Assessment of Genetic Diversity and Relationship of Tea Germplasm in Yunnan as Revealed by ISSR Markers

Abstract

The relationship and the genetic diversity of 134 accessions of the Yunnan tea [ Damellia sinensis (L.) O. Kuntze] germplasm belonging to 8 species were analyzed to provide guidance for breeding of tea tree. Using 18 inter-simple sequence repeats (ISSR) primers, a total of 475 fragments were amplified, of which 470 bands were polymorphic. The genetic similarity (GS) among the accessions tested ranged from 0.445 to 0.819 with an average of 0.512. These results indicated a rich diversity in the tested genetic germplasm of tea. Based on the cluster analysis using unweighted pair-group method with arithmetic average (UPGMA), all the tea accessions fell into 3 groups with no obviously geographical character. The principal component analysis (PCA) supported the clustering result, but relationships among accessions were more explicit in the PCA graph than the UPGMA dendrogram. The genetic variation among species was small, as the average GS among species was 0.92, ranging from 0.850 to 0.987.