云南大叶种茶树种质资源ISSR指纹图谱构建及遗传多样性分析

Fingerprinting Construction and Genetic Diversity Analysis of Yunnan Dayezhong Tea Germplasm Resources by ISSR Markers

利用ISSR标记构建了40份大叶种茶树资源的指纹图谱,用3种独立的方法(特殊的标记、特异的谱带类型、不同引物提供的谱带类型组合)可以有效地鉴别大叶种茶树种质资源,证明ISSR标记是鉴定茶树资源的有效方法。15条ISSR引物共扩增出275条谱带,其中274条具有多态性,占99.6%。40份材料间平均遗传相似系数、Nei′s基因多态性(gene diversity)和Shannon′s信息指数分别为0.4180、0.3797、0.5586。材料间的遗传多样性较高,说明材料间的遗传距离较远,亲缘关系较远,遗传基础较宽。ISSR聚类分析表明,40份种质资源被聚为3个类群,其中Ⅲ类群又聚为3个亚群。亲缘关系树状图在分子水平上清楚地显示了云南大叶种茶树资源间的亲缘关系,为今后茶树育种和杂交亲本的选择提供了依据。

The ISSR fingerprinting of 40 accessions of Dayezhong tea germplasm were constructed. Three independent ways, including unique ISSR markers, unique band patterns and combination of the band patterns, can identifythe tea varieties. The result showed ISSR were very effective in identifying tea germplasm. Totally 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 the tested tea germplasm were 0. 4180,0. 3797 and 0. 5586, respectively. This suggests that the genetic diversity of tea germplasm was high and the genetic base was wide. The cluster analysis based on ISSR markers revealed that the tea germplasm were clustered into three groups, in which the third group could be further classified into three subgroups. The dendrogram showed clear genetic relationships among the tested tea germplasm, and would provides the theoretical base for genetic improvement and selection of cross-bred parents in tea breeding.