Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The e...Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.展开更多
QTL Ici Mapping is freely available public software capable of building high-density linkage maps and mapping quantitative trait loci(QTL) in biparental populations. Eight functionalities are integrated in this softwa...QTL Ici Mapping is freely available public software capable of building high-density linkage maps and mapping quantitative trait loci(QTL) in biparental populations. Eight functionalities are integrated in this software package:(1) BIN: binning of redundant markers;(2) MAP: construction of linkage maps in biparental populations;(3) CMP: consensus map construction from multiple linkage maps sharing common markers;(4) SDL: mapping of segregation distortion loci;(5) BIP: mapping of additive, dominant, and digenic epistasis genes;(6) MET: QTL-by-environment interaction analysis;(7) CSL: mapping of additive and digenic epistasis genes with chromosome segment substitution lines; and(8) NAM: QTL mapping in NAM populations. Input files can be arranged in plain text, MS Excel 2003, or MS Excel 2007 formats. Output files have the same prefix name as the input but with different extensions. As examples, there are two output files in BIN, one for summarizing the identified bin groups and deleted markers in each bin, and the other for using the MAP functionality. Eight output files are generated by MAP, including summary of the completed linkage maps, Mendelian ratio test of individual markers, estimates of recombination frequencies, LOD scores, and genetic distances, and the input files for using the BIP, SDL,and MET functionalities. More than 30 output files are generated by BIP, including results at all scanning positions, identified QTL, permutation tests, and detection powers for up to six mapping methods. Three supplementary tools have also been developed to display completed genetic linkage maps, to estimate recombination frequency between two loci,and to perform analysis of variance for multi-environmental trials.展开更多
ζ （zeta）-carotene desaturase （ZDS） is a key enzyme for carotenoid biosynthesis, demonstrating high association with the yellow pigment （YP） content in wheat grain. Cloning ZDS gene and developing functional mar...ζ （zeta）-carotene desaturase （ZDS） is a key enzyme for carotenoid biosynthesis, demonstrating high association with the yellow pigment （YP） content in wheat grain. Cloning ZDS gene and developing functional markers are important for marker-assisted selection in wheat breeding. In the present study, the full-length DNA sequence of a ZDS gene on wheat chromosome 2A, designated TaZds-A1, was cloned, with 14 exons and 13 introns, and it has an open reading frame （ORF） of 1 707 bp, encoding 568 amino acid residues. A co-dominant functional marker, YP2A-1, was designed based on the polymorphisms of two alleles at the locus, TaZds-Ala and TaZds-Alb, yielding 183- and 179-bp fragments in TaZds-Ala and TaZds-Alb genotypes, respectively. A new QTL for YP content was detected on chromosome 2A, co-segregating with the functional marker YP2A-1 and TaZds-A1; it explained 11.3% of the phenotypic variance for YP content in a doubled haploid （DH） population from Zhongyou 9507/CA9632. Among 217 Chinese wheat cultivars and advanced lines, the average grain YP content of 126 cultivars with TaZds-Alb allele was 7.8% higher than that of 91 cultivars with TaZds- Ala allele.展开更多
Conventional plant breeding largely depends on phenotypic selection and breeder＇s experience, therefore the breeding efficiency is low and the predictions are inaccurate. Along with the fast development in molecular ...Conventional plant breeding largely depends on phenotypic selection and breeder＇s experience, therefore the breeding efficiency is low and the predictions are inaccurate. Along with the fast development in molecular biology and biotechnology, a large amount of biological data is available for genetic studies of important breeding traits in plants, which in turn allows the conduction of genotypic selection in the breeding process. However, gene information has not been effectively used in crop improvement because of the lack of appropriate tools. The simulation approach can utilize the vast and diverse genetic information, predict the cross performance, and compare different selection methods. Thus, the best performing crosses and effective breeding strategies can be identified. QuLine is a computer tool capable of defining a range, from simple to complex genetic models, and simulating breeding processes for developing final advanced lines. On the basis of the results from simulation experiments, breeders can optimize their breeding methodology and greatly improve the breeding efficiency. In this article, the underlying principles of simulation modeling in crop enhancement is initially introduced, following which several applications of QuLine are summarized, by comparing the different selection strategies, the precision parental selection, using known gene information, and the design approach in breeding. Breeding simulation allows the definition of complicated genetic models consisting of multiple alleles, pleiotropy, epistasis, and genes, by environment interaction, and provides a useful tool for breeders, to efficiently use the wide spectrum of genetic data and information available.展开更多
Wheat high-molecular-weight glutenin subunits(HMW-GS) determine dough elasticity and play an essential role in processing quality. HMW-GS are encoded by Glu-1 genes and controlled primarily at transcriptional level, i...Wheat high-molecular-weight glutenin subunits(HMW-GS) determine dough elasticity and play an essential role in processing quality. HMW-GS are encoded by Glu-1 genes and controlled primarily at transcriptional level, implemented through the interactions between cis-acting elements and trans-acting factors. However, transcriptional mechanism of Glu-1 genes remains elusive. Here we made a comprehensive analysis of cis-regulatory elements within 1-kb upstream of the Glu-1 start codon(-1000 to-1) and identified 30 conserved motifs. Based on motif distribution pattern, three conserved cis-regulatory modules(CCRMs), CCRM1(-300 to-101), CCRM2(-650 to-400), and CCRM3(-950 to-750), were defined, and their functions were characterized in wheat stable transgenic lines transformed with progressive 5′ deletion promoter::GUS fusion constructs. GUS staining, qP CR and enzyme activity assays indicated that CCRM2 and CCRM3 could enhance the expression level of Glu-1, whereas the 300-bp promoter(-300 to-1), spanning CCRM1 and core region(-100 to-1), was enough to ensure accurate Glu-1 initiation at 7 days after flowering(DAF) and shape its spatiotemporal expression pattern during seed development. Further transgenic assays demonstrated that CCRM1-2(-300 to-209) containing Complete HMW Enhancer(-246 to-209) was important for expression level but had no effect on expression specificity in the endosperm. In contrast, CCRM1-1(-208 to-101) was critical for both expression specificity and level of Glu-1. Our findings not only provide new insights to uncover Glu-1 transcription regulatory machinery but also lay foundations for modifying Glu-1 expression.展开更多
