Genetic Studies On 1000-Grain Weight Of Hybrid Rice By Two-Line Method

In this study, 74 combinations are obtained by crossing 8 photo-thermo-sterilities(indica) with 30 restoring lines. The study on genetic of 1000-grain weight Of all hybrid combinations F1 and parents are as follows : (1) 1000-grain weight of two parents (the male parentages, the female parentages and the mean of two parents) is very significantly positively correlated with 1000-grain weight in hybrids (F1), and the correlation coefficient is 0.4308**, 0.3523** and 0.5656** respectively. (2) The difference is significant among 1000-grain weight in hybrids (F1) .(3) The difference in 1000-grain weight general combining ability (GCA) and special combining ability (SCA) of parents are very significant . (4) The 1000-grain weight in hybrids (F1) is controlled by GCA and SCA of parents , and GCA of parents especially photo-thermo-sterilities parents play a more important role. (5) The heredity of 1000-grain weight in F1 hybrid rice by two-line is majorly controlled by gene, and the h2B is 99.40%, the h2N is 93.41%.According to the result of this research and the works on the 1000-grain weight by the formers , Breeding methods of choosing good 1000-grain weight in hybrids (F1) are discussed. Choosing good 1000-grain weight and higher GCA two parents, it is a good method for improving 1000-grainweight in hybrids (F1).