摘要由于梨(Pyrus)本身的自交不亲和特性导致不同地区品种间基因存在较大差异。为鉴定品种资源的多样性，探索重要的遗传特性，本研究利用覆盖梨全基因组17个连锁群中的134个核心简单重复序列(simple sequence repeat, SSR)标记对45份西洋梨(Pyrus communis L.)品种资源进行遗传多样性和群体结构分析，对不同来源的SSR标记进行多态性分析。结果表明，来自梨基因组的SSR标记多态性更高，更适合梨的遗传多样性研究；所有SSR引物共检测到673个等位基因，每个SSR位点平均扩增5.02个；45份西洋梨品种的观测等位基因数(observed number of alleles, Na)、有效等位基因数(effective number of alleles, Ne)、观测杂合度(observed heterozygosity, Ho)、期望杂合度(expected heterozygosity, He)以及Shannon信息指数(Shannon's information index, I)平均值分别为5.02、3.84、0.73、0.72和1.42；遗传相似系数和聚类分析结果表明，45份西洋梨具有较高的遗传多样性，且品种的演化趋势较均匀，欧洲和美洲的品种没有因地理位置不同而产生太大差异，而是不同来源地的品种相互交织在一起，更加体现了西洋梨之间广泛的基因交流；同时推测未知来源地的库介梨、费莱茵和地里拜瑞可能来源于西欧地区；群体结构分析表明，当K=2时，西洋梨分为Pop1和Pop2两大类群，利布林、波12、拉达那、地里拜瑞、红安久和孔德梨体现了较高的杂合性；不同品种的指纹图谱分析结果表明，至少需要两个以上的引物组合才能够将不同品种区分开。研究结果为全面评价西洋梨的遗传背景和特征、准确鉴定不同品种资源提供了科学依据和高效标记，为今后西洋梨种质资源的保护利用以及遗传育种提供基础资料。
Abstract：The genes of pear (Pyrus) cultivars from different areas are different due to the natural self-incompatibility character. In order to identify the diversity of different cultivars and explore the important genetic traits, 134 core simple sequence repeat (SSR) markers with high polymorphism which covered all 17 lingkage groups of pear were used to study the genetic variability and the group structure of 45 European pears (Pyrus communis L.). 673 alleles were detected through all SSR primers, with mean of 5.02 per SSR primer. The mean of observed number of alleles (Na), effective number of alleles (Ne), observed heterozygosity (Ho), expected heterozygosity (He) and Shannon's information index (I) were 5.02, 3.84, 0.73, 0.72 and 1.42, respectively. The results of clustering analysis and the genetic similarity coefficient showed that the 45 cultivars had high genetic diversity and the evolution trend of the varieties was even. The cultivars distributed in Europe and America and intertwined with each other, and had no much difference due to different location, which might reveal the close relationship with genetic background of Europion pears. The species with unknown sources of Kujieli, Feilaiyin and Dilibairui might originate from Western Europe. According to the analysis of population structure, when the K-value was 2, the population of European pear was divided into 2 groups: Pop1 and Pop2, and cultivars of Clapp's Liebling, Bo12, Radana, Dilibairui, Red Anjou and Le Conte showed high heterozygosity. Fingerprint identification of European pears showed that at least two markers should be used to separate different cultivars. The results provide scientific evidence and perfecct markers for comprehensively evaluating the genetic background and characteristic as well as identifying different germplasm correctly, and also provide basic data for protection of germplasm resources utilization and genetic breeding.
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