中文摘要：

利用12对微卫星（SSR）分子标记对涉及6省8个羊踯躅自然居群193个体的遗传多样性和遗传结构进行分析,探讨羊踯躅遗传多样性水平与分化程度的可能原因,为羊踯躅的保护提供科学依据。结果显示：（1）12对SSR引物共扩出260个等位基因,每个位点的平均等位基因数为21.667,平均有效等位基因数（Ne）为5.425,平均多态信息含量（PIC）为0.900;物种水平的Shannon多样性指数（I）为1.768,基因多样性指数（H）为0.777。（2）江西金溪（JX）的羊踯躅居群的遗传变异最丰富,福建政和（ZH）的遗传多样性水平最低。（3）基于无限等位基因模型（IAM）的遗传分化系数（F_（st））为0.142,基因流（N_m）为1.522;AMOVA分析显示羊踯躅居群内变异（87.71%）大于居群间变异（12.29%）。（4）遗传距离法聚类NJ分析和Structure分析均表明,8个自然群体被分为三大类群;Mantel检测发现,羊踯躅遗传距离与地理距离无显著相关性。研究表明,羊踯躅最好以就地保护为主,应优先保护江西金溪（JX）居群,同时增加对福建政和（ZH）和湖北京山（JS）居群的保护权重。讨论了羊踯躅较高遗传多样性和中等程度分化的可能原因。

英文摘要：

In the present study, 12 pairs of simple sequence repeat （SSR） primers were used to evaluate ge netic diversity and genetic structure of Rhododendron molle G. Don in eight populations from six prov- inces. The results showed that： （1）A total of 260 alleles with an average 21. 667 alleles per locus were am plified from 193 individuals. Average values of number of effective alleles （Ne） and polymorphism informa tion content （PIC） were 5. 425 and 0. 900,respectively. This species has higher genetic diversity and gene flow among different populations. For R. moHe,the Shannon＇ s information index （I） and Nei＇s gene diver- sity （H） were 1. 768 and 0. 777, respectively. （2）Comprehensive analysis suggested that Jinxi （Jiangxi Province） population exhibits great level of variability,whereas the population of Zhenghe （Fujian Prov- ince） exhibits the lowest level of variability. （3）The genetic differentiation coefficient （Fm） based on infi- nite allele model （IAM） was 0. 142 and the gene flow （Nm） was 1. 522,respectively. Analysis of molecular variance （AMOVA） revealed that the genetic variation mainly occurred within populations （accounted for 87.71 %）, more than inter-populations （accounted for 12.29 %）. （4）The results of neighbor joining （N J） a nalysis based on genetic distance and structure analysis showed that eight populations were clustered into three groups. The mantel test showed there was no significant correlation between genetic distance and ge- ographical distance in R. molle. Our results indicated the priority should be given to in situ conservation, natural populations in Jinxi, Zhenghe, and Jingshan （Hubei Province） deserve prior conservation. The possi- ble formation of the high level genetic diversity and the moderate differentiation of R. molle were also discussed.