Analysis of Characteristics and Heterosis of Three-Line Parents in Hybrid <I>Japonica</I> Rice

Abstract

Sixteen representative varieties each for BT-type cytoplasmic-nucleic male sterility (CMS) lines,maintainers and restorers were collected respectively,and 229 hybrid combinations were developed in this study.Then the correlations between parents and progenies were analysed on the all traits.The main results were as follows: (1) Compared with the maintainers,the restorers had higher plant height,thicker stalk and bigger panicle.The latent storage capacity of the maintainers and restorers was about 30 g on an average,and the restorers had less tillers,lower seed setting rate and lower 1000-grain weigh,resulting in the lower yield per plant.The chalkiness degree of restorers was higher than that of maintainers,while the amylose content of restorers was significantly lower than that of maintainers.(2) The mid-parent heterosis of hybrid japonica rice was strong,while the over-parent heterosis of most characters was weak excepting the competitive advantage of growth vigor.The panicles of hybrid japonica rice were big,showing the positive heterosis,but the seed setting rate had a negative heterosis,which was the main limiting factor on the yield heterosis of hybrid japonica rice.(3) Analysis of the correlation between parents and their progenies indicated that the correlation between the character values of F1 combinations and this mid-parent values was the best.Comparatively,the correlations between CMS lines and F1 in heading date and total spikelets per panicle were significant,while the correlations of restorers and F1 in plant height,filled grains per panicle,seed setting rate,yield per plant and quality characters were significant.