Virulence Analysis Of Wheat Stripe Rust Population In Southwest Of China

Wheat stripe (yellow) rust (Puccinia striiformis f.sp.tritici) was an important worldwide disease of cereal crops, it was also a serious biological disasters which have a long-term impact on the safety of Chinese wheat production, which had occurred nationally many times in history. Using the resistant varietie was the most economical and effective measure to control the disease, and monitoring the stripe rust dynamics of races timely and accurately was the foundation in controlling wheat stripe rust epidemiology. Getting known the structure of pathogen populations and their distribution in the over-wintering and over-summering areas of stripe rust in China Step by step, it would have a great significance in breeding for disease resistance and guiding the rational varieties distribution.The study was base on the gene-for-gene theory, selected 39 near-isogenic lines with single wheat stripe rust resistance gene and strain material containing wheat stripe rust resistance genes which already known, which were used for the virulence identification and virulence frequency analysis of 124 isolates of Chinese wheat stripe rust. The results showed that the colony of wheat stripe rust in the region of southwest China and Gansu have high virulence frequency and were stabile to the current vast majority international wheat stripe rust resistance gene. The colony of wheat stripe rust only avirulent to Yr5,Yr10,YrMoro,Yr24 and Yr26, which have high virulence to the rest of wheat stripe rust resistance gene(the virulence frequency was between 47.2%～99.1%) except Yr15 and Yr19(the virulence frequency was below 40%).As the virulence of the colony of wheat stripe rust, Sichuan region had the highest virulence, Guizhou region had the lowest virulence , Yunnan region had the middle one. Used NTSYSpc (version 2.10e) software for the polymorphism and cluster analysis of 124 isolates of Chinese wheat stripe rust,found that the similarity of virulence between the isolate was high except one,the resemble coefficient between the rest of the isolates was 0.66～1.00. The virulence frequency of the colony of wheat stripe rust in 2009 ascended notablely compared to three years ago,and mostly ranged above 90%. The study also farther confirmed the virulence of the isolate with same race have obvious difference.