高温胁迫对国稻6号开花结实习性的影响

为研究杂交稻对开花结实期高温胁迫的生理生态适应性, 选用具代表性的主栽杂交稻组合国稻6号、两优培九等, 人工设计极值高温40℃, 自始穗后第15天每天6 h进行热害处理, 以自然气候条件为对照, 测评结实的热害指数, 并从中选择对开花结实期高温胁迫反应差异较大的国稻6号与协优46, 观察高温胁迫对其开花结实习性的影响。结果表明, 国稻6号具较高耐热性似与其“被动避热”适应性有关, 主要表现在开花结实习性的变化, 首先是花期缩短, 花期集中, “粒间顶端优势”有所减弱; 其次是花时分散, 开花峰期峰值下降, 虽未见花时提前, 但见日初花量增加与花时向后延长2 h。

Effects of High Temperature Stress on Flowering and Grain-Setting Characteristics for Guodao 6

Worldwide warming climate is causing more and more disadvantages for farming. A better understanding of high temperature stress on rice production is necessary for sustainable agriculture. In present study, eight leading hybrid rice combinations were selected to study the physiological and morphological adaptability to 40℃ air temperature stress. Heat treatment was conducted by 6 h each day from initial heading through 15 days. Guodao 6 and Xieyou 46 showed significant differences in response to high temperature stress during flowering period, and were selected to do further study on their flowering and grain-setting characteristic to high temperature stress. It was observed that Guodao 6 showed a relative stability in grain setting under high temperature stress. This may be associated with its adaptability to heat avoidance, displaying flowering period shortened and “Apical grain superiority” weakened, as well as flowering clock decentralized and the flowering peak value decreased. Daily number of spikelet flowering increased and flowering clock delayed for 2 hours during initial heading period.