大粒水稻之遺傳研究III．穀產量、生物產量及收穫指數之遺傳

Abstract

The inheritance or grain yield, biological yield and harvest index for larger kernel size or rice were studied by mean of a 9×9 diallel crosses including parents and reciprocal crosses. Date from the F1 generation and parents were analyzed using the Griffing and the Jinks-Hayman methods of diallel analyses. The genetic variations of these three traits were significant among the parents. Both additive and dominance effects were important for all these traits. Furthermore, dominace effects were significantly larger than additive effects for these traits except that for harvest index that additive and dominance effect was about equal. Highly significant general combining ability (GCA) and specific combining ability (SCA) effects were observed for these traits. The GCA effects were more important than SCA effects, the ratio being 4: 1. Maternal effects existed in all these traits. Degrees of dominance of all these traits estimated by graphic and variance analyses showed over-dominance. The average frequency of positive and negative allel in parents were about equal for all traits. Number of dominance genes exceeded recessive genes for biological yield. Onthe other hand, both number of dominance and recessive genes were equal for grain yield and harvest index. Directions of dominance evaluated by regression plotting and correlation coefficient between Y(subscript r) and (W(subscript r)±V(subscript r)), were toward lower grain yield for grain yield and ambi-directions for biological yield and harvest index. Estimated heritabilities for all these traits were low.