Vitamin B is essential for maintaining normal life activities in humans and animals who have to intake the microelement from the outside, especially from cereal products. In the present study 166 Chinese and foreign w...Vitamin B is essential for maintaining normal life activities in humans and animals who have to intake the microelement from the outside, especially from cereal products. In the present study 166 Chinese and foreign wheat cultivars planted in two environments were characterized for variation in vitamin B1 and B2 contents. A genome-wide association study(GWAS) using the wheat 90 K SNP assay identified 17 loci for vitamin B1 and 7 for vitamin B2 contents. Linear regression analysis showed a significantly positive correlation of the number of favorable alleles with vitamin B1 and B2 contents. Marker-trait associations(MTAs) at IWB43809(6AS, 0cM) and IWB69903(6AS, 13cM) were new and stable, and significantly associated with vitamin B1 content across two environments. The loci identified in this study and associated SNP markers could be used for improvement of vitamin B1 and B2 contents to obtain superior quality along with grain yield in wheat.展开更多
Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT ge...Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.展开更多
Spike number(SN) per unit area is one of the major determinants of grain yield in wheat. Development of high-throughput techniques to count SN from large populations enables rapid and cost-effective selection and faci...Spike number(SN) per unit area is one of the major determinants of grain yield in wheat. Development of high-throughput techniques to count SN from large populations enables rapid and cost-effective selection and facilitates genetic studies. In the present study, we used a deep-learning algorithm, i.e., Faster Region-based Convolutional Neural Networks(Faster R-CNN) on Red-Green-Blue(RGB) images to explore the possibility of image-based detection of SN and its application to identify the loci underlying SN. A doubled haploid population of 101 lines derived from the Yangmai 16/Zhongmai 895 cross was grown at two sites for SN phenotyping and genotyped using the high-density wheat 660 K SNP array.Analysis of manual spike number(MSN) in the field, image-based spike number(ISN), and verification of spike number(VSN) by Faster R-CNN revealed significant variation(P < 0.001) among genotypes, with high heritability ranged from 0.71 to 0.96. The coefficients of determination(R^(2)) between ISN and VSN was 0.83, which was higher than that between ISN and MSN(R^(2)= 0.51), and between VSN and MSN(R^(2)= 0.50). Results showed that VSN data can effectively predict wheat spikes with an average accuracy of 86.7% when validated using MSN data. Three QTL Qsnyz.caas-4 DS, Qsnyz.caas-7 DS, and QSnyz.caas-7 DL were identified based on MSN, ISN and VSN data, while QSnyz.caas-7 DS was detected in all the three data sets. These results indicate that using Faster R-CNN model for image-based identification of SN per unit area is a precise and rapid phenotyping method, which can be used for genetic studies of SN in wheat.展开更多
Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide. The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars. Zho...Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide. The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars. Zhongmai 175 is an elite winter wheat cultivar conferring resistance to a broad spectrum of Puccinia striiformis f. sp. tritici（Pst） races. To identify the resistance gene in the cultivar, genetic analysis was conducted using the parents, F1, F2 and F2：3 populations derived from the cross of Lunxuan 987/Zhongmai 175. Segregations in the F2 and F2：3 populations indicated a single dominant gene conferring resistance to stripe rust in Zhongmai 175, temporarily designated Yr ZM175. Bulked segregant analysis（BSA） with wheat i Select 90 K SNP array determined a preliminary location of Yr ZM175. Subsequently, Yr ZM175 was mapped on chromosome 2AS using simple sequence repeats（SSR）, expressed sequence tags（EST） and newly-developed kompetitive allele specific PCR（KASP） markers, being flanked by Xgwm636 and Xwmc382 at genetic distances of 4.9 and 8.1 c M, respectively. Comparison of reaction patterns of Yr ZM175 on 23 Pst races or isolates and pedigree analysis with other genes on chromosome 2AS suggested that it is likely to be a new gene for resistance to stripe rust. The resistance gene and linked molecular markers will be useful in wheat breeding targeting for the improvement of stripe rust resistance.展开更多
The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci （QTLs） for resistance to powdery...The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci （QTLs） for resistance to powdery mildew in a population of 249 F2：3 lines from Strampelli/Huixianhong. Adult plant powdery mildew tests were conducted over 2 yr in Beijing and 1 yr in Anyang and simple sequence repeat （SSR） markers were used for genotyping. QTLs Qpm.caas-3BS, Qpm.eaas-5BL. 1, and Qpm.caas-7DS were consistent across environments whereas, Qpm.caas-2BS. 1 found in two environments, explained 0.4-1.6, 5.5-6.9, 27.1-34.5, and 1.0-3.5% of the phenotypic variation respectively. Qpm.caas-7DS corresponded to the genomic location of Pm38/Lr34/Yr18. Qpm.caas-4BL was identified in Anyang 2010 and Beijing 2011, accounting for 1.9-3.5% of phenotypic variation. Qpm.caas-2BS. 1 and Qpm.caas-5BL. 1 contributed by Strampelli and Qpm.caas-3BS by Huixianhong, seem to be new QTL for powdery mildew resistance. Qpm.caas-4BL, Qpm.caas-5BL.3, and Qpm.caas-7DS contributed by Strampelli appeared to be in the same genomic regions as those mapped previously for stripe rust resistance in the same population, indicating that these loci conferred resistance to both stripe rust and powdery mildew. Strampelli could be a valuable genetic resource for improving durable resistance to both powdery mildew and stripe rust in wheat.展开更多
Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N u...Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding.In the present study,198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs)underpinning four seedling biomass traits and five root system architecture(RSA)related traits.The plants were grown under hydroponic conditions with control,low and high N treatments(Ca(NO_(3))_(2)·4H_(2)O at 0,0.05 and 2.0 mmol L^(-1),respectively).Significant variations among the treatments and genotypes,and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98)were observed.Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP)array identified 51 QTLs from the three N treatments.Twelve new QTLs detected on chromosomes 1 AL(1)in the control,1 DS(2)in high N treatment,4 BL(5)in low and high N treatments,and 7 DS(3)and 7 DL(1)in low N treatments,are first reported in influencing the root and biomass related traits for N uptake.The most stable QTLs(RRS.caas-4 DS)on chromosome 4 DS,which were related to ratio of root to shoot dry weight trait,was in close proximity of the Rht-D1 gene,and it showed high phenotypic effects,explaining 13.1%of the phenotypic variance.Twenty-eight QTLs were clustered in 12 genetic regions.SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP)assays that underpin important traits in root development,including root dry weight,root surface area and shoot dry weight.These QTLs,clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.展开更多
Starch is a crucial component determining the processing quality of wheat(Triticum aestivum L.)-based products. Wheat starch generally contains A-type and B-type starch granules, having different effects on starch pro...Starch is a crucial component determining the processing quality of wheat(Triticum aestivum L.)-based products. Wheat starch generally contains A-type and B-type starch granules, having different effects on starch properties and end-use qualities. In the present study, 240 recombinant inbred lines(RILs) derived from a PH82-2/Neixiang 188 cross were grown in Anyang, Henan, China, during three cropping seasons. A-type and B-type granule contents were determined using a laser diffraction particle size analyzer, defined as the percentage of total starch volume. A total of 195 SSR and STS markers were used to construct a genetic map. QTL analysis was performed by composite interval mapping. Three QTL for A-type starch granule content were mapped on chromosomes 1DL, 7BL and 4AL, explaining5.6%, 5.2% and 3.8% of the phenotypic variation, respectively. These results provide useful information for improving starch quality in common wheat.展开更多
The plant hormone abscisic acid （ABA） regulates many important physiological and developmental processes in plants. The objective of this study was to clone the ABA 8′-hydroxylase gene in common wheat. In the prese...The plant hormone abscisic acid （ABA） regulates many important physiological and developmental processes in plants. The objective of this study was to clone the ABA 8′-hydroxylase gene in common wheat. In the present study, we used the eDNA sequence of barley HvCYP707A1 gene （GenBank accession no. AB239299） as a probe for BLAST search against the common wheat （Triticum aestivum L.） EST database in GenBank. All wheat ESTs sharing high similarity with the reference gene were subjected to contig assembly. Primers were designed based on the constructed contigs to clone the wheat CYP707A1 gene, designated as TaCYP707A1. The genomic DNA sequence of TaCYPTO7A1 gene comprised five exons and four introns, with a size of 2225 bp. The corresponding cDNA sequence of TaCYP707A1 was 1737 bp, containing an open reading frame （ORF） of 1431 bp, a 42-bp 5′-untranslated region （UTR） and a 264-bp 3′UTR, with 94.9% of identical sequences to HvCYP707A1 gene （AB239299）. The neighbor joining tree indicated that the deduced amino acid sequences of TaCYP707A1 gene was highly similar to those of barley and rice. The TaCYP707A1 gene was located on chromosome 6BL using a set of Chinese Spring nullisomic-tetrasomic lines and ditelosomic line 6BS. These results will be of high importance in understanding of molecular mechanism of ABA catabolism.展开更多
Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance(APR)to powdery mildew in the field for ov...Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance(APR)to powdery mildew in the field for over 60 years. To dissect the genetic basis of APR to powdery mildew in this cultivar, a mapping population of 137 double haploid(DH) lines derived from Pingyuan 50/Mingxian 169 was evaluated in replicated field trials for two years in Beijing(2009–2010 and 2010–2011) and one year in Anyang(2009–2010). A total of 540 polymorphic SSR markers were genotyped on the entire population for construction of a linkage map and QTL analysis. Three QTL were mapped on chromosomes 2BS(QPm.caas-2BS.2), 3BS(QPm.caas-3BS),and 5AL(QPm.caas-5AL) with the resistance alleles contributed by Pingyuan 50 explaining 5.3%,10.2%, and 9.1% of the phenotypic variances, respectively, and one QTL on chromosome 3BL(QPm.caas-3BL) derived from Mingxian 169 accounting for 18.1% of the phenotypic variance.QPm.caas-3BS, QPm.caas-3BL, and QPm.caas-5AL appear to be new powdery mildew APR loci.QPm.caas-2BS.2 and QPm.caas-5AL are possibly pleiotropic or closely linked resistance loci to stripe rust resistance QTL. Pingyuan 50 could be a potential genetic resource to facilitate breeding for improved APR to both powdery mildew and stripe rust.展开更多
The German wheat cultivar Ibis has excellent adult plant resistance（APR） to stripe rust in Gansu,a hotspot for stripe rust in China.To elucidate the genetic basis of APR to stripe rust in Ibis,237 F3 lines derived f...The German wheat cultivar Ibis has excellent adult plant resistance（APR） to stripe rust in Gansu,a hotspot for stripe rust in China.To elucidate the genetic basis of APR to stripe rust in Ibis,237 F3 lines derived from the cross Ibis/Huixianhong were evaluated at Tianshui,Gansu,in the 2008-2009 and 2009-2010 cropping seasons,and at Chengdu,Sichuan Province,China,in the 2009-2010 cropping season.Inoculations were conducted with a mixture of several prevalent Pst races in both locations.Maximum disease severity（MDS） data showed a continuous distribution of response,indicating quantitative nature of resistance to stripe rust in Ibis.The broad-sense heritability of MDS was 0.75 based on the mean values averaged across three environments.A total of 723 simple sequence repeat（SSR） markers were used to map the QTL for APR by inclusive composite interval mapping（ICIM）.QTLs mapping to chromosomes 2BS and 6BS,designated as QYr.caas-2BS.1 and QYr.caas-6BS.1,respectively,explained 4.1-40.7% of the phenotypic variance in MDS across environments.The major effect QTL QYr.caas-2BS.1,flanked by Xgwm148 and Xwmc360,was consistently detected at all three sites as well as the averaged data over three environments,accounting for 40.7,24.2,5.2 and 29.9% of phenotypic variance,respectively.The molecular markers closely linked to this QTL have potential for use in marker-assisted selection and gene pyramiding to improve the durability of stripe rust resistance in wheat breeding.展开更多
Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultiva...Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects：（1） higher amount of ordered short-range structure and a lower relative crystallinity,（2） higher gelatinization onset（To） temperatures and enthalpies（ΔH）, and lower gelatinization conclusion temperatures（Tc）,（3） greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.展开更多
