杂交水稻新品种在自然高温下的耐热性评价

Evaluation of Heat Tolerance of New Hybrid Rice Varieties under Natural High Temperature Conditions

2016年分别在湖北荆州、湖南桃源、安徽庐江3个不同生态区,利用自然发生的热害天气调查了23个杂交稻新品种及对照丰两优4号在不同生态区始穗前后遭遇高温的天数及其结实率,对各品种的耐热性进行评价。结果表明,2016年3个试点经历了强度大致相同的2段持续高温期,湖南桃源试验点中受高温危害品种比例最高,其次是湖北荆州,而安徽庐江地区由于播种迟,几乎所有品种在抽穗前后都避开了高温期,品种结实率基本正常。始穗前后均遭遇高温会加剧结实率下降,其下降幅度高于仅始穗前或始穗后遭遇高温;热害对杂交稻结实率的危害具有累加效应,热害天数越长,结实率下降幅度越大。对湖北荆州和湖南桃源2地受高温影响的各杂交稻品种进行耐热性筛选,发现其中4个表现为热敏感型,7个为耐热型,13个为疑似感类型。

The heat tolerance of 23 new hybrid rice varieties and the check variety Fengliangyou 4 was evaluated by investigating the number of days exposed to natural high temperature conditions around the initial heading stage and the corresponding seed setting rates of these varieties in different ecological areas at Jingzhou of Hubei Province, Taoyuan of Hunan Province and Lujiang of Anhui Province in 2016. The results showed that three experimental sites experienced two periods of sustained high temperature with roughly the same intensity in 2016. The proportion of the varieties affected by high temperature was the highest at Taoyuan, Hunan, followed by Jingzhou, Hubei. However, due to late planting, almost all varieties at Lujiang, Anhui avoided two high temperature periods around the heading stage, thus their seed setting rate was basically normal. If the high temperature occurred both before and after the initial heading stage, it would aggravate the decline of seed setting rate, and showed a greater decrease in seed setting rate than that when the high temperature occurred only before or after the initial heading stage. The heat damage had an accumulative effect on the seed setting rate of hybrid rice, because the more the number of heat damaging days, the more the seed setting rate decreased. The heat tolerance of 24 hybrid rice varieties affected by high temperature at Jingzhou, Hubei and Taoyuan, Hunan was evaluated. Of them, four were heat-sensitive, seven were heat-tolerant and 13 were suspected heat-sensitive.