Study on Genetic Diversity of Peculiar Sect. Thea (L.) Dye in Yunnan by ISSR Markers

ISSR technique was used to analyze genetic diversity of Peculiar Sect.Thea(L.)Dye in Yunnan.25 materals from tea germplasm bed of Tea Research Institue of Yunnan Academy of Agriculture Science were tested with polymorphic ISSR markers using 12 arbitrary 10-mer primers selected from 40 sangon primers.The level of polymorphism of the cultivars was extremely high.Among a total of 141 bands observed,139 bands were polymorphic in 25 cultivars tested,PPB was 98.5%,and only 2 bands did not reveal polymorphism.This showed Yunnan tea section plants abounded in genetic diversity.A dendrogram showing genetic relationships between them was constructed by an unweighted pair-group method with arithmetical averages(UPGMA)based on genetic distances.According to the dendrogram showing genetic relationships,25 materals could be divided into 6 groups when GS was 0.378 and 20 tea plants could be divided into 2 groups.The cultivars were classified based on the level of genetic DNA,especially their genetic variance.Genetic distances between each of cultivars varied from 0.151 to 0.580.The figure showed that tea trees in Yunnan took possession of much high genetic diversity on DNA molecular level.Both UPGMA and PCA(principal component analysis)showed similar genetic relationship.The results indicated that ISSR was a useful tool for molecular identification and relationship analysis of tea germplasms.