RAPD markers linked to the nuclear gene from Triticum timopheevii that confers compatibility with Aegilops squarrosa cytoplasm on alloplasmic durum wheat.

Alien cytoplasms cause a wide range of phenotypic alterations in the nucleus-cytoplasm (NC) hybrids in the Triticeae. Nuclear genomes of timopheevii wheat (Triticum timopheevii and Triticum araraticum) are fully compatible with the cytoplasm of Aegilops squarrosa, while those of a majority of emmer or durum wheat cultivars and more than half the wild emmer wheats are incompatible, and a maternal 1D chromosome is required to restore seed viability and male fertility in the NC hybrids. A euploid NC hybrid of Triticum durum cv. Langdon with Ae. squarrosa cytoplasm produced by introgressing the NC compatibility (Ncc) gene from T. timopheevii was used to identify random amplified polymorphic DNA (RAPD) markers linked to it. After a survey of 200 random decamer primers, four markers were selected, all of which were completely linked in 64 individuals of a SB8 mapping population. One marker was derived from a single locus, while three others were from interspersed repetitive sequences. Also, the hybrid chromosomes and those of the parental T. durum had identical C-banding patterns. RAPD-PCR analysis of 65 accessions from wild and cultivated tetraploid wheat species showed the exclusive presence of the markers in timopheevii wheat. In conclusion, the chromosomal region flanking Ncc of T. timopheevii is highly conserved in the genome of this group of tetraploid wheats.     

Resistance genes in wild accessions of Triticeae--inoculation test and STS marker analyses

Sequence tagged site (STS) markers have been developed recently to identify resistance genes in wheat. A number of wild relatives have been used to transfer resistance genes into wheat cultivars. Accessions of wild species of Triticeae: Aegilops longissima (4), Ae. speltoides (6), Ae. tauschii (8), Ae. umbellulata (3), Ae. ventricosa (3), Triticum spelta (2), T. timopheevi (3), T. boeoticum (4) and T. monococcum (1), 34 in total, were examined using PCR-STS markers for resistance genes against Puccinia recondita f.sp. tritici (Lr) and Erysiphe graminis (Pm). Additionally, a set of cv. Thatcher near-isogenic lines conferring resistance genes Lr 1, Lr 9, Lr 10, Lr 24, Lr 28, Lr 35 and Lr 37 were examined with the same procedure. Twenty-two accessions were tested using the inoculation test for resistance to Erysiphe graminis, Puccinia recondita, P. striiformis and P. graminis. The most resistant entries were those of Aegilops speltoides and Triticum timopheevi and among T. boeoticum accession #5353. Markers of all mentioned Lr resistance genes were identified in all corresponding cv. Thatcher near-isogenic lines (except Lr 35 gene marker). The following resistance gene markers were identified in wild Triticeae accessions: Lr 1 in two accessions of Ae. tauschii and one accession of Ae. umbellulata, Lr 9 in one accession of Ae. umbellulata, Lr 10 in one accession of T. spelta, Lr 28 in 11 accessions: Ae. speltoides (4), Ae. umbellulata (2), T. spelta (2) and T. timopheevi (3), Lr 37 in 3 accessions of Ae. ventricosa, Pm 1 in all 34 accessions, Pm 2 in 28 accessions, Pm 3 in all 4 accessions of T. boeoticum, 1 accession of T. spelta and 1 of T. timopheevi, and Pm 13 in 5 out of 6 accessions of Ae. speltoides. Reliability and usefulness of STS markers is discussed.     

