Genetic diversity and pathogenicity of Rhizoctonia solani isolates from Jiangsu Province

Genetic diversity of eighty seven isolates of Rhizoctonia solani was investigated by ISSR(inter-simple sequence repeat) technique,with 3 specific and stable primers selected from nine primers.A total of 76 sites were generated,among which 96.05% were polymorphic,indicating the high genetic diversity of these strains of Rhizoctonia solani.By clustering analysis,the isolates were classified into 7 ISSR groups,which were correlated with geographical origin of the isolates.The pathogenicities of the isolates were independent of the source of strains,polymorphisms of DNA bands and the ISSR clustering groups,however,they were positively correlated with growth rates of isolates.These results will contribute to further study on the population of Rhizoctonia solani,and provide reference for the screening of the germplasm resources against rice sheath blight using representative strains and the reasonable layout of the disease-resistant rice varieties.