Abstract：SSR and RAPD molecular markers were used to assess the genetic diversity among 80 isolates of Phytophthora infestans on potato(Solanum tuberosum) from Fujian, Heilongjiang, Hebei and Inner-mongolia. Polymorphism was identified by 13 SSR primers and 14 RAPD primers in the isolates of P. infestans on potato. A total of 76 bands were produced by SSRs with polymorphic bands accounting for 78.9% and similarity coefficient within 0.00 to 0.42. And a total of 189 bands were generated by RAPDs with polymorphic bands accounting for 95.2% and similarity coefficient ranging from 0.04 to 0.66. Analysis of genetic variation showed that there existed higher genetic variation in the Fujian populations in comparison to the populations of Heilongjiang, Hebei and Inner-mongolia. Nei's genetic identity analysis indicated that the populations of Heilongjiang and Inner-mongolia were closer than Fujian and Hebei populations revealed by SSRs and RAPDs. The results of cluster analysis revealed that some isolates from Fujian, the south region of China were distantly related to some isolates from Heilongjiang, Heibei and Inner-mongolia, the north of China and the Fujian populations had a higher genetic diversity than that of the others.
