벼의 粒重增大에 의한 收量性向上에 關한 硏究 Ⅱ. 벼 粒重과 粒長에 대한 遺傳分析

Studies on the yield potential increment by grain weight in rice Ⅱ. Genetic study on the grain weight and length

Six parent varieties and 15 F₁ hybrids of 6x6 partial diallel crosses were used in genetic study which was carried out to obtain basic informations on the breeding for high yielding rice varieties by increasing grain weight. Variance for general combining ability (GCA) and specific combining ability (SCA) were significant for all characters studied. GCA/SCA variance ratio indicated the additive gene effects were more important for all grain size characters. CGA effect of BG29, 5178 were highly positive, however Bomdia, IR 747 B2 were highly negative for all characters. In the analysis of variance, additive gene effects were more prevalent than dominant effects. Vr-Wr graph showed that short and small grain had partial dominance and the degree of dominance for all characters also pointed out that the grain character are mainly controlled by additive genetic factors. Estimared heritabilities for those characters were high in diallel-crossed F₁.