Genetic Diversity and Pathogenicity of Rhizoctonia solani Isolates Causing Sheath Blight Disease of Rice in Northeast Region
ZHANG You;WEI Song-hong;WANG Hai-ning;LI Shuai;LI Si-bo;LUO Wen-fang;College of Plant Protection, Shenyang Agricultural University;
In order to provide a basis for the comprehensive control of rice resistance to rice sheath blight, the relationship between genetic diversity and pathogenicity of R. solani in northeast region was established. In this study, 132 isolates of rice sheath blight were collected from the major rice producing areas in northeast of China. The pathogenicity and SRAP analysis were carried out among 112 multinucleate isolates(R. solani) and 20 binucleate isolates(R. oryzae). The results of SRAP cluster analysis showed that the genetic similarity coefficient of 112 multinucleate isolates of R. solani were 0.52-0.97, and were clustered into 15 clusters at the 78% genetic similarity level; the genetic similarity coefficient of 20 binucleate isolates of R.oryzae were 0.65-0.90, and were clustered into 7 clusters under 80% genetic similarity. There was no significant correlation between genetic structure and geographical origin. Rice variety Liaoxing 1 was used to determine the pathogenicity of all isolates and the results showed that 77.27% of the isolates were highly pathogenic, 8.33% moderate pathogenic, 14.39% weakly pathogenic, indicating that the pathogenicity differentiation of R. solani was more obvious in the northeast. The result of cluster analysis and pathogenicity test showed that there was no simple correspondence between SRAP groups and pathogenicity identification.