小麦异交群体选择分化的RAPD分析

The RAPD Marker Analysis of Wheat Outbreeding Population due to Selection Differentiation

用RAPD分子标记技术及数量遗传分析手段对小麦异交群体趋异选择 4代得到的各子群体的遗传关系进行了分析 ,并对两种结果进行了相关分析。采用 11个引物扩增出 134个位点 ,RAPD分析结果表明 ,群体具有丰富的遗传变异 ,整个群体的多态位点百分率达 0 .8134,杂合度达 0 .30 0 6 ;子群体间遗传分化较小 ,相对基因分化系数Gst为 0 .2 310 ,固定指数平均 0 .2 12 0 ,标准遗传距离为 0 .10 44± 0 .0 48,表明遗传变异多数来自群体之内。而数量遗传分析发现 ,选择性状进展都与预期方向相符 ,主成分遗传距离大部分达显著水平 ,说明选择使群体发生了相当程度的分化。对两种遗传距离进行聚类分析表明 ,二种信息间关系各类群成员多不一致。其原因可能在于 :数量性状是人工选择的目标 ,RAPD是基因组随机序列的扩增 ,二者之间的相关与引物选择有关。

The genetic relations of some subpopulations in the fourth generation of selection in outbreeding population of winter wheat were examined by RAPD techniques and quantitative analysis. The correlations of the two results were examined.For RAPD analysis, 11 primers were adopted, and 134 sites were amplified. The results showed that abundant genetic variations existed in the populations. In the whole population, the percentage of polymorphic sites (P) is 0.8134, and the averaged heterozygosity is 0.3006. However,genetic differentiation among subpopulations is small. The relative gene differentiation (Gst) is 0.2310,fixed index averages 0.2120, and the standard genetic distance between subpopulations is 0.1044±0.048.All above shows that most of the genetic variations existed within populations.The cluster results from RAPD analysis and principal component distances showed that similarity relations were only found in small part of the subpopulations. The reason for the results may be that the genes concerned for quantitative traits are selected directly,while the genes involved in RAPD analysis are only random samples of the whole genomes.