Effects Of Meteorological Conditions On Middle-season Rice Yield Components And High-temperature Early Warning Model

Rice is one of the most important grain crops in Anhui.Rice yield and grain quality for a given cultivar is mainly dependent upon local weather conditions such as temperature,precipitation,sunshine hours,relative humidity ,et al. At critical crop growth stages,particulary when high temperature occurs during rice heading stage,high temperature is great influence on rice flowering and pollination,lead to unfilled grains and undeveloped grains increasing more and seed-setting rate decreased,reduce yield significantly.Environmental conditions is one of most important determinants for rice yield and grain quality,particulary when high temperature occurs during rice heading stage.High temperature is great influence on seed-setting rate,and cause serious economic losses frequently.With the global warming,the high temperature events will increas during the sensitive period of rice.Therefore,it is very important to study on a model to simulate high temperature-induced sterility of rice .In both theory and parctice,the model which makes a reasonable cropping pattern of rice,earlying warning and prevention of high temperature damage,high-temperature impact assessment,and the technique of growing rice giving stable and high yields is posssible.This paper investigates the influence of high temperature on rice yield components during heading stage and the daily flowering habit of rice panicle.The model to simulate high temperature-induced sterility has been verified through testing data.Finally,applying the language of Visual Basic,the early warning system of high temperature-induced sterility of rice is established.The conclusions are as following:According to the results of interval sowing date test,the yield differences of Plot Yield by five Sowing date attained a very significant level(F=61.212,P<0.001). High temperature significantly influenced seed setting rate(p<0.05)with an decrease of 20% for tested variety,but no significant impact was found on the grain number per panicle and 1000-grain weight.The flowering percentage for single rice panicle firstly increases and then decrease during heading date.In contrast, the percentage change of daily flowering number for rice group is in a state of fluctuation at the early stage,then declined with the days generally.The temperature of leaf,panicle and canopy firstly increases and then decreases at 08:00~15:00 during rice heading stage.The relationship among them,the highest is panicle temperature , the lowest is canopy temperature.The leaf temperature and panicle temperature reach their maximum values at about 1 p.m,the canopy temperature at about 2 p.m.Though testing with experiment data and the results showed that the model of high temperature-induced sterility of rice were not only accurate but also applicable and the simulated and observed values were consistent(RMSE=0.04).Finally,applying the language of Visual Basic,combine growth durration model,high temperature-induced sterility model and weather forecast of mid long term, the early warning system of high temperature-induced sterility of rice is established.