China and CIMMYT have collaborated on wheat improvement for over 40 years and significant progress has been achieved in five aspects in China.A standardized protocol for testing Chinese noodle quality has been establi...China and CIMMYT have collaborated on wheat improvement for over 40 years and significant progress has been achieved in five aspects in China.A standardized protocol for testing Chinese noodle quality has been established with three selection criteria, i.e.,gluten quality, starch viscosity and flour color are identified as being responsible for noodle quality.Genomic approaches have been used to develop and validate genespecific markers, leading to the establishment of a KASP platform, and seven cultivars have been released through application of molecular marker technology.Methodology for breeding adult-plant resistance to yellow rust, leaf rust and powdery mildew, based on the pleiotropic effect of minor genes has been established, resulting in release of six cultivars.More than 330 cultivars derived from CIMMYT germplasm have been released and are now grown over 9% of the Chinese wheat production area.Additionally, physiological approaches have been used to characterize yield potential and develop high-efficiency phenotyping platforms.CIMMYT has also provided valuable training for Chinese scientists.Development of climate-resilient cultivars with application of new technology will be the priority for future collaboration.展开更多
Stripe or yellow rust(YR)and leaf rust(LR)cause large losses in wheat production worldwide.Resistant cultivars curtail the levels of losses.The present study aimed to identify quantitative trait loci(QTL)for YR and LR...Stripe or yellow rust(YR)and leaf rust(LR)cause large losses in wheat production worldwide.Resistant cultivars curtail the levels of losses.The present study aimed to identify quantitative trait loci(QTL)for YR and LR resistance in 147 F2:6 recombinant inbred lines(RIL)derived from the cross Fuyu 3/Zhengzhou 5389.The RIL population and parents were genotyped with the Wheat55 K single nucleotide polymorphism(SNP)array and simple sequence repeat(SSR)markers.All materials were also phenotyped for YR severity at Mianyang in Sichuan province and Baoding in Hebei province in the 2015/2016,2016/2017,and 2017/2018 cropping seasons,and LR severity at Zhoukou in Henan province and at Baoding in 2017/2018.Eleven QTL for YR resistance and five for LR resistance were detected using inclusive composite interval mapping(Ici Mapping).Four of these QTL on chromosomes 1 BL,2 BS,3 AL,and 5 AL conferred resistance to both YR and LR.The QTL on 1 BL was Lr46/Yr29,and that on 7 BL might be Lr68.The QTL on chromosome 2 BS was detected at a similar position to previously detected loci.QYr.hebau-3 AL/QLr.hebau-3 AL,QYr.hebau-5 AL/QLr.hebau-5 AL,QYr.hebau-7 DL,QYr.hebau-4 BS,QYr.hebau-6 DL,and QYr.hebau-2 AS are likely to be new.An SSR marker for QYr.hebau-7 DL was developed and validated in a diverse wheat panel from China,suggesting effectiveness in different genetic backgrounds.These QTL with closely linked SNP and SSR markers could be useful for marker-assisted selection in wheat breeding programs targeting durable resistance to both diseases.展开更多
The identification of stable quantitative trait locus(QTL)for yield-related traits and tightly linked molecular markers is important for improving wheat grain yield.In the present study,six yield-related traits in a r...The identification of stable quantitative trait locus(QTL)for yield-related traits and tightly linked molecular markers is important for improving wheat grain yield.In the present study,six yield-related traits in a recombinant inbred line(RIL)population derived from the Zhongmai 578/Jimai 22 cross were phenotyped in five environments.The parents and 262 RILs were genotyped using the wheat 50K single nucleotide polymorphism(SNP)array.A high-density genetic map was constructed with 1501 non-redundant bin markers,spanning 2384.95 cM.Fifty-three QTLs for six yield-related traits were mapped on chromosomes 1D(2),2A(9),2B(6),2D,3A(2),3B(2),4A(5),4D,5B(8),5D(2),7A(7),7B(3)and 7D(5),which explained 2.7-25.5%of the phenotypic variances.Among the 53 QTLs,23 were detected in at least three environments,including seven for thousand-kernel weight(TKW),four for kernel length(KL),four for kernel width(KW),three for average grain filling rate(GFR),one for kernel number per spike(KNS)and four for plant height(PH).The stable QTLs QKl.caas-2A.1,QKl.caas-7D,QKw.caas-7D,QGfr.caas-2B.1,QGfr.caas-4A,QGfr.caas-7A and QPh.caas-2A.1 are likely to be new loci.Six QTL-rich regions on 2A,2B,4A,5B,7A and 7D,showed pleiotropic effects on various yield traits.TaSus2-2B and WAPO-A1 are potential candidate genes for the pleiotropic regions on 2B and 7A,respectively.The pleiotropic QTL on 7D for TKW,KL,KW and PH was verified in a natural population.The results of this study enrich our knowledge of the genetic basis underlying yield-related traits and provide molecular markers for high-yield wheat breeding.展开更多
Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield.Here,we identified eight stable quantitative trait loci(QTL)for ...Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield.Here,we identified eight stable quantitative trait loci(QTL)for yield component traits,including five loci for thousand grain weight(TGW)and three for grain number per spike(GNS)in a recombinant inbred line population derived from cross Yangxiaomai/Zhongyou 9507 across four environments.Since grain size is a major determinant of grain weight,we also mapped QTL for grain length(GL)and grain width(GW).QTGW.caas-2D,QTGW.caas-3B,QTGW.caas-5A and QTGW.caas-7A.2 for TGW co-located with those for grain size.QTGW.caas-2D also had a consistent genetic position with QGNS.caas-2D,suggesting that the pleiotropic locus is a modulator of trade-off effect between TGW and GNS.Sequencing and linkage mapping showed that TaGL3-5A and WAPO-A1 were candidate genes of QTGW.caas-5A and QTGW.caas-7A.2,respectively.We developed Kompetitive allele specific PCR(KASP)markers linked with the stable QTL for yield component traits and validated their genetic effects in a diverse panel of wheat cultivars from the Huang-Huai River Valley region.KASP-based genotyping analysis further revealed that the superior alleles of all stable QTL for TGW but not GNS were subject to positive selection,indicating that yield improvement in the region largely depends on increased TGW.Comparative analyses with previous studies showed that most of the QTL could be detected in different genetic backgrounds,and QTGW.caas-7A.1 is likely a new QTL.These findings provide not only valuable genetic information for yield improvement but also useful tools for marker-assisted selection.展开更多
基金This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA24010104-2).
文摘Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.
