西双版纳地区古茶树遗传多样性分析

Genetic Diversity Analysis of Ancient Tea Plants in Xishuangbanna Area

摘要: 古树茶具有重要的科学和社会经济文化价值，但目前对其遗传多样性研究较少。本文利用8对SSR引物对古树茶种质资源进行遗传多样性分析，共检测到18个等位基因，居群的平均观察杂合度(Ho)为0.392，期望杂合度(He)为0.353，shannon信息指数(I)平均为0.578，多态位点百分率(P%)平均为75%，说明这些地区的古树茶资源具有丰富的遗传多样性。根据Nei’s遗传距离和遗传一致度来看，翁基和芒景遗传距离最小，为0.019，两者的一致度最高，为0.982；南糯山和大平掌的遗传距离相差最大，为0.303，一致度最低，为0.739。AMOVA分析显示，古茶树之间的遗传分化系数(Fst)为0.133，古茶树群体间属于中度分化，87%的遗传变异来自居群内，13%的遗传变异来自居群间。用UPGMA法，进行聚类分析，可将10个地区的古茶树资源分为2大类：一类是以老班章为代表的翁基、芒景、滑竹梁子和大平掌聚；另一类是以南糯山为代表的小勐宋、落水洞、麻黑和高山寨。本文研究结果将为古树茶遗传图谱构建、基因定位、亲缘关系和种质鉴定等研究提供理论依据，为珍稀古茶树资源的鉴定、保护和利用提供一定的遗传基础。

Abstract: Ancient tree tea has important scientific, social, economic and cultural value, but there is less re-search on its genetic diversity at present. In the study, 8 pairs of SSR primers were used to analyze the genetic diversity of the ancient tree tea and a total of 18 alleles were detected. Within the popu-lation, the average observed heterozygosity (Ho) was 0.392 and the expected heterozygosity (He) was 0.353. The average Shannon information index (I) was 0.578, and the average percentage of polymorphic loci (P%) was 75%, indicating that the ancient tea resources in these areas are rich in genetic diversity. According to Nei’s genetic distance and heritability, the genetic distance between Wengji and Mangjing was the closest (0.019) and has the highest similarity (0.982). The genetic distance between Nannuoshan and Dapingzhang had the largest difference of 0.303 and the lowest similarity with 0.739. AMOVA analysis showed that the genetic differentiation coefficient (Fst) between the ancient tea plants was 0.133, which indicated that the ancient tea tree population was moderately differentiated. Further analysis showed that 87% of the genetic variation was within the population and 13% of the genetic variation was among the different populations. The ancient tea tree resources in 10 regions can be divided into 2 categories using the UPGMA method for cluster analysis. One category includes Laobanzhang, Wengji, Mangjing, Huazhuliangzi and Dapingzhang, and another kind of cluster covers Nannuoshan, Xiaomengsong, Luoshuidong, Mahei and Gaoshanzhai. In this paper, the results will provide theoretical basis for research on the construction of genetic map, gene localization, germplasm identification and genetic relationship as well as genetic basis for the identification, protection and utilization of the rare ancient tea tree resources.