Abstract: In this study，genetic diversity in 70 accessions of Cucumis sativus L．from diferent countries or regions was assessed using AFLP markers，and the genetic relationship among the accessions was revealed by cluster analysis．Eight pairs of AFLP informative primers generated 425 scorable bands in total．66％ of which were polymorphic．The average expected heterozygosity of AFLP loci among all accessions Was 0.376．The heterozygosity among Chinese accessions Was higher than that am ong exotic accessions．C．sativus L．vat． xishuangbannanesis Qi et Yuan and India wild germpalsm had some special loci that were not present in cultivars． rhe special loci in China cuhivars are more than that in the germplasm from America and Europe．rhe exotic germplasm also has some special loci that was absent in Chinese germpalsm．Three groups were clustered based on AFLP markers，namely C．sativus L.Var.xishuangbannanesis Qi et Yuan group，C．sativus Var．hardwicki group and cuhivars group．C．sativus L．Var．xishuangbannanesis Qi et Yuan Was the farthest from cuhivars．India wild cucumber was the farther from cuhivars．At certain distance，Chinese cultivars could be diferentiated from the exotic germplasm． Most south China ecotypes and North China ecotypes could be grouped into diferent subgroups but a few diferent ecotypes went into a Sal’ne subgroup．These results are beneficial for US to use various target variants to widen the genetic background of cucumber cultivars．

Key words: Cucumis sativus L．, Germplasm resources, Genetic diversity, AFLP marker, Cluster analysis