Germplasm Identification Of Wheat Resistant To Stripe Rust And Powdery Mildew And QTL Mapping Of Stripe Rust Resistance Of "Xinong 1376"

Wheat is an important food crop in the world,and it is an extreme challenge to increase yield steadily under climate change and biological stress.Stripe rust is a biological nutritional fungal disease caused by stripe rust infecting wheat leaves.Powdery mildew is a wheat disease caused by Brucella gramineae.Under the condition of frequent occurrence of a variety of diseases,it poses a growing threat to wheat production around the world.Although the rational use of fungicides can effectively control the occurrence of wheat diseases,the high cost of fungicides and the adverse impact on the environment must be considered.Due to the change of dominant races and the emergence of new races,the resistance of some wheat germplasm was weakened or lost,thus accelerating the replacement frequency of wheat varieties.Therefore,continuous excavation of new genetic resources,breeding of persistent and resistant varieties,location and discovery of new resistance loci are the best strategies to control wheat diseases.In this study,305 germplasm materials from home and abroad were identified for resistance genes by using molecular markers closely linked to resistance genes.Combined with the grade of disease resistance in the field,the existence of resistance genes to stripe rust and powdery mildew in wheat germplasm was identified.Dig out wheat germplasm resources with concurrent resistance.At the same time,the RIL populations constructed by Xinong 1376 and Xiaoyan 81 were genotyped by50 KSNP chip,and a high-density genetic linkage map was constructed.Combined with the resistance of two parents and RIL population to stripe rust,the resistance gene was mapped and the resistance mechanism was analyzed,which provided a theoretical basis for breeding wheat varieties resistant to stripe rust.1.Among the 305 wheat germplasms,the number of wheat germplasm carrying Yr10,Yr15,Yr18,Yr26,Yr46,Pm8,Pm21 and Pm34 genes was 5,10,23,0,4,100,1,95,respectively.Among them,2,3,7,0,3,59,1 and 62 showed moderate resistance,respectively.It was found that the gene combinations Yr18+Pm8+Pm34,Yr46+Pm8,Yr46+Pm8,Yr46+Pm34,Yr18+Yr10,Yr18+Pm34,and Yr18+Pm8 were detected in only 15 materials,and these germplasm resources carrying combinations of single resistance genes and multipotent disease resistance genes acted as combined resistance to stripe rust and powdery mildew,while the wheat germplasm Fr03717 containing the Yr18+Pm34 gene combination achieved high levels of resistance to both diseases.Therefore,the frequent and alternating occurrence of multiple diseases can be avoided by making full use of the germplasm resources of multi-resistance gene combinations.2.Using the genetic linkage map constructed by 50 K chip,2720 molecular markers were divided into 34 linkage groups,covering the whole wheat genome.The total length of the map was 4692.55 c M,and the average genetic distance between markers was 1.73 c M.3.Both Xinong 1376 and Xiaoyan 81 were susceptible to stripe rust at seedling stage,while Xinong 1376 was highly resistant to stripe rust at adult stage.Seven QTL resistant to stripe rust were located on chromosomes 2A,2B,3A,4A,4B,5D and 7A by genetic map and RIL population in four environments.Among them,QYr.nwsuaf-4B and QYr.nwsuaf-5D are two stable micro-effect QTL,derived from Xiaoyan 81 and Xinong 1376,respectively.QYr.nwsuaf-3A,located on chromosome 3A,is a major QTL locus,explaining 7.83% of the 17.53%phenotypic variation,which can be detected in all four environments and originated from Xinong 1376.According to the source,effect,marker type of resistance site and the reference genome sequence of Chinese spring,it is considered that QYr.nwsuaf-3A may be a new stripe rust resistance site.