小麦A，B和D基因组同源DNA序列在进化过程中的演变研究

选取已定位的大麦1H染色体的STS标记NWG913为引物,在普通小麦（Tritium aestivum L.）及其4个可能的起源种乌拉尔图小麦（T.urartu T.)、栽培一粒小麦（T.monococcum.L)栽培二粒小麦（T.dicoccum S.）、方穗山羊草（Ae.squarrosa L.)上特异性扩增。扩增产物克隆测序后对其进行序列分析,由序列差异的程度来确定这几个物种之间的亲缘关系。实验结果表明,普通小麦（Tritium aestivum L.)的A基因组此段序列与乌拉尔图小麦（T.urartu T.)、栽培一粒小麦（T.monococcum L.)、栽培二粒小麦（T.dicoccum S.)A基因组此段序列完全相同;普通小麦的D基因组此段序列与方穗山羊草（Ae.squarrosa L.)也完全相同;普通小麦的B基因组此段序列和栽培二粒小麦B基因组此段序列有0．61％的差异。研究结果一方面对现有的普通小麦A、B、D基因组起源和进化理论给予了分子水平上的证明,同时也揭示了同一物种不同的基因组化进化速度存在差异。     

Molecular characterization of a diagnostic DNA marker for domesticated tetraploid wheat provides evidence for gene flow from wild tetraploid wheat to hexaploid wheat

All forms of domesticated tetraploid wheat (Triticum turgidum, genomes AABB) are nearly monomorphic for restriction fragment length polymorphism (RFLP) haplotype a at the Xpsr920 locus on chromosome 4A (Xpsr920-A1a), and wild tetraploid wheat is monomorphic for haplotype b. The Xpsr920-A1a/b dimorphism provides a molecular marker for domesticated and wild tetraploid wheat, respectively. Hexaploid wheat (Triticum aestivum, genomes AABBDD) is polymorphic for the 2 haplotypes. Bacterial artificial chromosome (BAC) clones hybridizing with PSR920 were isolated from Triticum urartu (genomes AA), Triticum monococcum (genomes AmAm), and T. turgidum ssp. durum (genomes AABB) and sequenced. PSR920 is a fragment of a putative ATP binding cassette (ABC) transporter gene (designated ABCT-1). The wheat ABCT-1 gene is more similar to the T. urartu gene than to the T. monococcum gene and diverged from the T. urartu gene about 0.7 MYA. The comparison of the sequence of the wheat A genome BAC clone with that of the T. urartu BAC clone provides the first insight into the microsynteny of the wheat A genome with that of T. urartu. Within 103 kb of orthologous intergenic space, 37 kb of new DNA has been inserted and 36 kb deleted leaving 49.7% of the region syntenic between the clones. The nucleotide substitution rate in the syntenic intergenic space has been 1.6 x 10(-8) nt(-1) year(-1), which is, respectively, 4 and 3 times as great as nucleotide substitution rates in the introns and the third codon positions of the juxtaposed gene. The RFLP is caused by a miniature inverted transposable element (MITE) insertion into intron 18 of the ABCT-A1 gene. Polymerase chain reaction primers were developed for the amplification of the MITE insertion site and its sequencing. The T. aestivum ABCT-A1a haplotype is identical to the haplotype of domesticated tetraploid wheat, and the ABCT-A1b haplotype is identical to that of wild tetraploid wheat. This finding shows for the first time that wild tetraploid wheat participated in the evolution of hexaploid wheat. A cline of the 2 haplotype frequencies exists across Euro-Asia in T. aestivum. It is suggested that T. aestivum in eastern Asia conserved the gene pool of the original T. aestivum more than wheat elsewhere.     

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

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

A novel molecular marker for the polyphenol oxidase gene located on chromosome 2B in common wheat