基金supported by the Natural Science Foundation of China (31271798)the Generation Challenge Program (GCP)HarvestP lus Challenge Program of CGIAR
文摘QTL Ici Mapping is freely available public software capable of building high-density linkage maps and mapping quantitative trait loci(QTL) in biparental populations. Eight functionalities are integrated in this software package:(1) BIN: binning of redundant markers;(2) MAP: construction of linkage maps in biparental populations;(3) CMP: consensus map construction from multiple linkage maps sharing common markers;(4) SDL: mapping of segregation distortion loci;(5) BIP: mapping of additive, dominant, and digenic epistasis genes;(6) MET: QTL-by-environment interaction analysis;(7) CSL: mapping of additive and digenic epistasis genes with chromosome segment substitution lines; and(8) NAM: QTL mapping in NAM populations. Input files can be arranged in plain text, MS Excel 2003, or MS Excel 2007 formats. Output files have the same prefix name as the input but with different extensions. As examples, there are two output files in BIN, one for summarizing the identified bin groups and deleted markers in each bin, and the other for using the MAP functionality. Eight output files are generated by MAP, including summary of the completed linkage maps, Mendelian ratio test of individual markers, estimates of recombination frequencies, LOD scores, and genetic distances, and the input files for using the BIP, SDL,and MET functionalities. More than 30 output files are generated by BIP, including results at all scanning positions, identified QTL, permutation tests, and detection powers for up to six mapping methods. Three supplementary tools have also been developed to display completed genetic linkage maps, to estimate recombination frequency between two loci,and to perform analysis of variance for multi-environmental trials.
基金supported by the National Natural Science Foundation of China (30871522 and 30830072)the National Basic Research Program of China(2009CB118300)an Earmarked Fund for the Modern Agro-Industry Technology Research System, China (CARS-3-1-3)
文摘ζ （zeta）-carotene desaturase （ZDS） is a key enzyme for carotenoid biosynthesis, demonstrating high association with the yellow pigment （YP） content in wheat grain. Cloning ZDS gene and developing functional markers are important for marker-assisted selection in wheat breeding. In the present study, the full-length DNA sequence of a ZDS gene on wheat chromosome 2A, designated TaZds-A1, was cloned, with 14 exons and 13 introns, and it has an open reading frame （ORF） of 1 707 bp, encoding 568 amino acid residues. A co-dominant functional marker, YP2A-1, was designed based on the polymorphisms of two alleles at the locus, TaZds-Ala and TaZds-Alb, yielding 183- and 179-bp fragments in TaZds-Ala and TaZds-Alb genotypes, respectively. A new QTL for YP content was detected on chromosome 2A, co-segregating with the functional marker YP2A-1 and TaZds-A1; it explained 11.3% of the phenotypic variance for YP content in a doubled haploid （DH） population from Zhongyou 9507/CA9632. Among 217 Chinese wheat cultivars and advanced lines, the average grain YP content of 126 cultivars with TaZds-Alb allele was 7.8% higher than that of 91 cultivars with TaZds- Ala allele.
文摘Conventional plant breeding largely depends on phenotypic selection and breeder＇s experience, therefore the breeding efficiency is low and the predictions are inaccurate. Along with the fast development in molecular biology and biotechnology, a large amount of biological data is available for genetic studies of important breeding traits in plants, which in turn allows the conduction of genotypic selection in the breeding process. However, gene information has not been effectively used in crop improvement because of the lack of appropriate tools. The simulation approach can utilize the vast and diverse genetic information, predict the cross performance, and compare different selection methods. Thus, the best performing crosses and effective breeding strategies can be identified. QuLine is a computer tool capable of defining a range, from simple to complex genetic models, and simulating breeding processes for developing final advanced lines. On the basis of the results from simulation experiments, breeders can optimize their breeding methodology and greatly improve the breeding efficiency. In this article, the underlying principles of simulation modeling in crop enhancement is initially introduced, following which several applications of QuLine are summarized, by comparing the different selection strategies, the precision parental selection, using known gene information, and the design approach in breeding. Breeding simulation allows the definition of complicated genetic models consisting of multiple alleles, pleiotropy, epistasis, and genes, by environment interaction, and provides a useful tool for breeders, to efficiently use the wide spectrum of genetic data and information available.
基金funded by the National Key Research and Development Program of China (2016YFD0100500)the National Natural Science Foundation of China (31571663, 31371623)Genetically Modified Organisms Breeding Major Project (2016ZX08009003-004)
文摘Wheat high-molecular-weight glutenin subunits(HMW-GS) determine dough elasticity and play an essential role in processing quality. HMW-GS are encoded by Glu-1 genes and controlled primarily at transcriptional level, implemented through the interactions between cis-acting elements and trans-acting factors. However, transcriptional mechanism of Glu-1 genes remains elusive. Here we made a comprehensive analysis of cis-regulatory elements within 1-kb upstream of the Glu-1 start codon(-1000 to-1) and identified 30 conserved motifs. Based on motif distribution pattern, three conserved cis-regulatory modules(CCRMs), CCRM1(-300 to-101), CCRM2(-650 to-400), and CCRM3(-950 to-750), were defined, and their functions were characterized in wheat stable transgenic lines transformed with progressive 5′ deletion promoter::GUS fusion constructs. GUS staining, qP CR and enzyme activity assays indicated that CCRM2 and CCRM3 could enhance the expression level of Glu-1, whereas the 300-bp promoter(-300 to-1), spanning CCRM1 and core region(-100 to-1), was enough to ensure accurate Glu-1 initiation at 7 days after flowering(DAF) and shape its spatiotemporal expression pattern during seed development. Further transgenic assays demonstrated that CCRM1-2(-300 to-209) containing Complete HMW Enhancer(-246 to-209) was important for expression level but had no effect on expression specificity in the endosperm. In contrast, CCRM1-1(-208 to-101) was critical for both expression specificity and level of Glu-1. Our findings not only provide new insights to uncover Glu-1 transcription regulatory machinery but also lay foundations for modifying Glu-1 expression.
基金supported by National Key Research and Development Programs of China(2016YFD0101802,2016YFE0108600,2014CB1381050)Gene Transformation Projects(2016ZX08002003–003)Core Research Budget of the Non–profit Governmental Research Institutions(Y2016XT06)
文摘Vitamin B is essential for maintaining normal life activities in humans and animals who have to intake the microelement from the outside, especially from cereal products. In the present study 166 Chinese and foreign wheat cultivars planted in two environments were characterized for variation in vitamin B1 and B2 contents. A genome-wide association study(GWAS) using the wheat 90 K SNP assay identified 17 loci for vitamin B1 and 7 for vitamin B2 contents. Linear regression analysis showed a significantly positive correlation of the number of favorable alleles with vitamin B1 and B2 contents. Marker-trait associations(MTAs) at IWB43809(6AS, 0cM) and IWB69903(6AS, 13cM) were new and stable, and significantly associated with vitamin B1 content across two environments. The loci identified in this study and associated SNP markers could be used for improvement of vitamin B1 and B2 contents to obtain superior quality along with grain yield in wheat.
