分期播种下拟高粱生育进程的温光特性

EFFECTS OF TEMPERATURE AND PHOTOPERIOD ON THE DEVELOPMENT OF SORGHUM PROPINQUUM SOWN AT DIFFERENT DATES

对拟高粱在南京分期播种条件下生育进程的变化及其与温度和日长的关系进行了初步的研究。拟高粱播种至成熟全生育期为176～141天,随播期延迟而缩短。播期对播种至分蘖的天数影响较大。播种至出苗的天数与最低温度呈极显著负相关(r=-0.9577),与5厘米地温呈二次曲线关系,地温为29.9℃时出苗最快。出苗至分蘖的天数则与平均气温(X)呈二次曲线关系((?)=252.08-18.22X+0.36X^2,F=33.3^(**)),平均气温为25.3℃时出苗至分蘖的天数最短。抽穗至成熟的天数与平均气温呈极显著负相关(r=-0.9475)。表明拟高粱播种至分蘖、抽穗至成熟均表现温度效应。短日处理拟高粱分蘖至抽穗的天数较对照缩短38～54天,可见拟高粱分蘖至抽穗主要表现日长效应,并随着温度的升高短日效应增强。拟高粱在南京不宜作收种用,收草则以4月下旬播种为宜。

The whole growing period of Sorghum propinquum is 141 to 176 days and shortens with the delay of sowing time.The sowing date had greater influence on the duration from sowing to tillering.The days from sowing to emergence were negatively related to the minimum temperature (r=-0.9577,p0.01),and had the quadratic function with the soil temperature (5cm).The days from emergence to tillering had the quadratic function with the average temperature (Y=252.08-18.22X+0.36X^2,F=33.3).The days from heading to ripening were significantly related to the avertage temperature (r=-0.9475). Above results indicated that the durations from sowing to tillering and from heading to ripening were most responsive to changing temperature.After the short daylength treatment the durations from tillering to head- ing significantly shortened 38～54 days.However,effects of shorter daylength on the development of S. propinquum were promoted with the increase of temperature.It was shown that the duration from tillering to heading was mainly controlled by the photoperiod.