Effects of High Temperature on Filling Rate of Early Rice and its Yield Components

High temperature weather occurs frequently in summer in the Yangtze River basin of China, which often leads to hot damage of early rice in its filling stage so that will affect rice filling rate and yield components. Using phytotron simulated different daily maximum temperature, put potted rice plants in it for different high temperature treatments in the milky stage of early rice. The results showed that: 1) If the early rice suffered for the weather that the maximum temperature is greater than or equal to 35°Cin the three days and the above date when it got into the milky stage, the empty grain rate and unfilled grain rate would increase with the increasing of temperature and processing time, full-grain rate would reduce with them, the total grain number did not change significantly, the filling rate was lower with the increasing of temperature and processing time. Premature aging of the early rice grain caused by high temperature is the fundamental reason for the high temperature forced cooked. 2) The high temperature appears earlier, the higher the temperature, the longer its duration, the more serious victims. Among them, the whole grain weight reduced about 4.25g compared with the normal. More than 34°C heat treatment is harmful to the grain filling, the 1000 grains weight of full-filled grains will down to about 22 to 24g (39°C for 2days to 23.1g), the control sample of grain weight is 27.5g. However, in some treatments, the grain weight increased slightly with the increasing of temperature and treatment days.