Population Structure And Original Study Of Puccinia Striiformis F.sp.tritici In The Key Winter Spore Production Regions In China In 2017

Stripe rust is one of the most important diseases in wheat production in China,which caused serious yield loss in wheat producing areas in usual years.In this study,296 wheat stripe rust samples collected from Hubei,Guizhou,Yunnan,Sichuan,Gansu,and Qinghai were isolated and harvested.Nineteen Chinese differentials and 18 near-isogenic lines were used to identify the virulent phenotypes.Simultaneously,13 pairs of SSR primers and 43 pairs of SNP primers were used for molecular genotyping.Based on the comparative analysis on the virulence structure and population genetic structure of the stripe rust pathogens,the main findings are as follows:(1)The physiological race analysis showed that the three major prevalence races of Chinese wheat stripe rust were CYR32,CYR34 and CYR33,accounting for 49.3%,11.5%and 4.4%,respectively.The proportion of CYR34 has exceeded CYR33,making it the second most important race inferior to CYR32.CYR34 can be detected in the stripe rust populations in all regions except for western Yunnan.Among them,the frequency of CYR34 in Sichuan was the highest,up to 34.4%;The frequency of CYR34 in eastern Yunnan and Gansu is 15.6% and 18.9% respectively;The frequency of CYR34 in northwest Hubei,southern Hubei,Guizhou and Qinghai is less than 10%,but it is very likely to have a dramatic increase in the next few years.(2)Both virulent phenotypes analysis and molecular genotyping analysis showed that the stripe rust populations in Gansu and Qinghai(northwestern over-summering areas)were the most abundant in genetic diversity.The genetic diversity of the stripe rust population in Sichuan(the key winter spore production)is middle,and the genetic diversity of the stripe rust populations in Hubei(the key winter spore production),Guizhou and the eastern of Yunnan(western over-summering areas)are low.The virulent phenotypes analysis showed that the results of virulent diversity indices were basically the same on the same set of differentials,and the results of the same virulent diversity indices were not consistent with different set of differentials.The virulent diversity in western Yunnan is the most abundant in Chinese differentials but low in the near-isogenic lines.This difference may be due to the fact that the virulent phenotype is not a neutral marker.The identification results depend on the differentials selected and does not objectively reflect the genetic diversity of the stripe rust populations.(3)Cluster analysis and gene flow analysis showed that the stripe rust in Hubei originated in Guizhou and eastern Yunnan in 2017,and the stripe rust in Sichuan was from in both the northwestern and the southwestern over-summering areas.Western Yunnan is an independent prevalent area of wheat stripe rust in China.