Polyphenol oxidase (PPO) is a major cause of time-dependent darkening and discoloration in Asian noodles and other wheat-based products. One of the best ways to reduce this undesirable darkening is to breed new wheat cultivars with low PPO activity using efficient and reliable markers. Based on the sequence of a PPO gene SSPPO-B1 (GenBank accession no. AB254804) located on chromosome 2B of common wheat, 26 pairs of primers were designed to detect polymorphisms between wheat cultivars with low and high PPO activity. F-8, one of these primer pairs, amplified double fragments (band ??a?? of approximately 400?bp and band ??b?? of approximately 600?bp) in the cultivars with low PPO activity, and a single fragment (only band a) in the cultivars with high PPO activity. The differences between the fragments a and b include five indels and several single nucleotide polymorphisms, which occurred in intron II of the PPO gene. F-8 can be used as a sequence-tagged site marker to discriminate between two alleles Ppo-B1a (GQ303713) and Ppo-B1b (AB254804). The screening of 284 accessions of the core collection of Chinese wheat germplasms using the marker F-8 showed that the double fragments were present in 188 accessions, and the single fragments were present in the remaining 96 accessions. Statistical analysis revealed that the cultivars with the double fragments had significantly lower mean PPO activity than those with the single fragments. We also screened the 284 accessions using two additional markers, PPO18 for Ppo-A1 on chromosome 2A and STS01 for Ppo-D1 on chromosome 2D. Results showed that the combination of markers F-8, PPO18, and STS01 could reliably predict PPO activity. These markers can be used in wheat breeding programs for low PPO activity selection to improve the quality of wheat-based products.     

QTL analysis of fertility-restoration against cytoplasmic male sterility in wheat

The cytoplasm of Triticum timopheevi causes cytoplasmic male sterility (CMS) in common wheat (T. aestivum) cv. 'Chinese Spring' (CS), and that of Aegilops kotschyi causes CMS in spelt wheat (T. spelta) var. duhamelianum (Sp). CS has fertility-restoring (Rf) genes against the latter cytoplasm and Sp has the ones against the former. To know the genetic system concerning to CMS, we crossed 66 F8 recombinant inbred lines (RILs) derived from a cross between CS and Sp as males to the alloplasmic lines of CS and Sp having the cytoplasms of T. timopheevi and Ae. kotschyi, respectively. The fertilities of respective F1 plants derived from the crosses were examined for QTL analysis. The major QTLs detected in both systems were located on the short arm of chromosome 1B. One minor QTL on chromosome 2B was also commonly detected in both of the systems, while other minor QTLs against T timopheevi cytoplasm were distributed on the chromosomes 2A, 4B, and 6A.     

Reassessing domestication events in the Near East: Einkorn and Triticum urartu

To reassess domestication events in the Near East, accessions of Triticum urartu from a well-described sampling were combined with a representative sample covering the Karacada? Einkorn wheat domestication. The observed DNA separation between the two wheat species accounts for the main differentiation, but geographic variation within T. urartu is evident and so is the domestication scenario among wild, feral, and domesticated Einkorn. In contrast to the clear DNA differences, it is difficult to separate living T. urartu from wild Einkorn based on morphology. With archaeobotanical material a distinction of carbonized remains of these two wheats is considered to be impossible. We reviewed the differences concerning morphology and maturity and combined these observations with information about archaeological sites in the Near East. In conclusion, the excavation sites in the middle Euphrates may contain T. urartu rather than Einkorn wheat and T. urartu may underlie the reported occurrence of the extinct 2-grained domesticated "Einkorn" wheat. The first Einkorn wheat domestication sensu stricto seems to have happened around the Karacada?, as reported earlier. The human dimension shown by the excavation of G?bekli Tepe can explain why domesticated phenotypes might have spread quickly.     

Microsatellite markers reveal chimeric origin of redesignated chromosome 4A of wheat from Triticum urartu and other species.

Although a new nomenclature has been adopted for wheat in which chromosome 4A (4AO) has been renamed 4B (4BN) and chromosome 4B (4BO) has been renamed 4A (4AN), their specific origin remains uncertain. The use of wheat microsatellite (WMS) markers mapped to chromosomes 4AN and 4BN in a set of polyploid wheats and diploid genome donors has unequivocally indicated that the entire short arm of 4AN, some part of 4ANL. and a segment of 4BNL were derived from Triticum urartu. The presence of a T. urartu-specific allele at locus gwm368 on 4BNL and of an Aegilops speltoides allele at locus gwm397 on 4ANL suggests the possibility of a reciprocal translocation between 4ANL and 4BNL. The subcentromeric and telomeric regions of 4ANL corresponding to heterochromatic C-bands were derived neither from diploid wheats nor from Ae. speltoides or Aegilops longissima.     

