.\\u000a The aim of this work was to validate quantitative trait loci (QTLs) associated with grain protein content (GPC) and gluten\\u000a strength measured by SDS sedimentation volume (SV) and to find additional QTLs expressed in Argentinean environments. Also,\\u000a epistatic QTL and QTL x

Veronica Conti; Pablo F. Roncallo; Valeria Beaufort; Gerardo L. Cervigni; Ruben Miranda; Carlos A. Jensen; Viviana C. Echenique

178

Partial characterization of glutathione S-transferases from wheat (Triticum spp.) and purification of a safener-induced glutathione S-transferase from Triticum tauschii.  

PubMed Central

Hexaploid wheat (Triticum aestivum L.) has very low constitutive glutathione S-transferase (GST) activity when assayed with the chloroacetamide herbicide dimethenamid as a substrate, which may account for its low tolerance to dimethenamid in the field. Treatment of seeds with the herbicide safener fluxofenim increased the total GST activity extracted from T. aestivum shoots 9-fold when assayed with dimethenamid as a substrate, but had no effect on glutathione levels. Total GST activity in crude protein extracts from T. aestivum, Triticum durum, and Triticum tauschii was separated into several component GST activities by anion-exchange fast-protein liquid chromatography. These activities (isozymes) differed with respect to their activities toward dimethenamid or 1-chloro-2,4-dinitrobenzene as substrates and in their levels of induction by safener treatment. A safener-induced GST isozyme was subsequently purified by anion-exchange and affinity chromatography from etiolated shoots of the diploid wheat species T. tauschii (a progenitor of hexaploid wheat) treated with the herbicide safener cloquintocet-mexyl. The isozyme bound to a dimethenamid-affinity column and had a subunit molecular mass of 26 kD based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme (designated GST TSI-1) was recognized by an antiserum raised against a mixture of maize (Zea mays) GSTs. Amino acid sequences obtained from protease-digested GST TSI-1 had significant homology with the safener-inducible maize GST V and two auxin-regulated tobacco (Nicotiana tabacum) GST isozymes. PMID:9276955

Riechers, D E; Irzyk, G P; Jones, S S; Fuerst, E P

1997-01-01

179

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

180

Dispersed benzoxazinone gene cluster: molecular characterization and chromosomal localization of glucosyltransferase and glucosidase genes in wheat and rye.  

PubMed

Benzoxazinones (Bxs) are major defensive secondary metabolites in wheat (Triticum aestivum), rye (Secale cereale), and maize (Zea mays). Here, we identified full sets of homeologous and paralogous genes encoding Bx glucosyltransferase (GT) and Bx-glucoside glucosidase (Glu) in hexaploid wheat (2n = 6x = 42; AABBDD). Four GT loci (TaGTa-TaGTd) were mapped on chromosomes 7A, 7B (two loci), and 7D, whereas four glu1 loci (Taglu1a-Taglu1d) were on chromosomes 2A, 2B (two loci), and 2D. Transcript levels differed greatly among the four loci; B-genome loci of both TaGT and Taglu1 genes were preferentially transcribed. Catalytic properties of the enzyme encoded by each homeolog/paralog also differed despite high levels of identity among amino acid sequences. The predominant contribution of the B genome to GT and Glu reactions was revealed, as observed previously for the five Bx biosynthetic genes, TaBx1 to TaBx5, which are separately located on homeologous groups 4 and 5 chromosomes. In rye, where the ScBx1 to ScBx5 genes are dispersed to chromosomes 7R and 5R, ScGT and Scglu were located separately on chromosomes 4R and 2R, respectively. The dispersal of Bx-pathway loci to four distinct chromosomes in hexaploid wheat and rye suggests that the clustering of Bx-pathway genes, as found in maize, is not essential for coordinated transcription. On the other hand, barley (Hordeum vulgare) was found to lack the orthologous GT and glu loci like the Bx1 to Bx5 loci despite its close phylogenetic relationship with wheat and rye. These results contribute to our understanding of the evolutionary processes that the Bx-pathway loci have undergone in grasses. PMID:21875895

Sue, Masayuki; Nakamura, Chihiro; Nomura, Taiji

2011-11-01

181

Dispersed Benzoxazinone Gene Cluster: Molecular Characterization and Chromosomal Localization of Glucosyltransferase and Glucosidase Genes in Wheat and Rye1[W  

PubMed Central

Benzoxazinones (Bxs) are major defensive secondary metabolites in wheat (Triticum aestivum), rye (Secale cereale), and maize (Zea mays). Here, we identified full sets of homeologous and paralogous genes encoding Bx glucosyltransferase (GT) and Bx-glucoside glucosidase (Glu) in hexaploid wheat (2n = 6x = 42; AABBDD). Four GT loci (TaGTa–TaGTd) were mapped on chromosomes 7A, 7B (two loci), and 7D, whereas four glu1 loci (Taglu1a–Taglu1d) were on chromosomes 2A, 2B (two loci), and 2D. Transcript levels differed greatly among the four loci; B-genome loci of both TaGT and Taglu1 genes were preferentially transcribed. Catalytic properties of the enzyme encoded by each homeolog/paralog also differed despite high levels of identity among amino acid sequences. The predominant contribution of the B genome to GT and Glu reactions was revealed, as observed previously for the five Bx biosynthetic genes, TaBx1 to TaBx5, which are separately located on homeologous groups 4 and 5 chromosomes. In rye, where the ScBx1 to ScBx5 genes are dispersed to chromosomes 7R and 5R, ScGT and Scglu were located separately on chromosomes 4R and 2R, respectively. The dispersal of Bx-pathway loci to four distinct chromosomes in hexaploid wheat and rye suggests that the clustering of Bx-pathway genes, as found in maize, is not essential for coordinated transcription. On the other hand, barley (Hordeum vulgare) was found to lack the orthologous GT and glu loci like the Bx1 to Bx5 loci despite its close phylogenetic relationship with wheat and rye. These results contribute to our understanding of the evolutionary processes that the Bx-pathway loci have undergone in grasses. PMID:21875895

Sue, Masayuki; Nakamura, Chihiro; Nomura, Taiji

2011-01-01

182

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

183

Wheat Diseases Atlas.  

E-print Network

small grains by clean cultivation and crop rotation. 4 Crown rot with decay at base of stalk Plant Parasitic Nematodes (Nematodes - Cyst, Root Knot, Root Lesion, Seed Gall, Stunt and others) Plant parasitic nematodes are nonsegmented roundworms... that mostly inhabit the soil and feed on roots of wheat and other plants. However, one species, called the wheat seed gall nematode, Anguina tritici, is a significant pathogen of wheat. It is detected on threshed wheat by the presence of galls and hard...

McCoy, Norman L.; Berry, Robert W.

1982-01-01

184

Wheat Streak Mosaic Virus  

E-print Network

Virus First discovered in Nebraska in 1922, wheat streak mosaic virus (WSMV) remains a threat today across most of the U.S. Central Plains. WSMV affects spring wheat, barley, corn, triticale, rye and numerous other annual and perennial grasses... Virus First discovered in Nebraska in 1922, wheat streak mosaic virus (WSMV) remains a threat today across most of the U.S. Central Plains. WSMV affects spring wheat, barley, corn, triticale, rye and numerous other annual and perennial grasses...

Morgan, Gaylon

2005-01-26

185

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

186

Populations  

NSDL National Science Digital Library

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

Galle, Janet R.; Warren, Patricia A.

2005-01-01

187

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

PubMed Central

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

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

2013-01-01

188

Discovery and mapping of single feature polymorphisms in wheat using Affymetrix arrays  

PubMed Central

Background Wheat (Triticum aestivum L.) is a staple food crop worldwide. The wheat genome has not yet been sequenced due to its huge genome size (~17,000 Mb) and high levels of repetitive sequences; the whole genome sequence may not be expected in the near future. Available linkage maps have low marker density due to limitation in available markers; therefore new technologies that detect genome-wide polymorphisms are still needed to discover a large number of new markers for construction of high-resolution maps. A high-resolution map is a critical tool for gene isolation, molecular breeding and genomic research. Single feature polymorphism (SFP) is a new microarray-based type of marker that is detected by hybridization of DNA or cRNA to oligonucleotide probes. This study was conducted to explore the feasibility of using the Affymetrix GeneChip to discover and map SFPs in the large hexaploid wheat genome. Results Six wheat varieties of diverse origins (Ning 7840, Clark, Jagger, Encruzilhada, Chinese Spring, and Opata 85) were analyzed for significant probe by variety interactions and 396 probe sets with SFPs were identified. A subset of 164 unigenes was sequenced and 54% showed polymorphism within probes. Microarray analysis of 71 recombinant inbred lines from the cross Ning 7840/Clark identified 955 SFPs and 877 of them were mapped together with 269 simple sequence repeat markers. The SFPs were randomly distributed within a chromosome but were unevenly distributed among different genomes. The B genome had the most SFPs, and the D genome had the least. Map positions of a selected set of SFPs were validated by mapping single nucleotide polymorphism using SNaPshot and comparing with expressed sequence tags mapping data. Conclusion The Affymetrix array is a cost-effective platform for SFP discovery and SFP mapping in wheat. The new high-density map constructed in this study will be a useful tool for genetic and genomic research in wheat. PMID:19480702

Bernardo, Amy N; Bradbury, Peter J; Ma, Hongxiang; Hu, Shengwa; Bowden, Robert L; Buckler, Edward S; Bai, Guihua

2009-01-01

189

Invisible Coatings for Wheat Kernels  

Microsoft Academic Search

Cereal Chem. 79(6):857-860 It is occasionally necessary to tag wheat kernels without altering their appearance. Coatings have potential applications to tag wheat of a particular color or protein class, diseased wheat such as Karnal bunt, or genetically modified wheat. This methodology will aid in development of cali- brations for sorting instruments. Procedures were developed to coat wheat kernels with invisible

M. S. Ram; Floyd E. Dowell; Larry Seitz

2002-01-01

190

Tolerance to Imidazolinone Herbicides in Wheat  

PubMed Central

An imidazolinone-tolerant wheat (Triticum aestivum L. em Thell) mutant in the winter wheat cultivar Fidel has been identified and characterized. The mutant was isolated from a population derived through seed mutagenesis of the variety with an aqueous solution containing sodium azide. Imidazolinone-tolerant wheat seedlings were selected from the M2 generation of the population in the presence of imazethapyr herbicide and identified as herbicide-insensitive individuals. The trait is inherited as a single semidominant gene and confers high levels of tolerance to imazethapyr. Acetohydroxyacid synthase activity in extracts from imidazolinonetolerant plants was less inhibited by imazethapyr than the enzyme from the wild type. The herbicide-tolerant plants have a completely normal phenotype and display no negative effects on growth and yield in either the absence or presence of imazethapyr. PMID:16653071

Newhouse, Keith E.; Smith, Wendy A.; Starrett, Mark A.; Schaefer, Thomas J.; Singh, Bijay K.

1992-01-01

191

Mitochondrial DNA heteroplasmy in wheat, Aegilops and their nucleus-cytoplasm hybrids.  

PubMed Central

A mitochondrial (mt) transcriptional unit, nad3-orf156, was studied in the nucleus-cytoplasm hybrids of wheat with D/D2 plasmons from Aegilops species and their parental lines. A comparative RFLP analysis and sequencing of the random PCR clones revealed the presence of seven sequence types and their polymorphic sites were mapped. All the hybrids possessed the paternal copies besides the maternal copies. More paternal copies were present in the D2 plasmon hybrids, whereas more maternal copies were present in the D plasmon hybrids. Two major copies were present with different stoichiometries in the maternal Aegilops parents. However, only a major D plasmon copy was detected in the hybrids, irrespective of their plasmon types. The hexaploid wheat parent (AABBDD genome) possessed the major D plasmon copy in approximately 5% stoichiometry, while no D plasmon-homologous copies were detected in the tetraploid wheat parent (AABB genome). The results suggest that the observed mtDNA heteroplasmy is due to paternal contribution of mtDNA. The different copy stoichiometry suggests differential amplification of the heteroplasmic copies among the hybrids and the parental lines. All editing sites and their editing frequencies were conserved among the lines, and only the maternal pattern of editing occurred in the hybrids. PMID:11973315

Hattori, Nobuaki; Kitagawa, Kazuaki; Takumi, Shigeo; Nakamura, Chiharu

2002-01-01

192

Wheat Production in Texas.  

E-print Network

Tascosa, are well suited to growing under these conditions. Fur- thermore, they are strong gluten wheats which will produce grain of satisfactory miliing and baking characteristics. Wheat often is grown continuously on the same land in the Rolling...~. area. Strong gluten wheats of high test rreigF' are needed for growing under irrigation becau\\r the protein content may be low if there is no4 adeauate nitrogen. Tascosa, Caprock, S'curdl I i' caddo and warrior are strong -gluten wheat. a...

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

1970-01-01

193

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

194

Structure, transcription and post-transcriptional regulation of the bread wheat orthologs of the barley cleistogamy gene Cly1.  

PubMed

The majority of genes present in the hexaploid bread wheat genome are present as three homoeologs. Here, we describe the three homoeologous orthologs of the barley cleistogamy gene Cly1, a member of the AP2 gene family. As in barley, the wheat genes (designated TaAP2-A, -B and -D) map to the sub-telomeric region of the long arms of the group 2 chromosomes. The structure and pattern of transcription of the TaAP2 homoeologs were similar to those of Cly1. Transcript abundance was high in the florets, and particularly in the lodicule. The TaAP2 message was cleaved at its miR172 target sites. The set of homoeolog-specific PCR assays developed will be informative for identifying either naturally occurring or induced cleistogamous alleles at each of the three wheat homoeologs. By combining such alleles via conventional crossing, it should be possible to generate a cleistogamous form of bread wheat, which would be advantageous both with respect to improving the level of the crop's resistance against the causative pathogen of fusarium head blight, and for controlling pollen-mediated gene flow to and from genetically modified cultivars. PMID:23381807

Ning, Shunzong; Wang, Ning; Sakuma, Shun; Pourkheirandish, Mohammad; Wu, Jianzhong; Matsumoto, Takashi; Koba, Takato; Komatsuda, Takao

2013-05-01

195

Isolation and sequence analysis of the wheat B genome subtelomeric DNA  

PubMed Central

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

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

2009-01-01

196

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

197

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

198

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

199

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

PubMed Central

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

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

2013-01-01

200

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

201

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

202

A study of cytological and morphological segregation in "F 1" three-species hybrids derived from hexaploid X diploid crosses of Gossypium  

E-print Network

LIBRARY A & R/l COLLEGE OF TEXAS A STUDY OF CYTOLOGICAL AND MORPHOLOGICAL SEGREGATION IN UF1 THREE-SPECIES HYBRIDS DERIVED FROM HEXAPLOID X DIPLOID CROSSES OF GOSSYPIUM A Dissertation Sy Abdul Rahman M. Meraon Submitted to the Graduate... School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 1955 Jfeijor Subject: Cytogenetics A STUDY OF CYTOLOGICAL AND MORPHOLOGICAL SEGREGATION IN "P^1 THREE...

Memon, Abdul Rahman M.

2013-10-04

203

Infestation of transgenic powdery mildew-resistant wheat by naturally occurring insect herbivores under different environmental conditions.  

PubMed

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

204

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

Alvarez-Alfageme, Fernando; von Burg, Simone; Romeis, Jorg

2011-01-01

205

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

206

Wheat-related disorders: A broad spectrum of 'evolving' diseases.  

PubMed

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; Mangiola, F

2014-08-01

207

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

208

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

PubMed Central

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

2013-01-01

209

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

Microsoft Academic Search

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

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

2005-01-01

210

Major quantitative trait loci for seminal root morphology of wheat seedlings  

Microsoft Academic Search

Vigorous early root growth at seedling stage has been shown to be important for efficient acquisition of nutrients in wheat\\u000a (Triticum aestivum L.). Identifying quantitative trait loci (QTL) for early root growth can facilitate the selection of wheat varieties with\\u000a efficient nutrient use. A recombinant inbred line population derived from two Chinese wheat varieties, Xiaoyan 54 and Jing\\u000a 411, was

Yongzhe RenXue; Xue He; Dongcheng Liu; Jingjuan Li; Xueqiang Zhao; Bin Li; Yiping Tong; Aimin Zhang; Zhensheng Li

211

Wheat quality evaluation methods to predict wheat flour tortilla production  

E-print Network

WHEAT QUALITY EVALUATION METHODS TO PREDICT WHEAT FLOUR TORTILLA PRODUCTION A Thesis by BARBIE DENISE SULLINS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1997 Major Subject: Food Science and Technology WHEAT QUALITY EVALUATION METHODS TO PREDICT WHEAT FLOUR TORTILLA PRODUCTION A Thesis by BARBIE DENISE SULLINS Submitted to Texas A8M University in partial fulfillment...

Sullins, Barbie Denise

2012-06-07

212

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

213

The developmental stage of inactivation of rye origin rRNA genes in the embryo and endosperm of wheat x rye F1 hybrids.  

PubMed

To identify the developmental stage during which the preferential inactivation of rRNA genes from the rye parent occurs in wheat x rye hybrids, nucleolar activity was evaluated in the embryo and endosperm of developing seeds of the hybrids. The hybrids were obtained from crosses of euploid and aneuploid lines of hexaploid wheat, Triticum aestivum cv. Chinese Spring, with rye, Secale cereale cv. Centeio do Alto. The number of nucleolar organizing regions (NORs) and nucleoli present in the embryo and endosperm cells of wheat, and wheat x rye F1 hybrids, at different times after fertilization was scored by silver staining. The inactivation of rDNA of rye origin in F1 hybrids occurs simultaneously in the embryo and in the endosperm between 4 and 5 days after fertilization, when these have been through six and 10 cell cycles respectively. We conclude that the genomic interactions leading to the inactivation of the rye origin rDNA is a time-dependent process, related to the developmental stage and independent of the number of cell cycles (DNA replication rounds) they have been through. PMID:7780660

Castilho, A; Queiroz, A; Neves, N; Barao, A; Silva, M; Viegas, W

1995-05-01

214

Recent Advances in Wheat Allelopathy  

Microsoft Academic Search

Wheat (Triticum aestivum), as one of the world’s important crops, has been studied in depth for its allelopathic potential in weed management. Research\\u000a on wheat allelopathy has progressed rapidly from the initial evaluation of allelopathic potential to the identification of\\u000a allelochemicals and genetic markers associated with wheat allelopathy. Allelopathic activity varied among wheat accessions.\\u000a Significant varietal differences in the production

Hanwen Wu; Min An; De Li Liu; Jim Pratley; Deirdre Lemerle

215

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.

