Effects Of Irrigation At Different Growth Stages On Grain Yield And WUE Of Wheat

Water is essential for the growth and production of crops,due to the time and space distribution,water deficit is becoming one of the main factors limiting wheat production worldwide.The present study was conducted in three locations:Key Laboratory of Crop Genetics and Physiology of Jiangsu Province,Yangzhou University,Ottawa Research and Development Center,and Suining agricultural demonstration zone during the wheat-growing season from October 2015 to June 2017.Xumai 33 was chosen as the research material in the pool-culture experiment.The crop growing before wheat was rice and/or corn.There were four levels of irrigation stage:control,irrigation at jointing stage,booting stage,jointing and booting stage.The aim was to study the effects of different stubble and irrigation modes on wheat yield and photosynthetic capacity.The experiment in Canada was conducted in green house,and the cultivar was spring wheat AAC-Scotia.The experiment was set three stages of drought and seven irrigations to investigate the effect of different irrigations after drought on yield,photosynthetic capacity and contents of osmotic adjustment substances.The experiment in Suining was about the different irrigation modes,which were border irrigation and sprinkling irrigation and the wheat variety was Xumai 33.The seven irrigation stages were jointing stage,booting stage,anthesis stage,jointing + booting stage,booting + anthesis stage,jointing + booting +anthesis stage.The experiment took different irrigation methods,different irrigation stages and combination to study the changes of yield and yield components,the physiological response to different treatments,and the WUE,aiming to provide the theory and practice basis for water-saving and high-yield w.heat production in southern regions of Yellow and Huai River.The main results were as follows:1.Significant differences could be observed in the growth situation of rice stubble and corn stubble.The leaf area index in booting stage of corn stubble were remarkably higher than rice stubble,and the biomass accumulation in anthesis stage of corn stubble was more than rice stubble.The SPAD,net photosynthetic rate,biomass accumulation and yield showed no significant differences after anthesis.The yield after jointing + booting stage irrigation was the highest,but the water use efficiency(WUE)was lower than the other treatments.The yield and WUE of booting stage irrigation was superior to other treatments.In the case of high yield as the primary purpose,the irrigation can be set in jointing + booting stage;the irrigation amount was 60 mm.The high yield and WUE taken into account in booting stage irrigation.2.Drought in booting and anthesis stage significantly reduced wheat production,which can be relieved after re-watering.Leaf area index reduced after drought in booting stage,meanwhile the biomass per area of flag leaf increased.In other words,drought caused the thickness of leaves increased.There is compensation for production in certain degree.Drought in anthesis resulted in reduction of kernel number per spike and 1000-kernel-weight,and the loss of wheat yield was more than that in booting stage.The yield of different soil relative water contents of 60-65%and 70-75%in the same stage showed no significant difference,which means the high yield received in water saving treatment.Irrigation after drought in booting stage had no effect on the yield,however,the water supply need to be abundant in Anthesis.3.The effects of irrigation in different stages on wheat was significantly different,the irrigation in jointing + booting stage increased the spike number,the irrigation in anthesis increased spike number and 1000-kernel-weight.The LAI,SPAD,net photosynthetic rate,biomass and nitrogen accumulation increased with the irrigation times,in the end,the yield increased as well,and there was an average 14.7%increase in yield.The jointing + booting stage treatment had the biggest effect at two times irrigation and jointing stage was the best time at only once irrigation.The protective enzyme activity and content of MDA reduced after irrigation,which means wheat was suffering a mild water stress.The yield of sprinkling irrigation was more than border irrigation in the same stage,but they had no significant effect on yield.The WUE of sprinkling irrigation was higher than border irrigation.Irrigation in jointing + booting + anthesis stage achieved the supreme yield after drought,and jointing + booting stage irrigation obtained the high yield and water saving after drought.