Targeted molecular mapping of a major wheat QTL for Fusarium head blight resistance using wheat ESTs and synteny with rice.

A major QTL for resistance to Fusarium head blight (FHB) in wheat, Qfhs.ndsu-3BS, has been identified and verified by several research groups. The objective of this study was to increase the marker density in this QTL region using STS (sequence-tagged site) markers developed from wheat expressed sequence tags (ESTs) near Qfhs.ndsu-3BS. Because wheat chromosome 3BS and rice chromosome 1S are syntenous, the sequences of P1-derived artificial chromosome (PAC) and (or) bacterial artificial chromosome (BAC) clones covering the sub-distal portion of rice chromosome 1S were used as queries for a BLASTn search to identify wheat ESTs most likely near Qfhs.ndsu-3BS. Sixty-eight out of 79 STS primer pairs designed from wheat ESTs amplified PCR products from the genomic DNA of Triticum aestivum 'Chinese Spring'. Twenty-eight STS markers were localized on chromosome 3BS by aneuploid analysis. Six out of the nine STS markers that could be mapped in the T. aestivum 'Sumai 3'/T. aestivum 'Stoa' population had higher R2 and LOD values for this QTL than the most significant marker reported previously. Therefore, leveraging genome sequence information available in rice for wheat genetics is an effective strategy to develop DNA markers for Qfhs.ndsu-3BS, and this strategy may have broad applications for targeted mapping of other traits in cereal crops.     

Quantification of genetic relationships among A genomes of wheats.

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

大麦1H特异性CAPs标记和ASA标记的创制

选取大麦1H染色体的STS标记MWG913特异性扩增小麦,把得到的片段进行克隆.用Taq酶切分类并测序,把得到的序列同大麦的序列进行比较.依据比较结果,选取对大麦特异的内切酶,用该酶来酶切大麦、小麦、黑麦、长穗偃麦草、中间偃麦草、簇毛麦的MWG913扩增产物,获得对大麦1H染色体特异的CAPs标记.同时,依据酶切位点碱基的差异设计引物对扩增的产物进行第二次扩增,得到该位点的一对染色体特异性ASA标记.     

<Emphasis Type="Italic">Pm37</Emphasis>, a new broadly effective powdery mildew resistance gene from <Emphasis Type="Italic">Triticum </Emphasis><Emphasis Type="Italic">timopheevii</Emphasis>

Powdery mildew is an important foliar disease in wheat, especially in areas with a cool or maritime climate. A dominant powdery mildew resistance gene transferred to the hexaploid germplasm line NC99BGTAG11 from T. timopheevii subsp. armeniacum was mapped distally on the long arm of chromosome 7A. Differential reactions were observed between the resistance gene in NC99BGTAG11 and the alleles of the Pm1 locus that is also located on chromosome arm 7AL. Observed segregation in F_2:3 lines from the cross NC99BGTAG11 × Axminster (Pm1a) demonstrate that germplasm line NC99BGTAG11 carries a novel powdery mildew resistance gene, which is now designated as Pm37. This new gene is highly effective against all powdery mildew isolates tested so far. Analyses of the population with molecular markers indicate that Pm37 is located 16 cM proximal to the Pm1 complex. Simple sequence repeat (SSR) markers Xgwm332 and Xwmc790 were located 0.5 cM proximal and distal, respectively, to Pm37. In order to identify new markers in the region, wheat expressed sequence tags (ESTs) located in the distal 10% of 7AL that were orthologous to sequences from chromosome 6 of rice were targeted. The two new EST-derived STS markers were located distal to Pm37 and one marker was closely linked to the Pm1a region. These new markers can be used in marker-assisted selection schemes to develop wheat cultivars with pyramids of powdery mildew resistance genes, including combinations of Pm37 in coupling linkage with alleles of the Pm1 locus.     

