Effects Of Supplemental Irrigation Based On Soil Moisture On Grain Yield And Water Use In Different High-yielding Wheat

In recent years,wheat,as one of the important food crops,has become an important raw material for the production of food consumer goods,which puts forward higher requirements for high grain yield.Water is directly related to crop growth,and the reduction of freshwater resources raises new problems for water-saving irrigation in agriculture.Therefore,on the premise of ensuring high yield of crops,saving water and fertilizer has become an important research topic to be solved urgently.YN1212,YN999,JM22,LY502,SN30,SN29,TK31,TK33,TS289 high-yield wheat varieties were used as experimental materials.Three irrigation gradients,W₀?no supplementary irrigation during the whole growth period,depending on natural precipitation?,W₁?70%sowing time,75%jointing time and 75%flowering time?,W₂?70%sowing time,80%jointing time and 80%flowering time?,were set up.The relationship between flag leaf physiological characteristics,dry matter accumulation and distribution,grain filling characteristics,water use efficiency and yield of wheat was studied.It provides a theoretical basis for future research on Water-saving Cultivation of wheat to improve yield.The results are as follows:1.Effects of irrigation on physiological characteristics of flag leaves of wheat at flowering stage:?1?Changes in chlorophyll content:The content of chlorophyll in Flag Leaves of wheat decreased at flowering stage.The changes of chlorophyll content in Flag Leaves of YN999,YN1212 and JM22 were significantly different from those of other varieties.Most cultivars had higher chlorophyll content under W₁ condition,and the content of chlorophyll decreased slowly in later stage,which laid a foundation for improving yield.?2?Changes in antioxidant enzyme activity:The activities of antioxidant enzymes?SOD,POD,CAT?in Flag Leaves of wheat at flowering stage increased first and then decreased.The peak time of SOD activity was inconsistent.The peak value of SOD activity appeared around 5 days after flowering,the peak value of POD activity appeared around 15 days after flowering,and the peak value of CAT activity appeared around 10 days after flowering.W₁ treatment was the best condition to maintain SOD,POD,CAT activity,scavenge free radicals in flag leaves,prolong leaf senescence time and increase yield.YN1212 and JM22 performed best.?3?Changes in malondialdehyde?MDA?content:Malondialdehyde?MDA?content in Flag Leaves of wheat increased gradually at flowering stage.YN1212,YN999 and JM22 had low MDA content in Flag Leaves under supplementary irrigation.W₁ treatment was the best treatment to obtain lower MDA and delay leaf senescence.2.Effects of irrigation on dry matter accumulation,transport and distribution from flowering to maturity of wheat:?1?Effects on dry matter distribution in panicles:The dry matter partitioning rate of JM22 and SN30 was higher in W₀ treatment.When the supplementary irrigation amount reached 80%,YN1212,YN999 and other grains could obtain higher distribution rate.In W₁ treatment,LY502 and JM22 obtained higher dry matter allocation of ears?except grains?.Higher dry matter partitioning rate was obtained in TS28 grains.?2?The effects on the transport characteristics of dry matter:Dry matter transport before anthesis,contribution rate of dry matter to grain and dry matter accumulation after anthesis are greatly affected by wheat varieties.Dry matter accumulation and transport of YN1212,JM22 and YN999 in W₁ treatment were significantly higher than those in other treatments,which was beneficial to yield formation.Supplementary irrigation is beneficial to the accumulation of economic output.3.Effect of irrigation on Grain Filling Characteristics of wheat during grain filling stage:?1?Influences on grouting rate:Irrigation had no significant effect on the grouting rate,but had a significant effect on the time when the maximum grouting rate appeared.When the soil moisture content reaches 75%,the time of maximum grouting rate can be delayed.?2?Influences on grouting time:Supplementary irrigation plays an important role in prolonging the filling time.Appropriate irrigation should be carried out according to the variety differences.YN1212and YN999 can prolong the filling time when the soil moisture content reaches 75%.4.Effect of irrigation on water use efficiency of wheat:The water use efficiency of wheat was the highest when the soil moisture content reached 75%.W₁ treatment is the best condition for YN999 and YN1212 to improve water use efficiency and yield.5.Influences of irrigation on Yield and related factors:Supplementary irrigation had significant effects on panicle number and 1000-grain weight at maturity stage.W₁ treatment is the best treatment for high yield under this experimental condition.The yields of YN1212 and YN999 were higher in all treatments,and they had variety advantages.