普通气候年景下江汉平原超级杂交稻结实率及其与气候条件的关系

采用扬两优6号等9个湖北目前推广的超级杂交稻组合,以汕优63为对照,从2008年4月19日起采用分期播种法每10d播种1次,考查品种结实率变化及其与结实前后主要气象因子的相关关系。结果表明,2008年水稻生育期间的气象条件总体为雨日阴天稍多,但仍属于普通气候年景。9个超级杂交稻组合7个播期结实稳定、正常,各播期间结实率最高与最低相差6.1个百分点。但各播期的结实率总体上仍表现为越早播,结实率越高(日均温为24～29℃时),结实率随孕穗和开花结实期日均温降低而降低,每降低1℃结实率约降低0.8个百分点。同组合同播期不同抽穗批次茎蘖结实率在前4个播期差别较小,但从第5播期后,部分组合的第3抽穗批次分蘖的结实率出现明显下降。结实率在不同播期间的差异与抽穗后15d期间的日平均气温、抽穗前后40d期间日照时数和抽穗前后7d期间最高气温呈极显著正相关。

Seed Setting Rates and Their Correlations with Meteorological Factors under Normal Climatic Conditions in Super Hybrid Rice in the Jianghan Plain, China

A multiple sowing experiment was conducted with nine major super hybrid rice combinations (with Shanyou 63 as control) in Hubei, China as materials to elucidate the basic pattern of seed setting rate of super hybrid rice in the mid season rice growing season, and its correlation with cardinal meteorological factors (CMF). Seeds were sown for seven times from April 19 on at a 10 day interval, and the seed setting rates of rice plants and the relative CMF were recorded in 2008. The result showed that the overall meteorological condition this year was characterized by more rainy and cloudy than normal, but no typical extreme weather has ever happened. All of the plants of the nine combinations with seven sowing dates showed high and stable seed setting rates. However, the basic pattern of seed setting rate was that the earlier the planting, the greater the seed setting rate, irrespective of the combinations. Seed setting rate decreased with the decrease of daily mean temperature at a rate of 0.8 percent point per 1℃ on average. Various tillers with varied heading dates within the same hill of the same combination showed no difference in seed setting rate in the four earlier sowing crops, from the fifth sowing crop on, the tillers with a later heading within the hill showed a decline in seed setting rate compared to the earlier heading ones. Differences of seed setting rate from different crops were highly correlated with daily mean temperature within 15 days period after heading, the accumulative radiation hours per day within 15 days before and 25 days after heading, and the daily maximum temperature within 7 days before and after heading.