Effect of Long-term Subculture on Callus from Maize Immature Embryo

[Objective] The calluses quality changes were studied in long-term subculture condition. [Method] Calluses derived from five maize genotypes were used to investigate the calluses quality change after 10 and 20 times subculture. [Result]The result showed that the growing capacity,embryogenic callus rate,regeneration frequency of callus with 20 times subculture declined significantly compared with those of callus with 10 times subculture. The declines of type Ⅰ calluses which derived from three genotypes were significant,but that of type Ⅱcallus which derived from two genotypes were not. [Conclusion]This demonstrate that during long term subculture,quality of type Ⅱ callus is steady,that of type Ⅰcallus is changeable. So type Ⅱ callus is more ideal for establishing the long term culture system than the type Ⅰcallus.