Exploration of the strong heterosis of intersubspecies cross of rice has been hindered by the sterility problem in indica/japonica hybrids. Such incompatibility can be overcome by incorporation of the wide compatibility gene S_5~(11) into indica or japonica breeding lines. An alternation is to develop male sterile lines with S_5~n. From a cross of Zhenshan 97B, the main tainer line of WA type male sterile line Zhenshan 97A, with Pecos, a wide compatibility line from USA, a WA type male sterile line with wide compat ibility named as Shanqin A was successfully developed through successive selling and baekcrossing simultaneously (see figure). Exploration of the strong heterosis of intersubspecies cross of rice has been hindered by the sterility problem in indica / japonica hybrids. Such incompatibility can be overcome by incorporation of the wide compatibility gene S_5-11 (11) into indica or japonica breeding lines. An alternation is to develop male sterile lines with S_5 ~ n. From a cross of Zhenshan 97B, the main tainer line of WA type male sterile line Zhenshan 97A, with Pecos, a wide compatibility line from USA, a WA type male sterile line with wide compat ibility named as Shanqin A was successfully developed through successive selling and baekcrossing simultaneously (see figure).