杂交水稻中超显性效应的分析

Identification of Over-dominance QTL in Hybrid Rice Combinations

本文提出亚群体分析法 ,在二个衍生于杂交稻推广组合的F2 群体中 ,挑选均匀分布于连锁图谱的DNA标记作为固定因子 ,分别根据每个固定因子的基因型将F2 群体分成三类亚群体 :母本型 (I型 )、父本型 (II型 )和杂合型 (III型 )。在大量III型亚群体中 ,杂合度与产量和穗数呈显著正相关。在表现这种相关性的III型亚群体内分析产量QTL和穗数QTL,发现超显性作用是研究组合杂种优势的主要遗传基础。

Two F2 populations were each derived from a commercial hybrid and used for identification of genetic factors contributing to heterosis of rice.DNA markers distributing evenly in the linkage maps were selected as fixing factors.The F2 populations were divided into three types of sub populations based on the genotypes of each fixing factor:maternal type (Type I),paternal type (Type II) and heterozygous type (Type III).In a large number of Type III sub populations,significant correlations were observed between heterozygosity and grain yield,and between heterozygosity and number of panicle.QTL analysis in Type III sub populations showing such correlations indicated that over dominance was the major genetic basis of heterosis in the two crosses.