Significant difference in pathogenicity of MAT1-1 and MAT1-2 isolates in potato pathogen Alternaria alternata

Alternaria alternata collected from seven provinces (Heilongjiang，Inner Mongolia，Shandong，Henan，Hubei，Fujian and Yunnan）in China were molecularly characterized using neutral SSR markers and mating typespecificprimers. Among them，234 distinct genotypes were selected for pathogenicity analysis by detached leaf assay.The result indicated that，on average，the pathogen from South displayed higher pathogenicity than that from North. For example，the pathogenicity of pathogen from Fujian was 98.29% higher than that from Shandong. The result also showeda significant difference in pathogenicity between MAT1-1 and MAT1-2 isolates. On average，MAT1-2 isolate displayed 15.34% higher pathogenicity than MAT1-1 isolate.