Effect of High Temperature at Meiosis Stage on Seed-Setting Rate in Rice

Abstract High temperature, especially at flowering stage and meiosis stage, causes sterility of florets and yield reduction in rice ( Oryza sativa L.). To evaluate the effect of high temperature on rice yield quantitatively, 2 rice cultivars, Huajing 1 ( japonica ) and Teyou 559 ( indica hybrid) were treated with ladder temperatures (31, 33, 35, 37, 39, and 41°C) for 1, 3, and 5 d at meiosis stage in Artificial Climate incubators. The high temperature stress was conducted for 5 h (8:40–13:30) at each treatment day. The natural temperature treatment was set as the control. The seed-setting rates of both cultivars were slightly affected ( P > 0.05) when temperature was lower than 33°C. But with the increase of temperature and its duration, seed-setting rate decreased gradually. The relationship between daily relative seed-setting rate (RSS) and temperature was fitting with a quadratic equation. The total effect of high temperature at meiosis stage on RSS was described with the products of daily RSS.