The Relation Between InDel Genetic Distance and Heterosis in Rice

Heterosis is a common phenomenon in plant species, which has been extensively utilized in different crops. Genetic distance is one of important basis for selecting parents in hybrid breeding. There is a relation between the genetic distance and heterosis and hybrid rice combinations usually show a stronger heterosis with larger genetic distance between parental lines. In this study, 160 hybrid rice combinations were made by incomplete duallel cross using 10 sterile lines and 16 self-bred restorer lines. Moreover, the indica-japonica gene frequencies of 26 lines were identified by 20 pairs of the InDel markers. The relationships between the InDel genetic distance and the phenotype heterosis were analyzed. Here, the results showed that the InDel genetic distance between parents could be used to predict phenotype value of effective panicle per plant and control heterosis of yield per plant and seed setting rate of the tested rice combinations. The optimal distance between the parents was in the interval 0.1-0.55 for the control heterosis of several main yield traits including effective panicle per plant, filled grains per panicle and yield per plant of combinations. The present result will provide a useful reference for hybrid rice parents selection in breeding.