Abstract: Super hybrid rice Guodao 6 was used to analyze its tolerance against natural high temperature stress with different sowing times in field and a greenhouse treatment with controlled high temperature(40-42℃) during flowering to filling was conducted in 2005 and 2006.Differences in seed setting rate under different treatments were observed and heat injury index,grain yield and yield components were analyzed.Compared with control hybrid rice Xieyou 46,Guodao 6 showed stable yield and spikelet fertility and lower heat injury index under high temperature stress,indicating higher tolerance to high temperature.The spikelet sterility was positively correlated with daily average temperature,especially with daily maximum temperature and the coefficients of correlation for Guodao 6 were 0.8604 and 0.9850(P<0.05),respectively.Meanwhile,daily maximum temperature showed less effect on seed setting rate than daily average temperature during filling,their coefficients of correlation for Guodao 6 were 0.7352 and 0.9317(P<0.05),respectively.

Key words: super hybrid rice, flowering, filling, high temperature stress, spikelet fertility

摘要： 以超级杂交稻国稻6号（内2优6号）为材料，于2005-2006年在杭州分期播种，通过不同齐穗期条件下的产量及产量构成因子变异研究，分析开花结实期自然高温对灌浆结实的影响，同时在温室条件下设置可控极值高温（40～42℃）测定热害指数。国稻6号对开花结实期自然高温或设计极值高温的反应明显较对照协优46钝感，两者在小穗育性和热害指数上的差异达显著水平（P<0.05）。试验结果还表明国稻6号随花期日平均温度升高小穗不育率增加，尤其与日最高温度的关系更为密切，两者的相关系数分别为0.8604和0.9850（P<0.05）,表明日最高温度对小穗育性伤害更烈。而灌浆结实期日最高温度对国稻6号结实率的影响不如日平均温度，相关系数分别为0.7352和0.9317（P<0.05）。

关键词: 超级杂交稻, 开花, 结实, 高温热害, 小穗育性