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

2014-01-01

216

Evaluation of broiler performance when fed Roundup-Ready wheat (event MON 71800), control, and commercial wheat varieties.  

PubMed

We evaluated the nutritional value of broiler diets containing approximately 40% wheat grain from Roundup Ready wheat (MON 71800), its similar nontransgenic control (MON 71900), or reference commercial wheat varieties. The feeding trial lasted 40 d, and each treatment consisted of 10 replicates of 1-d-old Ross 308 broilers (5 pens of males and 5 pens of females). Each pen contained 12 birds, and at d 13 birds were randomly removed until 9 birds remained. Body weight and feed intake were measured on pen basis at 40 d. At d 41, four broilers per pen were slaughtered. The carcasses were dissected, and cut-up yields were determined. Dry matter, protein, and fat contents of breast meat were determined. The data were analyzed by an ANOVA procedure. The BW and feed conversion at d 40 averaged 2,450 g and 1.52, respectively. There were no significant treatment x sex interactions, except for evisceration yield with significant differences (P < 0.05) in yield between birds fed 2 commercial wheat varieties. Data for final BW, feed conversion, carcass yield, and breast meat were not statistically different (P < 0.05) between broilers fed MON 71800 or MON 71900 or the population of birds fed commercial wheat varieties, except a lower carcass yield at d 41 for birds fed the nontransgenic control wheat. Thus MON 71800 was nutritionally equivalent to nongenetically modified wheat varieties when fed to broilers. PMID:15339007

Kan, C A; Hartnell, G F

2004-08-01

217

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

218

Characterization of tetraploid wheat germplasm for resistance to Pseudocercosporella herpotrichoides, cause of eyespot disease  

Microsoft Academic Search

Eyespot disease, caused by Pseudocercosporella herpotrichoides , can be devastating to winter wheat grown in north- ern Europe and the northwest USA. Accessions from eight different tetraploid wheat species randomly extracted from core collections were scored for resistance to eyespot disease using a -glucuronidase (GUS)-transformed strain of P. herpotrichoides. The GUS values for the combined population followed a quasi-Gaussian distribution.

Giovanni Figliuolo; Stephen S. Jones; Timothy D. Murray; Peir Luigi; Spagnoletti Zeuli

1998-01-01

219

Seasonal development of wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), in Saskatchewan, Canada  

Microsoft Academic Search

Wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), was first detected as early as 1901 in western Canada. The first major outbreak in Saskatchewan was recorded in 1983. In 1984, Saskatchewan wheat midge populations were found to be parasitized by the egg parasitoid, Macroglenes penetrans (Kirby) (Hymenoptera: Pteromálidae). This paper describes the effect of temperature on diapause termination, larval and pupal

J. F. Doane; O. Olfert

2008-01-01

220

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.

Hays, Lana

2009-01-01

221

Floral Initiation in Wheat  

Microsoft Academic Search

The gap in understanding between genetic control and physiological processes of differentiation is far from being bridged; but it is being narrowed by a coordinated approach from both directions. The genetic system controlling the stability of floral differentiation in a series of wheat genotypes with progressively disturbed floral morphogenesis provides an experimental means of investigating the elements of the physiological

Otto Frankel

1976-01-01

222

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.

223

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

PubMed Central

Background Bread wheat, one of the world’s staple food crops, has the largest, highly repetitive and polyploid genome among the cereal crops. The wheat genome holds the key to crop genetic improvement against challenges such as climate change, environmental degradation, and water scarcity. To unravel the complex wheat genome, the International Wheat Genome Sequencing Consortium (IWGSC) is pursuing a chromosome- and chromosome arm-based approach to physical mapping and sequencing. Here we report on the use of a BAC library made from flow-sorted telosomic chromosome 3A short arm (t3AS) for marker development and analysis of sequence composition and comparative evolution of homoeologous genomes of hexaploid wheat. Results The end-sequencing of 9,984 random BACs from a chromosome arm 3AS-specific library (TaaCsp3AShA) generated 11,014,359?bp of high quality sequence from 17,591 BAC-ends with an average length of 626?bp. The sequence represents 3.2% of t3AS with an average DNA sequence read every 19?kb. Overall, 79% of the sequence consisted of repetitive elements, 1.38% as coding regions (estimated 2,850 genes) and another 19% of unknown origin. Comparative sequence analysis suggested that 70-77% of the genes present in both 3A and 3B were syntenic with model species. Among the transposable elements, gypsy/sabrina (12.4%) was the most abundant repeat and was significantly more frequent in 3A compared to homoeologous chromosome 3B. Twenty novel repetitive sequences were also identified using de novo repeat identification. BESs were screened to identify simple sequence repeats (SSR) and transposable element junctions. A total of 1,057 SSRs were identified with a density of one per 10.4?kb, and 7,928 junctions between transposable elements (TE) and other sequences were identified with a density of one per 1.39?kb. With the objective of enhancing the marker density of chromosome 3AS, oligonucleotide primers were successfully designed from 758 SSRs and 695 Insertion Site Based Polymorphisms (ISBPs). Of the 96 ISBP primer pairs tested, 28 (29%) were 3A-specific and compared to 17 (18%) for 96 SSRs. Conclusion This work reports on the use of wheat chromosome arm 3AS-specific BAC library for the targeted generation of sequence data from a particular region of the huge genome of wheat. A large quantity of sequences were generated from the A genome of hexaploid wheat for comparative genome analysis with homoeologous B and D genomes and other model grass genomes. Hundreds of molecular markers were developed from the 3AS arm-specific sequences; these and other sequences will be useful in gene discovery and physical mapping. PMID:22559868

2012-01-01

224

Next-generation sequencing applications for wheat crop improvement.  

PubMed

Bread wheat (Triticum aestivum; Poaceae) is a crop plant of great importance. It provides nearly 20% of the world's daily food supply measured by calorie intake, similar to that provided by rice. The yield of wheat has doubled over the last 40 years due to a combination of advanced agronomic practice and improved germplasm through selective breeding. More recently, yield growth has been less dramatic, and a significant improvement in wheat production will be required if demand from the growing human population is to be met. Next-generation sequencing (NGS) technologies are revolutionizing biology and can be applied to address critical issues in plant biology. Technologies can produce draft sequences of genomes with a significant reduction to the cost and timeframe of traditional technologies. In addition, NGS technologies can be used to assess gene structure and expression, and importantly, to identify heritable genome variation underlying important agronomic traits. This review provides an overview of the wheat genome and NGS technologies, details some of the problems in applying NGS technology to wheat, and describes how NGS technologies are starting to impact wheat crop improvement. PMID:22268223

Berkman, Paul J; Lai, Kaitao; Lorenc, Michal T; Edwards, David

2012-02-01

225

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

PubMed Central

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

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

2010-01-01

226

Purification and characterization of (1-->3, 1-->4)-beta-glucan endohydrolases from germinated wheat (Triticum aestivum).  

PubMed

A (1-->3, 1-->4)-beta-glucan 4-glucanohydrolase [(1-->3, 1-->4)-beta-glucanase, EC 3.2.1.73] was purified to homogeneity from extracts of germinated wheat grain. The enzyme, which was identified as an endohydrolase on the basis of oligosaccharide products released from a (1-->3, 1-->4)-beta-glucan substrate, has an apparent pI of 8.2 and an apparent molecular mass of 30 kDa. Western blot analyses with specific monoclonal antibodies indicated that the enzyme is related to (1-->3, 1-->4)-beta-glucanase isoenzyme EI from barley. The complete primary structure of the wheat (1-->3, 1-->4)-beta-glucanase has been deduced from nucleotide sequence analysis of cDNAs isolated from a library prepared using poly(A)+ RNA from gibberellic acid-treated wheat aleurone layers. One cDNA, designated lambda LW2, is 1426 nucleotide pairs in length and encodes a 306 amino acid enzyme, together with a NH2-terminal signal peptide of 28 amino acid residues. The mature polypeptide encoded by this cDNA has a molecular mass of 32,085 and a predicted pI of 8.1. The other cDNA, designated lambda LW1, carries a 109 nucleotide pair sequence at its 5' end that is characteristic of plant introns and therefore appears to have been synthesized from an incompletely processed mRNA. Comparison of the coding and 3'-untranslated regions of the two cDNAs reveals 31 nucleotide substitutions, but none of these result in amino acid substitutions. Thus, the cDNAs encode enzymes with identical primary structures, but their corresponding mRNAs may have originated from homeologous chromosomes in the hexaploid wheat genome. PMID:8358032

Lai, D M; Høj, P B; Fincher, G B

1993-08-01

227

21 CFR 184.1322 - Wheat gluten.  

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

2014-04-01

228

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

229

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

230

21 CFR 184.1322 - Wheat gluten.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

231

Tetraploid Wheat Landraces in the Mediterranean Basin: Taxonomy, Evolution and Genetic Diversity  

PubMed Central

The geographic distribution of genetic diversity and the population structure of tetraploid wheat landraces in the Mediterranean basin has received relatively little attention. This is complicated by the lack of consensus concerning the taxonomy of tetraploid wheats and by unresolved questions regarding the domestication and spread of naked wheats. These knowledge gaps hinder crop diversity conservation efforts and plant breeding programmes. We investigated genetic diversity and population structure in tetraploid wheats (wild emmer, emmer, rivet and durum) using nuclear and chloroplast simple sequence repeats, functional variations and insertion site-based polymorphisms. Emmer and wild emmer constitute a genetically distinct population from durum and rivet, the latter seeming to share a common gene pool. Our population structure and genetic diversity data suggest a dynamic history of introduction and extinction of genotypes in the Mediterranean fields. PMID:22615891

Oliveira, Hugo R.; Campana, Michael G.; Jones, Huw; Hunt, Harriet V.; Leigh, Fiona; Redhouse, David I.; Lister, Diane L.; Jones, Martin K.

2012-01-01

232

Characterization of a Wheat R2R3-MYB Transcription Factor Gene, TaMYB19, Involved in Enhanced Abiotic Stresses in Arabidopsis.  

PubMed

MYB-type proteins have been shown to participate in multiple stress responses. In the present study, we identified a gene in wheat induced by multiple abiotic stresses, TaMYB19, which encodes a R2R3-type MYB protein. Three highly homologous sequences of TaMYB19 were isolated from hexaploid wheat. Using the nulli-tetrasomic (NT) lines of Chinese Spring wheat, the three sequences were localized to chromosomes 1A, 1B and 1D and designated as TaMYB19-A, TaMYB19-B and TaMYB19-D, respectively. The expression patterns of these three genes were similar under different stress conditions. The TaMYB19-B sequence was selected for further analysis. The TaMYB19-B protein localized to the nucleus. A detailed characterization of Arabidopsis transgenic plants overexpressing the TaMYB19-B gene revealed that the TaMYB19-B protein could improve tolerance to multiple stresses during the seedling stage. We also found that the overexpression of TaMYB19-B resulted in changes in several physiological indices and altered the expression levels of a number of abiotic stress-related genes, allowing the plants to overcome adverse conditions. These results indicate that the TaMYB19 protein plays an important role in plant stress tolerance and that modification of the expression of this protein may improve abiotic stress tolerance in crop plants. PMID:25146486

Zhang, Lichao; Liu, Guoxiang; Zhao, Guangyao; Xia, Chuan; Jia, Jizeng; Liu, Xu; Kong, Xiuying

2014-10-01

233

Wheat Invertases 1  

PubMed Central

Wheat coleoptiles have two distinct invertases, a soluble and a cell wall-bound form as indicated by results from cytochemical and biochemical studies. These enzyme activities differ in their pH optima, chromatographic behavior on diethylaminoethyl cellulose, kinetic properties, thermal stability, and response to light treatment. The soluble invertase was purified to near homogeneity by diethylaminoethyl-cellulose, concanavalin-A Sepharose, and Sephacryl S-300 chromatography. The overall purification was 175-fold with a recovery of about 26%. The holoenzyme has an apparent molecular weight of 158,000 and subunit molecular weight of 53,000 as estimated by polyacrylamide gel electrophoresis under denaturing conditions. Illumination of wheat seedlings caused an increase in the cell wall, but not the soluble, invertase activity. Images Fig. 1 Fig. 4 PMID:16664223

Krishnan, Hari B.; Blanchette, Joan T.; Okita, Thomas W.

1985-01-01

234

On Phaeosphaeria nodorum in wheat.  

E-print Network

??The fungus Phaeosphaeria nodorum (anamorph Stagonospora nodorum) causes stagonospora nodorum blotch on wheat. Besides environmental conditions the biology of the pathogen is an important parameter… (more)

Blixt, Eva

2009-01-01

235

Functional properties of soy hulls supplemented wheat flour  

Microsoft Academic Search

Purpose – Almost 90 per cent of the wheat produced in Pakistan is used for chapattis and rotis preparation. Unleavened flat bread (chapattis and rotis) is staple food of Pakistani population. The present study was carried out to prepare composite flour and to assess suitable level of composition. The main aim was to introduce soy hulls as a rich source

Faqir Muhammad Anjum; Muhammad Issa Khan; Masood Sadiq Butt; Shahzad Hussain; Muhammad Abrar

2006-01-01

236

Genomic prediction in CIMMYT maize and wheat breeding programs  

PubMed Central

Genomic selection (GS) has been implemented in animal and plant species, and is regarded as a useful tool for accelerating genetic gains. Varying levels of genomic prediction accuracy have been obtained in plants, depending on the prediction problem assessed and on several other factors, such as trait heritability, the relationship between the individuals to be predicted and those used to train the models for prediction, number of markers, sample size and genotype × environment interaction (GE). The main objective of this article is to describe the results of genomic prediction in International Maize and Wheat Improvement Center's (CIMMYT's) maize and wheat breeding programs, from the initial assessment of the predictive ability of different models using pedigree and marker information to the present, when methods for implementing GS in practical global maize and wheat breeding programs are being studied and investigated. Results show that pedigree (population structure) accounts for a sizeable proportion of the prediction accuracy when a global population is the prediction problem to be assessed. However, when the prediction uses unrelated populations to train the prediction equations, prediction accuracy becomes negligible. When genomic prediction includes modeling GE, an increase in prediction accuracy can be achieved by borrowing information from correlated environments. Several questions on how to incorporate GS into CIMMYT's maize and wheat programs remain unanswered and subject to further investigation, for example, prediction within and between related bi-parental crosses. Further research on the quantification of breeding value components for GS in plant breeding populations is required. PMID:23572121

Crossa, J; Pérez, P; Hickey, J; Burgueño, J; Ornella, L; Cerón-Rojas, J; Zhang, X; Dreisigacker, S; Babu, R; Li, Y; Bonnett, D; Mathews, K

2014-01-01

237

HETEROSIS STUDIES IN WHEAT CROSSES  

Microsoft Academic Search

A study was undertaken to estimate the heterotic and heterobeltiotic effects in wheat during the year 2002-03 at Wheat Research Institute, AARI, Faisalabad, Pakistan to identify combinations expressing high hybrid vigour. Fifteen F1 single crosses were developed and planted alongwith their 8 parents. Data were recorded on grain yield, tillers per plant, grains per spike, 1000-grain weight and plant height.

Fida Hussain; Makhdoom Hussain; M. Muzaffar Iqbal; Mansoor A. Akhtar

2007-01-01

238

Combining abilities and heritability of callus formation and plantlet regeneration in wheat ( Triticum aestivum L.) anther cultures  

Microsoft Academic Search

Frequency of callus formation in wheat (Triticum aestivum L. em. Thell) anthers cultured in vitro and the frequency of subsequent plantlet formation from such calli were examined in a diallel population produced from five inbred spring wheat cultivars. Two of the five cultivars were believed to possess relatively high frequencies of response and the other three relatively low response frequencies,

M. D. Lazar; P. S. Baenziger; G. W. Schaeffer

1984-01-01

239

Wheat Production in Texas.  

E-print Network

of bakery flour. Comanche (Oro x Tenmarq) was developer1 by the Kansas station but distributed simultane- ously by the Kansas, Oklahoma and Texas sta- tions in 1942. The variety is widely adapted and because of its excellent milling and baking char... 57.0 5-1 6-1 4 56.3 5-3 5-29 Figure 14. Bread dough as mixed in a modern bakery plant. This mass of dough will produce hundreds of loaves of bread. are mild, so intermediate winter-type and true spring-type wheat varieties may be grown from...

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

1960-01-01

240

Wheat Pasture Poisoning.  

E-print Network

treatment appears to be the injection of a calcium gluconate solution with or without fortification with magnesium and phosphorus. Recovery seems to be speeded by removing the cow from wheat pasture fox a short time. No recurrence was o~bselrved ii animal... in the plant as a possible cause of grass tetany. The minerals were potassium, sodium, magnesium and calcium. They observed changes in certain of these ratios in for- age when cases of grass tetany developed in the Netherlands. However, when these same...

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

1956-01-01

241

Drought tolerance in wheat.  

