Analysis Of Differences In Water Use Efficiency Among Winter Wheat Cultivars And Key Influencing Factors

The water resources crisis in the main winter wheat production areas in China is intensifying,and the WUE differences of winter wheat varieties（lines）and their influencing factors are discussed to provide guidance for the selection of high-efficiency water-use varieties and the development of water-saving cultivation techniques.Based on the previous research results,this study screened 10 winter wheat genotypes with significant differences in WUE and different plant types as experimental materials,and conducted field trials at the Shunyi Experimental Station of Chinese Academy of Agricultural Sciences from 2015 to 2018 for three consecutive growing seasons.Two types of water treatments,rain-fed and supplementary irrigation,were set with high,medium and low planting densities for two varieties with different plant types.Trying to explore the differences in WUE between genotypes and influencing factors,focusing on revealing the influence of genotype,plant type,density,soil moisture conditions and other factors on population canopy characteristics and population water consumption.The main results of the study were as follows:（1）There were significant differences in genotypes in yield,water consumption and WUE.WUE is most affected by genotype,followed by water conditions.Yield and water consumption are most affected by water conditions,followed by genotype.Under the two water conditions,Shijiazhuang 8 and Jinmai47 have higher grain yield and WUE,and the WUE of 908092 and Jing 411 were lower,both of which have lower output but higher water consumption.（2）Plant type significantly affected water consumption by affecting canopy characteristics.Group water consumption and CTD showed a significant negative correlation.In the Jinmai 47 population with flat leaves and loose plant types,the inner leaves of each group were shadowed by each other,and the CTD was large,and the water consumption was low;the upright,compact plant type Jing 411 had small water and heat exchange resistance,the CTD was small,and the water consumption was large.（3）The interaction of planting density and plant type significantly affected the canopy characteristics,which in turn affected the water consumption of winter wheat,and was affected by soil moisture conditions.Under the conditions of rain-fed and supplementary irrigation,Jinmai 47 had higher water consumption in high-density planting and lower medium-density and low-density plantings.There was no significant difference between the two.Under rain-fed conditions,the water consumption of the three planting densities of Jing 411 had significant differences,high density>medium density>low density.Under the condition of supplementary irrigation,there was no significant difference in water consumption of Jing 411 between high-density and medium-density waters,which were significantly higher than that of low-density.（4）Under rain-fed and supplementary irrigation conditions,with the growth and development process,theδ¹³C value continued to increase from the early filling stage to the late filling stage.Theδ¹³C value of the 10 winter wheat genotypes ranked did not change much.Under two water conditions,the correlation between the stable carbon isotope composition in the leaves and the population WUE on the yield scale at the filling stage reached a significant level.（5）Under two water conditions,the number of spikes per spike,the number of spikes,and the weight of thousand kernels showed significant differences among genotypes.Increasing the number of spikes under rain-fed conditions was a prerequisite for increasing yield,and the number of spikes per grain and1000-grain weight had a greater effect on yield increase under supplementary irrigation.The accumulation of dry matter and growth rate in the main growth stages of different genotypes were significantly different,and the increase potential of yield came from the increase of biomass.With the increase of density,the grain yield increased significantly,and the yield of compact winter wheat was significantly lower than that of loose winter wheat at the same planting density.