阶段高温对不同小麦品种产量的影响及其耐热性差异研究

为应对小麦高温灾害,筛选耐热丰产种质资源,通过裂区试验,以阶段高温为主区(在开花期、花后5～10 d、11～15 d、16～20 d和21～25 d进行高温胁迫,分别用H_1、H_2、H_3、H_4和H_5表示,以自然生长条件为对照),以品种为副区(选用济麦22、矮抗58、衡4399、淮麦33、石麦22、山农20、郑麦7698和邯6172耐热性不同的8个冬小麦品种),于2016-2017和2017-2018两个小麦生长季,研究了不同阶段高温对小麦产量及穗粒数、粒重等的影响,并分析了不同品种的耐热性。结果表明, H_1、H_2、H_3、H_4和H_5处理的两年平均产量分别较对照下降59.7%、49.5%、26.2%、36.4%和34.5%,穗粒数分别减少17.9、14.8、5.9、1.2和4.0粒,千粒重分别降低0.3、1.8、7.3、13.8和12.6 g。从品种看,自然生长条件下郑麦7698、淮麦33和衡4399的产量较高,石麦22的产量最低;高温条件下郑麦7698、山农20和衡4399的产量较高,淮麦33为受高温影响最大的品种,两年减产幅度均最高;两种条件下郑麦7698、衡4399和山农20的综合产量均较高,淮麦33最低。阶段高温对不同品种的影响不同,且存在年际间差异。2016-2017年度山农20、衡4399和石麦22的H_2处理均较对照增产,但其他阶段高温处理均减产。高温胁迫后郑麦7698的减产幅度在2016-2017年度最小,而在2017-2018年度仅次于减产幅度最大的淮麦33。郑麦7698、衡4399和山农20的两年几何平均产量均较高,淮麦33最低。从热感指数看,衡4399、山农20和郑麦7698的热感指数指标大部分小于1,淮麦33、济麦22、石麦22热感指数指标大部分大于1;其他品种的热感指数指标有的时段高温大于1,有的小于1。综合产量和热感指数指标,衡4399、山农20和郑麦7698的耐热性好,淮麦33、济麦22和石麦22的耐热性较差。

Impacts of High Temperature in Different Periods on Yield and Evaluation of Heat Tolerance in Wheat Varieties

In order to relieve the high temperature hazards and screen heat-tolerant and high-yielding germplasm resources of wheat, experiments were conducted in 2016-2017 and 2017-2018 wheat growing seasons. A split block design was used, with five temperature stress treatments as the main blocks (at flowering, 5-10 days,11-15 days, 16-20 days, and 21-25 days after flowering represented by H₁, H₂, H₃, H₄ and H₅, with no stress as CK). Each heat stress treatment were conducted by covering plastic film for 5 hours (11:00-16:00) every day for the specific periods. Eight winter wheat varieties (Jimai 22, Aikang 58, Heng 4399, Huaimei 33, Shimai 22, Shannong 20, Zhengmai 7698 and Han 6172) were used as sub-blocks. The yield, yield components and heat susceptibility indices of different varieties were investigated. The results showed that the average yield of two years for H₁, H₂, H₃, H₄ and H₅ was reduced by 59.7%, 49.5%, 26.2%, 36.4% and 34.5%; the grain number per spike was reduced by 17.9, 14.8, 5.9, 1.2 and 4.0 grains and the 1 000-grain weight was reduced by 0.3, 1.8, 7.3, 13.8 and 12.6 g, compared with those of CK, respectively. For varieties, the average yield of Zhengmai 7698, Huaimai 33 and Heng 4399 was higher under natural conditions in two years, whereas that of Shimai 22 was lowest. The average yield of Zhengmai 7698, Shannong 20 and Heng 4399 was higher under high temperature conditions, whereas Huaimai 33 was seriously affected and had maximum yield reduction in both years. The yields of Zhengmai 7698, Heng 4399 and Shannong 20 were higher and Huaimai 33 was lowest under both conditions. Different cultivars performed differently under heat stress at various stages in the two years. In 2016-2017, Shannong 20, Heng 4399 and Shimai 22 showed increased yield compared to their CKs only under H₂ treatment. The variety Zhengmai 7698 had the least yield reduction under heat stress in 2016-2017 but showed great yield reduction following Huaimai 33 in 2017-2018. The geometric mean yield of Zhengmai 7698, Heng 4399 and Shannong 20 were comparatively higher and Huaimai 33 was the lowest in the two years. According to the indices of heat sensitivity, the values of Heng 4399, Shannong 20 and Zheng 7698 were mostly less than 1, while those of Huaimai 33, Jimai 22 and Shimai 22 were mostly greater than 1, and the values of other varieties were not consistent. Taking both the yield and indices of heat sensitivity into consideration, Heng 4399, Shannong 20 and Zhengmai 7698 were heat-resistant varieties; Huaimai 33, Jimai 22 and Shimai 22 were heat-sensitive varieties.