中国籼稻亚种内的群体结构及地理生态分化

籼稻是亚洲和世界其他一些地区广为种植的主要栽培稻亚种,同时也是我国杂交水稻恢复系的主要来源.研究籼稻亚种内的遗传结构和遗传多样性对中国栽培稻亚种内的分类和演化以及水稻杂种优势利用具有重要的理论和实践意义.本研究通过36个SSR标记对1582份籼稻地方品种的群体结构和地理生态分化进行了分析.结果表明,利用分子标记所做基于模型和基于遗传距离的群体结构表现一致,即早籼稻生态型可划分为4个地理生态群,中间型生态型可划分为3个地理生态群,晚籼稻生态型可划分为2个地理生态群.当地的生态环境和空间隔离是形成地理分化的主要原因.地理生态群既体现了品种间的遗传差异又是对不同生态环境适应的反映,可用于籼稻亚种内杂种优势群划分的依据.根据SSR标记在各个生态型及地理生态群的基因型分布,筛选了可用于鉴别各生态型和地理生态群的SSR特征等位变异并建立了相应的SSR分子判别式.通过SSR分子判别式选择籼稻的中间类型开展籼粳杂种优势研究以及选择不同地理生态类型开展籼稻亚种内杂种优势研究,有助于突破籼粳杂种优势利用的障碍和加强籼稻亚种内杂种优势利用.

Genetic structure and eco-geographical differentiation of cultivated Hsien rice (Oryza sativa L.subsp.indica) in China revealed by microsatellites

Indica is not only an important rice subspecies widely grown in Asia and the rest of the world,but also one of the major genetic backgrounds of hybrid rice in China.Therefore,studies on the genetic structure and genetic diversity of indica rice germplasm resources are important for research on the origin,evolution,and classification of cultivated rice in China.Using a genetically representative core collection of 1582 rice landraces of indica in China,the genetic structure,geographic differentiation,and diversity were analyzed.The model-based structure analysis of varieties within three ecotypes revealed nine eco-geographical types,which are partially consistent with some of the ecological zones in China.Local ecological adaption and physical isolation have contributed to the differentiation of eco-geographical types,which could be used to develop heterotic groups of indica.To facilitate the identification of different ecotypes and eco-geographical groups,we provide the SSR character alleles of each ecotype or geographical eco-group and a rapid discrimination method based on these character alleles.The character alleles and the rapid discrimination method could be used to guide the development of heterotic groups,to select hybrid parents,and as an efficient protocol for screening of hybrid crosses.