核质互作不育和光敏核不育聚合的粳稻不育系选育

 针对粳型核质互作不育系高温自交结实和粳型光敏核不育系低温自交结实的现状，选择BT型核质互作不育系与含有BT型保持基因的粳型光敏核不育系，通过杂交和回交，使雄性核不育基因与核质互作不育基因聚合，育成了粳型光敏核质互作不育系2308SA和2310SA。该不育系的不育性是由两套相互独立的基因系统控制的，分期播种育性观察结果表明，在长日高温下，雄性光敏核不育隐性纯合基因控制水稻不育性，避免了BT型不育基因因穗期受高温影响而导致不育系自交结实；在长日适温下，水稻不育性由核不育基因和核质互作不育基因共同控制而表现稳定；在低温（低于光敏不育系不育临界温度）或短日适温（日最高气温<32℃）下，BT型核质互作不育基因控制水稻不育性，消除了育性敏感期低温导致核不育系"打摆子"造成杂交种子不纯的风险。还对粳型光敏感核质互作不育系的可恢性、可繁性和配合力进行了研究。

Development and Study of Japonica Male Sterile Lines Integrating Cytoplasmic Male Sterility and Photosensitive Genic Male Sterility

It is the fact that high temperature induces seed set of the BT type of cytoplasmic male sterility (CMS) and low temperature induces seed set of the photo-sensitive genic male sterility (PGMS). By crossing the CMS line with the PGMS japonica line with maintainer gene, the photo-sensitive cytoplasmic male sterility (PCMS) lines, 2308SA and 2310SA, were bred. Because of integrating PGMS and CMS genes, the sterility of PCMS japonica is controlled by two group of male sterile genes. The results of observation on the fertility of plants by different sowing times showed: 1. Under the conditions of natural long-day photoperiod and over 35℃, the PGMS gene regulated the sterility of PCMS japonica. The higher the temperature, the lower the pollen fertility and bagged seed set of PCMS japonica, which avoided the effect of high temperature inducing the seed set of CMS. 2. When long-day photoperiod and between 35℃ and the critical sterility inducing temperature of PGMS, both PGMS and CMS gene controlled sterility of PCMS japonica, and they so which exhibit stable characters. 3. Under the critical sterility inducing temperature or short-day photoperiod and the highest daily temperature (<32℃), the BT type of CMS gene regulated the sterility of PCMS so that the PGMS gene would render the male sterility insusceptible to occasional cool summer days when this PCMS line adopted for hybrid seed production develops into panicle differetiation stage. Moreover, the fertility restoration, seed production and combining ability of PCMS japonica in order to utilize it better in future were also studied.