田间高温严重降低杂交水稻制种的异交结实

在江苏盐城制种基地设置长期多品种分期播种试验,旨在探讨不同开花结实前后田间气象条件对结实的影响;2013年盐城在8月中下旬发生连续18d高温天气,该时期与各播期制种水稻的开花前时段相重叠。与2011年相比,水稻组合新两优223的制种结实率平均降低6.89个百分点,达显著水平。不同组合受高温影响,结实率降幅不同,其中,新两优223异交高温耐性强于新两优香四和新两优223改。2013年多组合各播期水稻异交结实率与水稻始穗期前后10d日平均气温呈显著负相关;回归分析表明,水稻始穗期前后10d日平均气温达28.0℃,异交结实开始受影响,达29.0℃时异交结实大幅下降。

Out-Crossing Seed Setting Rate Was Seriously Reduced By High-Temperature in Hybrid Rice Seed Production Under Field Conditions

The experiment with different seeding  date was conducted at the hybrid rice seed production site   in Yancheng City   to explore the impact of weather conditions at the heading  stage on   seed setting rates for female parents.    Exposed to consecutive high temperature  lasting for 11 days  in the mid to end of August 2013, in Yancheng,  before  blooming,   seed setting rate of the female parent in 2013  was significantly reduced by 6.89 percent on average  compared with  that  in 2011. Meanwhile there has been great differences in  high temperature sensitivity  among  various combinations, with Xinliangyouxiang 4 and Xinliangyou 223 gai being more insensitive than Xinliangyou 223. The out crossing rates of all the female parents showed a significant negative correlation with   high temperature   in 2013, but no correlation in 2011 in comparison. Regression analysis showed that when the 10 d average temperature before and after heading stage increased up to 28.0℃, the out crossing rate of the female parents began to fall, and when it came to 29.0℃ the out crossing rate  significantly reduced.