Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and population structure of four natural Prunus mira populations from Tibet. A total of 376 bands were amplified from four natural populations by 20 primers, and 338 SRAP loci were found to be polymorphic. A relatively high level of intraspecific genetic diversity was revealed: PPB (percentage of polymorphic loci) =89. 89% , H (Nei's gene diversity) = 0. 194 3, I (Shannon's information index) =0. 295 5 at the population level, and PPB=89. 89% , H = 0. 246 0, 1 = 0. 383 9 at the species level. A low degree of genetic differentiation occurred among P. mira populations as indicated by a Gst (Nei's Gst analysis) of 0. 170 9 but the gene flow between populations was high (1. 213 0). UPGMA (unweighted pair group method with arithmetic mean) cluster analysis showed that the 70 individuals were not clustered into four clusters corresponding to the four populations. There was relatively high genetic diversity, low genetic differentiation and a high degree of gene flow between P. mira populations.%利用SRAP标记对来自西藏境内的4个光核桃自然居群的遗传多样性和群体遗传结构进行了分析和评价.选用20对引物对4个居群的70份材料进行扩增,检测到338个多态位点.在居群水平上,多态位点百分率为63.96％,Nei's基因多样性和Shannon's信息指数分别为0.194 3和0.295 5.在物种水平上,多态位点百分率为89.89％,Nei's基因多样性和Shannon's信息指数分别为0.246 0和0.383 9.居群间的遗传分化系数为0.170 9,居群间的基因流为1.213 0.UPGMA聚类图中,70个个体未按4个居群各自聚在一起.结果表明,光核桃遗传多样性水平较高,居群间遗传分化较小,居群间的基因交流程度较高.
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