日本岛屿山茶种群遗传结构的ISSR分析

为查明日本岛屿山茶种群的生存状况及了解岛屿隔离对山茶种群遗传结构的影响，采用ISSR分子标记，利用筛选的20条引物对日本5个山茶（Camellia japonica）种群的遗传结构进行分析。结果表明：山茶种群的多态位点百分比（PPB）为70.29％，Nei’s基因多样性指数（H_E）为0.281 9，Shannon信息多态性指数（H）为0.409 5，与其它岛屿种群相比遗传多样性水平较高，表明山茶种群的生存状况较好。基因分化系数G_st=0.205 7，种群间具有较高的遗传分化；地理距离与遗传距离具有显著相关性（r=0.821 7，p<0.05），UPGMA也将同岛种群聚在一起，表明岛屿隔离对山茶种群的遗传分化具有重要影响。借鉴日本岛屿山茶种群的保护经验，建议加强我国岛屿山茶种群的就地保护力度，同时建立山茶种质资源库，促进基因交流。

ISSR Analysis on the Population Genetic Structure of Camellia japonica of Japanese Islands

Camellia japonica is an important horticultural species widely distributed in East-Asia.Five populations of C.japonica were analyzed by ISSR markers to detect the genetic structure.Twenty primers produced scorable markers were applied.The percentage of polymorphic loci,Nei’s gene diversity and Shannon’s Information Index were 70.29%,0.281 9 and 0.409 5,indicating C.japonica had a higher level of genetic diversity than other insular plants.The coefficient gene differentiation(Gst) was 0.205 7,the effect of geographical isolation had great influences and significant correlation was found between genetic distance and geographic distance(r=0.821 7,P<0.05).UPGMA analysis revealed that populations in the same island had a close relationship.Taking examples from the experience of Japan,management strategies were proposed that natural population should be protected in situ from human disturbance to facilitate its natural generation.Constructing germplasm resources and cultivating plants mutually collected from different populations are necessary to enhance the gene flow.