利用EST-SSR标记研究适制绿茶与乌龙茶品种的遗传多样性与遗传结构

基于26个EST-SSR标记研究了31份适制绿茶和37份适制乌龙茶品种的遗传多样性差异,结果表明两类品种在23个EST-SSR位点上的等位变异数目相等,另3个位点各存在一个等位位点的差异。乌龙茶品种遗传多样性指数（H）、多态性信息含量（PIC）和平均遗传距离(GD)均略高于绿茶品种。基于数学模型的聚类分析将供试品种分为两个亚类群,亚群A中67.9%的品种为乌龙茶适制品种;亚群B中71.0%的供试绿茶品种聚类其中。基于Nei’s遗传距离的聚类分析将供试品种分为3个类群,其中类群Ⅰ和Ⅱ中以乌龙茶品种为主,分别占聚类品种数的69.6%和66.7%;而类群Ⅲ中61.3%的供试绿茶品种聚类其中。多数品种按适制类型聚类,说明绿茶和乌龙茶品种间的遗传结构存在差异。但也有部分品种在不同的群体结构中呈穿插分布,推测与其适制类型划分的恰当性、地理来源和遗传背景有关。

Genetic Diversity and Population Structure among Green Tea and Oolong Tea Cultivars Based on EST-SSR Markers

The genetic diversity between 31 green tea cultivars and 37 Oolong tea cultivars were compared by using 26 EST-SSR markers. Results showed that number of alleles among green tea cultivars was same as that of Oolong tea cultivars except three loci amplified by primers 1036, ccmp6 and 788. Higher level of Nei’s gene diversity (H), polymorphic information contents (PIC) and average genetic distance (GD) were revealed among Oolong tea cultivars comparing to those of green tea cultivars. Based on mathematic simulation model, 68 tea cultivars were grouped into two populations, A and B. In population A, Oolong tea cultivars accounted for 67.9% of clustering samples, while in population B there had 71% of tested green tea cultivars were clustered. Whereas all tested cultivars were clustered into three populations according to Nei’s genetic distance. Oolong tea cultivars occupied 69.6% and 66.7% of clustering samples in populationⅠand Ⅱ, respectively, while 61.3% of tested green tea cultivars were clustered into population Ⅲ. These results showed that most of cultivars were clustered into the same population according to theirs processing suitability. However it is exceptive for a few of cultivars, which may be attributed to theirs improper categorization for processing suitability, geographic origin and genetic background.