SSR标记遗传距离与粳稻杂种优势的相关性分析

Analysis on Correlation Between Heterosis and Genetic Distance Based on Simple Sequence Repeat Markers in japonica Rice

利用SSR分子标记对30个粳稻品种进行遗传多样性分析,继而研究分子标记遗传距离与按照NCⅡ设计获得的200个杂交组合主要产量性状杂种优势的相关性,探讨分子标记遗传距离预测杂种优势的可行性。结果表明,64对SSR引物共检测到185条多态性片段,平均每对引物2.9条,每个SSR位点的多态性信息含量指数(PIC值)变化范围为0.064～0.844,平均为0.380。以SSR标记遗传相似系数为原始数据,按UPGMA聚类方法将30个亲本材料划分为7大类群,分类结果与系谱关系基本相符。分子标记遗传距离与杂种性状平均值的相关除每穗总粒数外均达到显著或极显著水平,与杂种优势的相关均达到极显著水平,相关系数介于-0.361～0.359,说明分子标记可用于水稻杂种优势群的划分和遗传多样性分析,但相关程度还不足以预测产量杂种优势。

Genetic diversity among 30 japonica rice was studied using the simple sequence repeat（SSR） markers, and relationship between genetic distance based on SSR markers and yield heterosis was analyzed using the materials consisted of 30 parents and 200 F1 hybrids with a 20 × 10 diallel crossing design, The results indicated that 64 pairs of SSR primers could produce 185 steady polymorphic bands among 30 parents averaging 2.9 bands for each pair of primers. The polymorphic index content （PIC） values varied from 0. 064 to 0. 844 with an average of 0. 380. Cluster analysis by UPGMA classified 30 parents into seven groups based on genetic similarity, which was coincident with the heterotic groups determined by their pedigree analysis. The correlations between the genetic distance and yield heterosis and hybrid performance were significant except for the total number of spikelets per panicle, and the coefficients of correlations were ranged from --0. 361 to 0. 359. It is suggested that the molecular markers could be used as a useful tool for assigning heterotic group and measuring genetic diversity, but not for predicting heterosis because the coefficient of relationship between the genetic distance based on SSR markers and yield heterosis was too small.