PubMed

Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress. PMID:24319376

Nezhadahmadi, Arash; Prodhan, Zakaria Hossain; Faruq, Golam

2013-01-01

242

Drought Tolerance in Wheat  

PubMed Central

Drought is one of the most important phenomena which limit crops' production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants' vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL) mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea), responsive to abscisic acid (Rab), rubisco, helicase, proline, glutathione-S-transferase (GST), and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress. PMID:24319376

Prodhan, Zakaria Hossain; Faruq, Golam

2013-01-01

243

Using multi-spectral imagery to detect and map stress induced by Russian wheat aphid  

NASA Astrophysics Data System (ADS)

Scope and Method of Study. The rationale of this study was to assess the stress in wheat field induced by the Russian wheat aphid using multispectral imagery. The study was conducted to (a) determine the relationship between RWA and edaphic and topographic factors; (b) identify and quantify the spatial pattern of RWA infestation within wheat fields; (c) differentiate the stress induced by RWA from other stress causing factors. Data used for the analysis included RWA population density from the wheat field in, Texas, Colorado, Wyoming, and Nebraska, Digital Elevation Model from the Unites States Geological Survey (USGS), soil data from the Soil Survey Geographic database (SSURGO), and multispectral imagery acquired in the panhandle of Oklahoma. Findings and Conclusions. The study revealed that the population density of the Russian wheat aphid was related to topographic and edaphic factors. Slope and sand were predictor variables that were positively related to the density of RWA at the field level. The study has also demonstrated that stress induced by the RWA has a specific spatial pattern that can be distinguished from other stress causing factors using a combination of landscape metrics and topographic and edaphic characteristics of wheat fields. Further field-based studies using multispectral imagery and spatial pattern analysis are suggested. The suggestions require acquiring biweekly multispectral imagery and collecting RWA, topographic and edaphic data at the sampling points during the phonological growth development of wheat plants. This is an approach that may pretend to have great potential for site specific technique for the integrated pest management.

Backoulou, Georges Ferdinand

244

7 CFR 810.2201 - Definition of wheat.  

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2014-01-01

245

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2011 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2011-01-01

246

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2013 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2013-01-01

247

7 CFR 810.2201 - Definition of wheat.  

Code of Federal Regulations, 2012 CFR

...Definition of wheat. Grain that, before the removal of dockage, consists of 50 percent or more common wheat (Triticum aestivum L.), club wheat (T. compactum Host.), and durum wheat (T. durum Desf.) and not more than 10...

2012-01-01

248

Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence.  

PubMed

A novel family of antifungal peptides was discovered in the wheat Triticum kiharae Dorof. et Migusch. Two members of the family, designated Tk-AMP-X1 and Tk-AMP-X2, were completely sequenced and shown to belong to the ?-hairpinin structural family of plant peptides with a characteristic C1XXXC2-X(n)-C3XXXC4 motif. The peptides inhibit the spore germination of several fungal pathogens in vitro. cDNA and gene cloning disclosed unique structure of genes encoding Tk-AMP-X peptides. They code for precursor proteins of unusual multimodular structure, consisting of a signal peptide, several ?-hairpinin (4-Cys) peptide domains with a characteristic cysteine pattern separated by linkers and a C-terminal prodomain. Three types of precursor proteins, with five, six or seven 4-Cys peptide modules, were found in wheat. Among the predicted family members, several peptides previously isolated from T. kiharae seeds were identified. Genes encoding Tk-AMP-X precursors have no introns in the protein-coding regions and are upregulated by fungal pathogens and abiotic stress, providing conclusive evidence for their role in stress response. A combined PCR-based and bioinformatics approach was used to search for related genes in the plant kingdom. Homologous genes differing in the number of peptide modules were discovered in phylogenetically-related Triticum and Aegilops species, including polyploid wheat genome donors. Association of the Tk-AMP-X genes with A, B/G or D genomes of hexaploid wheat was demonstrated. Furthermore, Tk-AMP-X-related sequences were shown to be widespread in the Poaceae family among economically important crops, such as barley, rice and maize. PMID:23702306

Utkina, Lyubov L; Andreev, Yaroslav A; Rogozhin, Eugene A; Korostyleva, Tatyana V; Slavokhotova, Anna A; Oparin, Peter B; Vassilevski, Alexander A; Grishin, Eugene V; Egorov, Tsezi A; Odintsova, Tatyana I

2013-08-01

249

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

Microsoft Academic Search

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

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

2007-01-01

250

Quantitative trait loci for aluminum resistance in Chinese wheat landrace FSW  

Microsoft Academic Search

Aluminum (Al) toxicity is a major constraint for wheat production in acid soils worldwide. Chinese landrace FSW demonstrates\\u000a a high level of Al resistance. A population of recombinant inbred lines (RILs) was developed from a cross between FSW and\\u000a an Al-sensitive Chinese line, ND35, using single seed descent, to map quantitative trait loci (QTLs) for Al resistance. Wheat\\u000a reaction to

Shibin Cai; Gui-Hua Bai; Dadong Zhang

2008-01-01

251

Characterization of tetraploid wheat germplasm for resistance to Pseudocercosporella herpotrichoides, cause of eyespot disease  

Microsoft Academic Search

Eyespot disease, caused by Pseudocercosporella herpotrichoides, can be devastating to winter wheat grown in northern Europe and the northwest USA. Accessions from eight different tetraploid wheat species randomly extracted from core collections were scored for resistance to eyespot disease using a ß-glucuronidase (GUS)-transformed strain of P. herpotrichoides. The GUS values for the combined population followed a quasi-Gaussian distribution. Three species,

Giovanni Figliuolo; Stephen S. Jones; Timothy D. Murray; Peir Luigi Spagnoletti Zeuli

1998-01-01

252

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

PubMed

Wheat is the main food for the majority of Iran's population. Precise estimation of wheat yield change in future is essential for any possible revision of management strategies. The main objective of this study was to evaluate the effects of climate change, CO2 concentration, technology development and their integrated effects on wheat production under future climate change. This study was performed under two scenarios of the IPCC Special Report on Emission Scenarios (SRES): regional economic (A2) and global environmental (B1). Crop production was projected for three future time periods (2020, 2050 and 2080) in comparison with a baseline year (2005) for Khorasan province located in the northeast of Iran. Four study locations in the study area included Mashhad, Birjand, Bojnourd and Sabzevar. The effect of technology development was calculated by fitting a regression equation between the observed wheat yields against historical years considering yield potential increase and yield gap reduction as technology development. Yield relative increase per unit change of CO2 concentration (1 ppm(-1)) was considered 0.05 % and was used to implement the effect of elevated CO2. The HadCM3 general circulation model along with the CSM-CERES-Wheat crop model were used to project climate change effects on wheat crop yield. Our results illustrate that, among all the factors considered, technology development provided the highest impact on wheat yield change. Highest wheat yield increase across all locations and time periods was obtained under the A2 scenario. Among study locations, Mashhad showed the highest change in wheat yield. Yield change compared to baseline ranged from -28 % to 56 % when the integration of all factors was considered across all locations. It seems that achieving higher yield of wheat in future may be expected in northeast Iran assuming stable improvements in production technology. PMID:23397072

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

2014-04-01

253

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

NASA Astrophysics Data System (ADS)

Wheat is the main food for the majority of Iran's population. Precise estimation of wheat yield change in future is essential for any possible revision of management strategies. The main objective of this study was to evaluate the effects of climate change, CO2 concentration, technology development and their integrated effects on wheat production under future climate change. This study was performed under two scenarios of the IPCC Special Report on Emission Scenarios (SRES): regional economic (A2) and global environmental (B1). Crop production was projected for three future time periods (2020, 2050 and 2080) in comparison with a baseline year (2005) for Khorasan province located in the northeast of Iran. Four study locations in the study area included Mashhad, Birjand, Bojnourd and Sabzevar. The effect of technology development was calculated by fitting a regression equation between the observed wheat yields against historical years considering yield potential increase and yield gap reduction as technology development. Yield relative increase per unit change of CO2 concentration (1 ppm-1) was considered 0.05 % and was used to implement the effect of elevated CO2. The HadCM3 general circulation model along with the CSM-CERES-Wheat crop model were used to project climate change effects on wheat crop yield. Our results illustrate that, among all the factors considered, technology development provided the highest impact on wheat yield change. Highest wheat yield increase across all locations and time periods was obtained under the A2 scenario. Among study locations, Mashhad showed the highest change in wheat yield. Yield change compared to baseline ranged from -28 % to 56 % when the integration of all factors was considered across all locations. It seems that achieving higher yield of wheat in future may be expected in northeast Iran assuming stable improvements in production technology.

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

2014-04-01

254

Applications of Suits spectral model to wheat  

NASA Technical Reports Server (NTRS)

Canopy reflectance calculations for a spring type Mexican wheat, Penjamo, are compared with published data on Scout winter wheat. Good agreement exists between model calculations and experimental data in the spectral range, 500 nm to 750 nm, suggesting that the model parameters for wheat can be applied to different cultivars of wheat in the same growth stage. Wheat canopy reflectance is dependent upon surface soil type and this dependency is examined with the Suits' spectral model. In this particular growth stage wheat reflectance is shown to be nearly independent of soil reflectance in the visible wavelengths and progressively dependent at longer wavelengths in the infrared.

Chance, J. E.

1977-01-01

255

Linkage disequilibrium and genome-wide association mapping in tetraploid wheat (Triticum turgidum L.).  

PubMed

Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker-trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker-trait associations. PMID:24759998

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

2014-01-01

256

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

PubMed Central

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 hard to culture on media, the use of most genetic and molecular techniques in studying genes involved in the wheat-Pst interactions has been largely limited. The objective of this study was to identify transcriptionally regulated genes during an incompatible interaction between wheat and Pst using cDNA-AFLP technique Results A total of 52,992 transcript derived fragments (TDFs) were generated with 64 primer pairs and 2,437 (4.6%) of them displayed altered expression patterns after inoculation with 1,787 up-regulated and 650 down-regulated. We obtained reliable sequences (>100 bp) for 255 selected TDFs, of which 113 (44.3%) had putative functions identified. A large group (17.6%) of these genes shared high homology with genes involved in metabolism and photosynthesis; 13.8% to genes with functions related to disease defense and signal transduction; and those in the remaining groups (12.9%) to genes involved in transcription, transport processes, protein metabolism, and cell structure, respectively. Through comparing TDFs identified in the present study for incompatible interaction and those identified in the previous study for compatible interactions, 161 TDFs were shared by both interactions, 94 were expressed specifically in the incompatible interaction, of which the specificity of 43 selected transcripts were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Based on the analyses of homology to genes known to play a role in defense, signal transduction and protein metabolism, 20 TDFs were chosen and their expression patterns revealed by the cDNA-AFLP technique were confirmed using the qRT-PCR analysis. Conclusion We uncovered a number of new candidate genes possibly involved in the interactions of wheat and Pst, of which 11 TDFs expressed specifically in the incompatible interaction. Resistance to stripe rust in wheat cv. Suwon11 is executed after penetration has occurred. Moreover, we also found that plant responses in compatible and incompatible interactions are qualitatively similar but quantitatively different soon after stripe rust fungus infection. PMID:20067621

2010-01-01

257

SNP-revealed genetic diversity in wild emmer wheat correlates with ecological factors  

PubMed Central

Background Patterns of genetic diversity between and within natural plant populations and their driving forces are of great interest in evolutionary biology. However, few studies have been performed on the genetic structure and population divergence in wild emmer wheat using a large number of EST-related single nucleotide polymorphism (SNP) markers. Results In the present study, twenty-five natural wild emmer wheat populations representing a wide range of ecological conditions in Israel and Turkey were used. Genetic diversity and genetic structure were investigated using over 1,000 SNP markers. A moderate level of genetic diversity was detected due to the biallelic property of SNP markers. Clustering based on Bayesian model showed that grouping pattern is related to the geographical distribution of the wild emmer wheat. However, genetic differentiation between populations was not necessarily dependent on the geographical distances. A total of 33 outlier loci under positive selection were identified using a FST-outlier method. Significant correlations between loci and ecogeographical factors were observed. Conclusions Natural selection appears to play a major role in generating adaptive structures in wild emmer wheat. SNP markers are appropriate for detecting selectively-channeled adaptive genetic diversity in natural populations of wild emmer wheat. This adaptive genetic diversity is significantly associated with ecological factors. PMID:23937410

2013-01-01

258

Searching for DNA introgressed from wheat and for wheat-like grain proteins in a rice x wheat hybridization derivative  

Microsoft Academic Search

The DNA of a putative rice x wheat hybridization derivative (X Oryticum oryzoides) from China, the DNA of its parental rice cultivar and the DNA of a wheat line were digested with ten different restriction endonucleases, resolved by agarose electrophoresis, Southern blotted and hybridized using genomic wheat DNA as a probe. Phenol extracted, ethanol and cetyltrimethylammonium bromide precipitated DNA of

Hannu Ahokas

1993-01-01

259

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

NASA Astrophysics Data System (ADS)

Wheat is a crop of global importance supplying more than half of the world's population with carbohydrates. We examined, whether climate change induced rainfall patterns towards less frequent but heavier events alter wheat agroecosystem productivity and functioning under three different soil types. Therefore, in a full-factorial experiment Triticum aestivum L. was cultivated in 3 m2 lysimeter plots containing the soil types sandy calcaric phaeozem, gleyic phaeozem or calcic chernozem. Prognosticated rainfall patterns based on regionalised climate change model calculations were compared with current long-term rainfall patterns; each treatment combination was replicated three times. Future rainfall patterns significantly reduced wheat growth and yield, reduced the leaf area index, accelerated crop development, reduced arbuscular mycorrhizal fungi colonisation of roots, increased weed density and the stable carbon isotope signature (?13C) of both old and young wheat leaves. Different soil types affected wheat growth and yield, ecosystem root production as well as weed abundance and biomass. The interaction between climate and soil type was significant only for the harvest index. Our results suggest that even slight changes in rainfall patterns can significantly affect the functioning of wheat agroecosystems. These rainfall effects seemed to be little influenced by soil types suggesting more general impacts of climate change across different soil types. Wheat production under future conditions will likely become more challenging as further concurrent climate change factors become prevalent.

Tabi Tataw, James; Baier, Fabian; Krottenthaler, Florian; Pachler, Bernadette; Schwaiger, Elisabeth; Whylidal, Stefan; Formayer, Herbert; Hösch, Johannes; Baumgarten, Andreas; Zaller, Johann G.

2014-05-01

260

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

PubMed

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

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

2010-10-01

261

Stress-induced changes in wheat grain composition and quality.  

PubMed

Abiotic stresses such as drought, salinity, waterlogging, and high temperature cause a myriad of changes in the metabolism of plants, and there is a lot of overlap in these changes in plants in response to different stresses such as drought and salinity. These stress-induced metabolic changes cause impaired crop growth thereby resulting in poor yield. The metabolic changes taking place in several plant species due to a particular abiotic stress have been revealed from the whole plant to the molecular level by researchers, but most studies have focused on organs such as leaf, stem, and root. Information on such stress-induced changes in seed or grains is infrequent in the literature. From the information that is available, it is now evident that abiotic stress can induce considerable changes in the composition and quality of cereal grains including those of wheat, the premier staple food crop in the world. Thus, the present review discusses how far different types of stresses, mainly salinity, drought, high temperature, and waterlogging, can alter the wheat grain composition and quality. By fully uncovering the stress-induced changes in the nutritional values of wheat grains it would be possible to establish whether balanced supplies of essential nutrients are available to the human population from the wheat crop grown on stress-affected areas. PMID:24580559

Ashraf, M

2014-01-01

262

Trichothecene genotypes of Fusarium graminearum from wheat in Uruguay.  

PubMed

Gibberella zeae (Schwein.) Petch (anamorph F. graminearum Schwabe) is the primary causal agent of FHB of wheat in Uruguay. In the last decade, F. graminearum has produced destructive epidemics on wheat in Uruguay, causing yield losses and price discounts due to reduced seed quality. Strains of F. graminearum clade usually express one of three strain-specific profiles of trichothecene metabolites: nivalenol and its acetylated derivatives (NIV chemotype), deoxynivalenol and 3-acetyldeoxynivalenol (3-AcDON chemotype), or deoxynivalenol and 15-acetyldeoxynivalenol (15-AcDON chemotype). A multiplex PCR assay of Tri3, Tri5, and Tri7 was used to determine the trichothecene genotype of 111 strains of F. graminearum collected during 2003 and 2009 growing seasons from fields located in the major wheat production area of Uruguay. The result showed that all except one of the isolates were of DON genotype, with the remainder of NIV genotype in years 2003 and 2009. All strains with the DON genotype were also of the 15-AcDON genotype in 2003 and nearly all (45/50) in 2009. No DON/3-AcDON genotypes were found in either growing season. No potential shifts in the populations were found in the trichothecene genotypes between 2003 and the 2009 epidemic FHB harvest seasons. This study provides the first data on trichothecene genotypes of F. graminearum strains isolated from wheat in Uruguay and add to the current regional knowledge of trichothecene genotypes. PMID:23414559

Pan, Dinorah; Calero, Natalia; Mionetto, Ana; Bettucci, Lina

2013-03-01

263

Floral Transformation of Wheat  

NASA Astrophysics Data System (ADS)

A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

264

CULTIVAR DESCRIPTION CDC Kestrel winter wheat  

E-print Network

of the Canada Western Red Winter Wheat class. Key words: Triticum aestivum L., cultivar description, wheat (BAROC). Mots clés: Triticum aestivum L., description de cultivar, blé (d'automne) CDC Kestrel is a high-yielding, semidward winter wheat (Triticum aestivum L.) that was developed at the Crop Development Centre, University

Saskatchewan, University of

265

Original article Wheat gluten feed in diets  

E-print Network

Original article Wheat gluten feed in diets for intensive bull beef production * LO Fiems, CV; The use of wheat gluten feed in concentrate diets for beef bulls has been investigated in 3 experiments. Sugar-beet pulp was replaced by 15% wheat gluten feed in the first experiment and by 15, 30 or 45

Paris-Sud XI, Université de

266

WHEAT KERNEL PHYSICAL PROPERTIES AND MILLING PROCESS  

Microsoft Academic Search

A b s t r a c t . Studies concerning the relations between wheat kernel physical properties and milling properties have been carried out since the beginning of the cereal processing industry. The aim of the present work was to show the application of the most important physical properties of wheat for the evaluation of wheat technological qua lity,

Dariusz Dziki; Janusz Laskowski

267

The value of break crops for wheat  

Microsoft Academic Search

The yield of wheat growing after a broadleaf break crop generally exceeds that of wheat growing after wheat or other cereals. The presumed reasons for the yield benefit vary between break crops. They include reduced root and foliar disease, increased supply of soil water and mineral N, reduced assimilate loss to mycorrhizas, and, after legumes, growth stimulation following hydrogen gas

John Angus; Mark Peoples; John Kirkegaard; MH Ryan; L Ohlander

268

Pyruvate orthophosphate dikinase in wheat leaves  

SciTech Connect

Pyruvate orthophosphate dikinase (PPDK) was found in wheat (Triticum aestivum L. cv Cheyenne (CI 8885)) leaves both by activity assays and by the protein blot method. The specific activity of the wheat enzyme is comparable to that of PPDK from maize leaves. Of the total soluble protein in wheat leaves, about 0.05% was PPDK, comparable to the amount in the immature wheat seed and about 1/70th the amount found in mesophyll cells of maize. Immunoprecipitation of wheat PPDK with maize enzyme antiserum indicates partial identity, and the apparent subunit molecular weight is the same based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Aoyagi, K.; Bassham, J.A.