基金supported by the National Natural Science Foundation of China(31161140346 and 31461143021)the Beijing Municipal Science and Technology Project,China(D151100004415003)+1 种基金the National Key Technology R&D Program of China(2014BAD01B05)the earmarked fund for China Agriculture Research System(CARS-3-1-3)
文摘Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.
基金funded by the National Natural Science Foundation of China (31671691, 3171101265, and 31961143007)the National Key Research and Development Program of China(2016YFD0101804)the Fundamental Research Funds for the Institute Planning in Chinese Academy of Agricultural Sciences(S2018QY02)。
文摘Spike number(SN) per unit area is one of the major determinants of grain yield in wheat. Development of high-throughput techniques to count SN from large populations enables rapid and cost-effective selection and facilitates genetic studies. In the present study, we used a deep-learning algorithm, i.e., Faster Region-based Convolutional Neural Networks(Faster R-CNN) on Red-Green-Blue(RGB) images to explore the possibility of image-based detection of SN and its application to identify the loci underlying SN. A doubled haploid population of 101 lines derived from the Yangmai 16/Zhongmai 895 cross was grown at two sites for SN phenotyping and genotyped using the high-density wheat 660 K SNP array.Analysis of manual spike number(MSN) in the field, image-based spike number(ISN), and verification of spike number(VSN) by Faster R-CNN revealed significant variation(P < 0.001) among genotypes, with high heritability ranged from 0.71 to 0.96. The coefficients of determination(R^(2)) between ISN and VSN was 0.83, which was higher than that between ISN and MSN(R^(2)= 0.51), and between VSN and MSN(R^(2)= 0.50). Results showed that VSN data can effectively predict wheat spikes with an average accuracy of 86.7% when validated using MSN data. Three QTL Qsnyz.caas-4 DS, Qsnyz.caas-7 DS, and QSnyz.caas-7 DL were identified based on MSN, ISN and VSN data, while QSnyz.caas-7 DS was detected in all the three data sets. These results indicate that using Faster R-CNN model for image-based identification of SN per unit area is a precise and rapid phenotyping method, which can be used for genetic studies of SN in wheat.
基金supported by the National Basic Research Program of China(2013CB127700)the National Natural Science Foundation of China(31261140370)+1 种基金the International Collaboration Projects from the Ministry of Science and Technology,China(2013DFG30530)the China Agriculture Research System(CARS-3-1-3)
文摘Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide. The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars. Zhongmai 175 is an elite winter wheat cultivar conferring resistance to a broad spectrum of Puccinia striiformis f. sp. tritici（Pst） races. To identify the resistance gene in the cultivar, genetic analysis was conducted using the parents, F1, F2 and F2：3 populations derived from the cross of Lunxuan 987/Zhongmai 175. Segregations in the F2 and F2：3 populations indicated a single dominant gene conferring resistance to stripe rust in Zhongmai 175, temporarily designated Yr ZM175. Bulked segregant analysis（BSA） with wheat i Select 90 K SNP array determined a preliminary location of Yr ZM175. Subsequently, Yr ZM175 was mapped on chromosome 2AS using simple sequence repeats（SSR）, expressed sequence tags（EST） and newly-developed kompetitive allele specific PCR（KASP） markers, being flanked by Xgwm636 and Xwmc382 at genetic distances of 4.9 and 8.1 c M, respectively. Comparison of reaction patterns of Yr ZM175 on 23 Pst races or isolates and pedigree analysis with other genes on chromosome 2AS suggested that it is likely to be a new gene for resistance to stripe rust. The resistance gene and linked molecular markers will be useful in wheat breeding targeting for the improvement of stripe rust resistance.
基金supported by the National Basic Research Program of China (2013CB127700)the International Collaboration Project,Ministry of Agriculture,China (2011-G3)+1 种基金the National Natural Science Foundation of China (31261140370)the China Agriculture Research System (CARS-3-1-3)
文摘The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci （QTLs） for resistance to powdery mildew in a population of 249 F2：3 lines from Strampelli/Huixianhong. Adult plant powdery mildew tests were conducted over 2 yr in Beijing and 1 yr in Anyang and simple sequence repeat （SSR） markers were used for genotyping. QTLs Qpm.caas-3BS, Qpm.eaas-5BL. 1, and Qpm.caas-7DS were consistent across environments whereas, Qpm.caas-2BS. 1 found in two environments, explained 0.4-1.6, 5.5-6.9, 27.1-34.5, and 1.0-3.5% of the phenotypic variation respectively. Qpm.caas-7DS corresponded to the genomic location of Pm38/Lr34/Yr18. Qpm.caas-4BL was identified in Anyang 2010 and Beijing 2011, accounting for 1.9-3.5% of phenotypic variation. Qpm.caas-2BS. 1 and Qpm.caas-5BL. 1 contributed by Strampelli and Qpm.caas-3BS by Huixianhong, seem to be new QTL for powdery mildew resistance. Qpm.caas-4BL, Qpm.caas-5BL.3, and Qpm.caas-7DS contributed by Strampelli appeared to be in the same genomic regions as those mapped previously for stripe rust resistance in the same population, indicating that these loci conferred resistance to both stripe rust and powdery mildew. Strampelli could be a valuable genetic resource for improving durable resistance to both powdery mildew and stripe rust in wheat.
基金the National Key R&D Program of China(2016YFD0101804-6)the National Natural Science Foundation of China(31671691)the International Science&Technology Cooperation Program of China(2016YFE0108600)。
文摘Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement.Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding.In the present study,198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs)underpinning four seedling biomass traits and five root system architecture(RSA)related traits.The plants were grown under hydroponic conditions with control,low and high N treatments(Ca(NO_(3))_(2)·4H_(2)O at 0,0.05 and 2.0 mmol L^(-1),respectively).Significant variations among the treatments and genotypes,and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98)were observed.Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP)array identified 51 QTLs from the three N treatments.Twelve new QTLs detected on chromosomes 1 AL(1)in the control,1 DS(2)in high N treatment,4 BL(5)in low and high N treatments,and 7 DS(3)and 7 DL(1)in low N treatments,are first reported in influencing the root and biomass related traits for N uptake.The most stable QTLs(RRS.caas-4 DS)on chromosome 4 DS,which were related to ratio of root to shoot dry weight trait,was in close proximity of the Rht-D1 gene,and it showed high phenotypic effects,explaining 13.1%of the phenotypic variance.Twenty-eight QTLs were clustered in 12 genetic regions.SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP)assays that underpin important traits in root development,including root dry weight,root surface area and shoot dry weight.These QTLs,clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.
