Seed Setting Rates and Their Correlations with Meteorological Factors under Normal Climatic Conditions in Super Hybrid Rice in the Jianghan Plain, China
TIAN Xiao-hai1,*;WU Chen-yang1; YUAN Li1; WANG Xiao-ling1;MA Guo-hui1,2
1College of Agriculture, Yangtze University, Jingzhou 434025, China; 2China National Hybrid Rice R & D Center, Changsha 410125, China; *Corresponding author, E-mail: xiaohait@sina.com
Abstract：
A multiplesowing 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 midseason rice growing season, and its correlation with cardinal meteorological factors (CMF). Seeds were sown for seven times from April 19 on at a 10day 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.
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2010, Vol. 24 
