Heredity Analysis Of Yield-related Traits Of Rice Lines Derived From Indica And Japonica Subspecies Cross

Lines derived from Indica and Japonica subspecies cross of rice were developed by Agricultural Science Institution of San Ming through the way of continuous polymerization and accumulation of different genes of wide compatibility and restorative genetic. It is an important theoretical sense and guidance value to explore the inheritance disciplines of yield-related traits and evaluate the using value of breeding for nurturing hybrid rice with strong practical advantages. In this study, 3 lines possessing long fringe and big grain and 5 restorative lines derived from Indica and Japonica cross were screened out as research objects. According to imperfection double cross design(3×5), a suit of genetic materials including 2 generations of parents and F1 was selected. With the addictive-dominant genetic model(AD model) and statistical analysis methods of quantitative traits of plants, the genetic effect,heterosis and genetic correlation of the 15 yield-related traits were analyzed systematically. The main research results are as follows:1. Analysis of phenotypic value of lines derived from Indica and Japonica subspecies cross of rice in yield-related traits indicated that average value of parents were higher than F1 in 8 traits which contain number of effective fringe of per plant, real grain number of per fringe, total grain number of per fringe, seed-setting rate, grain length, grain aspect ratio, number of first branches and number of secondary branches in 15 traits, the remaining 7 traits showed the opposite. It showed that F1 were the higher in height and the lower in seed-setting rate and the fewer and longer in number of branches, but 1000-grain weight and grain weight of per plant were higher. Coefficient of variation of parents were higher than F1 in 8 traits which contain fringe length, real grain number of per fringe, total grain number of per fringe, 1000-grain weigh, grain length, grain aspect ratio, number of first branches and number of secondary branches in 15 traits, the remaining 7 traits showed the opposite.2. Analysis of genetic variance components of lines derived from Indica and Japonica subspecies cross of rice in yield-related traits indicated that the heredity of 8 traits which contain real grain number of per fringe, total grain number of per fringe, 1000-grain weight, number of first branches, number of secondary branches, grain length, grain width and grain aspect ratio were mainly controlled by additive effect. The heredity of the 7 traits which contain effective fringe of per plant, seed-setting rate, grain weight of per plant, fringe length, length of first branches, length of secondary branches and plant height were mainly controlled by dominant effect. The traits of 1000-grain weight, grain length, grain aspect ratio of CD-1,CD-2 and CD-3 of parents showed significant positive additive effects. Real grain number of per fringe and total grain number of per fringe of derived lines of Minghui503, Minghui512, Minghui118, Minghui502 and Minghui413 showed significant positive additive effects. The traits of 1000-grain weight and grain length of combination of CD-3/Minghui512 showed the strongest and highly significant positive dominant effect. The traits of grain weight of per plant and length of secondary branches of combination of CD-3/Minghui 413 showed highly significant positive dominant effect. 3. Analysis of heterosis of lines derived from Indica and Japonica subspecies cross of rice in yield-related traits indicated that the 7 traits which contain plant height, fringe length, 1000-grain weight, grain weight of per plant, grain width, length of first branches and length of secondary branches in F1 showed significant positive average advantage of the group. Combination of CD-3 /Minghui502 has obvious average advantages in increasing length of fringe. The combination of CD-2/Minghui502 has obvious average advantages in improving the grain weight of per plant. The 4 traits which contain plant height, grain width, length of first branches and length of secondary branches showed significant positive super-parents advantage of the group and combination of CD-1/Minghui512 has obvious super-parents advantage in increasing the effective fringe of per plant. Combinations of CD-1/Minghui502 and CD-3/Minghui503 have separately obvious super-parents advantage in increasing length of first branches and length of secondary branches.4. Analysis of genetic correlation of lines derived from Indica and Japonica subspecies cross of rice in yield-related traits indicated that traits of the effective fringe of per plant and grain weight of per plant were significant dominant positive correlation as major and the effective fringe of per plant and total grain number of per fringe were significant dominant negative correlation as major. Traits of total grain number of per fringe and seed-setting rate were highly significant dominant negative correlation as major. There were significant additive negative correlation between fringe length and number of first branches, number of secondary branches. There were significant dominant positive correlation between fringe length and length of first branches, length of secondary branches. Length of secondary branches and length of first branches, number of secondary branches were significant dominant positive correlation as major. Grain length and grain width were significant dominant negative correlation as major. Grain width and grain aspect ratio were significant negative additive correlation as major. In addition, there were significant or highly significant correlations between most of traits of fringe part and real grain number of per fringe, total grain number of per fringe, 1000-grain weight in additive and dominant correlation. The traits of 1000-grain weight and grain length , grain aspect ratio were both highly significant positive correlation. Number of first branches,number of secondary branches and grain length,grain width,grain aspect ratio were all additive correlation as major in additive and dominant correlation. Length of first branches, length of secondary branches and grain length, grain width, grain aspect ratio were all dominant correlation as major in additive and dominant correlation.