1983-01-01

269

Texas Wheat Flows and Transportation Modes, 1975.  

E-print Network

was hauled by railroads, and nearly 80 percent of the wheat flowing to the Corpus Christi port was transported by railroads. Trucks were relatively more important in intrastate wheat movements (from Texas elevators to other Texas elevators or Texas flour... consistency of split on wheat received by elevators from sources - Texas elevators and out-of-state rs. For example, 99 percent of the wheat re by Northern High Plains elevators from other elevators was truck-delivered, and only 2.8 of the wheat received...

Fuller, Stephen; Paggi, Mechel; Engler, Dwayne

1977-01-01

270

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8?-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition  

PubMed Central

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8?-hydroxyase gene which was highly expressed during seed development (TaABA8?OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8?OH1 on the D genome (TaABA8?OH1-D) was identified in Japanese cultivars including ‘Tamaizumi’. However, a single mutation in TaABA8?OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8?OH1 on the A genome (TaABA8?OH1-A), TM1833, was identified from gamma-ray irradiation lines of ‘Tamaizumi’. TM1833 (a double mutant in TaABA8?OH1-A and TaABA8?OH1-D) showed lower TaABA8?OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in ‘Tamaizumi’ (a single mutant in TaABA8?OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8?OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-01-01

271

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8'-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition.  

PubMed

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8'-hydroxyase gene which was highly expressed during seed development (TaABA8'OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8'OH1 on the D genome (TaABA8'OH1-D) was identified in Japanese cultivars including 'Tamaizumi'. However, a single mutation in TaABA8'OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8'OH1 on the A genome (TaABA8'OH1-A), TM1833, was identified from gamma-ray irradiation lines of 'Tamaizumi'. TM1833 (a double mutant in TaABA8'OH1-A and TaABA8'OH1-D) showed lower TaABA8'OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in 'Tamaizumi' (a single mutant in TaABA8'OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8'OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-03-01

272

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

PubMed Central

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

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

2009-01-01

273

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

PubMed Central

Wheat, like many other staple cereals, contains low levels of the essential micronutrients iron and zinc. Up to two billion people worldwide suffer from iron and zinc deficiencies, particularly in regions with predominantly cereal-based diets. Although wheat flour is commonly fortified during processing, an attractive and more sustainable solution is biofortification, which requires developing new varieties of wheat with inherently higher iron and zinc content in their grains. Until now most studies aimed at increasing iron and zinc content in wheat grains have focused on discovering natural variation in progenitor or related species. However, recent developments in genomics and transformation have led to a step change in targeted research on wheat at a molecular level. We discuss promising approaches to improve iron and zinc content in wheat using knowledge gained in model grasses. We explore how the latest resources developed in wheat, including sequenced genomes and mutant populations, can be exploited for biofortification. We also highlight the key research and practical challenges that remain in improving iron and zinc content in wheat. PMID:24600464

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

2014-01-01

274

Phytochemical and pharmacological perspectives of wheat grain and lupin seed  

Microsoft Academic Search

Wheat and lupin are important crops grown in Australia with massive production every year. Traditionally, both wheat and lupin have been consumed as human foods for their health benefits, which may be due in part to the biologically active phytochemicals they contain. This thesis describes the phytochemical and pharmacological investigations of wheat bran, different wheat bran layers, wheat germ, lupin

Lei Liu

2009-01-01

275

Mechanistic analysis of wheat chlorophyllase  

Microsoft Academic Search

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

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

2005-01-01

276

A laboratory-based comparison of a molluscicide and an alternative food source (red clover) as means of reducing slug damage to winter wheat.  

PubMed

Slugs are major pests of many crops in the UK, including winter wheat, yet current methods of control are often unreliable. This study investigates the potential use of red clover, as an alternative food source, to reduce the amount of damage caused to winter wheat by the field slug, Deroceras reticulatum (Müller). Two laboratory-based studies, each conducted over a 7-day period, investigated the effects of red clover seedlings and commercial metaldehyde pellets on damage to winter wheat seeds and seedlings. The results indicate that metaldehyde applications, in the form of commercially available pellets, resulted in significantly greater protection to wheat seeds compared with red clover, whereas metaldehyde and red clover were equally as effective in reducing damage to wheat seedlings. A further laboratory experiment investigated the effect of two slug population densities (48 and 16 adults m(-2)) and high and low red clover seed rates (125% and 75% of a standard rate) on damage to wheat seeds. Results showed that, at the highest slug population density, red clover sown at 125% of the standard rate gave 99% protection to wheat seeds, compared with the 75% seed rate which gave 55%. At the lower slug population density, both seed rates of red clover resulted in similar levels of protection. Implications for the potential use of red clover as an alternative food source for reducing damage to winter wheat in field conditions are discussed. PMID:15838932

Brooks, Andrew S; Wilcox, Andrew; Cook, Richard T; Crook, Mitchell J

2005-07-01

277

Management of herbicide resistance in wheat cropping systems: learning from the Australian experience.  

PubMed

Herbicide resistance continues to escalate in weed populations infesting global wheat (Triticum aestivum L.) crops, threatening grain production and thereby food supply. Conservation wheat production systems are reliant on the use of efficient herbicides providing low-cost, selective weed control in intensive cropping systems. The resistance-driven loss of herbicide resources combined with limited potential for new herbicide molecules means greater emphasis must be placed on preserving existing herbicides. For more than two decades, since the initial recognition of the dramatic consequences of herbicide resistance, the challenge of introducing additional weed control strategies into herbicide-based weed management programmes has been formidable. Throughout this period, herbicide resistance has expanded unabated across the world's wheat production regions. However, in Australia, where herbicide resources have become desperately depleted, the adoption of harvest weed seed control is evidence, at last, of a successful approach to sustainable weed management in wheat production systems. Growers routinely including strategies to target weed seeds during crop harvest, as part of herbicide-based weed management programmes, are now realising significant weed control and crop production benefits. When combined with an attitude of zero weed tolerance, there is evidence of a sustainable weed control future for wheat production systems. The hard-learned lessons of Australian growers can now be viewed by global wheat producers as an example of how to stop the continual loss of herbicide resources in productive cropping systems. PMID:24318955

Walsh, Michael J; Powles, Stephen B

2014-09-01

278

Advanced backcross QTL analysis for the identification of quantitative trait loci alleles from wild relatives of wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Advanced backcross QTL (AB-QTL) analysis was used to identify quantitative trait loci (QTLs) for yield and yield components in a BC2F2 population derived from a cross between the German winter wheat variety 'Prinz' and the synthetic wheat line W-7984 developed by CIMMYT. Two hundred and ten microsatellite markers were employed to genotype 72 pre-selected BC2F2 plants and phenotypic data were

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

2003-01-01

279

TaMFT-A1 Is Associated with Seed Germination Sensitive to Temperature in Winter Wheat  

PubMed Central

The ability of seed to germinate under favorable environmental conditions is critical for seedling emergence, plant establishment, subsequent development and growth of adult plants, and it is controlled by internal genetic factors and external environmental factors. Winter wheat in the southern Great Plains is often planted six weeks before the optimal planting date to produce more biomass for cattle grazing during the winter season. A high seed germination rate in this higher soil temperature environment is required for this specific management system. In this study, a major QTL for temperature-sensitive germination was mapped on the short arm of chromosome 3A (QTsg.osu-3A) in a RIL population generated from two winter wheat cultivars. Furthermore, TaMFT-A1, previously reported to regulate seed dormancy and pre-harvest sprouting in spring wheat cultivars, was mapped tightly associated with the peak of QTsg.osu-3A. However, allelic variation in TaMFT-A1 between the two winter wheat cultivars differed from that was observed in spring wheat cultivars. There were 87 SNPs (single nucleotide polymorphisms) and 12 indels (insertions/deletions) in TaMFT-A1 between the Jagger allele for high germination and the 2174 allele for low germination in the after-ripened seeds, in comparison with 2 SNPs between the two alleles for differential pre-harvest sprouting in spring wheat cultivars. The Jagger TaMFT-A1 allele is a novel haplotype and appears extensively in winter wheat cultivars. TaMFT-A1 transcript levels were up-regulated by high temperature but down-regulated by low temperature or seed storage time. These findings suggest that TaMFT-A1 may invoke different mechanisms for controlling seed dormancy/germination among winter wheat cultivars. PMID:24069187

Wang, Shuwen; Zhu, Meirong; Carver, Brett F.; Yan, Liuling

2013-01-01

280

TaMFT-A1 is associated with seed germination sensitive to temperature in winter wheat.  

PubMed

The ability of seed to germinate under favorable environmental conditions is critical for seedling emergence, plant establishment, subsequent development and growth of adult plants, and it is controlled by internal genetic factors and external environmental factors. Winter wheat in the southern Great Plains is often planted six weeks before the optimal planting date to produce more biomass for cattle grazing during the winter season. A high seed germination rate in this higher soil temperature environment is required for this specific management system. In this study, a major QTL for temperature-sensitive germination was mapped on the short arm of chromosome 3A (QTsg.osu-3A) in a RIL population generated from two winter wheat cultivars. Furthermore, TaMFT-A1, previously reported to regulate seed dormancy and pre-harvest sprouting in spring wheat cultivars, was mapped tightly associated with the peak of QTsg.osu-3A. However, allelic variation in TaMFT-A1 between the two winter wheat cultivars differed from that was observed in spring wheat cultivars. There were 87 SNPs (single nucleotide polymorphisms) and 12 indels (insertions/deletions) in TaMFT-A1 between the Jagger allele for high germination and the 2174 allele for low germination in the after-ripened seeds, in comparison with 2 SNPs between the two alleles for differential pre-harvest sprouting in spring wheat cultivars. The Jagger TaMFT-A1 allele is a novel haplotype and appears extensively in winter wheat cultivars. TaMFT-A1 transcript levels were up-regulated by high temperature but down-regulated by low temperature or seed storage time. These findings suggest that TaMFT-A1 may invoke different mechanisms for controlling seed dormancy/germination among winter wheat cultivars. PMID:24069187

Lei, Lei; Zhu, Xinkai; Wang, Shuwen; Zhu, Meirong; Carver, Brett F; Yan, Liuling

2013-01-01

281

19 CFR 19.32 - Wheat manipulation; reconditioning.  

Code of Federal Regulations, 2011 CFR

...Duties 1 2011-04-01 2011-04-01 false Wheat manipulation; reconditioning. 19.32 Section 19.32 Customs...Space Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The mixing,...

2011-04-01

282

Study of wheat protein based materials  

NASA Astrophysics Data System (ADS)

Wheat gluten is a naturally occurring protein polymer. It is produced in abundance by the agricultural industry, is biodegradable and very inexpensive (less than $0.50/lb). It has unique viscoelastic properties, which makes it a promising alternative to synthetic plastics. The unplasticized wheat gluten is, however, brittle. Plasticizers such as glycerol are commonly used to give flexibility to the articles made of wheat gluten but with the penalty of greatly reduced stiffness. Former work showed that the brittleness of wheat gluten can also be improved by modifying it with a tri-thiol additive with no penalty of reduced stiffness. However, the cost of the customer designed tri-thiol additive was very high and it was unlikely to make a cost effective material from such an expensive additive. Here we designed a new, inexpensive thiol additive called SHPVA. It was synthesized from polyvinyl alcohol (PVA) through a simple esterification reaction. The mechanical data of the molded wheat gluten/SHPVA material indicated that wheat gluten was toughened by SHPVA. As a control, the wheat gluten/PVA material showed no improvement compared with wheat gluten itself. Several techniques have been used to characterize this novel protein/polymer blend. Differential scanning calorimetric (DSC) study showed two phases in both wheat gluten/PVA and wheat gluten/SHPVA material. However, scanning electron microscope (SEM) pictures indicated that PVA was macroscopically separated from wheat gluten, while wheat gluten/SHPVA had a homogeneous look. The phase image from the atomic force microscope (AFM) gave interesting contrast based on the difference in the mechanical properties of these two phases. The biodegradation behavior of these protein/polymer blends was examined in soil. SHPVA was not degraded in the time period of the experiment. Wheat gluten/SHPVA degraded slower than wheat gluten. We also developed some other interesting material systems based on wheat gluten, including the wheat gluten/basalt composite and wheat gluten/clay composite materials. Their mechanical properties and biodegradation behaviors were determined.

Ye, Peng

283

Impact of United States international wheat policy  

E-print Network

, an accord, along the lines of an international wheat agreement, appears possible. Poorer importing countries stress that such an agreement should be This thesis is consistent in format and style with Reutlinger, S. A Simulation Eodel for Evaluating..., for instance, is currently offering new incentives to its wheat producers and has raised stockholding objectives. One factor underlying stalemated efforts at achieving a successful new international wheat agreement is the fundamental deaand...

Richards, Dean

2012-06-07

284

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

PubMed Central

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

2011-01-01

285

Copyright 2004 by the Genetics Society of America DOI: 10.1534/genetics.104.034777  

E-print Network

of an Expressed Sequence Tag (EST) Resource for Wheat (Triticum aestivum L.): EST Generation, Unigene Analysis leading to a large-scale deletion bin map of the hexaploid (2n 6x 42) wheat genome (Triticum aestivum L wheat (2n 6x 42, Triticum aesti- increased food production. Hexaploid wheat is com-vum L.) is one

Gill, Kulvinder

286

Achieving yield gains in wheat.  

PubMed

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

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

2012-10-01

287

Association Mapping of Kernel Size and Milling Quality in Wheat (Triticum aestivum L.) Cultivars  

Microsoft Academic Search

Association mapping is a method for detection of gene effects based on linkage disequilibrium (LD) that complements QTL analysis in the development of tools for molecular plant breeding. In this study, association mapping was performed on a selected sample of 95 cultivars of soft winter wheat. Population structure was estimated on the basis of 36 unlinked simple-sequence repeat (SSR) markers.

Flavio Breseghello; Mark E. Sorrells

2006-01-01

288

Phenology, diapause, and overwintering of the wheat bug, Nysius huttoni (Hemiptera: Lygaeidae), in Canterbury, New Zealand  

Microsoft Academic Search

At Lincoln, Canterbury, New Zealand, two generations of the wheat bug (Nysius huttoni) developed in annual weeds (Stellaria media, Coronopus didymus, and Polygonum aviculare) between October and February in 1990–91 and 1991–92. Flight trapping indicated that a proportion of the population emigrated from the weeds soon after adult emergence when new habitats, such as patches of fathen (Chenopodium album) and

J. A. Farrell; M. W. Stufkens

1993-01-01

289

Increasing field scale water productivity of rice-wheat systems in the Indo Gangetic Basin  

Microsoft Academic Search

Rice-wheat (RW) systems of the Indo-Gangetic Basin (IGB) are of immense importance for food security and livelihoods in South Asia. However, there are grave concerns about their sustainability, let alone their ability to increase production in pace with population growth. In particular, current levels of groundwater extraction are unsustainable in much of the north west IGB. There is an urgent

E. Humphreys; S. S. Kukal; H. Turral; A. Sikka

290

Systems Responses to Progressive Water Stress in Durum Wheat  

PubMed Central

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

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

2014-01-01

291

Economic Effects of Standardizing Wheat Protein Reporting,  

National Technical Information Service (NTIS)

Wheat protein content has traditionally been reported on an 'as-is' moisture basis by the U.S. wheat trade. In an effort to provide inspection results which are easier to evaluate and compare, the Federal Grain Inspection Service (FGIS) began reporting pr...

L. A. Hoffman, J. L. Harwood, M. N. Leath

1988-01-01

292

Spatial distribution of the cereal leaf beetle (Coleoptera: Chrysomelidae) in wheat.  

PubMed

A 2-yr study was conducted in wheat fields in South Carolina involving weekly sampling of cereal leaf beetle, Oulema melanopus (L.). In each of the six fields of this study, temporal patterns showed two distinct peaks in March and in May of adult O. melanopus. Populations decreased as wheat plants matured. In 2009, larval populations had one peak in April in between the two adult peaks. The ?(2) statistics for observed and Poisson predicted distributions of O. melanopus indicated nonrandom distribution for adults and larvae. In addition, the values of I(D) were >1 for adults and larvae in both years across sampling dates. These results indicate that the sampling distributions of both adult and larval populations of O. melanopus were aggregated. Slopes of Taylor power's law (b) and patchiness regressions (?) were significantly (P < 0.05) different than one in all cases, except for b in 2008 for adults. Across sampling dates, the distance from field border had a significant effect on adult O. melanopus in both years, but not on larval O. melanopus. Densities of adult O. melanopus were greatest at 0 m (the field edge), and decreased at 5-25 m from the field edge. The inverted distance weighted interpolation method showed considerable levels of spatial variability in densities within fields. High densities along the edge of wheat fields suggests that localized control methods in wheat may be effective in reducing migration of O. melanopus and damage in corn, Zea mays L. PMID:22182561

Reay-Jones, Francis P F

2010-12-01

293

A study of the tolerance block approach to special stratification. [winter wheat in Kansas  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Twelve winter wheat LACIE segments in Kansas were used to compare the performance of three clustering methods: (1) BCLUST, which uses a spectral distance function to accumulate clusters; (2) blocks-alone, which divides spectral space into equally populated blocks; and (3) block-seeds, which uses spectral means of blocks-alone as seeds for accumulating distance-type clusters. Both BCLUST and block-seeds performed equally well and outperformed blocks-alone significantly. Their average variance ratio of about 0.5 showed imperfect separation of wheat from non-wheat. This result points to the need to explore the achievable crop separability in the spectral/temporal domain, and suggest evaluating derived features rather than data channels as a means to achieve purer spectral strata.

