西藏地区雪层杜鹃遗传多样性的AFLP分析

采用AFLP技术对西藏地区雪层杜鹃（Rhododendron nivale）5个天然种群135份材料进行遗传多样性和遗传分化研究。筛选得出的6对引物共扩增产物273条DNA片段，扩增多态位点百分率为85.71%。5个雪层杜鹃种群的遗传多样性指标表现了相似的变化趋势，Nei基因多样性指数（h）和Shannon信息指数（I）的变化趋势一致，均为工布江达县种群 < 米林种群 < 嘎隆拉种群 < 色季拉山种群 < 红拉山种群。POPGENE分析结果表明雪层杜鹃在物种水平（PPL=85.71%，I=0.415 1，h=0.273）具有较高的遗传多样性，种群水平（PPL=62.26%，I=0.280 3，h=0.184 1）的遗传多样性较低。AMOVA分析结果表明36%的遗传变异存在于种群间，64%的遗传变异存在于种群内，雪层杜鹃种群间的遗传分化系数（G_st=0.324）与AMOVA分析得到的遗传变异分布结果一致。UPGMA聚类结果说明雪层杜鹃的遗传距离与地理距离和海拔高度没有明显的相关性。综合分析，引起雪层杜鹃的遗传变异的原因可能是地理环境不同和种群的生境类型差异。最后就雪层杜鹃的合理开发和保护提出建议。

Assessment of Genetic Diversity of Rhododendron nivale in Tibetan,China using AFLP Markers

To determine the correlation among genetic variations, the geographic location of a population, and factors that influence high-level genetic diversity, the genetic diversity of 135 Rhododendron nivale samples was studied using amplified fragment length polymorphisms(AFLP). A total of 273 amplification products were generated from 6 selective primer combinations, of which 85.71% were polymorphic. The results of POPGENE showed the change trends of the percentage of polymorphic(PPL), Nei's genetic diversity(h) and Shannon's index(I) were similar. The change trends of Nei's genetic diversity(h) and Shannon's index(I) were Gongbujiada < Milin < Galongla < Sejila Mountain < Hongla Mountain. The POPGENE analysis showed that R.nivale had higher genetic diversity at species level(PPL=85.71%, I=0.415 1, h=0.273) but lower at population level(PPL=62.26%, I=0.280 3, h=0.184 1). Both the results of POPGENE(G_st=0.324) and AMOVA(36% among populations, 64% within populations) showed that the most genetic variance existed within the populations. UPGMA tree plots indicated that there was no significant correlation between the genetic distance and the geographic distance among the R.nivale populations. At last, some conservation strategies for R.nivale germplasm were put forward.