基金supported by the National Natural Science Foundation of China (31171547)China Agriculture Research System (CARS-3-1-3).
文摘Starch is a crucial component determining the processing quality of wheat(Triticum aestivum L.)-based products. Wheat starch generally contains A-type and B-type starch granules, having different effects on starch properties and end-use qualities. In the present study, 240 recombinant inbred lines(RILs) derived from a PH82-2/Neixiang 188 cross were grown in Anyang, Henan, China, during three cropping seasons. A-type and B-type granule contents were determined using a laser diffraction particle size analyzer, defined as the percentage of total starch volume. A total of 195 SSR and STS markers were used to construct a genetic map. QTL analysis was performed by composite interval mapping. Three QTL for A-type starch granule content were mapped on chromosomes 1DL, 7BL and 4AL, explaining5.6%, 5.2% and 3.8% of the phenotypic variation, respectively. These results provide useful information for improving starch quality in common wheat.
基金supported by the National Basic Research Program of China(2009CB118300)the National 863 Program of China(2006AA10Z1A7and2006AA100102)the International Collaboration Project from the Ministry of Agriculture of China(2006-G2)
文摘The plant hormone abscisic acid （ABA） regulates many important physiological and developmental processes in plants. The objective of this study was to clone the ABA 8′-hydroxylase gene in common wheat. In the present study, we used the eDNA sequence of barley HvCYP707A1 gene （GenBank accession no. AB239299） as a probe for BLAST search against the common wheat （Triticum aestivum L.） EST database in GenBank. All wheat ESTs sharing high similarity with the reference gene were subjected to contig assembly. Primers were designed based on the constructed contigs to clone the wheat CYP707A1 gene, designated as TaCYP707A1. The genomic DNA sequence of TaCYPTO7A1 gene comprised five exons and four introns, with a size of 2225 bp. The corresponding cDNA sequence of TaCYP707A1 was 1737 bp, containing an open reading frame （ORF） of 1431 bp, a 42-bp 5′-untranslated region （UTR） and a 264-bp 3′UTR, with 94.9% of identical sequences to HvCYP707A1 gene （AB239299）. The neighbor joining tree indicated that the deduced amino acid sequences of TaCYP707A1 gene was highly similar to those of barley and rice. The TaCYP707A1 gene was located on chromosome 6BL using a set of Chinese Spring nullisomic-tetrasomic lines and ditelosomic line 6BS. These results will be of high importance in understanding of molecular mechanism of ABA catabolism.
基金supported by the National Key Basic Research Program of China(2013CB127700)National Natural Science Foundation of China(31261140370 and 31260319)+4 种基金International Collaboration Projects from the Chinese Ministry of Science and Technology(2011DFG32990)the Ministry of Agriculture(2011-G3)the National High Technology ResearchProgram of China(2012AA101105)the China Agriculture Research System(CARS-3-1-3)full scholarship support for Ph.D. studies from the China Scholarship Council(2008GXZA85)
文摘Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the major wheat diseases worldwide. The Chinese wheat landrace Pingyuan 50 has shown adult-plant resistance(APR)to powdery mildew in the field for over 60 years. To dissect the genetic basis of APR to powdery mildew in this cultivar, a mapping population of 137 double haploid(DH) lines derived from Pingyuan 50/Mingxian 169 was evaluated in replicated field trials for two years in Beijing(2009–2010 and 2010–2011) and one year in Anyang(2009–2010). A total of 540 polymorphic SSR markers were genotyped on the entire population for construction of a linkage map and QTL analysis. Three QTL were mapped on chromosomes 2BS(QPm.caas-2BS.2), 3BS(QPm.caas-3BS),and 5AL(QPm.caas-5AL) with the resistance alleles contributed by Pingyuan 50 explaining 5.3%,10.2%, and 9.1% of the phenotypic variances, respectively, and one QTL on chromosome 3BL(QPm.caas-3BL) derived from Mingxian 169 accounting for 18.1% of the phenotypic variance.QPm.caas-3BS, QPm.caas-3BL, and QPm.caas-5AL appear to be new powdery mildew APR loci.QPm.caas-2BS.2 and QPm.caas-5AL are possibly pleiotropic or closely linked resistance loci to stripe rust resistance QTL. Pingyuan 50 could be a potential genetic resource to facilitate breeding for improved APR to both powdery mildew and stripe rust.
基金supported by the National Natural Science Foundation of China(30821140351)China Agriculture Research System(CARS-3-1-3)
文摘The German wheat cultivar Ibis has excellent adult plant resistance（APR） to stripe rust in Gansu,a hotspot for stripe rust in China.To elucidate the genetic basis of APR to stripe rust in Ibis,237 F3 lines derived from the cross Ibis/Huixianhong were evaluated at Tianshui,Gansu,in the 2008-2009 and 2009-2010 cropping seasons,and at Chengdu,Sichuan Province,China,in the 2009-2010 cropping season.Inoculations were conducted with a mixture of several prevalent Pst races in both locations.Maximum disease severity（MDS） data showed a continuous distribution of response,indicating quantitative nature of resistance to stripe rust in Ibis.The broad-sense heritability of MDS was 0.75 based on the mean values averaged across three environments.A total of 723 simple sequence repeat（SSR） markers were used to map the QTL for APR by inclusive composite interval mapping（ICIM）.QTLs mapping to chromosomes 2BS and 6BS,designated as QYr.caas-2BS.1 and QYr.caas-6BS.1,respectively,explained 4.1-40.7% of the phenotypic variance in MDS across environments.The major effect QTL QYr.caas-2BS.1,flanked by Xgwm148 and Xwmc360,was consistently detected at all three sites as well as the averaged data over three environments,accounting for 40.7,24.2,5.2 and 29.9% of phenotypic variance,respectively.The molecular markers closely linked to this QTL have potential for use in marker-assisted selection and gene pyramiding to improve the durability of stripe rust resistance in wheat breeding.
基金financial support from the National Natural Science Foundation of China (31171547,31401651)
文摘Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects：（1） higher amount of ordered short-range structure and a lower relative crystallinity,（2） higher gelatinization onset（To） temperatures and enthalpies（ΔH）, and lower gelatinization conclusion temperatures（Tc）,（3） greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.
