Genetic diversity and molecular discrimination of wild tea plants from Yunnan Province based on inter-simple sequence repeats (ISSR) markers

To efficiently assess and discriminate wild tea germplasms, inter-simple sequence repeats (ISSR) were used to determine genetic relationships among 40 wild tea plants. A total of 275 bands were generated with 15 ISSR primers, of which 274 (99.6%) were polymorphic. The mean genetic similarity coefficient, the mean Nei’s gene diversity (h) and the mean Shannon’s information index (I) of tea cultivars were 0.4180, 0.3797 and 0.5586, respectively. This suggested that the genetic diversity of wild tea trees and the genetic base were very wide. Unweighted pair group method with arithmetic mean (UPGMA) cluster analysis showed clear genetic relationships among these germplasms, and the major clusters were related to known pedigree relationships. Besides, from the bands amplified, there were three independent ways to identify the tea varieties, such as unique ISSR markers, unique band patterns and a combination of the band patterns provided by different primers. Finally, the ISSR fingerprints of 40 tea germplasms were constructed by the combination of the band patterns. This research indicated that ISSR markers were very effective in differentiating the wild tea varieties, too.