Evaluation Of Stripe Rust Resistance And Analysis Of Yr Genes In 305 Wheat Cultivars From The Main Wheat-growing Regions In China

Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici(Pst),is a serious threat to wheat production in China due to the characteristics of rapid prevalence,wide area occurrence,and serious damage.Planting resistant cultivars is the one of the most effective measures to control stripe rust.However,the frequent variation of Pst virulence results in the loss of the resistance of wheat cultivars.Therefore,it is important to explore and screen germplasm resources for resistant cultivars breeding.The objectives of this study were: Ⅰ)to clarify the resistance to predominant races of Pst and the distribution of resistance genes in wheat core germplasm,as well as several breeding cultivars from main wheat-producing regions in China,Ⅱ)and to screen out high-quality resistance resources of wheat to lay a foundation for rational utilization and distribution of resistant varieties and genes.A total of 305 wheat cultivars were identified for phenotyping and genotyping resistance to Pst.The main results of this study are as follows:Among the 305 cultivars,132 showed different types of resistance,and most of cultivars showed adult-plant resistance.40 cultivars(13.1%)carry all-stage resistance,71 cultivars(23.3%)carry adult-plant resistance,12 cultivars(3.9%)carry high-temperature all-stage resistance,and 9 cultivars(2.9%)carry high-temperature adult-plant resistance.The cultivars resistant to stripe rust at seedling stage were detected in the greenhouse.Among the 305 wheat cultivars,130 and 86 cultivars showed moderate or higher resistance to CYR32 and CYR34 at the seedling stage,accounting for 42.6% and 28.2% of the total cultivars,respectively;58cultivars were resistant to CYR32 and CYR34,accounting for 19.1% of the total cultivars.The cultivars resistant to CYR31,CYR32,CYR33,and CYR34 were detected in the field under artificial inoculation.The results showed that 136 cultivars were resistant to CYR31,CYR32,CYR33,and CYR34,accounting for 44.6% of the total cultivars.The resistant cultivars in the field test were further inoculated with CYR32 in the greenhouse for adult-plant resistance identification.The results showed that 120 cultivars were resistant to CYR32,accounting for 39.3% of the total cultivars.The resistance genes of the tested cultivars were diverse,and their resistance mainly came from the pyramiding of resistance genes.The results of molecular detection showed that 22 cultivars carry Yr9,66 cultivars carry Yr10,18 cultivars carry Yr17,127 cultivars carry Yr18,14 cultivars carry Yr26,53 cultivars carry Yr30,17 cultivars carry Yr41,275 cultivars carry Yr80,32 cultivars carry QYrst.wgp-6BS.1.Among all tested cultivars,Yr18 and Yr80 were most frequently detected,and Yr5,Yr15,and Yr36 were not detected.None of the above resistance genes were detected in one resistant cultivar.It is presumed that other known resistance genes or unknown genes were existed in the cultivar.112 of 132 cultivars with different types of resistance contained two or more resistance genes.Among all the detected resistance genes,Yr9,Yr17,Yr26,and Yr41 showed high resistance to Pst when co-existed with other Yr genes.