Discussion on available value of indica-compatible japonica line in inbred rice breeding

Indica-japonica crossing is a powerful approach to broaden genetic basis and develop elite variety， indica-compatible japonica line is situated a special position in indica-japonica crossing breeding. Indica-compatible japonica line is japonica line with indical S type，the concept was put forward by Zhang gui-quan in 1994，the line was developed as A line in indica- japonica hybrid. The relations between indica-compatible japonica line with other concepts such as wide-compatibility，specific compatibility，indica- japonica hybrid，indica- japonica varity，indica rice introgressed by japonica rice were distinguished. The reason why indica-compatible japonica line couldn’t be qualified as a registered variety is the low efficiency of development of indica-compatible japonica line，the difficulty of application of indica-compatible japonica line in inbred rice breeding is the low efficiency of development of indicacompatible japonica line and small scale of concerned breeding. The line is actually important in large-scale indicajaponica crossing breeding. The approach to apply the line was expounded. The efficiency to develop indica rice introgressed by japonica rice via application of indica-compatible japonica line，the breeding for indica-compatible japonica line was carried out preliminarily .