Core collection of a representative germplasm population in brassica napus

Chinese. 【目的】分析甘蓝型油菜的遗传多样性,遴选核心种质。【方法】将来自欧洲、亚洲、加拿大、澳大利亚和中国几个不同地区的甘蓝型油菜500余份,按照其品质特点、地理位置、生长习性分组并按比例取样,建立由87个品种组成的预选核心种质。采用EST-STS标记和SSR标记对其进行分析,剔除遗传冗余,选出代表该500余份资源的核心种质并进行分子标记多样性评价和表型特征分析。【结果】在相同的选择背景下,EST-STS和SSR标记的多态性检出率相仿（39%～40%）,每对EST引物与SSR引物产生的多态性条带相近。聚类分析在遗传相似系数0.65处把87个品种分成中国和国外油菜两个类群,进一步在约0.70处类群Ⅰ和类群Ⅱ又分别产生中国＂双低＂、中国＂双高＂以及欧洲冬油菜和欧洲春油菜各两个亚组。根据遗传多样性分析,剔除遗传相似系数大于或等于0.85的遗传冗余,获得78个品种的核心种质。【结论】EST-STS是一种经济、有效具有功能信息的分子标记,功效与普通SSR标记相仿;遗传多样性和聚类分析结果为甘蓝型油菜4个组的划分提供了依据;78个品种组成的核心种质保留了预选核心种质的遗传多样性和结构,可作为本研究中500余份品种资源的核心种质加以利用和保存。

English. [Objective ] Investigating the genetic diversity and selecting core collection of rapeseed. [Method ] According to previous researches, 500 accessions from Europe, Asia, Canada, Australia and China were divided into four groups based on their qualities, geographic regions and growth habits. A primary core collection of 87 accessions was sampled from each group in same proportion. EST-STS and SSR markers were applied to measure their genetic diversities, eliminate the genetic redundancy and evaluate diversity indices of molecular markers for developing core collection. Phenotypes of individual core gene pool were analyzed and compared. [Result] Under the same selection background, two types of marker showed similar polymorphism rate （39%-40%）, and polymorphic fragments number. Cluster analysis divided the 87 accessions into two groups （ Ⅰ, Ⅱ） at similarity coefficient of 0.65, further two subgroups from each group were generated, respectively. A core collection consisted of 78 accessions was constructed after eliminating genetic redundancy above 0.85 genetic similarity coefficients. [ Conclusion ] The results indicated that EST-STS was economic, effective and fimctional marker with similar efficacy compared with normal SSRs. The genetic diversity and cluster analysis supported the classification of four groups in Brassica napus. 78 accessions retaining the most genetic diversity and structure could be utilized and preserved as core germplasm collection for 500 initial raoeseed resources.