Response of Physiological and Yield Characters of Different Wheat Cultivars to Drought Stress at Grain Filling Stage

LI Guoling; QI Xueli; ZHANG Zhiqiang; LUO Peng; XIN Jun'an; LI Yanfeng; SHI Lixia

doi:10.15933/j.cnki.1004-3268.2018.04.002

Abstract：In order to explore the response of physiological and yield characters of different winter wheat cultivars to drought stress at grain filling stage,both wheat varieties Zhoumai 18 and Zhongmai No.1 were grown in an auto-rain-shelter,and the physiological and yield characters of the two varieties were measured under normal irrigation and drought treatments.The results showed that Zhongmai No.1 had better tolerance to drought stress.There was no significant difference between Zhoumai 18 and Zhongmai No.1 in the physiological and yield characters under the normal irrigation treatment.After drought treatment,the net photosynthetic rate of Zhoumai 18 and Zhongmai No.1 decreased by 37.86％ and 27.68％,maximum photochemical efficiency decreased by 23.15％ and 15.12％,the relative variable fluorescence values at K point increased by 41.94％ and 25.31％ and at J point increased by 54.51％ and 26.98％,the content of proline increased by 19.43％ and 26.60％,the content of chlorophyll a + b decreased by 30.96％ and 17.51％,the content of malondialdehyde increased by 59.66％ and 38.52％,the activity of superoxide dismutase increased by 15.81％ and 24.89％,dry root weight decreased by 37.76％ and 21.21％,respectively;the grain number per spike decreased by 13.52％ and 7.36％,1 000-grain weight decreased by 13.76％ and 6.04％,and yield per plant decreased by 25.53％ and 16.16％.The decrease of grain number and 1 000-grain weight lead to the yield decline.The physiological and yield characters of Zhongmai No.1 were better than those of Zhoumai 18 under drought treatments.Collectively,under drought stress Zhongmai No.1 has higher content of osmotic adjustment substances,higher antioxidant enzyme activities and dry root weight,thereby reducing the injury to wheat,delaying chlorophyll decomposition,maintaining higher photosynthesis rate,and obtaining higher yield,which is the drought-resistant physiological mechanism of Zhongmai No.1.