QTL Mapping And Genetic Effect Analysis Of Adult-Plant Resistance To Stripe Rust In Heyne×Lakin Population

Stripe rust caused by Puccinia striiformis f.sp.tritici(Pst)is one of the most damaging disease in wheat production,especially in the northwest region of china.Breeding varities with sripe rust resisitance is an effective mean for sripe rust resisitance.Furthermore,adult-plant resistance(APR)genes play a great role in preventing stripe rust and could be used in wheat breeding.In this study,145 F6 generation recombinant inbred lines were selected from Heyne ×Lakin hybridization,and a high density genetic linkage map was constructed for this RIL population.On this basis,we have identified a series of adult-plant resistance(APR)quantitative trait locus(QTLs)on chromosomes and screened several relevant molecular markers which closely linked to the QTLs.The objective of this study is finding useful molecular markers for marker-assisted selection of wheat with adult-plant resistance and laying foundation for further fine mapping and gene cloning of wheat adult-plant resistance(APR)genes.The concusion of this study:1.The stripe rust race CYR31 and CYR32 was used to infect the RIL population and their parents to identify their sensitive to stripe rust.The results showed that: Both two parents were susceptible to stripe rust(IT:7-9)at seedling stage.However,at adult stage,the parent Heyne showed resistance to stripe rust(IT: 2-4,MDS: 10-30),but the parent Lakin was still susceptible to stripe rust(IT:7-9,MDS: 60-90).On the other hand,there were significant differences in APR of each strain of the RIL population.TI mean: 5.7-7.2,range: 0-9;MDS mean: 24.8%-66.4%,range: 0-100%.These results indicated that Heyne has adult-plant resistance(APR)and the APR to stripe rust of RIL population was continuously distributed that assumed to be a quantitative trait.2.InfiniumTM iSelect 9K chip and 1001 SSR markers were used to analyze the RIL population.Finally,a total of 2240(2068 SNP,172 SSR)genotype markers were obtained.Using the MAP module of QTL IciMapping4.0 software,we have constructed a genetic linkage map,which contained2210 markers(2 068 SNPs and 142 SSRs)that mapped to all 21 wheat chromosomes.Thislinkage map covered 2139.35 cM of total genetic distance with an average marker interval of 0.96 cM.3.In this study,the inclusive composite interval mapping(ICIM)method was used to detect the three indexes of APR to wheat stripe rust resistance(response type,maximum severity and relative area under disease progress curve)with additive QTL.Finally,9 additive QTLs for APR to stripe rust were identified on seven chromosomes including 1AL,1BL,2BL,3AL,3B,4BL and 5AL.For IT,five QTLs were detected on chromosome 1AL,1BL,2BL,3B and 4BLand explained the phenotypic variation from 5.6% to 17.1%.For MDS,two QTLs were identified on chromosome 2BL and 5AL,and explained the phenotypic variation from 13.2% to 13.9%.For rAUDPC two QTLs mapped on chromosome 2BL and 3AL explained its phenotypic variation from 7.5% to 8.7%.Evaluation of additive QTL and environment(AE)interactions from multi-environment trials have identifiedthree environmental interaction QTLs.Two QTLs with AE interactions were detected at QIt.hwwgr-2BL and QIt.hwwgr-3B,comes from IT detection and this AE interaction effect could explain 5.2% and 6.9% of the phenotypic variation,respectively.One AE interaction QTL that comes from MDS was identified at QMds.hwwgr-2BLand it could explain 1.7% of the phenotypic variation.Furthermore,QIt.hwwgr-2BL?QMds.hwwgr-2BL and QrAudpc.hwwgr-2BL have a co-located interval between IWA7955-IWA5810 on chromosome 2BL.