Effect of various combinations of temperature during different phenological periods on indica rice yield and quality in the Yangtze River Basin in China
Debao Tu, Yang Jiang, Li-juan ZHANG, Mingli Cai, Cheng-fang LI, Cougui Cao
Abstract
Rice grain yield and quality declines due to unsuitable temperature induced by wide regions and various sowing dates. This study was aimed to evaluate the effects of temperature at different phenological periods on rice yield and quality, and to obtain suitable temperature for phenological periods in the Yangtze River Basin. Therefore, this study took regional varieties, and experiments of different sowing dates under different areas were carried out in the Yangtze River Basin to observe and compare the differences in rice growth, yield and quality. Results showed that the rice growth, grain yield and quality had significant differences in sowing dates and areas, which were related to the average daily temperature during vegetative period (VT) and the first 20 days of grain filling period (GT20). In addition, there was a smaller variation of the average daily temperature in reproductive period (RT) than that of these two phenological periods. Therefore, according to the VT and GT20 thresholds of different yield and quality, experiment results were divided into 4 scenarios (I, II, Ⅲ, and Ⅳ) in this study. In scenario I, high head rice production (rice grain yield multiply by head rice rate) and rice quality could be obtained; compared with scenario I, the head rice production of scenarios III and IV decreased by 30.1% and 27.6%; in scenario II, the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3% higher than those of scenario I, respectively. In conclusion, scenario I combination with VT ranges of 22.8 ℃-23.9 ℃ and GT20 ranges of 24.2℃-27.0℃ or combination with VT ranges from 23.9℃ to 25.3℃, and GT20 ranges from 24.2℃ to 24.9℃ are recommended to achieve the high rice grain yield and quality in the Yangtze River Basin by adjusting sowing date and selecting rice varieties with suitable growth periods.