中文摘要：

【目的】评价清凉峰地区三叶海棠的遗传多样性水平,为其保护提供理论依据。【方法】利用10对SSR引物,对清凉峰地区的36份三叶海棠样品进行了遗传多样性分析,并从中随机抽取6,9,12,15,18,27,34株大小不同的样本,组成7个群体进行遗传多样性特征比较。【结果】（1）10对引物在36份样品中的多态性等位基因数（Na）平均值为7.1（5.0~10.0）,有效等位基因数（Ne）平均值为3.954（1.527～5.786）,平均观察杂合度（Ho）为0.781（0.194～1.000）,平均期望杂合度（He）为0.699（0.345～0.827）,香农多样性指数（I）平均值为1.458（0.662～1.918）;（2）采用UPGMA法构建的系统树中,很明显地将36份供试样品划分为两组,与用贝叶斯聚类方法得到的结果一致,对三叶海棠所有样品进行的主成分分析进一步证实了以上结果;（3）群体样本量≥15株时,样本量就不会对群体内遗传多样性水平、遗传一致度及群体内等位基因数目产生明显的影响。【结论】清凉峰地区三叶海棠的遗传多样性水平较高,其群体明显分化为2个基因源,三叶海棠群体遗传多样性研究和种质收集保存中的适宜样本量为≥15株,研究供试样品可以反映清凉峰地区三叶海棠遗传多样性的总体水平。

英文摘要：

【Objective】The aims of this study were to assess the genetic diversity and to provide needed information for the development of conservation strategies for Malus sieboldii in Qingliangfeng region.【Method】Ten pairs of SSR（Simple Sequence Repeats） primers were used to evaluate genetic diversity of 36 accessions.Seven populations with different sample sizes（6,9,12,15,18,27 and 34 plants） were established by randomly selecting from 36 individuals,and used to compare the characteristics of genetic diversity with one another.【Results】（1） The results showed that mean number of polymorphic alleles（Na） was 7.1（5.0 to 10.0）,effective alleles（Ne）per locus was 3.954（1.527 to 5.786）,the observed heterozygosity（Ho）was 0.781（0.194 to 1.000）,the expected heterozygosity（He） was 0.699（0.345 to 0.827）,and mean Shannon s information index（I）was 1.458（0.662 to 1.918）.（2） Based on the UPGMA cluster analysis,36 samples were divided into two groups,which was similar to the results based on Bayesian clustering method and the PCA（principal component analysis）;（3） The sample size would not significantly affect the level of genetic diversity,genetic identity and numbers of rare alleles within population when it was not less than 15.【Conclusions】 The results indicated that Malus sieboldii in Qingliangfeng region had a high level of genetic diversity and displayed a highly mixed population structure which represented the two gene pools.The suitable sample sizes for collection and conservation,and the study on genetic diversity of Malus sieboldii were not less than 15.The accessions of Malus sieboldii in this study could reflect the whole level of genetic diversity in Qingliangfeng region.