Richardson, W. (principal investigator)

1979-01-01

294

Influence of aFusarium culmorum inoculation of wheat onin sacco dry matter degradation of wheat straw and wheat chaff.  

PubMed

The aim of this study was to investigate the effect of aFusarium culmorum inoculation of wheat on thein sacco dry matter degradation (DG) of wheat straw and wheat chaff in dairy cows. The ruminal disappearance of dry matter was measured with thein situ nylon bag technique. Samples of wheat straw and wheat chaff from non-inoculated andFusarium-inoculated wheat were used to examine the ruminal dry matter degradability. Samples were subjected to ruminal incubation in two dairy cous fitted with a permanent rumen fistula and incubated for 4, 8, 16, 24, 48, 72, 96 and 120 h. To describe the degradation kinetics, the equation by Ørskov and McDonald (1979) was used. DG rates obtained for contaminates straw and chaff were higher compared to the corresponding rates of the non-contaminated samples, which is assumed to be due to the activity of fungal enzymes. It can be concluded that an infection of wheat withF. culmorum may have an influence on the dry matter degradation of straw and chaff. PMID:23605214

Brinkmeyer, U; Dänicke, S; Lehmann, M; Lebzien, P; Valenta, H; Flachowsky, G

2005-03-01

295

Clusters of genes encoding fructan biosynthesizing enzymes in wheat and barley.  

PubMed

Fructans are soluble carbohydrates with health benefits and possible roles in plant adaptation. Fructan biosynthetic genes were isolated using comparative genomics and physical mapping followed by BAC sequencing in barley. Genes encoding sucrose:sucrose 1-fructosyltransferase (1-SST), fructan:fructan 1-fructosyltransferase (1-FFT) and sucrose:fructan 6-fructosyltransferase (6-SFT) were clustered together with multiple copies of vacuolar invertase genes and a transposable element on two barley BAC. Intron-exon structures of the genes were similar. Phylogenetic analysis of the fructosyltransferases and invertases in the Poaceae showed that the fructan biosynthetic genes may have evolved from vacuolar invertases. Quantitative real-time PCR was performed using leaf RNA extracted from three wheat cultivars grown under different conditions. The 1-SST, 1-FFT and 6-SFT genes had correlated expression patterns in our wheat experiment and in existing barley transcriptome database. Single nucleotide polymorphism (SNP) markers were developed and successfully mapped to a major QTL region affecting wheat grain fructan accumulation in two independent wheat populations. The alleles controlling high- and low- fructan in parental lines were also found to be associated in fructan production in a diverse set of 128 wheat lines. To the authors' knowledge, this is the first report on the mapping and sequencing of a fructan biosynthetic gene cluster and in particular, the isolation of a novel 1-FFT gene from barley. PMID:22864927

Huynh, Bao-Lam; Mather, Diane E; Schreiber, Andreas W; Toubia, John; Baumann, Ute; Shoaei, Zahra; Stein, Nils; Ariyadasa, Ruvini; Stangoulis, James C R; Edwards, James; Shirley, Neil; Langridge, Peter; Fleury, Delphine

2012-10-01

296

Resistance to soil-borne wheat mosaic virus (SBWMV) in durum wheat. H Lapierre 1, HH Lapierre H  

E-print Network

in the 2 resis- tant durum wheat cvs 17 d after seed germination at 15°C in infected soil. At the same dateResistance to soil-borne wheat mosaic virus (SBWMV) in durum wheat. H Lapierre 1, HH Lapierre H cedex; 2 Coopérative de la Franciade, F-41021 Blois, France) Two durum wheat cvs (Seti and Prodigal

Paris-Sud XI, Université de

297

Gene Flow in Genetically Modified Wheat  

PubMed Central

Understanding gene flow in genetically modified (GM) crops is critical to answering questions regarding risk-assessment and the coexistence of GM and non-GM crops. In two field experiments, we tested whether rates of cross-pollination differed between GM and non-GM lines of the predominantly self-pollinating wheat Triticum aestivum. In the first experiment, outcrossing was studied within the field by planting “phytometers” of one line into stands of another line. In the second experiment, outcrossing was studied over distances of 0.5–2.5 m from a central patch of pollen donors to adjacent patches of pollen recipients. Cross-pollination and outcrossing was detected when offspring of a pollen recipient without a particular transgene contained this transgene in heterozygous condition. The GM lines had been produced from the varieties Bobwhite or Frisal and contained Pm3b or chitinase/glucanase transgenes, respectively, in homozygous condition. These transgenes increase plant resistance against pathogenic fungi. Although the overall outcrossing rate in the first experiment was only 3.4%, Bobwhite GM lines containing the Pm3b transgene were six times more likely than non-GM control lines to produce outcrossed offspring. There was additional variation in outcrossing rate among the four GM-lines, presumably due to the different transgene insertion events. Among the pollen donors, the Frisal GM line expressing a chitinase transgene caused more outcrossing than the GM line expressing both a chitinase and a glucanase transgene. In the second experiment, outcrossing after cross-pollination declined from 0.7–0.03% over the test distances of 0.5–2.5 m. Our results suggest that pollen-mediated gene flow between GM and non-GM wheat might only be a concern if it occurs within fields, e.g. due to seed contamination. Methodologically our study demonstrates that outcrossing rates between transgenic and other lines within crops can be assessed using a phytometer approach and that gene-flow distances can be efficiently estimated with population-level PCR analyses. PMID:22216349

Rieben, Silvan; Kalinina, Olena; Schmid, Bernhard; Zeller, Simon L.

2011-01-01

298

Short-term variability of plant populations within a regularly disturbed habitat  

Microsoft Academic Search

The changing populations of weeds during 13 years of the Broadbalk continuous wheat experiment were analysed to investigate the extent of differences in shortterm variability of cover between species. The data were from two sections of the experiment where winter wheat was grown continuously under herbicide treatment for 13 and 6 years respectively. Logistic regressions were fitted to the data.

L. G. Firbank

1993-01-01

299

Ultrafiltration to fractionate wheat polypeptides.  

PubMed

An ultrafiltration process allowing the fractionation of two kinds of polypeptides issued from limited chymotryptic hydrolysis of wheat gliadins was applied to wheat gluten hydrolysates. Hydrophilic and poorly charged polypeptides were well transmitted through an inorganic ZrO2-based membrane at acidic pH, whereas hydrophobic and positively charged polypeptides were highly retained. By combining reversed-phase and cation-exchange chromatography (CEC), it was proved that the fractionation of the polypeptides was based on electrostatic repulsion of the charged polypeptides by the positively charged membrane. After a continuous diafiltration process, retentates containing 75 to 88% of hydrophobic polypeptide and permeates containing 84 to 90% of hydrophilic polypeptides were recovered, depending on the size of membrane used. Even if the ultrafiltration fractions were less purified than fractions issued from CEC, it was shown that they exhibited very different foaming properties: permeate did not produce nor stabilize foams, whereas retentate was more efficient than the whole hydrolysates and BSA. PMID:11302444

Berot, S; Popineau, Y; Compoint, J P; Blassel, C; Chaufer, B

2001-03-25

300

Wheat production in controlled environments  

NASA Technical Reports Server (NTRS)

Conditions are optimized for maximum yield and quality of wheat to be used in a controlled environment life support system (CELSS) in a Lunar or Martian base or a spacecraft. With yields of 23 to 57 g/sq m/d of edible biomass, a minimum size for a CELSS would be between 12 and 30 sq m per person, utilizing about 600 W/sq m of electrical energy for artificial light. Temperature, irradiance, photoperiod, carbon dioxide levels, humidity, and wind velocity are controlled in growth chambers. Nutrient solutions (adjusted for wheat) are supplied to the roots via a recirculating system that controls pH by adding HNO3 and controlling the NO3/NH4 ratio in solution. A rock-wool plant support allows direct seeding and densities up to 10,000 plants sq m. Densities up to 2000 plants/sq m appear to increase seed yield. Biomass production increases almost linearily with increasing irradiance from 400 to 1700 micromol/sq m/s of photosynthetic photon flux, but the efficiency of light utilization decreases over this range. Photoperiod and temperature both have a profound influence on floral initiation, spikelet formation, stem elongation, and fertilization.

Salisbury, Frank B.; Bugbee, Bruce; Bubenheim, David

1987-01-01

301

Micromilling enhances iron bioaccessibility from wholegrain wheat.  

PubMed

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

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

2014-11-19

302

Separability study of wheat and small grains  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Barley showed significant separability from spring wheat, both multitemporally and on a single date chosen near the turning time for barley. Oats showed occasional multitemporal separability from barley and spring wheat; however, the cause of this separability was not well understood. Oats showed no significant separability from spring wheat on any single date during the growing season. By pooling data from segments having an acquisition near the turning time for barley, a fixed unitemporal projection for aiding in the labeling of barley versus spring wheat and oats was constructed. This projection has about the same separability of barley from spring wheat and oats as the unitemporal greeness versus brightness plot. The new fixed projection has the advantage that barley occurs consistently in the same general location on the plot with respect to spring wheat and oats. Attempts to construct a fixed multitemporal or a segment-dependent multitemporal projection for aiding in the labeling of spring wheat versus other small grains were unsuccessful due to segment availability and the fact that each segment has a unique acquisition history.

Lennington, R. K.; Marquina, N. E. (principal investigators)

1978-01-01

303

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

PubMed

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

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

2014-01-01

304

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

PubMed Central

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

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

2012-01-01

305

Differential contribution of two Ppd-1 homoeoalleles to early-flowering phenotype in Nepalese and Japanese varieties of common wheat  

PubMed Central

Wheat landraces carry abundant genetic variation in heading and flowering times. Here, we studied flowering-related traits of two Nepalese varieties, KU-4770 and KU-180 and a Japanese wheat cultivar, Shiroganekomugi (SGK). These three wheat varieties showed similar flowering time in a common garden experiment. In total, five significant quantitative trait loci (QTLs) for three examined traits, the heading, flowering and maturation times, were detected using an F2 population of SGK/KU-4770. The QTLs were found at the Ppd-1 loci on chromosomes 2B and 2D and the 2B QTL was also confirmed in another F2 population of SGK/KU-180. The Ppd-D1 allele from SGK and the Ppd-B1 alleles from the two Nepalese varieties might be causal for early-flowering phenotype. The SGK Ppd-D1 allele contained a 2-kb deletion in the 5? upstream region, indicating a photoperiod-insensitive Ppd-D1a allele. Real-time PCR analysis estimating the Ppd-B1 copy number revealed that the two Nepalese varieties included two intact Ppd-B1 copies, putatively resulting in photoperiod insensitivity and an early-flowering phenotype. The two photoperiod-insensitive Ppd-1 homoeoalleles could independently contribute to segregation of early-flowering individuals in the two F2 populations. Therefore, wheat landraces are genetic resources for discovery of alleles useful for improving wheat heading or flowering times. PMID:24399909

Nguyen, Anh T.; Iehisa, Julio C. M.; Mizuno, Nobuyuki; Nitta, Miyuki; Nasuda, Shuhei; Takumi, Shigeo

2013-01-01

306

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

PubMed Central

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

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

307

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

PubMed

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

Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

2013-01-01

308

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

PubMed Central

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

2012-01-01

309

Wheat Flour Tortilla: Quality Prediction and Study of Physical and Textural Changes during Storage  

E-print Network

and tortillas were compared using five wheat samples. Refined flour doughs were more extensible and softer than whole wheat flour doughs. Whole wheat flour tortillas were larger, thinner and less opaque than refined flour tortillas. Refined wheat flour had much...

Ribeiro De Barros, Frederico

2010-07-14

310

Fitness attributes of Fusarium graminearum isolates from wheat in New York possessing a 3-ADON or 15-ADON trichothecene genotype.  

PubMed

In all, 50 isolates of Fusarium graminearum from wheat spikes in New York, including 25 isolates each of the 15-acetyl-deoxynivalenol (15-ADON) and 3-ADON genotype, were tested to determine whether 3-ADON isolates are more fit for saprophytic survival and pathogenicity on wheat spikes than are 15-ADON isolates. The isolates were characterized and compared for 14 different attributes of saprophytic fitness and pathogenic fitness on a susceptible wheat variety. Isolates of the two genotypes could not be differentiated for most of these traits. Three principle components-ascospore production on corn stalks, total trichothecene amount in wheat kernels, and incidence of diseased spikelets up from the point of inoculation-accounted for 29.4, 18.9, and 10.8% of the variation among the isolates, respectively. A bootstrapping procedure grouped the isolates into two distinct groups, with 27 and 23 isolates each, with isolates from both genotypes represented in similar proportions (15-ADON/3-ADON, n = 14/13 and 11/12). Within the contemporary population of F. graminearum causing wheat head blight in New York, isolates with a 3-ADON genotype did not possess any detectable advantage over isolates with a 15-ADON genotype in saprophytic fitness or in pathogenic fitness on a susceptible wheat cultivar. PMID:24283539

Spolti, Pierri; Del Ponte, Emerson M; Cummings, Jaime A; Dong, Yanhong; Bergstrom, Gary C

2014-05-01

311

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

PubMed

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

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

2014-08-01

312

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

PubMed Central

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

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

2013-01-01

313

Detection of irradiated wheat by germination  

NASA Astrophysics Data System (ADS)

A 5—day germination test was used to identify irradiated wheat. Wheat was irradiated and then germinated in dishes at 25-28°C for 5 days. Germination was inhibited with the dose of 3.3 kGy. Almost all grains did not germinate at 10 kGy. The growth of shoots and roots was retarded at 0.33 kGy and seriously inhibited at 0.5 kGy or over. The average lentgh of shoots at 0.5 kGy was about 20 mm and the shoots failed to grow. This effect was irreversible during postirradiation storage. It is a good index for identification of irradiated wheat. The effects of wheat varieties and old seed on germination were studied.

Zhu, S.; Kume, T.; Ishigaki, I.

1993-07-01

314

Two phase sampling for wheat acreage estimation  

NASA Technical Reports Server (NTRS)

A two-phase Landsat-based sample allocation and wheat proportion estimation method was developed. The technique employs manual, Landsat full frame-based wheat or cultivated land proportion estimates from a large number of segments comprising a first sample phase to optimally allocate a small phase-two sample of computer or manually processed segments. Proportion estimates from each phase are then linked by regression or probability proportional to estimated size estimators to provide wheat proportion estimates and standard errors by reporting unit. Application to the Kansas Southwest CRD (Crop Reporting District) for 1974 produced a wheat acreage estimate for that CRD within 2.42% of the USDA SRS-based estimate using a lower CRD inventory budget than for a simulated reference LACIE (Large Area Crop Inventory Experiment) system.

Thomas, R. W.; Hay, C. M.

1977-01-01

315

Determinants of Wheat Import Demand: Pakistan.  

National Technical Information Service (NTIS)

Pakistan is one of Asia's major producers and consumers of wheat. Recent trends indicate significant growth in future imports under current policies. The United States has historically dominated the Pakistani market because government purchase procedures ...

M. Ash, R. Landes

1993-01-01

316

CULTIVAR DESCRIPTION CDC Clair winter wheat  

E-print Network

of the Canada Western Red Winter Wheat class. Key words: Triticum aestivum L., cultivar description, wheat est un blé d'automne (Triticum aestivum L.) demi-nain à rendement élevé et à paille forte, doté d de l'ouest canadien (BAROC). Mots clés: Triticum aestivum L., description de cultivar, blé (d

Saskatchewan, University of

317

Analysis of the wheat endosperm transcriptome  

Microsoft Academic Search

Among the cereals, wheat is the most widely grown geographically and is part of the staple diet in much of the world. Understanding\\u000a how the cereal endosperm develops and functions will help generate better tools to manipulate grain qualities important to\\u000a end-users. We used a genomics approach to identify and characterize genes that are expressed in the wheat endosperm. We

Debbie L. Laudencia-Chingcuanco; Boryana S. Stamova; Gerard R. Lazo; Xiangqin Cui; Olin D. Anderson

2006-01-01

318

Wheat Production in the Panhandle of Texas.  

E-print Network

seedlings usually will provide more grazing for livestock and produce a better cover for protection against blowing, but there are sev- eral disadvantages to early seeding. Early-seeded wheat may deplete the soil of most of the available moisture during... seedlings usually will provide more grazing for livestock and produce a better cover for protection against blowing, but there are sev- eral disadvantages to early seeding. Early-seeded wheat may deplete the soil of most of the available moisture during...

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

1952-01-01

319

Wheat yield forecasts using Landsat data  

NASA Technical Reports Server (NTRS)

Leaf area index and percentage of vegetative cover, two indices of crop yield developed from Landsat multispectral scanning data, are discussed. Studies demonstrate that the Landsat indicators may be as highly correlated with winter wheat yield as estimates based on traditional field sampling methods; in addition, the Landsat indicators may account for variations in individual field yield which are not explainable by meteorological data. A simple technique employing early-season Landsat data to make wheat yield predictions is also considered.

Colwell, J. E.; Rice, D. P.; Nalepka, R. F.

