Abstract: Characteristics of light and tempreature and optimum flowering time of parents of Pearl millet (Pennisetum americanum) × Napier grass (P.purpureum) during hybrid production were studied by sowing in different time and short-day treatment.The results showed: ①Temperature summation from short-day treatment to heading date on Napier grass N51 was different in year and between years.Days from short-day treatment to heading date was stable about 36.7 ± 4.5 days.②Sterility line Pearl millet　Tift23A is warm and short-day crop.Differences were significant both days from sowing to heading date　and temperature summation in different years due to climate change.③Base tempreature of Napier grass and Pearl millet Tift23A were about 13.66℃ and 14.8℃ respectively.④Optimum flowering time for hybrid production of Pearl millet × Napier grass was last ten days in August, so sowing time for sterility line Pearl millet Tift23A on first and tenth in June, and Napier grass N51 should be on 15, July and with short-day treatment.It can be obtained flowering time agreement.

Key words: Flowering time agreement, Hybrid, Pennisetum americanum, P. purpureum, Temperature summation

摘要： 通过分期短日处理和分期播种的方法,研究了美洲狼尾草与象草杂交种生产中双亲的光温特性,探讨杂交制种适宜花期的选择。试验结果表明:1.象草N51短日处理至抽穗期的积温值在年度间及年内的差异均较大。而处理至抽穗的天数较稳定为36.7±4.5天。2.美洲狼尾草不育系Tift23A为喜温短日作物,由于年度间气候差异表现为不同年份播种至抽穗的天数差异极大,可达20天以上。积温值年度间及年内差异也极大。3.象草的有效下限温度为13.6℃,美洲狼尾草不育系Tift23A约为14.8℃。4.杂交制种的适宜花期为8月下旬,即美洲狼尾草不育系Tift23A在6月1日、10日分期播种,而象草N51在7月15日进行短日处理,可实现花期相遇。

关键词: 美洲狼尾草, 象草, 杂交种, 花期相遇, 积温