Exploration And Genetic Analysis Of Stripe Rust Resistance Of Wheat Resource In Adult Plant Stage

Common wheat(Triticum aestivum L.)is an important cereal crop and serves as a staple food source in many countries.However,it is frequently challenged by diseases,among which stripe or yellow rust(YR),caused by Puccinia striiformis Westend.f.sp.tritici Erikss.(Pst),is one of the most damaging.The reasonable deployment of adult plant resistance(APR)wheat varieties is one of the best methods for controlling this disease.Wheat landraces are valuable resources for identifying the genes/QTLs responsible for disease resistance.Therefore,extensive collection,excavation and transfer of disease-resistant materials have important social and economic benefits.In this study,we used 161 wheat materials collected from all over the world and challenged them with stripe rust in adult plant stage for five years.Then all of these materials were genotyped by 660 K SNP chip.Based on these genotype and phenotype data,we carried out the genome-wide association study.Meanwhile QTL mapping for the selected elite resistance cultivars Humai 15 and Chakwal 86 was implemented.The main results of this study were as follows:1.The 161 wheat materials collected from the worldwide have been challenged by stripe rust for five-year in Yangling and Tianshui in adult plant stage.It is found that the advance lines show the lowest infection type and disease severity,indicating that the breeders are increasing emphasis on disease-resistant breeding.Based on the highest infection type and maximum disease severity under these 10 environments,47 materials which show high resistance were selected and could be used for disease resistant breeding.2.Combined with 660 K SNP chip genotyping data,genome-wide association analysis of adult plant resistance to stripe rust was implemented.18 stable QTLs which distributed on 12 chromosomes were mapped.Compared with published data,5 QTLs identified as QYr.nwafu-2D.1,QYr.nwafu-2D.3,QYr.nwafu-5D,QYr.nwafu-6D and QYr.nwafu-7D may be new adult plant resistance QTLs.3.The mapping population of recombinant inbred lines(RILs)derived from the cross between resistance cultivar Humai 15 and susceptible cultivar Mingxian169 was used for QTL analysis.By genotyping with KASP markers and 90 K SNP array,one major QTL QYrhm.nwafu-2BC was identified on the centromere of chromosome which accounted for up to 47.2% of the phenotypic variation.This QTL is similar to the QTL QYr.nwafu-2B.2 which identified by GWAS.Two minor QTL were identified on the chromosome arms 3BS and 4BL.4.The QTL mapping population of RILs was derived from the cross between wheat cultivars Chakwal 86 and Mingxian 169.The population was genotyped by 35 K SNP array,two major QTLs were mapped on 1BL and 3BS of Chakwal 86,where the QTL on 1BL might be Yr29/Lr46 and the site on 3BS QYrcw.nwafu-3BS might be a new site.The QTL QYrcw.nwafu-3BS was not detected in the GWAS analysis may be due to rare variations or insufficient effect.The flanking markers of the QYrcw.nwafu-3BS have been developed into KASP markers for wheat large-scale molecular-assisted resistance breeding.