Physiological Characteristics And Water Use Efficiency Of Winter Wheat With Different Genotypes Under No-tillage Method

In recent years,the potential evapotranspiration of winter wheat increased significantly during the whole growth period due to climate warming,resulting in a significant decrease in water utilization ratio,further aggravating the contradiction between water supply and demand.No-tillage can directly affect soil ecological environment and regulate water,fertilizer,gas and heat in soil.However,No-tillage can reduce average soil temperature,high daily daily water consumption during the whole growth period,reduce crop grain to leaf ratio,slow down winter wheat growth rate,affect spike number and dry matter production,and ultimately reduce crop yield.In addition,the physiological characteristics of different genotypes also vary.The improvement of physiological characteristics such as chlorophyll content,plasma membrane stability and photosynthesis is the physiological basis for winter wheat to maintain high photosynthesis and high water utilization.Therefore,to explore whether the physiological characteristics of winter wheat of different genotypes under no-tillage mode can make up for the negative effect of no-tillage,two tillage methods and two genotypes of winter wheat were selected for the split zone test in the experiment station of Shandong Agricultural University in 2017-2018 and 2018-2019.The main area was no-tillage(NT)and conventional tillage(CT),and the secondary area was Tainong 18(F)and Jimai 22 genotype(J).By measuring the physiological indexes of winter wheat: tiller number of winter wheat;Net photosynthetic rate,stomatal conductance and transpiration rate;Fluorescence parameters of flag leaf;Chlorophyll index content;Canopy photosynthetically active radiation;Blade water potential;The changes of malondialdehyde(MDA),superoxide dismutase(SOD),peroxidase(POD)and other physiological enzyme activity indexes,as well as soil water content,were studied to investigate the changes of physiological characteristics and water use efficiency of winter wheat.The test results showed that:Humidity of the air near the ground is higher than under conventional tillage treatment of no-tillage and processing,conventional tillage treatment of population and the accumulation of dry matter were significantly higher than that of no-tillage treatment.The population number of Jimai 22 was higher than that of Tainong 18,but the dry matter quality was lower than that of Tainong 18.In addition,compared with conventional tillage,no-tillage can significantly improve the winter wheat before flowering storage photosynthate turn traffic,transport rate and its contribution rate on the grain,however,no-tillage can significantly reduce the amount of dry matter accumulation after flowering in allocation amount of grain and contribution rate of grain.NTF had the highest transpiration rate and net photosynthetic rate.Compared with conventional tillage treatment,no-tillage treatment could significantly improve transpiration rate and net photosynthetic rate.Under no-tillage method,the leaf water potential and leaf water retention capacity of winter wheat were lower than that of conventional tillage,the damage degree of membrane structure was increased,and the change of leaf water loss rate in vitro was opposite to that of leaf water retention capacity.On the other hand,conventional cultivation can increase the activity of SOD and POD antioxidant enzymes in flag leaves and reduce the accumulation of MDA,indicating that winter wheat under conventional cultivation can maintain the stability of photosynthesis.At the heading,flowering and filling stages of winter wheat,the interception rate of PAR under conventional tillage was higher than that under no-tillage.Under the same genotype,the potential active Fv/Fo of conventional tillage treatment was higher than that of no-tillage treatment,while the difference in the initial light energy conversion efficiency of each treatment was not significant.Winter wheat under conventional tillage can capture more light radiation through the canopy for photosynthesis and dry matter production,while no-tillage results in a decrease in dry matter accumulation.Under the same genotype,no-tillage significantly reduced the water consumption of winter wheat throughout its growth period and was able to regulate soil water content in different soil layers,No-tillage treatment can significantly increase the water content of 0-10 cm soil layer.Under the same tillage method,Tainong 18 significantly reduced soil water consumption by reducing tillers.The results showed that compared with conventional tillage,no-tillage significantly reduced yield,but also significantly increased 1000-kernel weight.The yield of CT significantly increased by 14.78% and 15.73% over NT,respectively.As for genotype,although the 1000-kernel weight of Jimai 22 was significantly higher than that of Tainong 18,the yield of Jimai 18 was significantly higher than that of Jimai 22 by 8.81% and 7.59%,because Tainong 18 could significantly increase the kernel numbers and kernel numbers per-spike.According to the coupling effect,CTF treatment has the highest yield.Under no-tillage method,the yield of Tainong 18 was significantly higher than that of Jimai 22.Changes in yield components not only affect the yield of winter wheat but also ultimately affect the wue of winter wheat.Compared with conventional tillage,WUE under no-tillage method is lower,but WUE under NTF treatment is higher than NTJ.The results showed that no-tillage reduced leaf water potential,leaf water retention,canopy radiation interception and dry matter accumulation,ultimately reduced the number of ears of winter wheat,resulting in reduced yield,and genotypes could compensate for the negative effect of physiological characteristics and reduced yield of no-tillage winter wheat.