热胁迫对不同小麦品种灌浆速率的影响

为了给小麦高产稳产和耐热新品种选育提供依据,对北部冬麦区和黄淮冬麦区的12个推广小麦品种在正常及热胁迫下的产量、千粒重及灌浆过程进行了研究。试验于2014—2015年度在河北省辛集马兰农场进行,用大棚升温作为热胁迫处理,在小麦灌浆期对不同品种在正常及热胁迫处理下的灌浆速率进行测定,收获后测定产量和千粒重,并计算热感指数。结果表明,‘中麦175’、‘衡4399’、‘衡4444’、‘CA0816’和‘中麦875’在自然生长及热胁迫处理下有较高的产量。在小麦灌浆中后期的籽粒快增期及缓增期发生的热胁迫会通过影响灌浆速率显著影响小麦的千粒重及产量。根据千粒重热感指数对不同小麦品种的耐热性进行评估,发现‘京冬8号’、‘CA0816’、‘CA1062’、‘中麦875’、‘中麦895’及‘衡4444’的千粒重热感指数1,是耐热性较好的品种;其他品种的千粒重热感指数≥1,是热敏感品种。对不同品种在正常及热胁迫条件下的灌浆速率进行分析,发现热胁迫对不同耐热性品种灌浆速率产生影响的起始时间不同,耐热性好的品种的灌浆速率在灌浆后期才会受到热胁迫的影响,热敏感品种在灌浆中期即受到热胁迫的影响。总之,‘CA0816’、‘中麦875’和‘衡4444’是丰产性和耐热性都较好的品种;‘衡4399’和‘中麦175’的千粒重热感指数一般,但产量在自然生长及热胁迫下均较高;‘京冬8号’耐热性好,丰产性略差。以上品种均可作为优异的耐热资源在育种中加以利用,在育种实践中需联合使用品种的产量数据和千粒重热感指数来评估该品种在耐热性育种中的价值。

Effects of heat stress on grain-filling rate of different wheat varieties

AbstractIn order to achieve high and stable yield and offer information for the selection of heat tolerant new varieties of wheat, the yield, 1000-kernel weight and grain-filling rate of 12 wheat varieties collected across the North China Wheat Belt and Huanghuai Wheat Region were studied under normal and heat treatments. The experiment was conducted in 2014-2015 at Malan Farm in Xinji, Hebei Province. A greenhouse was used as heating facility. Then grain-filling rate was measured for any increase in dry grain weight of different wheat varieties under normal and heated conditions. The yield and 1000-kernel weight were also analyzed after harvest. The results showed that yields of ‘Zhongmai 175’, ’Heng 4399’, ‘Heng 4444’, ‘CA0816’ and ‘Zhongmai 875’ were higher than those of other wheat varieties under both normal and heated conditions. Wheat grain weight was significantly affected by heating during rapid and slow grain-filling stages by reducing grain-filling rate. An evaluation of heat tolerance using the thermal index of yield and 1000-kernel weight showed that ‘Jingdong 8’, ‘CA0816’, ‘CA1062’, ‘Zhongmai 875’, ‘Zhongmai 895’ and ‘Heng 4444’ were heat-tolerant wheat varieties with the thermal index less than 1. Then, the other wheat varieties were heat -sensitive varieties with thermal index greater than or equal to 1. Wheat grain-filling rate, which was affected by high temperatures, differed for wheat varieties at grain-filling stage. Grain-filling rate of heat-tolerant varieties was affected at the last period of grain-filling whereas that of heat-sensitive varieties was affected at the middle period of grain-filling. In conclusion, ‘CA0816’, ‘Zhongmai 875’ and ‘Heng 4444’ wheat varieties showed both good yield and high heat-tolerance. Then ‘Heng 4399’ and ‘Zhongmai 175’ had a general thermal index for 1000-kernel weight whereas the related yield was high under both normal and heat treatments. Also ‘Jingdong 8’ showed a good heat tolerance with slightly lower yield. All the wheat varieties tested were as heat-tolerant wheat varieties for use in wheat breeding. We proposed further evaluation of both yield and thermal index of 1000-kernel weight in heat-tolerant wheat breeding.