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

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

Single nucleotide polymorphism in wheat chromosome region harboring Fhb1 for Fusarium head blight resistance

Fusarium head blight (FHB) is a destructive disease that reduces wheat grain yield and quality. To date, the quantitative trait locus on 3BS (Fhb1) from Sumai 3 has shown the largest effect on FHB resistance. Single nucleotide polymorphism (SNP) is the most common form of genetic variation and is suitable for high-throughput marker-assisted selection (MAS). We analyzed SNPs derived from 23 wheat expressed sequence tags (ESTs) that previously mapped near Fhb1 on chromosome 3BS. Using 71 Ning 7840/Clark BC7F7 recombinant inbred lines and the single-base extension method, we mapped seven SNP markers between Xgwm533 and Xgwm493, flanking markers for Fhb1. Five of the SNPs explained 45–54% of the phenotypic variation for FHB resistance. Haplotype analysis of 63 wheat accessions from eight countries based on SNPs in EST sequences, simple sequence repeats, and sequence tagged sites in the Fhb1 region identified four major groups: (1) US-Clark, (2) Asian, (3) US-Ernie, and (4) Chinese Spring. The Asian group consisted of Chinese and Japanese accessions that carry Fhb1 and could be differentiated from other groups by marker Xsnp3BS-11. All Sumai 3-related accessions formed a subgroup within the Asian group and could be sorted out by Xsnp3BS-8. The SNP markers identified in this study should be useful for MAS of Fhb1 and fine mapping to facilitate cloning of the Fhb1 resistance gene.     

中国特有小麦Gli-1、Gli-2和Glu-1位点的遗传多样性(英文)

运用APAGE和SDS_PAGE方法 ,研究了 32份中国特有小麦Gli_1、Gli_2和Glu_1位点的遗传多样性。在 1 4份云南铁壳麦 (Triticumaestivumssp .yunnaneseKing)中 ,共出现 8种醇溶蛋白带型和 3种高分子谷蛋白带型。在 9份西藏半野生小麦 (T .aestivumssp .tibetanumShao )中 ,发现 9种醇溶蛋白带型和 4种高分子谷蛋白带型。在 9份新疆稻麦 (T .petropavlovskyiUdacz.etMigusch .)中 ,观察到 9种醇溶蛋白带型和 5种高分子谷蛋白带型 ,其中 1份新疆稻麦 (稻麦 2 )具有Glu_D1编码的新亚基 2 .1 1 0 .1。在这 3种中国特有小麦群体中 ,Gli_1位点分别检测出 1 0、1 4和1 1个等位基因 ;Gli_2位点各具有 1 1、1 4和 1 2个等位基因 ;Glu_1位点也分别出现 5、6和 8个等位基因。云南铁壳麦、西藏半野生小麦和新疆稻麦群体内的Nei’s遗传变异系数分别为 0 .3798、0 .56 2 5和 0 .56 93。这些结果说明 ,与云南铁壳麦相比 ,西藏半野生小麦和新疆稻麦群体内的遗传变异相对较大。     

Using Next Generation Sequencing for Multiplexed Trait-Linked Markers in Wheat

With the advent of next generation sequencing (NGS) technologies, single nucleotide polymorphisms (SNPs) have become the major type of marker for genotyping in many crops. However, the availability of SNP markers for important traits of bread wheat ( Triticum aestivum L.) that can be effectively used in marker-assisted selection (MAS) is still limited and SNP assays for MAS are usually uniplex. A shift from uniplex to multiplex assays will allow the simultaneous analysis of multiple markers and increase MAS efficiency. We designed 33 locus-specific markers from SNP or indel-based marker sequences that linked to 20 different quantitative trait loci (QTL) or genes of agronomic importance in wheat and analyzed the amplicon sequences using an Ion Torrent Proton Sequencer and a custom allele detection pipeline to determine the genotypes of 24 selected germplasm accessions. Among the 33 markers, 27 were successfully multiplexed and 23 had 100% SNP call rates. Results from analysis of "kompetitive allele-specific PCR" (KASP) and sequence tagged site (STS) markers developed from the same loci fully verified the genotype calls of 23 markers. The NGS-based multiplexed assay developed in this study is suitable for rapid and high-throughput screening of SNPs and some indel-based markers in wheat.     

