Segregation Analysis Of Hybrid Rice Quality Traits

In this study, four hybrid parents with different genetic relationship were used to establish two hybrid F2 populations and explore the genetic segregation of eight quality traits separation. The two hybrid F2 populations were Keihui36/Huanghuazhan, 96 populations(P1) and Wanhui 88/Japonica197, 120 populations(P2). The results were as follows:1. Analysis of frequency distribution of quality traits in P1 and P2 populations showed that the most individuals of F2 populations tend to be parents in brown rice rate(BR), milled rice rate(MR), grain length(GL), the length/width ration(L/W) and stably inherit good traits from parents, even though a few were lower than those of parents or showed transgressive heterosis. In contrast, the phenotypic characteristics of head milled rice rate(HR), chalkiness(C), percentage of grains with chalkiness(PGWC), amylose content(AC) had a significant difference with those of the parents,especially in C and PGWC. Therefore, populations failed to stably inherit good genetic traits from parents. In this research, two individuals with low C and PGWC selected, which were the number 34 from P1 populations and the number 56 from P2 populations, both of the AC in two hybrid F2 populations and HR in P1 populations showed normal distribution, while other quality traits showed non-normal distribution.2. The analysis of coefficient of variation(CV) revealed that the CV of C in both P1 and P2 populations had the highest value. They were 103.9% and 94.6%,respectively, while the CV of BR, MR, GL, AC and L/W were relatively low. The CV of PGWC and HR were next to those of C.3. The correlation analysis of eight quality traits showed: BR and MR, C and PGWC in two hybrid F2 populations had significant positive correlations.4. The cluster analysis of quality traits showed that the first group in P1 populations with19 individuals had the highest average of HR and GL; the second group with 21 individuals had the lowest average of GL, the average of other quality traits were middle; the third with 56 individuals, accounting for 58% of the total population, had the highest average of BR, AC and MR, and the lowest average of PGWC and C. On the other hand, the first group in P2 populations with 89 individuals,accounting for 74% of the total population, had the highest average rate of HR and GL, the lowest average of PGWC and C; the second group with 10 individuals had the lowest average of BR, MR and L, the highest average of PGWC and C, the average of HR and AC were middle; the third group with 21 individuals had the highest average of BR, AC and MR.5. Compared PGWC of the hybrid F2, the phenotype and genotype of them were different. By the use of SSR RM21938 which closed to the gene of grains chalkiness and showed significantly different from their parents, the number 34 in P1 populations could stably inherited the good traits of one of the parent Huanghuazhan and showed transgressive heterosis, it failed in RM234 with invalid band. The genotype and phenotype were different in both P1 and P2 populations.