A total of 126 Phytophthora infestans isolates were collected from Harbin,Suihua and Qiqihar Cities of Heilongjiang Province from 2015 to 2017. Analysis on their mating types,mt DNA haplotypes,SSR genotypes and multi-locus genotypes were carried out. The results indicated that 3 mating types of A1,A2 and self-fertility were found in 126 strains isolated,accounting for 88.1%,6.3% and 5.6% of the total isolates,respectively. Two mt DNA haplotypes,Ⅰa and Ⅱa,were identified,accounting for 17.5% and 82.5% of the...