一粒小麦抗白粉病和条锈病基因的分析

一粒小麦是普通小麦抗性改良的宝贵资源.本研究对24份一粒小麦分别进行了白粉病和条锈病混合菌种苗期接种鉴定,进一步分别用一套白粉病菌菌株(15个)对2份乌拉尔图小麦和条锈病菌小种(21个)对1份栽培一粒小麦进行接种鉴定,其中乌拉尔图小麦UR206能抵抗所有供试白粉菌菌株,UR204除对白粉菌菌株E11感病外,对其余菌株表现抗性;栽培一粒小麦MO205对不同条锈菌小种表现出不同的抗性反应,研究表明乌拉尔图小麦UR206、UR204和栽培一粒小麦MO205分别含有与已知抗白粉病和抗条锈病基因不同的新基因.对乌拉尔图小麦UR204、UR206和栽培一粒小麦MO205分别进行抗白粉和条锈病基因的遗传分析,结果表明乌拉尔图小麦UR204和UR206分别含有一对显性抗白粉病基因,栽培一粒小麦MO205含有两对独立遗传的显性抗条锈病基因.     

乌拉尔图小麦Viviparous-1基因的单倍型及其表达特性研究

该研究采用PCR和半定量RT-PCR方法,对乌拉尔图小麦（Triticum urartu）休眠基因Viviparous-1A（Vp-1A）的单倍型进行分析,并通过建立系统进化树,对Vp-1A基因在乌拉尔图小麦、普通小麦和其他近缘种间的系统发育关系进行分析。结果表明：（1）在20份乌拉尔图小麦中共发现4种新等位变异类型,分别命名为TuVp-1Abgi、TuVp-1Adfi、TuVp-1Aefi和TuVp-1Acgh。与普通小麦的TaVp-1Aa(AJ400712)基因相比,这4种单倍型主要是在第3内含子中有多个TTC不同重复,在第2和第5内含子中存在序列的缺失以及SNPs;（2）用ABA处理种子胚后,4种不同单倍型材料的mRNA表达水平发生变化,表明这4种单倍型对ABA敏感性不同;（3）乌拉尔图小麦中Vp-1A基因不同单倍型,在第2、第3和第5内含子中碱基序列的插入和缺失,影响了Vp-1A基因的表达特性及对ABA的敏感性,从而影响种子休眠特性;（4）鉴定和分析发现,乌拉尔图小麦TuVp-1Adfi单倍型可作为小麦穗发芽抗性资源。     

AFLP and STS tagging of a major QTL for Fusarium head blight resistance in wheat

Large-scale field screening for Fusarium head blight (FHB) resistance in wheat is difficult because environmental factors strongly influences the expression of resistance genes. Marker-assisted selection (MAS) may provide a powerful alternative. Conversion of amplified fragment length polymorphism (AFLP) markers into sequence-tagged site (STS) markers can generate breeder-friendly markers for MAS. In a previous study, one major quantitative trait locus (QTL) on chromosome 3BS was identified by using EcoRI-AFLP and a recombinant inbred population derived from the cross Ning 7840/Clark. Further mapping with PstI-AFLPs identified five markers that were significantly associated with the QTL. Three of them individually explained 38% to 50% of the phenotypic variation for FHB resistance. Two of them (pAGT/mCTG57, pACT/mCTG136) were linked to the QTL in coupling, and another (pAG/mCAA244) was linked to the QTL in repulsion. Successful conversion of one AFLP marker (pAG/mCAA244) yielded a co-dominant STS marker that explains about 50% of the phenotypic variation for FHB resistance in the population. The STS was validated in 14 other cultivars and is the first STS marker for a FHB resistance QTL converted from an AFLP marker.