Correlation between the Parental Indica-japonica Characteristics of Recombinant Inbred Lines from an Indica-japonica Cross and Heterosis

In order to enhance the foresightedness of the heterosis utilization in two-line hybrid rice subspecies,with 5 dual-purpose genic male sterile lines and 9 recombinant inbred lines with different indica-japonica degrees as materials,the correlation between parental indica-japonica characteristics and heterosis was studied.The results showed that the indica-japonica characteristics identified with the 1st～2nd ear-node lengths of hybrid F1 showed the correlation between indica-japonica difference and yield heterosis better.The stronger the indica characteristic of male parent was,the bigger its heterosis was and the stronger the japonica characteristic of female parent was,the bigger its heterosis was.The increment of japonica characteristic was in favor of enhancing the heterosis on full grains per ear,available ears,seed setting rate and 1 000-seed weight and the increment of indica characteristic was in favor of enhancing the heterosis on total grains per ear and seed setting density.The utilization of heterosis of indica-japonica subspecies should regard the breeding of indica compatible japonica male sterile lines and good indica restorer lines(male parental lines) as the main objects and use the combination mode with japonica female parent and indica male parent.