雄性不稔 雙稻를 利用한 벼 一代雜種 種子生産 Ⅱ. 細胞質的 雄性不稔 雙稻의 開花特性과 自然交雜率

Hybrid seed production using multiple pistillate male sterile rices Ⅱ. Flowering characteristics and natural outcrossing rate of the multiple pistillate cytoplasmic male sterile rices

Increasing natural outcrossing rate of the male sterile lines is the most essential problem in hybrid rice breeding. This experiment was carried out to test outcross rate of the multiple pistillate cytoplasmic male sterile(MPCMS) rice. Flowering characteristics such as rate of opened floret, rate of stigma exsertion and opened floret angle of the MPCMS lines were compared with those of the single pistillate cytoplasmic male sterile(SPCMS) lines. After planting the MPCMS line and their maintainer lines alternatively in field, natural outcrossing rate were investigated and compared with that of SPCMS lines. Rate of opened floret and rate of stigma exsertion of the Indica MPCMS lines were lower than those of the Indica control however those of Japonica MPCMS lines were higher than those of Japonica control. Opened floret angle and anthesis duration of the Indica MPCMS lines were lower and shorter than the Indica control, however those of Japonica MPCMS lines were higher and longer than those of Japonica control. Natural outcrossing rate of the Japonica MPCMS lines were higher than those of Japonica control, but that of the Indica MPCMS lines were lower than that of Indica control.