Abstract Levels of genetic diversity within and among 56 germplasm of Pyrus were analyzed using SSR markers. 40 bands were amplified by six informative and reliable prmiers screened, of which 38 (95% ) were polymorphic, with an average of 6.3 alleles per locus. Nei’s gene diversity index ranged from 0.0354 to 0.491 with an average of 0.1964 , effective number of alleles range from1.0367 to 1.9648 with an average of 1.2958. Genetic diversity difference among tested pear cultivars was relatively low based on Shannon index (0.3256). 44 pear cultivars could be distinguished by SSR markers except the mutant cultivars. UPGMA cluster analysis was performed with soft NTYSIS-pc2.01, the clades formed including four populations at the dice coefficient of 0.71. Pyrus bretschneideri Rehd., P. ussuriensis Maxim. and P. pyrifolia Nakai. originating in China interveined each other and could not form group independently .