1977-01-01

320

Rustproofing wheat for a changing climate  

Microsoft Academic Search

This paper offers projections of potential effects of climate change on rusts of wheat and how we should factor in a changing\\u000a climate when planning for the future management of these diseases. Even though the rusts of wheat have been extensively studied\\u000a internationally, there is a paucity of information on the likely effects of a changing climate on the rusts

Sukumar Chakraborty; Jo Luck; Grant Hollaway; Glenn Fitzgerald; Neil White

2011-01-01

321

The Impact of the CIMMYT Wheat Breeding Program on Wheat Yields in Mexico's Yaqui Valley, 1990-2002: Implications for the Future of Public Wheat Breeding  

Microsoft Academic Search

CIMMYT has invested a large and significant amount of public expenditures in wheat breeding research each year for several decades. Estimates of the impact of the wheat breeding program on wheat yield increases provides information to scientists, administrators, and policy makers regarding the efficacy and the rate of return to these investments, providing important information for future funding decisions. Using

Lawton Lanier Nalley; Andrew P. Barkley

2007-01-01

322

Physical mapping of wheat aquaporin genes.  

PubMed

Aquaporins are water channel proteins that control the flow of water across cellular membranes and play vital roles in all aspects of plant-water relations. Our previous identification of 35 wheat PIP and TIP aquaporin genes showed they formed a large family with many conserved features that are thought to be important in structure and function. The present work focussed on determining the positions of these genes in the wheat genome in order to help investigate their functions in water uptake and transport. Genomic locations of wheat PIPs and TIPs were predicted using a number of reported rice-wheat comparative maps and additional in silico approaches. Physical mapping of select genes utilising aneuploid stocks and progenitor DNAs placed these on chromosomes 2B, 2D, 6B and 7B and helped to clarify the individual genes and homoeologues. The compilation of all in silico and physical mapping work confirmed many of the orthologous relationships between wheat and rice and/or barley genes, and synteny in the related areas of genome. These results further reinforce that wheat PIP and TIP proteins are most likely to have similar functions to those closely related in rice, including water permeability and abiotic stress response, and provide important tools for future investigations into the involvement of this complex gene family in traits related to plant-water relations and osmotic stress response. PMID:19924390

Forrest, Kerrie L; Bhave, Mrinal

2010-02-01

323

Impact of fertilizing pattern on the biodiversity of a weed community and wheat growth.  

PubMed

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

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

2014-01-01

324

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

PubMed Central

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

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

2014-01-01

325

Genetic mapping and marker development for resistance of wheat against the root lesion nematode Pratylenchus neglectus  

PubMed Central

Background The Rlnn1 locus, which resides on chromosome 7A of bread wheat (Triticum aestivum L.) confers moderate resistance against the root lesion nematode Pratylenchus neglectus. Prior to this research, the exact linkage relationships of Rlnn1 with other loci on chromosome 7A were not clear and there were no simple codominant markers available for selection of Rlnn1 in wheat breeding. The objectives of the research reported here were to (1) develop an improved genetic map of the Rlnn1 region of chromosome 7A and (2) develop molecular markers that could be used in marker-assisted selection to improve resistance of wheat against P. neglectus. Results A large-effect quantitative trait locus (QTL) for resistance against P. neglectus was genetically mapped using a population of Excalibur/Kukri doubled haploid lines. This QTL coincides in position with the rust resistance gene(s) Lr20/Sr15, the phytoene synthase gene Psy-A1 and 10 molecular markers, including five new markers designed using wheat-rice comparative genomics and wheat expressed sequence tags. Two of the new markers are suitable for use as molecular diagnostic tools to distinguish plants that carry Rlnn1 and Lr20/Sr15 from those that do not carry these resistance genes. Conclusions The genomic location of Rlnn1 was confirmed to be in the terminal region of the long arm of chromosome 7A. Molecular markers were developed that provide simple alternatives to costly phenotypic assessment of resistance against P. neglectus in wheat breeding. In Excalibur, genetic recombination seems to be completely suppressed in the Rlnn1 region. PMID:24377498

2013-01-01

326

Evaluation of a High-Speed Color Sorter for Segregation of Red and White Wheat  

Microsoft Academic Search

A high-speed color sorter has the potential to help wheat breeders purify their white wheat breeding lines and white wheat exporters to meet purity requirements of end users. For this reason, a commercial color sorter was evaluated for sorting mixed red and white wheat. Ten wheat blends containing 95% white and 5% red wheat by mass were produced by mixing

Melchor C. Pasikatan; Floyd E. Dowell

327

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

PubMed Central

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

2013-01-01

328

Systems responses to progressive water stress in durum wheat.  

PubMed

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

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

2014-01-01

329

Effects on performance of ground wheat with or without insoluble fiber or whole wheat in sequential feeding for laying hens.  

PubMed

Sequential feeding (SF) is an innovative system for laying hens consisting of nutrients separating energy, protein, and calcium supplies to fulfill nutrient requirements at the relevant time of day. In previous studies, hens received whole wheat in the morning and a balancer diet (rich in protein and calcium) in the afternoon. To improve SF utilization, the aim was to substitute whole wheat in the morning by an alternative energy supply: ground wheat and ground corn, with or without a proportion of whole wheat and insoluble fiber. The goal was to obtain the advantages observed in previous experiments with whole wheat [bigger gizzard, thinner hens, reduced feed conversion ratio (FCR)]. Four hundred thirty-two ISA Brown hens were housed in collective cages from 20 to 35 wk of age divided into 8 different treatments: a continuous control diet, a sequential diet with whole wheat in the morning, 3 wheat-based diets (ground wheat, ground wheat and 20% whole wheat, and ground wheat with 5% insoluble fiber) and 3 ground corn-based (ground corn, ground corn and 20% whole wheat, and ground corn with 5% insoluble fiber) provided in the morning. All sequential regimens received the same balancer diet rich in protein and calcium in the afternoon. Whole wheat SF gave the best results with an improved FCR compared with continuous control and all other SF diets. Wheat- and corn-based diets showed intermediate results between whole wheat SF and continuous feeding. Gizzard weight was higher and hens were lighter than with conventional continuous feeding, leading to an average FCR improvement of 3.2% compared with a continuous control. Thus, it is possible in SF diets to substitute, at least partially, whole wheat by ground wheat or ground corn with added insoluble fiber or some whole wheat, allowing more flexibility and economic optimization. PMID:23960132

Traineau, M; Bouvarel, I; Mulsant, C; Roffidal, L; Launay, C; Lescoat, P

2013-09-01

330

Testing and validating the CERES-wheat (Crop Estimation through Resource and Environment Synthesis-wheat) model in diverse environments  

NASA Technical Reports Server (NTRS)

CERES-Wheat is a computer simulation model of the growth, development, and yield of spring and winter wheat. It was designed to be used in any location throughout the world where wheat can be grown. The model is written in Fortran 77, operates on a daily time stop, and runs on a range of computer systems from microcomputers to mainframes. Two versions of the model were developed: one, CERES-Wheat, assumes nitrogen to be nonlimiting; in the other, CERES-Wheat-N, the effects of nitrogen deficiency are simulated. The report provides the comparisons of simulations and measurements of about 350 wheat data sets collected from throughout the world.

Otter-Nacke, S.; Godwin, D. C.; Ritchie, J. T.

1986-01-01

331

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

PubMed Central

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

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

2014-01-01

332

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

PubMed

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

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

2012-10-01

333

Identification and characterization of a novel powdery mildew resistance gene PmG3M derived from wild emmer wheat, Triticum dicoccoides.  

PubMed

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most important wheat diseases worldwide. Wild emmer wheat, Triticum turgidum ssp. dicoccoides, the tetraploid ancestor (AABB) of domesticated bread and durum wheat, harbors many important alleles for resistance to various diseases, including powdery mildew. In the current study, two tetraploid wheat mapping populations, derived from a cross between durum wheat (cv. Langdon) and wild emmer wheat (accession G-305-3M), were used to identify and map a novel powdery mildew resistance gene. Wild emmer accession G-305-3M was resistant to all 47 Bgt isolates tested, from Israel and Switzerland. Segregation ratios of F(2) progenies and F(6) recombinant inbred line (RIL) mapping populations, in their reactions to inoculation with Bgt, revealed a Mendelian pattern (3:1 and 1:1, respectively), indicating the role of a single dominant gene derived from T. dicoccoides accession G-305-3M. This gene, temporarily designated PmG3M, was mapped on chromosome 6BL and physically assigned to chromosome deletion bin 6BL-0.70-1.00. The F(2) mapping population was used to construct a genetic map of the PmG3M gene region consisted of six simple sequence repeats (SSR), 11 resistance gene analog (RGA), and two target region amplification polymorphism (TRAP) markers. A second map, constructed based on the F(6) RIL population, using a set of skeleton SSR markers, confirmed the order of loci and distances obtained for the F(2) population. The discovery and mapping of this novel powdery mildew resistance gene emphasize the importance of the wild emmer wheat gene pool as a source for crop improvement. PMID:22159825

Xie, Weilong; Ben-David, Roi; Zeng, Bin; Distelfeld, Assaf; Röder, Marion S; Dinoor, Amos; Fahima, Tzion

2012-03-01

334

agronomie: agriculture and environment A new disease of wheat caused  

E-print Network

1996) Summary — Late maturity wheat plants (Triticum aestivum L) culivars Trigomax and Buck. Alternaria leaf blight / wheat / Triticum aestivum / Alternaria triticimaculans Résumen — Une nueva enfermedad del trigo causada por Alternaria triticimaculans en Argentina. Plantas de trigo (Triticum aestivum

Paris-Sud XI, Université de

335

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2011 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2011-04-01

336

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2012 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2012-04-01

337

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2013 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2013-04-01

338

21 CFR 137.200 - Whole wheat flour.  

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2014-04-01

339

21 CFR 137.200 - Whole wheat flour.  

Code of Federal Regulations, 2010 CFR

...unaltered. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley...Fungal alpha -amylase,” “Fungal ?-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional...

2010-04-01

340

21 CFR 139.180 - Wheat and soy noodle products.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Wheat and soy noodle products. 139.180 Section 139.180 ...HUMAN CONSUMPTION MACARONI AND NOODLE PRODUCTS Requirements for Specific Standardized Macaroni and Noodle Products § 139.180 Wheat and soy...

2010-04-01

341

Original article Competitive ability of wheat cultivars with wild oats  

E-print Network

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

Paris-Sud XI, Université de

342

Genome-wide gene expression analysis supports a developmental model of low temperature tolerance gene regulation in wheat (Triticum aestivum L.)  

PubMed Central

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 expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring Manitou and spring Norstar)) cultivars, wherein the locus for the vernalization gene Vrn-A1 was swapped between the parental winter Norstar and spring Manitou in the derived near-isogenic lines winter Manitou and spring Norstar. Global expression of genes in the crowns of 3-leaf stage plants cold-acclimated at 6°C for 0, 2, 14, 21, 38, 42, 56 and 70 days was examined. Results Analysis of variance of gene expression separated the samples by genetic background and by the developmental stage before or after vernalization saturation was reached. Using gene-specific ANOVA we identified 12,901 genes (at p < 0.001) that change in expression with respect to both genotype and the duration of cold-treatment. We examined in more detail a subset of these genes (2,771) where expression was highly influenced by the interaction between these two main factors. Functional assignments using GO annotations showed that genes involved in transport, oxidation-reduction, and stress response were highly represented. Clustering based on the pattern of transcript accumulation identified genes that were up or down-regulated by cold-treatment. Our data indicate that the cold-sensitive lines can up-regulate known cold-responsive genes comparable to that of cold-hardy lines. The levels of expression of these genes were highly influenced by the initial rate and the duration of the gene's response to cold. We show that the Vrn-A1 locus controls the duration of gene expression but not its initial rate of response to cold treatment. Furthermore, we provide evidence that Ta.Vrn-A1 and Ta.Vrt1 originally hypothesized to encode for the same gene showed different patterns of expression and therefore are distinct. Conclusion This study provides novel insight into the underlying mechanisms that regulate the expression of cold-responsive genes in wheat. The results support the developmental model of LT tolerance gene regulation and demonstrate the complex genotype by environment interactions that determine LT adaptation in winter annual cereals. PMID:21649926

2011-01-01

343

Genetic analysis of durable resistance against leaf rust in durum wheat  

Microsoft Academic Search

The Italian durum wheat cultivar Creso possesses a high level of durable resistance to leaf rust based on both hypersensitive\\u000a and non-hypersensitive components. In order to investigate the genetic basis of this resistance, a segregating population\\u000a composed of 123 recombinant inbred lines (RILs) derived from the cross Creso × Pedroso, was evaluated for disease severity\\u000a in adult plants under field conditions. Furthermore,

Daniela Marone; Ana I. Del Olmo; Giovanni Laidò; Josefina C. Sillero; Amero A. Emeran; Maria A. Russo; Pina Ferragonio; Valentina Giovanniello; Elisabetta Mazzucotelli; Anna M. De Leonardis; Pasquale De Vita; Antonio Blanco; Luigi Cattivelli; Diego Rubiales; Anna M. Mastrangelo

2009-01-01

344

Plant Growth Inhibitory Compounds from Aqueous Leachate of Wheat Straw  

Microsoft Academic Search

When seedlings of lettuce, cress, rice and wheat were incubated with the leachate of wheat straw, the roots growth of lettuce\\u000a and garden cress were particularly inhibited. The leachate of wheat straw (100 g eq.\\/l) showed 80.5 and 79.4% inhibition for\\u000a lettuce and cress roots, respectively. The inhibitory activity was stronger as the concentration of wheat straw leachate was\\u000a greater. This

Hiroshi Nakano; Satoshi Morita; Hideyuki Shigemori; Koji Hasegawa

2006-01-01

345

Engineering greater aluminium resistance in wheat by over-expressing TaALMT1  

PubMed Central

Background and Aims Expected increases in world population will continue to make demands on agricultural productivity and food supply. These challenges will only be met by increasing the land under cultivation and by improving the yields obtained on existing farms. Genetic engineering can target key traits to improve crop yields and to increase production on marginal soils. Soil acidity is a major abiotic stress that limits plant production worldwide. The goal of this study was to enhance the acid soil tolerance of wheat by increasing its resistance to Al3+ toxicity. Methods Particle bombardment was used to transform wheat with TaALMT1, the Al3+ resistance gene from wheat, using the maize ubiquitin promoter to drive expression. TaALMT1 expression, malate efflux and Al3+ resistance were measured in the T1 and T2 lines and compared with the parental line and an Al3+-resistant reference genotype, ET8. Key Results Nine T2 lines showed increased TaALMT1 expression, malate efflux and Al3+ resistance when compared with untransformed controls and null segregant lines. Some T2 lines displayed greater Al3+ resistance than ET8 in both hydroponic and soil experiments. Conclusions The Al3+ resistance of wheat was increased by enhancing TaALMT1 expression with biotechnology. This is the first report of a major food crop being stably transformed for greater Al3+ resistance. Transgenic strategies provide options for increasing food supply on acid soils. PMID:20338951

Pereira, Jorge F.; Zhou, Gaofeng; Delhaize, Emmanuel; Richardson, Terese; Zhou, Meixue; Ryan, Peter R.

2010-01-01

346

21 CFR 139.138 - Whole wheat macaroni products.  

...macaroni products by § 139.110(a), (f)(2), (f)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as the sole wheat ingredient; and (2) None of the optional ingredients permitted...

2014-04-01

347

21 CFR 139.138 - Whole wheat macaroni products.  

Code of Federal Regulations, 2011 CFR

...macaroni products by § 139.110(a), (f)(2), (f)(3), and (g), except that: (1) Whole wheat flour or whole durum wheat flour or both are used as the sole wheat ingredient; and (2) None of the optional ingredients permitted...

2011-04-01

348

Haplotype diversity at fusarium head blight resistance QTLs in wheat  

Microsoft Academic Search

Fusarium head blight (FHB) reduces grain yield and quality in common and durum wheat. Host FHB resistance is an effective control measure that is achieved by stacking multiple resistance genes into a wheat line. Therefore, breeders would benefit from knowing which resistance sources carry different resistance genes. A diverse collection of FHB-resistant and -susceptible wheat lines was characterized with microsatellite

C. A. McCartney; D. J. Somers; G. Fedak; W. Cao

2004-01-01

349

Anisotropic Characteristics Analysis of Red Edge Parameters for Winter Wheat  

Microsoft Academic Search

Based on canopy hyperspectral bidirectional reflectance data and their ancillary parameters, bidirectional reflectance properties of winter wheat were analyzed in the visible and near infrared (VNIR) regions. The results show that winter wheat exhibit strong anisotropic characteristics in the solar principal plane. In addition, the bidirectional reflectance properties of winter wheat change in intensity and trend, because the canopy structural

Xuehong Zhang; Yansong Bao

350

Population Connection: Population Education  

NSDL National Science Digital Library

Population Connection "is the national grassroots population organization that educates young people and advocates progressive action to stabilize world population at a level that can be sustained by Earth's resources." The Population Connection's Education Program develops "age-appropriate curricula to complement students' science and social science instruction about human population trends and their impacts on natural resources, environmental quality and human well-being." The Population Education website offers a variety of educational resources including downloadable classroom activities and readings, and newsletters for teachers and students. The site also provides information about professional development opportunities for educators and free population education workshops held at universities for pre-service teachers and graduate students.

