Genetic Differences of Parents and Its Relation to Heterosis in Early Hybrid Rice

Using 4 CMS lines, 7 restorer lines and their 28 hybrids as the materials, the genetic difference of early hybrid rice parents and its relation to F 1 heterosis were studied through principal component and cluster analysis of 8 agronomic characters. The results showed that the average genetic distance was 5.926 8 ranging from 0.348 9 to 19.252 7 among all genetic distances of the 11 parents. There was a genetic difference to some extent among the parents and the genetic difference was greater within maintainers than within restorers, but the genetic difference between maintainers and restorers was not much different from that within maintainers or restorers. The analysis of correlation between the genetic distance of both parents and heterosis of their F 1 hybrids showed that there was not a correlation between them among the tested early hybrid rice parents.