两系法杂交稻两优培九结实率稳定性及其与温度的关系

分析了1999~2000年中国南方稻区19个区域试验点和5个生产试验点两优培九的结实率和产量。与汕优63相比，两优培九结实率要低4.3~7.5个百分点，但变异系数相近；产量水平及其变异系数则相近。在南京（32sup]。/sup]3′N, 118sup]。/sup]48′E）5月5~25日播种，两优培九在9月4日之前齐穗，结实率为75%~90%，产量在1 kg/m2以上；播种期推迟至6月14~15日，出穗期将延迟至9月17~21日，结实率比适宜播期的结实率低10~15个百分点。开花受精期5 d日均温平均值在13.7~28.5℃范围内，温度每增加1℃，受精率提高1.9%~10.7%。花粉育性与始花前5 d日均温平均值呈极显著的二次多项式相关。抽穗期适宜日均温（受精率≥90%）和安全日均温（受精率≥75%）分别为26.5℃和22.9℃。结果显示，北纬34sup]。/sup]以南地区为两优培九适宜种植区，宜将开花期安排在日均温为26~28℃的时期。

Stablility of Seed Setting Rate for a Two-Line Hybrid Rice Liangyoupeijiu in Associated with Temperature

In comparison with an indica hybrid rice Shanyou 63 (CK), Liangyoupeijiu, a two-line indica hybrid rice, showed the seed setting rate of 75.2%-77.2% which was lower by 4.3%-7.5% than that of CK, and approxima te values of grain yield and its variance as planting in southern China in 1999 -2000. Sowing during 5-25th, May in Nanjing (32°3′N, 118°48′E), China, Liangyoupeijiu headed before 4th, September, showed seed setting rate of 75%-90%, and grain yield over 1 kg/m². Its heading date would be late as 17-21st, September, and seed setting rate would be lowed by 10%-15% in comparison with a suitable sowing date if its sowing date be delayed as 14-15th, June. When flowering took place within an average daily temperature range from 13.7-28.5℃, spikelet fertility (SP) of rice was increased by 1.9%-10.7%, for each degree rise of temperature. The suitable (SP≥90%) and safe (SP≥75%) temperatures at flowering stage were 26.5℃ and 22.9℃, respectively. To get a high and stable seed setting rate for cultivating Liangyoupeijiu, areas being south of 34°N would be suitable, and the average daily temperature during heading stage would be at 26-28℃.