杂交水稻耐热性评价

 以100个杂交水稻组合为材料，于50%穗开花日起，置于最高温38℃下处理3 d，以相对结实率作为耐高温性评价指标，研究杂交水稻花期高温胁迫对结实率的影响。结果表明，Y两优646、广占63 4S×R558、宜香5979、Y两优2号以及Y两优896为耐高温组合；Ⅱ优838、丰优199与荆楚优37为高温敏感性组合。对耐热性不同的组合的来源进行分析发现，大部分具有相同母本的组合表现出一致的耐热性，说明母本对杂交水稻的耐热性起主导作用。

Evaluation of Heat Resistance in Hybrid Rice

Heat resistance  during flowering was evaluated with 100 hybrid combinations as materials. The rice plants were subjected to heat stress at 38℃ for 3 days as 50% spikelets flowered. Based on relative spikelet fertility rate, they were divided into heat tolerant combinations, semi heat tolerant combinations and heat sensitive combinations. Therefore, Y Liangyou 646, Guangzhan 63 4S×R558, Yixiang 5979, Y Liangyou 2 and Y Liangyou 896 are heat tolerant combinations, whereas Ⅱyou 838, Fengyou 199 and Jingchuyou 37 are heat sensitive combinations. Analysis of origin of combinations  with different  heat tolerance indicated that most hybrid  combinations derived from the same female parent showed  similar heat resistance. It indicated female parent played an more important role in heat tolerance of hybrid rice.