A Preliminary Study on the Relationship Between the Indica-japonica Differentiation of Parents and Heterosis in Dian Type Hybrid Rice by RAPD Markers

The relationship between the indica japonica differentiation of parents and heterosis of hybrid rice was studied with 10 sterile lines, 10 maintainer lines, and 38 restorer lines of Dian type hybrid rice and 40 hybrids derived from the sterile lines and restorer lines. A parabolic correlation between the indica japonica diffe rentiation of parents and heterosis of hybrid rice was detected by RAPD markers. When certain indica japanica differentiation between parents exists, the percentage of combinations with positive heterosis and the mean he terosis of hybrids was high. It does not mean that a great difference of parents will lead to stronger hetesosis in hybrids and a much great difference in parents seldom bring positive heterotic hybrids. Suitable difference in percentage of indica alleles of parents with stronger heterotic hybrid was 12%-16%.