351

Cereal-Based Gluten-Free Food: How to Reconcile Nutritional and Technological Properties of Wheat Proteins with Safety for Celiac Disease Patients  

PubMed Central

The gluten-free diet is, to date, the only efficacious treatment for patients with Celiac Disease. In recent years, the impressive rise of Celiac Disease incidence, dramatically prompted changes in the dietary habit of an increasingly large population, with a rise in demand of gluten-free products. The formulation of gluten-free bakery products presents a formidable challenge to cereal technologists. As wheat gluten contributes to the formation of a strong protein network, that confers visco-elasticity to the dough and allows the wheat flour to be processed into a wide range of products, the preparation of cereal-based gluten-free products is a somehow difficult process. This review focuses on nutritional and technological quality of products made with gluten-free cereals available on the market. The possibility of using flour from naturally low toxic ancient wheat species or detoxified wheat for the diet of celiacs is also discussed. PMID:24481131

Lamacchia, Carmela; Camarca, Alessandra; Picascia, Stefania; Di Luccia, Aldo; Gianfrani, Carmen

2014-01-01

352

Characterization of Wheat GlutenCharacterization of Wheat Gluten Proteins by HPLC and MALDIProteins by HPLC and MALDI  

E-print Network

Characterization of Wheat GlutenCharacterization of Wheat Gluten Proteins by HPLC and MALDIProteins/or classification of commercial wheat samples. 2. The procedure characterizes gluten proteins of Teal and Durum sequencing with MS/MS. 3. Among gluten proteins that have been identified are glutenin high molecular weight

Ens, Werner

353

Wheat productivity estimates using LANDSAT data  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Objective measurements of percent green wheat cover on May 21 were significantly correlated with yield, as were measurements of green LAI and LANDSAT data. Three data sets from the Finney test site were analyzed from LANDSAT passes on 22 November 1974, 15 April 1975, and 21 May 1975. After mean signal values in each band were computed for each sufficiently large wheat field, the mean values were correlated with the farmer estimates of wheat grain yield in order to assess relative information content. It is clear that the single best spectral temporal band for predicting yield is the 15 April red band (0.6-0.7 microns, band 5), with the 15 April green band (0.5-0.6 microns, band 4) a close second.

Nalepka, R. F.; Colwell, J. (principal investigators); Rice, D. P.

1976-01-01

354

A novel mastrevirus infecting wheat in India.  

PubMed

A new mastrevirus (family Geminivridae) infecting wheat in India was detected by rolling-circle amplification (RCA). The complete nucleotide sequence of the virus was determined to be 2783 bp long. Analysis of the nucleotide sequence revealed identity and a genome organisation typical of a mastrevirus. An identical virus was detected in the candidate insect vector (leafhopper) collected from the field. Agroinoculation of young wheat plants with an infectious clone of the virus resulted in dwarfing of plants, identical to what was observed in the field, confirming that this novel virus was the causative agent of the disease. Considering the low degree of sequence identity to any known mastrevirus, the virus described here is suggested to be a member of a new species. Based on symptoms, we propose the name "wheat dwarf India virus". PMID:22752839

Kumar, Jitendra; Singh, Sudhir P; Kumar, Jitesh; Tuli, Rakesh

2012-10-01

355

Response of wheat to sulfur fertilization  

SciTech Connect

Coker 747/sup 3/ wheat (Triticum aestivum L.) was grown on Keo silt loam (coarse-silty, mixed, thermic Dystric Fluventic Entrochrepts) with four S sources applied at various rates for two years. The innate S level of this soil was not adequate for optimum grain yield; therefore, additional S significantly increased grain yield and S concentration and decreased N/S ratios in wheat tissue. Minimum S concentration and N/S ratios in plant tissue for maximum yield ranged from 1.3 to 2.73 g S/kg and 9.5 to 19.2, respectively.

Mahler, R.J.; Maples, R.L.

1986-01-01

356

Wheat Versus Milo for Dairy Cows.  

E-print Network

BULLE -, -1' CAA~ AGRICULTURAL ciiPERIMER~5dTFl A. B. CONNOR, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS DIVISION OF DAIRY HUSBANDRY Wheat Versus Milo For Dairy Cows IT, 1933 4ND ME , 0. WAI ZAL COLLEGE 0 resident IF TEXA STATION...BULLE -, -1' CAA~ AGRICULTURAL ciiPERIMER~5dTFl A. B. CONNOR, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS DIVISION OF DAIRY HUSBANDRY Wheat Versus Milo For Dairy Cows IT, 1933 4ND ME , 0. WAI ZAL COLLEGE 0 resident IF TEXA STATION...

Copeland, O. C. (Orlin Cephas)

1933-01-01

357

Pre-Harvest Sprouting in Wheat  

E-print Network

E-336 1/05 Gaylon Morgan, State Extension Small Grains Specialist Texas A&M University, College Station, Texas P re-Harvest Wheat has a minimal seed-dormancy mecha- nism, which can lead to seed sprouting prior to har- vest (pre-harvest sprouting... conditions prior to harvest, (2) temperatures during such wet weather, (3) the growth stage of ripening grain, and (4) the inherent dormancy level attributable to a variety?s genetics. Germination begins as a wheat kernel absorbs moisture and swells...

Morgan, Gaylon

2005-01-26

358

Microbial ecology dynamics during rye and wheat sourdough preparation.  

PubMed

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

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

2013-12-01

359

Genetic basis of qualitative and quantitative resistance to powdery mildew in wheat: from consensus regions to candidate genes  

PubMed Central

Background Powdery mildew (Blumeria graminis f. sp. tritici) is one of the most damaging diseases of wheat. The objective of this study was to identify the wheat genomic regions that are involved in the control of powdery mildew resistance through a quantitative trait loci (QTL) meta-analysis approach. This meta-analysis allows the use of collected QTL data from different published studies to obtain consensus QTL across different genetic backgrounds, thus providing a better definition of the regions responsible for the trait, and the possibility to obtain molecular markers that will be suitable for marker-assisted selection. Results Five QTL for resistance to powdery mildew were identified under field conditions in the durum-wheat segregating population Creso?×?Pedroso. An integrated map was developed for the projection of resistance genes/ alleles and the QTL from the present study and the literature, and to investigate their distribution in the wheat genome. Molecular markers that correspond to candidate genes for plant responses to pathogens were also projected onto the map, particularly considering NBS-LRR and receptor-like protein kinases. More than 80 independent QTL and 51 resistance genes from 62 different mapping populations were projected onto the consensus map using the Biomercator statistical software. Twenty-four MQTL that comprised 2–6 initial QTL that had widely varying confidence intervals were found on 15 chromosomes. The co-location of the resistance QTL and genes was investigated. Moreover, from analysis of the sequences of DArT markers, 28 DArT clones mapped on wheat chromosomes have been shown to be associated with the NBS-LRR genes and positioned in the same regions as the MQTL for powdery mildew resistance. Conclusions The results from the present study provide a detailed analysis of the genetic basis of resistance to powdery mildew in wheat. The study of the Creso?×?Pedroso durum-wheat population has revealed some QTL that had not been previously identified. Furthermore, the analysis of the co-localization of resistance loci and functional markers provides a large list of candidate genes and opens up a new perspective for the fine mapping and isolation of resistance genes, and for the marker-assisted improvement of resistance in wheat. PMID:23957646

2013-01-01

360

New approach to the fungal decontamination of wheat used for wheat sprouts: effects of aminolevulinic acid.  

PubMed

Nowadays, there is a growing interest in natural, minimally processed, nutritional and healthy foods. Sprouted seeds can be offered as natural nutritive products. Regrettably, existing seed decontamination technologies are limited and have specific disadvantages. 5-aminolevulinic acid (5-ALA) as a novel and effective tool for wheat decontamination from microfungi is proposed in this work. Inhibition of wheat with 5-ALA revealed a drastically suppressed development of microfungi. Studies of wheat germination characteristics showed that 5-ALA stimulates the growth of wheat seedlings and roots without impairing the vigor of germination and the viability of seeds. 5-ALA also induces either marginal or significant activities of antioxidant enzymes which can be associated with enhanced cellular capacity to detoxify reactive oxygen species. The results indicate that 5-ALA application may be an effective, environmentally friendly and inexpensive technology to be used in producing sprouts for human consumption. PMID:17350127

Luksiene, Zivile; Danilcenko, Honorata; Taraseviciene, Zivile; Anusevicius, Zilvinas; Maroziene, Audrone; Nivinskas, Henrikas

2007-05-01

361

Natural variation in grain composition of wheat and related cereals.  

PubMed

The wheat grain comprises three groups of major components, starch, protein, and cell wall polysaccharides (dietary fiber), and a range of minor components that may confer benefits to human health. Detailed analyses of dietary fiber and other bioactive components were carried out under the EU FP6 HEALTHGRAIN program on 150 bread wheat lines grown on a single site, 50 lines of other wheat species and other cereals grown on the same site, and 23-26 bread wheat lines grown in six environments. Principal component analysis allowed the 150 bread wheat lines to be classified on the basis of differences in their contents of bioactive components and wheat species (bread, durum, spelt, emmer, and einkorn wheats) to be clearly separated from related cereals (barley, rye, and oats). Such multivariate analyses could be used to define substantial equivalence when novel (including transgenic) cereals are considered. PMID:23414336

Shewry, Peter R; Hawkesford, Malcolm J; Piironen, Vieno; Lampi, Ann-Maija; Gebruers, Kurt; Boros, Danuta; Andersson, Annica A M; Åman, Per; Rakszegi, Mariann; Bedo, Zoltan; Ward, Jane L

2013-09-01

362

Efficient production of haploid wheat ( Triticum aestivum ) through crosses between Japanese wheat and maize ( Zea mays )  

Microsoft Academic Search

Four Japanese wheat varieties, three crossable and one non-crossable with Hordeum bulbosum, were pollinated with maize pollen of 5 genotypes. By the application of 2,4-dichlorophenoxyacetic acid after pollination, embryos kept developing on wheat plants until 14 days after pollination. The frequency of embryo formation was significantly different among the maize genotypes, varying from 18.0% to 31.9%, but not among the

Kazuhiro Suenaga; Kousuke Nakajima

1989-01-01

363

[Disease index inversion of wheat stripe rust on different wheat varieties with hyperspectral remote sensing].  

PubMed

It is becoming more and more important to use mixed wheat varieties to control wheat stripe rust. Different wheat varieties were planted in field and stripe rust was caused by artificial inoculation. Disease index (DI) was assessed and the canopy reflection data of wheat canopy were obtained by ASD FieldSpec HandHeld FR(325-1 075 nm) made by ASD Company. The correlation analysis between DI and spectral data (reflectance and the first derivative) was conducted, and the estimation models between DI and reflection data (reflectance at 690 and 850 nm, SDr, NDVI and RVI) were built using linear regression method. The results showed that different combinations of wheat varieties had the similar variation at different disease index. DI has positive correlation with reflectance of wheat canopy in visible region, and has significant negative correlation in the near infrared region. DI has stable negative correlation with the first derivative in the region of 700-760 nm and with big fluctuation in other regions. The correlation was compared between DI and hyperspectral derivative index, and SDr has the best correlation with DI. DI estimation models were built based on the canopy reflectance at 690 and 850 nm, SDr, NDVI and RVI. The determinant coefficient of the models is between 0.588 and 0.855, 0.669 and 0.911, 0.534 and 0.773, and 0.587 and 0.751, respectively, and all the models were fit well. The results indicated that DI of wheat stripe rust could be inverted using hyperspectral remote sensing technique and that the inversion effect was hardly influenced by the different combinations of wheat varieties. PMID:20210168

Guo, Jie-Bin; Huang, Chong; Wang, Hai-Guang; Sun, Zhen-Yu; Ma, Zhan-Hong

2009-12-01

364

On-farm impacts of zero tillage wheat in South Asia's rice–wheat systems  

Microsoft Academic Search

The recent slow down in productivity growth in the irrigated areas of the Indo-Gangetic Plains of South Asia has led to a quest for resource-conserving technologies that can reduce production costs, save water and improve production. Findings from farm surveys are used to evaluate the on-farm impacts of zero tillage (ZT) wheat in the rice–wheat systems of India's Haryana state

Olaf Erenstein; Umar Farooq; R. K. Malik; Muhammad Sharif

2008-01-01

365

Composition and stability of anthocyanins in blue-grained wheat.  

PubMed

Wheat grain is recognized as a good source of potentially health-enhancing components such as dietary fiber, phenolics, tocopherols, and carotenoids. Anthocyanins, another group of bioactive compounds, are found in blue and purple wheat grains. In the present study, a blue aleurone spring wheat line "Purendo 38" with relatively high content of total anthocyanins was used to investigate the composition and stability of anthocyanins over three crop years. Commercial cultivars of purple (Konini) and red (Katepwa) wheats were included in the study. Separation of anthocyanins by high-performance liquid chromatography (HPLC) showed that each wheat had a distinct anthocyanin profile. Four major anthocyanins were separated from blue wheat extracts as compared to five anthocyanins in purple wheat. Cyanidin 3-glucoside was the predominant anthocyanin in purple wheat, whereas it was the second major anthocyanin in blue wheat. The predominant anthocyanin in blue wheat, making up approximately 41% of the total anthocyanin content, remains to be structurally unidentified. Blue wheat anthocyanins were thermally most stable at pH 1. Their degradation was slightly lower at pH 3 as compared to pH 5. Increasing the temperature from 65 to 95 degrees C increased degradation of blue wheat anthocyanins. Addition of SO(2) during heating of blue wheat had a stabilizing effect on anthocyanin pigments. The optimal SO(2) concentrations were 500-1000 ppm for whole meals and 1000-3000 ppm for isolated anthocyanins. Further studies are underway to identify and verify individual anthocyanins in blue wheat and their potential end uses. PMID:12670152

Abdel-Aal, El-Sayed M; Hucl, Pierre

2003-04-01

366

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

E-print Network

with a 90% germination rate. Double-crop soybeans are drilled with a seeding rate of 195,000 seeds per acreCont. Rot. Rot. DC Cont. Rot. Rot. DC Cont. Rot. Rot. DC Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Corn Corn Beans Wheat Beans Expected yield per acre2 118 126 39 62 23 149 158 49 70 29

Jackson, Scott A.

367

Molecular characterization of wheat polyphenol oxidase (PPO)  

Microsoft Academic Search

It is well-established that the enzyme polyphenol oxidase (PPO) is involved in undesirable browning of noodles, chapattis, middle east flat breads and steamed breads. Methods for measuring PPO activity have been developed, and the variation of PPO activity among wheat (Triticum aestivum L.) cultivars has been well documented. However, there is no report on the identification and characterization of a

T. Demeke; C. Morris

2002-01-01

368

Rheological properties of wheat flour doughs  

Microsoft Academic Search

Summary A comparative study was made of the large deformation and rupture properties of doughs from a medium strength and a weak wheat flour. Experiments were made by stretching, at a uniform rate, dough rings immersed in a liquid of matching density to prevent the rings from deforming under their own weight. Data were obtained on doughs differing in water

N. W. Tschoegl; J. A. Rinde; T. L. Smith

1970-01-01

369

Wheat Proteins Improve Cryopreservation of Rat Hepatocytes  

E-print Network

ARTICLE Wheat Proteins Improve Cryopreservation of Rat Hepatocytes Me´lanie Grondin, Francine Hamel.1002/bit.22270 ABSTRACT: Hepatocytes are an important physiological model for in vitro studies of drug metabolism and toxicity. However, fresh hepatocytes are not always available and hence cyopreservation

Sarhan, Fathey

370

Disulphide Bonds in Wheat Gluten Proteins  

Microsoft Academic Search

Disulphide bonds play a key role in determining the structure and properties of wheat gluten proteins. Comparison of the sequences of monomeric gliadins and polymeric glutenin subunits allows the identification of conserved and variant cysteine residues. Direct disulphide bond determination demonstrates that the conserved cysteine residues present in S-rich prolamins (?-type gliadins, ?-type gliadins and LMW subunits) form intra-chain disulphide

P. R. Shewry; A. S. Tatham

1997-01-01

371

Genetic transformation of wheat via particle bombardment.  

PubMed

Since its first invention in the late 1980s the particle gun has evolved from a basic gunpowder driven machine firing tungsten particles to one more refined which uses helium gas as the propellant to launch alternative heavy metal particles such as gold and silver. The simple principle is that DNA-coated microscopic particles (microcarriers) are accelerated at high speed by helium gas within a vacuum and travel at such a velocity as to penetrate target cells. However, the process itself involves a range of parameters which are open to variation: microparticle type and size, gun settings (rupture pressure, target distance, vacuum drawn, etc.), preparation of components (e.g., gold coating), and preparation of plant tissues. Here is presented a method optimized for transformation of wheat immature embryos using the Bio-Rad PDS-1000/He particle gun to deliver gold particles coated with a gene of interest and the selectable marker gene bar at 650 psi rupture pressure. Following bombardment, various tissue culture phases are used to encourage embryogenic callus formation and regeneration of plantlets and subsequent selection using glufosinate ammonium causes suppression of non-transformed tissues, thus assisting the detection of transformed plants. This protocol has been used successfully to generate transgenic plants for a wide range of wheat varieties, both spring and winter bread wheats (T. aestivum L.) and durum wheats (T. turgidum L.). PMID:24243206

Sparks, Caroline A; Jones, Huw D

2014-01-01

372

Disease Update in Wheat Gaylon Morgan  

E-print Network

There are three major foliar leaf diseases that commonly occur in Texas wheat fields, including Leaf Rust, Stripe Rust, and Powdery Mildew. On any given year, some regions of the state will usually have economically damaging levels of one or more of these diseases. In most years, significant Leaf Rust or Stripe Rust can

Mukhtar, Saqib

373

Transgenic wheat plants: a powerful breeding source  

Microsoft Academic Search

Plant breeders are always interested in new genetic resources. In thepast, the sources have been limited to existing germplasm. Geneticengineering now provides the opportunity for almost unlimited strategies tocreate novel resources. As a first stage, the Applied Biotechnology Center(ABC) at CIMMYT developed a method for the mass production of fertiletransgenic wheat (Triticum aestivum L.) that yields plants ready fortransfer to

A. Pellegrineschi; S. McLean; M. Salgado; L. Velazquez; R. Hernandez; R. M. Brito; M. Noguera; A. Medhurst; D. Hoisington

2001-01-01

374

Efflux Of Nitrate From Hydroponically Grown Wheat  

NASA Technical Reports Server (NTRS)

Report describes experiments to measure influx, and efflux of nitrate from hydroponically grown wheat seedlings. Ratio between efflux and influx greater in darkness than in light; increased with concentration of nitrate in nutrient solution. On basis of experiments, authors suggest nutrient solution optimized at lowest possible concentration of nitrate.

Huffaker, R. C.; Aslam, M.; Ward, M. R.

1992-01-01

375

Genetic, hormonal, and physiological analysis of late maturity ?-amylase in wheat.  

