Studies on the genetic diversity of Rhizoctonia solani AG-1-IA from six provinces in the southern China

The genetic diversity of Rhizoctonia solani AG?1 IA in the southern China was studied by testing 72 isolates of the pathogen for their polymorphisms in RAPD patterns and pathogenicity.The isolates were collected from six provinces,including Hainan,Fujian,Guangxi,Yunnan,Hu′nan and Guangdong,which represent the typical geographical features of the southern China.The results showed that there existed rich genetic diversity in all the isolates.Following PCR amplification of the fungal genomic DNA with 10 arbitrary primers and agarose electrophoresis,a total of 210 DNA bands were found,of which 5 were specific bands and 205 were polymorphic bands,the polymorphic rate was 98%.The isolates tested were classified into six groups at a 0 54 similarity level,whereas the isolates from the same province clustered to the same genetic group or subgroup.The polymorphic bands were closely related with the geographic location,but not obviously related with the pathogenicity of the isolates.