Genetic diversity and conservation strategy of Psilopeganum sinense, a rare species in the Three-Gorges Reservoir area
三峡库区稀有植物裸芸香的遗传多样性和保育策略

The genetic diversity of 128 individuals from six Psilopeganum sinense populations from the Three-Gorges Reservoir area was analyzed using RAPD. Thirteen primers produced a total of 85 scorable markers, of which 57 (67. 06% ) were polymorphic. The percentage of polymorphic loci of the six populations was 25.97% (FD) , 29.73% (WX) , 24.32% (WS) , 43.21% (BD) , 30.26% (XS) , and 39. 19% (ZG) , respectively. As analyzed by POPGENE 1. 31 and NTSYS 2. 10, the genetic diversity of Psilopeganum sinense was high, with an average Nei's gene diversity of 0.2082 and an average Shannons Information Index of 0.3196. In contrast, the genetic diversity within each population was low, with an average Neis gene diversity of 0. 1094 and an average Shannons Information Index 0. 1641. In addition, Gst was 0. 5391 and Nm was 0. 4275 , indicating more differentiation and less gene exchange between populations than within populations. The UPGMA cluster analysis showed that the six populations were genetically clustered into two groups, of which one was the Fengdu population and the other consisted of the remaining five populations distributed geographically with the Badong population as the center. A positive correlation (r =0. 93094 ,p =0. 9861) existed between geographical distance and genetic distance. Finally we discussed the cause of the endangerment status Psilopeganum sinense and proposed some management strategies for effectively protecting this species.