Improvement Of Identification Method For Resistance To Wheat Sharp Eyespot And Genome-wide Association Analysis

Rhizoctonia solani is a soil-borne fungal disease caused by Rhizoctonia cerealis and Rhizoctonia solani,which seriously threatens wheat yield.However,the identification of wheat sharp eyespot resistance was mainly inoculated at the adult stage in the field,seriously restricting the identification efficiency.In order to improve the identification efficiency of wheat sharp eyespots resistance,a rapid identification and improvement method of wheat sharp eyespot resistance was established by inoculating diseased wheat grains into wheat seedlings in greenhouse.At the same time,202 domestic and foreign wheat varieties（lines）were used as materials to mine the resistance gene loci and candidate genes at seedling and adult stages of wheat sharp eyespo by genome-wide association analysis.The main results were as follows:1.This study improved the method of identification of sharp eyespo resistance at seedling stage.The method of double inoculation at seeding stage and one-leaf stage was adopted to improve the effect and stability of the disease.Because the inoculation time is one week ahead of the previous methods,it also improves the efficiency of inoculation identification.The results of identification of sheath blight resistance in 202 wheat varieties（lines）at seedling stage showed that the correlation coefficient of sheath blight disease index changed significantly from 0.690 to 0.850 after four repetitions.At the same time,the correlation coefficient of sheath blight disease index in seedling stage and adult stage was 0.623 in different environments.Significant correlation indicated that the method of identification of sheath blight resistance at seedling stage established in this study could accurately identify sheath blight resistance of wheat varieties.2.A total of 10 resistant materials with moderate or higher resistance to sheath blight were identified in the field and greenhouse.The order of resistance was CI12633,Shanhe 6,Half-awn wheat,Half-truncated awn,Spring of China,Red clam,Red Star wheat,Pingyuan 50,Pingyang 181 and Zhengmai 8998.3.Genome-wide association analysis of sharp eyespo resistance at seedling and adult stages in 202 wheat cultivars was carried out using 90 K SNP chip.88 SNPs and 73 SNPs loci related to sheath blight resistance at seedling stage and 73 SNPs loci related to sharp eyespo resistance at adult stage were detected,mainly on chromosomes 2A and 7A.Ten of the 10 SNP markers（RAC875_c16339₂65 、RAC875_rep_c108098₆ 、 Kukri_rep_c108232₄28 、 JD_c42022₃19 、Tdurum_contig37375₂67、IAAV5054、Tdurum_contig17366₇31、Ku_c15750₇61、Tdurum_contig4676₃592、Excalibur_rep_c111181₄53）were repeated in different environments at seedling and adult stages.Functional annotations of these reproducible SNP loci were performed in the wheat Chinese Spring database.It was found that they were related to translation protein and glycosyl hydrolases.