基于EST-SSR标记的云南大叶茶资源遗传多样性分析

Genetic Diversity Analysis of Daye Tea Germplasm in Yunnan Based on EST-SSR Markers

丰富的遗传变异对提高作物的环境适应性和加快遗传改良进度至关重要。为进一步了解云南大叶茶种质资源的遗传多样性,利用28对SSR引物对94份大叶茶种质材料进行遗传多样性分析,结果共检测到等位基因128个,平均每个位点为4.57个;Shannon信息指数(I)在0.91~1.66之间,最小为5087位点0.91,最大为1696位点1.66,平均每个位点为1.30;多态性信息含量(PIC)数值在0.476~0.753之间,最小为5087位点0.476,最大为1696位点0.753,平均值为0.64;平均观测杂合度和平均期望杂合度分别为0.71、0.70。通过对94份供试材料来源地遗传分化分析和聚类分析表明,材料的遗传变异主要存在于不同来源地之间而非同一来源地内。并且多数同一来源的材料分散在不同类群中,材料来源地间遗传距离与地理距离不存在显著的相关性。研究认为,聚类结果与多态性信息含量等参数值分析结果一致,表现出丰富的遗传多样性。这可为云南茶树资源的育种和创新利用提供研究基础。

Abundant genetic variation is very important for improving environmental adaptability and genetic improvement of crop. In order to know the genetic diversity of Daye tea germplasm resources in Yunnan,94 tea germplasms were selected for the analysis using 28 pairs of SSR primers. A total of 128 distinctive loci were detected with the mean as 4. 57; the Shannon's information index( I) ranged from 0. 91 to 1. 66 with the mean as 1. 30,and 0. 91 and 1. 66 were in the loci 5087 and 1969 respectively; the polymorphism informationcontent( PIC) ranged from 0. 476 to 0. 753 with the mean as 0. 64,and 0. 476 and 0. 753 were also in the loci5087 and 1696 respectively; the average observed heterozygosity and the average expected heterozygosity were 0. 71 and 0. 70 respectively. The results of genetic differentiation analysis and cluster analysis for the source areas of 94 tea germplasms showed that genetic variation mainly existed between the germplasms from different source areas but not from the same source area,and most germplasms from the same source area distributed in different groups; there was no significant correlation between the genetic distance and the geographical distance. It was concluded that the cluster analysis and the analysis of PIC had the same results,which showed abundant genetic diversity. These results could provide research foundations for breeding,innovation and utilization of Yunnan tea germplasms.