Quantitative Analysis on the Effects of High Temperature at Meiosis Stage on Seed-Setting Rate of Rice Florets

Abstract

High temperature,especially happened at flowering stage and meiosis stage,would cause sterility of rice florets and became one of restricting factors of rice yield.With the global warming,the high temperature events will increase during crop growth process.In order to evaluate the effect of high temperature on yield quantitatively,it is important to quantify the relationship between temperature and seed-setting rate.Previous studies have focused on the above relationship during flowering stage,but litter discussed the relationship during meiosis stage.In this study a controlled experiment during meiosis stage was conducted at Jiangsu Academy of Agricultural Sciences,China with two cultivars,TY559 and HJ1 under six temperature levels (31,33,35,37,39,and 41℃) and three durations (1,3,and 5 d).High temperature lasted five hours from 8:40 to 13:40 each day,and natural environment was set as CK.The effect of high temperature on seed setting rate and the quantitative relationship between seed setting rate and temperature were analyzed.The results showed that temperature below 33℃ had no significant effect on seed setting rate,but with the increase of temperature and its duration the seed setting rate decreased gradually.The daily relative seed setting rate could be expressed in terms of temperature with a quadratic equation,and the total effect of high temperature during meiosis stage on relative seed setting rate could be expressed in the product of daily relative seed setting rates.Further,combining the diurnal change of temperature,the quantitative effect factor under the nature diurnal change pattern of temperature was discussed.This study provided a quantitative method for calculating the effect of high temperature at meiosis stage on seed setting rate of rice,and would help to improve high temperature-induced sterility model in rice.