Research Progress of Differentiation and Hybrid Breeding between Indica and Japonica Rices

Indica and Japonica rice hybrids easy to produce ultra-parents variations and heterosis,with vast reservoir of genetic potential.The rice yield further enhance hopes on the direct use of the subspecific heterosis,but achieving this goal still faces many difficulties,solution depends on the in-depth study of the mechanism of indica and japonica differentiation and hybrids heterosis.It was reviewed and prospected that origin and differentiation of Asian cultivated rice,classification methods and evaluation of the indica and japonica,history of hybrid breeding between indica and japonica,the main problems and solution in hybrid breeding between indica and japonica,the relationship between degree of differentiation of indica and japonica and heterosis of cross between indica and japonica,the relationship of subspecies characteristics and economic characters and the effects of ecological environments on the filial generation of cross between indica and japonica rice,to provide a scientific basis and references for direct use of the heterosis of cross between indica and japonica subspecies in super rice breeding.