Analysis of Relationship between Indica-Japonica Differentiation of Parents and Heterosis in Dian Type Hybrid Rice by SSR Markers

The relationship between the Indica-Japonica differentiation of parents and heterosis of hybrid rice was studied with 4 sterile lines,31 restoring lines of Dian type hybrid rice and 31 hybrids derived from the sterile lines and restoring lines by using 18 pairs of Indica-Japonica diagnostic primers.The results indicated that in the tested 18 loci,4 sterile lines were Japonica,31 restore lines were Japonica-like but some of tested loci were Indica-like and the Pi was 0-27.8 %. There was a correlation between the Indica-Japonica differentiation of parent detected and genetic distance by SSR markers and some of characters of heterosis of hybrid rice.When certain Indica-Japanica differentiation between parents exists,the percent of combinations with super heterotic hybrid and the mean heterosis of hybrids were high.But that did not mean that more difference of parents led to better heterosis in hybrids,and suitable difference of Indica alleles of parents of extreme heterotic hybrid was 5.6 %.