Utilizing heterosis and Combining ability for yield and associated traits in two line hybrid rice system

The inheritance of some rice agronomic characteristics associated with environmental genic male sterile (EGMS), twenty hybrids which produced by crossing among four lines and five testers. Analysis of variance of combining ability revealed significant differences among genotypes, crosses, lines, testers and line x tester interactions. The significant differences among the lines, testers and lines x testers indicated that the genotypes had wide genetic diversity among themselves for all traits except days to heading, chlorophyll content, panicle length and apparent heterosis for parents. Five hybrids WTSC9059S x Sakha101, WTSC9039S x Sakha102, WTSC9059S x Sakha108, WTSC9039S x Sakha108 and WTSC9039S x Sakha101 having better mean yield performance are recommended for heterosis breeding. All traits were studied are governed by non-additive type of genes which necessitates selection in later generations for improvement. Variances of SCA were higher than the GCA variances for traits studied which indicated predominance of non-additive gene action in the inheritance of the traits.本研究围绕与环境型核雄性不育（environmental genic male sterile, EGMS）相关的部分水稻农艺性状的遗传特性展开分析，以4个不育系与5个测验系杂交配制得到20个杂交组合。配合力方差分析结果显示，基因型、杂交组合、不育系、测验系以及不育系×测验系互作间均存在极显著差异。除抽穗天数、叶绿素含量、穗长以及亲本表观杂种优势外，供试基因型在其余所有性状上均具有丰富的遗传多样性。其中，WTSC9059S×Sakha101、WTSC9039S×Sakha102、WTSC9059S×Sakha108、WTSC9039S×Sakha108及WTSC9039S×Sakha101这5个杂交组合的平均产量表现优异，可推荐用于杂种优势育种。本研究所考察的所有性状均受非加性基因调控，因此需在后续世代开展选择以实现性状改良。供试性状的特殊配合力（special combining ability, SCA）方差均高于一般配合力（general combining ability, GCA）方差，表明该类性状的遗传以非加性基因效应为主导。