早籼稻谷粒性状遗传效应的分析

以广陆矮４号等８个粗短粒品种和湘早籼３号等５个细长粒品种进行不完全双列杂交，采用加－显遗传模型，对早籼谷粒性状进行了遗传分析。结果表明，谷粒性状属于多基因控制的数量遗传。粒长、粒宽、粒厚、长宽比、粒重和穗重等性状主要受制于基因的加性效应，其狭义遗传率为５０．９％—９５．０％，均达极显著水平。相对遗传进度表明，长宽比性状的选择效果好于其它性状。亲本和杂交组合遗传效应预测值表明，在长粒品种中容易选出谷粒长宽比大和宽度小的亲本，而在谷粒厚度大的品种中则易选出粒重和穗重高的亲本。浙农９２１、湘８６－７０和湘早籼３号等亲本在粒形和产量性状改良中具有很大的增值作用，其中浙农９２１／湘８６－７０、中１５６／湘８６－７０和浙农９２１／湘早籼３号等组合能够显著降低粒宽、增加粒长和长宽比以及提高粒重和穗重。

Analysis of genetic effects of grain traits in indica rice

Genetic effects analysis of grain traits were based on the experirment with the early season indica rice(Oryza sativa L.subsp.indica)by using an addative-dominance genetic model.The crosses were made using eight short grain varieties Guangluai 4 etc)as females and five long grain varieties (Xiangzaoxian 3 etc)as males in incomplete diallel crosses.The results indicated that grain traits studied were quantitatively inherited.Grain traits were mainly controlled by addi-tive genetic effects.Narrow-sense heritabilities were significant for all grain traits and the esti-mates were around 50.9% 95.0%.Selecting effects for ratio of grain length to width were better than those of other traits. The predicted parents and crosses indicated that it was easy to select the parents with narrow grain and larger ratio of grain length to width in varieties with long grain.The varieties,Xiang 86-70, Xiangzaoxian 3 and Zhenong 921,were better parents in improving grain shape and yield traits.The crosses,Zhenong 921/Xiang 86-70,Zhong 156/Xiang 86:70,Zhenong 921/Xiangzaoxian 3,could significantly increase grain length,grain weight,panicle weight and decrease grain width.