基金funded by the National Natural Science Foundation of China (31461143021, 31761143006)
文摘China and CIMMYT have collaborated on wheat improvement for over 40 years and significant progress has been achieved in five aspects in China.A standardized protocol for testing Chinese noodle quality has been established with three selection criteria, i.e.,gluten quality, starch viscosity and flour color are identified as being responsible for noodle quality.Genomic approaches have been used to develop and validate genespecific markers, leading to the establishment of a KASP platform, and seven cultivars have been released through application of molecular marker technology.Methodology for breeding adult-plant resistance to yellow rust, leaf rust and powdery mildew, based on the pleiotropic effect of minor genes has been established, resulting in release of six cultivars.More than 330 cultivars derived from CIMMYT germplasm have been released and are now grown over 9% of the Chinese wheat production area.Additionally, physiological approaches have been used to characterize yield potential and develop high-efficiency phenotyping platforms.CIMMYT has also provided valuable training for Chinese scientists.Development of climate-resilient cultivars with application of new technology will be the priority for future collaboration.
基金supported by the National Natural Science Foundation of China(31361140367,31571662,31601299)。
文摘Stripe or yellow rust(YR)and leaf rust(LR)cause large losses in wheat production worldwide.Resistant cultivars curtail the levels of losses.The present study aimed to identify quantitative trait loci(QTL)for YR and LR resistance in 147 F2:6 recombinant inbred lines(RIL)derived from the cross Fuyu 3/Zhengzhou 5389.The RIL population and parents were genotyped with the Wheat55 K single nucleotide polymorphism(SNP)array and simple sequence repeat(SSR)markers.All materials were also phenotyped for YR severity at Mianyang in Sichuan province and Baoding in Hebei province in the 2015/2016,2016/2017,and 2017/2018 cropping seasons,and LR severity at Zhoukou in Henan province and at Baoding in 2017/2018.Eleven QTL for YR resistance and five for LR resistance were detected using inclusive composite interval mapping(Ici Mapping).Four of these QTL on chromosomes 1 BL,2 BS,3 AL,and 5 AL conferred resistance to both YR and LR.The QTL on 1 BL was Lr46/Yr29,and that on 7 BL might be Lr68.The QTL on chromosome 2 BS was detected at a similar position to previously detected loci.QYr.hebau-3 AL/QLr.hebau-3 AL,QYr.hebau-5 AL/QLr.hebau-5 AL,QYr.hebau-7 DL,QYr.hebau-4 BS,QYr.hebau-6 DL,and QYr.hebau-2 AS are likely to be new.An SSR marker for QYr.hebau-7 DL was developed and validated in a diverse wheat panel from China,suggesting effectiveness in different genetic backgrounds.These QTL with closely linked SNP and SSR markers could be useful for marker-assisted selection in wheat breeding programs targeting durable resistance to both diseases.
基金This work was funded by the Core Research Budget of the Non-profit Governmental Research Institutions,Institute of Crop Sciences,CAAS(S2022ZD04)the Agricultural Science and Technology Innovation Program,CAAS(CAAS-ZDRW202002)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST)(2020QNRC001).
文摘The identification of stable quantitative trait locus(QTL)for yield-related traits and tightly linked molecular markers is important for improving wheat grain yield.In the present study,six yield-related traits in a recombinant inbred line(RIL)population derived from the Zhongmai 578/Jimai 22 cross were phenotyped in five environments.The parents and 262 RILs were genotyped using the wheat 50K single nucleotide polymorphism(SNP)array.A high-density genetic map was constructed with 1501 non-redundant bin markers,spanning 2384.95 cM.Fifty-three QTLs for six yield-related traits were mapped on chromosomes 1D(2),2A(9),2B(6),2D,3A(2),3B(2),4A(5),4D,5B(8),5D(2),7A(7),7B(3)and 7D(5),which explained 2.7-25.5%of the phenotypic variances.Among the 53 QTLs,23 were detected in at least three environments,including seven for thousand-kernel weight(TKW),four for kernel length(KL),four for kernel width(KW),three for average grain filling rate(GFR),one for kernel number per spike(KNS)and four for plant height(PH).The stable QTLs QKl.caas-2A.1,QKl.caas-7D,QKw.caas-7D,QGfr.caas-2B.1,QGfr.caas-4A,QGfr.caas-7A and QPh.caas-2A.1 are likely to be new loci.Six QTL-rich regions on 2A,2B,4A,5B,7A and 7D,showed pleiotropic effects on various yield traits.TaSus2-2B and WAPO-A1 are potential candidate genes for the pleiotropic regions on 2B and 7A,respectively.The pleiotropic QTL on 7D for TKW,KL,KW and PH was verified in a natural population.The results of this study enrich our knowledge of the genetic basis underlying yield-related traits and provide molecular markers for high-yield wheat breeding.
基金funded by the National Natural Science Foundation of China(91935304 and 32272182)Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences.
文摘Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield.Here,we identified eight stable quantitative trait loci(QTL)for yield component traits,including five loci for thousand grain weight(TGW)and three for grain number per spike(GNS)in a recombinant inbred line population derived from cross Yangxiaomai/Zhongyou 9507 across four environments.Since grain size is a major determinant of grain weight,we also mapped QTL for grain length(GL)and grain width(GW).QTGW.caas-2D,QTGW.caas-3B,QTGW.caas-5A and QTGW.caas-7A.2 for TGW co-located with those for grain size.QTGW.caas-2D also had a consistent genetic position with QGNS.caas-2D,suggesting that the pleiotropic locus is a modulator of trade-off effect between TGW and GNS.Sequencing and linkage mapping showed that TaGL3-5A and WAPO-A1 were candidate genes of QTGW.caas-5A and QTGW.caas-7A.2,respectively.We developed Kompetitive allele specific PCR(KASP)markers linked with the stable QTL for yield component traits and validated their genetic effects in a diverse panel of wheat cultivars from the Huang-Huai River Valley region.KASP-based genotyping analysis further revealed that the superior alleles of all stable QTL for TGW but not GNS were subject to positive selection,indicating that yield improvement in the region largely depends on increased TGW.Comparative analyses with previous studies showed that most of the QTL could be detected in different genetic backgrounds,and QTGW.caas-7A.1 is likely a new QTL.These findings provide not only valuable genetic information for yield improvement but also useful tools for marker-assisted selection.
