Combining Abilities and Heterosis of Quality Characters in Japonica Hybrid Rice

The combining abilities and heterosis of 12 quality characters in F1 japonica hybrid rice were studied with 9 new BT-type japonica sterile lines and 5 restorer lines by NCⅡ design.General combining ability(GCA) variance of all characters was significant or highly significant.Except milled rice length and ratio of length to width,specific combining ability(SCA) variance was significant or highly significant for other characters.Milled rice rate,head rice rate,tasted value and amylose content were controlled by both additive and non-additive effects,while other characters were mainly controlled by additive effect.Grain shape and tasting quality were influenced by both sterile lines and restorer lines,while milling quality and appearance quality were mainly influenced by restorer lines.Most quality characters of hybrids rice showed the measurements between their parents,except that milled rice rate,head rice ratio and tasted value showed heterobeitiosis.There was a significant or highly significant positive relationship between the combining ability and heterosis of most charac ters.Based on the GCA effect and SCA variances of the parents,sterile lines 95122A and Xiangjing 8016A and restorer lines J16 and R187 are recommendable and can be widely used for high quality breeding of japonica hybrid rice.