PubMed

Late maturity ?-amylase (LMA) is a genetic defect that is commonly found in bread wheat (Triticum aestivum) cultivars and can result in commercially unacceptably high levels of ?-amylase in harvest-ripe grain in the absence of rain or preharvest sprouting. This defect represents a serious problem for wheat farmers, and apart from the circumstantial evidence that gibberellins are somehow involved in the expression of LMA, the mechanisms or genes underlying LMA are unknown. In this work, we use a doubled haploid population segregating for constitutive LMA to physiologically analyze the appearance of LMA during grain development and to profile the transcriptomic and hormonal changes associated with this phenomenon. Our results show that LMA is a consequence of a very narrow and transitory peak of expression of genes encoding high-isoelectric point ?-amylase during grain development and that the LMA phenotype seems to be a partial or incomplete gibberellin response emerging from a strongly altered hormonal environment. PMID:23321420

Barrero, Jose M; Mrva, Kolumbina; Talbot, Mark J; White, Rosemary G; Taylor, Jennifer; Gubler, Frank; Mares, Daryl J

2013-03-01

376

Genetic, Hormonal, and Physiological Analysis of Late Maturity ?-Amylase in Wheat1[W][OA  

PubMed Central

Late maturity ?-amylase (LMA) is a genetic defect that is commonly found in bread wheat (Triticum aestivum) cultivars and can result in commercially unacceptably high levels of ?-amylase in harvest-ripe grain in the absence of rain or preharvest sprouting. This defect represents a serious problem for wheat farmers, and apart from the circumstantial evidence that gibberellins are somehow involved in the expression of LMA, the mechanisms or genes underlying LMA are unknown. In this work, we use a doubled haploid population segregating for constitutive LMA to physiologically analyze the appearance of LMA during grain development and to profile the transcriptomic and hormonal changes associated with this phenomenon. Our results show that LMA is a consequence of a very narrow and transitory peak of expression of genes encoding high-isoelectric point ?-amylase during grain development and that the LMA phenotype seems to be a partial or incomplete gibberellin response emerging from a strongly altered hormonal environment. PMID:23321420

Barrero, Jose M.; Mrva, Kolumbina; Talbot, Mark J.; White, Rosemary G.; Taylor, Jennifer; Gubler, Frank; Mares, Daryl J.

2013-01-01

377

Tripartite interactions of Barley yellow dwarf virus, Sitobion avenae and wheat varieties.  

PubMed

The tripartite interactions in a pathosystem involving wheat (Triticum aestivum L.), the Barley yellow dwarf virus (BYDV), and the BYDV vector aphid Sitobion avenae were studied under field conditions to determine the impact of these interactions on aphid populations, virus pathology and grain yield. Wheat varietal resistance to BYDV and aphids varied among the three wheat varieties studied over two consecutive years. The results demonstrated that (1) aphid peak number (APN) in the aphid + BYDV (viruliferous aphid) treatment was greater and occurred earlier than that in the non-viruliferous aphid treatment. The APN and the area under the curve of population dynamics (AUC) on a S. avenae-resistant variety 98-10-30 was significantly lower than on two aphid-susceptible varieties Tam200(13)G and Xiaoyan6. (2) The production of alatae (PA) was greater on the variety 98-10-30 than on the other varieties, and PA was greater in the aphid + BYDV treatment on 98-10-30 than in the non-viruliferous aphid treatment, but this trend was reversed on Tam200(13)G and Xiaoyan6. (3) The BYDV disease incidence (DIC) on the variety 98-10-30 was greater than that on the other two varieties in 2012, and the disease index (DID) on Tam200(13)G was lower than on the other varieties in the aphid + BYDV and BYDV treatments in 2012, but not in 2011 when aphid vector numbers were generally lower. (4) Yield loss in the aphid + BYDV treatment tended to be greater than that in the aphid or BYDV alone treatments across varieties and years. We suggested that aphid population development and BYDV transmission tend to promote each other under field conditions. The aphids + BYDV treatment caused greater yield reductions than non-viruliferous aphids or virus treatment. Wheat varietal resistance in 98-10-30 affects the aphid dispersal, virus transmission and wheat yield loss though inhibits aphid populations from increasing. PMID:25184214

Liu, Xiao-Feng; Hu, Xiang-Shun; Keller, Mike A; Zhao, Hui-Yan; Wu, Yun-Feng; Liu, Tong-Xian

2014-01-01

378

Genome-Wide Association Study Reveals Novel Quantitative Trait Loci Associated with Resistance to Multiple Leaf Spot Diseases of Spring Wheat  

PubMed Central

Accelerated wheat development and deployment of high-yielding, climate resilient, and disease resistant cultivars can contribute to enhanced food security and sustainable intensification. To facilitate gene discovery, we assembled an association mapping panel of 528 spring wheat landraces of diverse geographic origin for a genome-wide association study (GWAS). All accessions were genotyped using an Illumina Infinium 9K wheat single nucleotide polymorphism (SNP) chip and 4781 polymorphic SNPs were used for analysis. To identify loci underlying resistance to the major leaf spot diseases and to better understand the genomic patterns, we quantified population structure, allelic diversity, and linkage disequilibrium. Our results showed 32 loci were significantly associated with resistance to the major leaf spot diseases. Further analysis identified QTL effective against major leaf spot diseases of wheat which appeared to be novel and others that were previously identified by association analysis using Diversity Arrays Technology (DArT) and bi-parental mapping. In addition, several identified SNPs co-localized with genes that have been implicated in plant disease resistance. Future work could aim to select the putative novel loci and pyramid them in locally adapted wheat cultivars to develop broad-spectrum resistance to multiple leaf spot diseases of wheat via marker-assisted selection (MAS). PMID:25268502

Bonman, J. Michael; Xiong, Mai; Brown-Guedira, Gina; Adhikari, Tika B.

2014-01-01

379

Genome-wide association study reveals novel quantitative trait Loci associated with resistance to multiple leaf spot diseases of spring wheat.  

PubMed

Accelerated wheat development and deployment of high-yielding, climate resilient, and disease resistant cultivars can contribute to enhanced food security and sustainable intensification. To facilitate gene discovery, we assembled an association mapping panel of 528 spring wheat landraces of diverse geographic origin for a genome-wide association study (GWAS). All accessions were genotyped using an Illumina Infinium 9K wheat single nucleotide polymorphism (SNP) chip and 4781 polymorphic SNPs were used for analysis. To identify loci underlying resistance to the major leaf spot diseases and to better understand the genomic patterns, we quantified population structure, allelic diversity, and linkage disequilibrium. Our results showed 32 loci were significantly associated with resistance to the major leaf spot diseases. Further analysis identified QTL effective against major leaf spot diseases of wheat which appeared to be novel and others that were previously identified by association analysis using Diversity Arrays Technology (DArT) and bi-parental mapping. In addition, several identified SNPs co-localized with genes that have been implicated in plant disease resistance. Future work could aim to select the putative novel loci and pyramid them in locally adapted wheat cultivars to develop broad-spectrum resistance to multiple leaf spot diseases of wheat via marker-assisted selection (MAS). PMID:25268502

Gurung, Suraj; Mamidi, Sujan; Bonman, J Michael; Xiong, Mai; Brown-Guedira, Gina; Adhikari, Tika B

2014-01-01

380

Alterations and Abnormal Mitosis of Wheat Chromosomes Induced by Wheat-Rye Monosomic Addition Lines  

PubMed Central

Background Wheat-rye addition lines are an old topic. However, the alterations and abnormal mitotic behaviours of wheat chromosomes caused by wheat-rye monosomic addition lines are seldom reported. Methodology/Principal Findings Octoploid triticale was derived from common wheat T. aestivum L. ‘Mianyang11’×rye S. cereale L. ‘Kustro’ and some progeny were obtained by the controlled backcrossing of triticale with ‘Mianyang11’ followed by self-fertilization. Genomic in situ hybridization (GISH) using rye genomic DNA and fluorescence in situ hybridization (FISH) using repetitive sequences pAs1 and pSc119.2 as probes were used to analyze the mitotic chromosomes of these progeny. Strong pSc119.2 FISH signals could be observed at the telomeric regions of 3DS arms in ‘Mianyang11’. However, the pSc119.2 FISH signals were disappeared from the selfed progeny of 4R monosomic addition line and the changed 3D chromosomes could be transmitted to next generation stably. In one of the selfed progeny of 7R monosomic addition line, one 2D chromosome was broken and three 4A chromosomes were observed. In the selfed progeny of 6R monosomic addition line, structural variation and abnormal mitotic behaviour of 3D chromosome were detected. Additionally, 1A and 4B chromosomes were eliminated from some of the progeny of 6R monosomic addition line. Conclusions/Significance These results indicated that single rye chromosome added to wheat might cause alterations and abnormal mitotic behaviours of wheat chromosomes and it is possible that the stress caused by single alien chromosome might be one of the factors that induced karyotype alteration of wheat. PMID:23936213

Fu, Shulan; Yang, Manyu; Fei, Yunyan; Tan, Feiquan; Ren, Zhenglong; Yan, Benju; Zhang, Huaiyu; Tang, Zongxiang

2013-01-01

381

Chicken thigh, chicken liver, and iron-fortified wheat flour increase iron uptake in an in vitro digestion/Caco-2 cell model.  

PubMed

The objective of this study was to test meat and fortified-food combinations to identify those that optimize iron uptake in an in vitro digestion/Caco-2 cell model, a proxy for iron bioavailability. Four experiments tested combinations of meats such as chicken (blood, spleen, liver, thigh), beef (cube steak), and fish (whole-fish meal) with iron-fortified foods (rice cereal, maize-soy flour, wheat flour). Chicken liver, thigh, spleen, blood, or fish meal increased the Caco-2 cell iron uptake from these combined with rice cereal (P< .05). Chicken liver, thigh, blood, and beef increased the Caco-2 cell iron uptake from these combined with wheat flour (P< .05). Chicken liver and thigh were tested further. Compared with the liver or thigh alone, adding fortified foods to these meats did not increase the Caco-2 cell iron uptake (P >or= .05). Adding either meat to the 3 fortified foods increased the Caco-2 cell iron uptake of the fortified foods (P< .05). Chicken liver, chicken thigh, and wheat flour were selected for an infant porridge because the combinations with the highest Caco-2 cell iron uptake were chicken thigh + wheat flour, chicken liver + wheat flour, and chicken liver + maize-soy flour, and wheat flour was the least expensive fortified food sold in the target population. Per unit of iron, the chicken thigh + wheat flour and chicken liver + wheat flour combinations resulted in the highest bioavailable iron. In the proportion of 3:1 fortified food:meat examined, meat increases the bioavailability of iron-fortified foods, but iron-fortified foods do not enhance total iron bioavailability when added to meat. PMID:19083498

Pachón, Helena; Stoltzfus, Rebecca J; Glahn, Raymond P

2008-12-01

382

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2012-07-01

383

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2013-07-01

384

40 CFR 406.30 - Applicability; description of the normal wheat flour milling subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the normal wheat flour milling subcategory. 406.30 Section...MILLS POINT SOURCE CATEGORY Normal Wheat Flour Milling Subcategory § 406.30 Applicability; description of the normal wheat flour milling subcategory. The...

2011-07-01

385

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2011-07-01

386

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2013-07-01

387

40 CFR 406.40 - Applicability; description of the bulgur wheat flour milling subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the bulgur wheat flour milling subcategory. 406.40 Section...MILLS POINT SOURCE CATEGORY Bulgur Wheat Flour Milling Subcategory § 406.40 Applicability; description of the bulgur wheat flour milling subcategory. The...

2012-07-01

388

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2014-07-01

389

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2013 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2013-07-01

390

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2010-07-01

391

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2012 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2012-07-01

392

40 CFR 406.100 - Applicability; description of the wheat starch and gluten subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the wheat starch and gluten subcategory. 406.100 Section 406...POINT SOURCE CATEGORY Wheat Starch and Gluten Subcategory § 406.100 Applicability; description of the wheat starch and gluten subcategory. The provisions...

2011-07-01

393

Seeding rate and seed size as management techniques for ryegrass (Lolium Multiflorum, Lam) in winter wheat  

E-print Network

Higher seeding rates and larger seed sizes could enhance the competitiveness of wheat with ryegrass. Growth room and field research evaluated the effects of wheat seeding rates and seed size in competition with Italian ryegrass. Winter wheat seeds...

Cook, Casey Lee

2005-08-29

394

Reduction in fat uptake of doughnut by microparticulated wheat bran.  

PubMed

Wheat flour-microparticulated wheat bran (MWB) mixture and composites were prepared, and their potential as an oil repellent was evaluated in doughnuts. As MWB content increased, the oil-holding capacity decreased, and there were significant changes in water-holding capacity (p < 0.05). As MWB content increased, the fat content of doughnuts decreased. In addition, the wheat flour-MWB composite was more effective for preventing fat uptake than the wheat flour-MWB mixture. The hardness of the composite was higher than the mixture, although volume and weight decreased and surface colour became darker than that of the mixture. As the proportion of wheat bran in the doughnut formulation increased, the inner crust achieved a uniform cell size and cellular integrity was improved. Based on these data, wheat flour-MWB composites are appropriate for use in doughnut formulas with low fat uptake. PMID:22639853

Kim, Bum-Keun; Chun, Yong-Gi; Cho, Ah-Ra; Park, Dong-June

2012-12-01

395

[Allelopathic effects of companion weed Descurainia sophia on wheat].  

PubMed

By using the techniques of laboratory bioassay, this paper studied the effects of Descurainia sophia extract on the germination rate, germination index, vigor index, root length, shoot height, fresh weight, and dry weight of wheat, and measured the contents of MDA, Chla/Chlb and carotene as well as the karyokinesis index of 5 more sensitive wheat strains. The results showed that D. sophia extract had allelopathic effects on all test wheat strains, though the responses of the strains were significantly different. The test 3 physiological indices of 5 more sensitive wheat strains suggested that the action spot of the allelopathic substances of D. sophia might be the cell membrane of wheat, and the measurement of karyokinesis index indicated that D. sophia extract had inhibitory effects on wheat karyokinesis. PMID:17330486

Yang, Chao; Mu, Xiaoqian

2006-12-01

396

Oat and wheat as contact allergens in personal care products.  

PubMed

Oat and wheat are used as ingredients in various cosmetics and personal care products because of their moisturizing properties. Impaired barrier functions in atopic dermatitis (AD) may increase the risks of sensitization to oat and wheat proteins via skin. Immediate- and delayed-type hypersensitivity reactions to oat and wheat in personal care products have been reported in previous studies, and most of those cases were patients with AD. Patch testing with oat and wheat proteins should be performed more frequently, especially in atopic children. It may help identify contact dermatitis, which may be a cause of flares in patients with AD. Complete avoidance of oat- or wheat-derived products is suggested as we cannot conclude that some oat- or wheat-derived components such as oils are free of protein. PMID:24201466

Pootongkam, Suwimon; Nedorost, Susan

2013-01-01

397

Wheat resistance to leaf blast mediated by silicon  

Microsoft Academic Search

Blast, caused by Pyricularia grisea, is one of the most important diseases of wheat. The effects of silicon (Si) on this wheat disease were studied. Plants of\\u000a wheat cultivars Aliança and BH-1146 were grown in plastic pots containing Si-deficient soil amended with either calcium silicate\\u000a (+Si) or calcium carbonate (?Si). The content of Si in leaf tissue was significantly increased

M. S. Xavier Filha; F. A. Rodrigues; G. P. Domiciano; H. V. Oliveira; P. R. Silveira; W. R. Moreira

2011-01-01

398

Copyright 2004 by the Genetics Society of America DOI: 10.1534/genetics.104.034785  

E-print Network

and Evaluation of cDNA Libraries for Large-Scale Expressed Sequence Tag Sequencing in Wheat (Triticum aestivum L (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86

Gill, Kulvinder

399

Microsatellite mutation rate during allohexaploidization of newly resynthesized wheat.  

PubMed

Simple sequence repeats (SSRs, also known as microsatellites) are known to be mutational hotspots in genomes. DNA rearrangements have also been reported to accompany allopolyploidization. A study of the effect of allopolyploidization on SSR mutation is therefore important for understanding the origin and evolutionary dynamics of SSRs in allopolyploids. Three synthesized double haploid (SynDH) populations were made from 241 interspecific F(1 )haploid hybrids between Triticum turgidum L. and Aegilops tauschii (Coss.) through spontaneous chromosome doubling via unreduced gametes. Mutation events were studied at 160 SSR loci in the S(1) generation (the first generation after chromosome doubling) of the three SynDH populations. Of the 148260 SSR alleles investigated in S(1) generation, only one mutation (changed number of repeats) was confirmed with a mutation rate of 6.74 × 10-6. This mutation most likely occurred in the respective F(1) hybrid. In comparison with previously reported data, our results suggested that allohexaploidization of wheat did not increase SSR mutation rate. PMID:23202911

Luo, Jiangtao; Hao, Ming; Zhang, Li; Chen, Jixiang; Zhang, Lianquan; Yuan, Zhongwei; Yan, Zehong; Zheng, Youliang; Zhang, Huaigang; Yen, Yang; Liu, Dengcai

2012-01-01

400

Evaluation of trends in wheat yield models  

NASA Technical Reports Server (NTRS)

Trend terms in models for wheat yield in the U.S. Great Plains for the years 1932 to 1976 are evaluated. The subset of meteorological variables yielding the largest adjusted R(2) is selected using the method of leaps and bounds. Latent root regression is used to eliminate multicollinearities, and generalized ridge regression is used to introduce bias to provide stability in the data matrix. The regression model used provides for two trends in each of two models: a dependent model in which the trend line is piece-wise continuous, and an independent model in which the trend line is discontinuous at the year of the slope change. It was found that the trend lines best describing the wheat yields consisted of combinations of increasing, decreasing, and constant trend: four combinations for the dependent model and seven for the independent model.

Ferguson, M. C.

1982-01-01

401

Wheat seed proteins regulated by imbibition independent of dormancy status.  

PubMed

Seed dormancy is an important trait in wheat (Trticum aestivum L.) and it can be released by germination-stimulating treatments such as after-ripening. Previously, we identified prote