Genetic Diversity and Phylogenetic Relationship of Cucumber (Cucumis sativus L.) Germplasm Based on RAPD Analysis

In this study, the genetic diversity among 66 cucumber accessions from different countries or regions was assessed by means of RAPD makers, and the genetic relationship among the accessions was revealed by cluster analysis. A total of 253 scorable bands were detected with 29 informative RAPD primers among 66 accessions. Of them, 195 bands (77 08%) were polymorphic. The diversity shown by different primer was greatly different. The average heterozygosity of RAPD loci in 66 accessions was 0 388. The heterozygosity of Chinese germplasm was slightly higher than that of the exotic accessions. The accessions from south China were more diverse than that from north China. The genetic diversity of south China′s ecotypes was higher than that of north China′s ecotypes. This implies that the south China may be the primary region of evolution of cucumber.66 accessions could be clustered into eight groups based on RAPD data by cluster analysis. Accessions from Xishuangbanna could be distinguished from other germplasm, and the exotic germplasm went into the same group or independent group. There was not certain association between the molecular genetic relationship revealed by RAPD markers and the morphological similarity and geographical distribution, especially among the Chinese cultivated accessions.