南方红豆杉种源遗传多样性和遗传分化

Provenance Genetic Diversity and Genetic Differentiation of Taxus wallichiana var. mairei

利用ISSR分子标记对来自10省区15个南方红豆杉代表性种源,研究揭示其种源遗传多样性及地理变化、种源遗传分化等。结果表明：南方红豆杉具有丰富的遗传多样性,物种水平上的遗传多样性为0.4192,多态百分率（PPL）、Nei＇s基因多样性（HE）和Shannon信息多样性指数（I）分别变化在80.00%-93.33%、0.3393-0.3873、0.4926-0.5615。南方红豆杉种源遗传多样性受其产地经度和纬度非线性共同影响,偏南和偏西地区种源的遗传多样性较低,而偏东和偏北地区种源遗传多样性则较高。因试验的南方红豆杉种源其原产地种群皆是较大的古树种群,且片断化的时间较短,加上其特有的繁育特性,种源间基因分化系数为0.1211,仅有8.75%的遗传变异存在于种源间,而91.25%的遗传变异来自于种源内。UPMGA聚类结果还显示,除福建武平和武夷山2个较小种群的种源外,试验种源可按地域大致划分为偏东和偏北,及偏南和偏西2个种源区。

Taxus wallichiana var.mairei is one of the endangered and important species in tht southern China.In this study,genetic diversityand genetic diversity and genetic differentiation of 15 representative provenances were analyzed to provide a theoretical basis for its genetic conservation strategy with ISSR markers.A high genetic diversity（0.4192）for T.wallichiana var.mairei was detected.The percentage of Population polymorphic loci,Nei＇s genetic diversity and Shannon＇s information diversity index ranged from 80.00% to 93.33%,0.3393 to 0.3873 and 0.4926 to 0.5615 respectively.The genetic diversity of T.wallichiana var.mairei provenances was affected by both latitude and longitude in nonlinear manner.The provenances from the middle and the east part of China showed higher genetic diversity than those from the southern and the western part of China.As the tested provenances were derived from ancient woods with a large area,a short fragmentation period,and the special breeding characteristics,the genetic differentiations among these prorenances studied were small and the genetic relationship was quiteclose.Molecular variance analysis demonstrated 0.1211 that genetic variation among-provenance and within-provenance accounted for 8.75% and 91.25% of the total genetic variation respectively.Analysis of Nei＇s unbiased genetic distance showed the 15 tested provenances except Wuping and Wuyishan in Fujian could be clustered into 2 groups,which distribute mainly in the north-east and south-west area of the South 2 provenance area.