When being planted in wide areas in southern China (23°23' - 33°23' N, 98°35’ - 129°19' E, sea level above 2.7 - 1285m), Liangyoupeijiu (LYPJ), a two-line hybrid rice combination, showed a seed setting rate of 75.2-77.2%, which was lower by 4.3-7.5 percent point than that of an indica hybrid rice Shanyou 63 (CK), with similar values of grain yield and coefficients of variation to CK. Sowing during 5-25th of May in Nanjing (32°3' N. 118°48' E), China, LYPJ headed before 4th September, and gave a seed setting rate of 75 - 90%, and grain yield over 1 kg/m^2. If the sowing date was delayed to 14 - 15th, June, its heading date would be as late as 17th - 21st September, and seed setting rate would be declined by 10-15% in comparison with that on a suitable sowing date. When flowering took place at an average daily temperature range of 13.7-28.5℃ for five days, the spikelet fertility (SF) would be increased by 1.9-10.7%, for each increment of 1℃. The suitable (SF≥90%) and safe (SF≥75%)temperatures for flowering stage were indicated to be 26.5° and 22.9°, respectively. To get a high and stable seed set in cultivating LYPJ, it was recommended that LYPJ would be planted in the areas south of 34°N, and the favorable average daily temperature during flowering stage should be at 26 - 28℃.
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