云南古茶树(园)遗传多样性的ISSR分析

云南省保存有20多万亩古茶园,这些古茶树(阿萨姆变种Camellia sinensis var.assamica)种质资源可能含有各种优良基因,对未来茶树良种选育有重要意义。本研究采用ISSR分子标记技术对云南省十个有代表性的古茶园遗传多样性进行分析,十个居群的多态位点百分率(P)为56.5%~90.9%;Nei'氏遗传距离(He)居群平均是0.281,阿萨姆变种水平内是0.461;Shannon多样性指数(Ho)居群平均是0.418,阿萨姆变种水平内是0.653。而居群间遗传分化系数Gst=0.391,和Shannon多样性指数分析(36.0%)和AMOVA分析结果(39.7%)相一致,说明阿萨姆变种60.9%的遗传变异来自居群的个体间,39.1%的遗传变异来自居群间。研究结果揭示阿萨姆变种居群遗传多样性高,居群间遗传变异存在中度的遗传分化,这可能是由于茶树种内高度异交的特性和生境片段化所致。基于观察到的居群遗传信息,建议采取就地保护和迁地保护的保护策略。

Genetic Diversity of Ancient Tea Plant in Yunnan Province of China Revealed by Inter-simple Sequence Repeat(ISSR) Polymerase Chain Reaction

Tea plant Camellia sinensis var. assamica] populations in Yunnan province of China cultivated since ancient times are important genetic resources for future breeding of new tea cultivars. To evaluate the genetic diversity within and between Yunnan ten representative populations and to formulate conservation strategies for the ancient tea populations in Yunnan was conducted by ISSR technique in this study. The genetic diversity within populations calculated from Nei's genetic diversity (He) was estimated to be 0.281, on average, at the population level and 0.461 at the variety level, while Shannon indices (Ho) of population level and Assam variety level were 0.418 and 0.653, respectively and the percentage of polymorphic loci (P) of the ten populations ranged between 56.5% to 90.9%, respectively. Coefficients of gene differentiation (Gst) within the population was 0.391, in agreement with the result of Shannon' diversity indices analysis (36.0%) and analysis of molecular variance (AMOVA) among population (39.7%), which illuminated that 60.9% of the variation in Assam variety were from the individuals of the population, and 39.1% of the genetic variation were from the population. The result indicatedCamellia var. assamica variety possesses high genetic diversity and medium genetic differentiation was existed in the genetic variation between population. This could be caused by the highly outcrossing nature and habitat fragmentation of tea species. Conservation strategy are suggested including in situ strategies and ex situ strategies based on the observed genetic information of population.