Study On Relationships Of Seedling Root Traits With Grain Yiled & Quality Of Wheat(Triticum Aestivum L.) Cultivars With Different Nitrogen Use Efficiency

In this study,field experiments and hydroponic experiments were used to combine research methods.18 wheat cultivars with significant differences in the morphological and quantitative traits of seminal root system in wheat seedling were used as materials.Three nitrogen levels were set in hydroponic experiments: normal nitrogen(5 mmol/L),high nitrogen(45 mmol/L),and low nitrogen(0.05 mmol/L),to explore the root morphological characteristics of wheat seedlings at different nitrogen levels.The relationship between plant dry weight and nitrogen accumulation,and the difference in root morphology of wheat cultrivars with different nitrogen efficiency was clarified,which provided a basis for root morphology identification of wheat cultrivars with different nitrogen efficiency at seedling.The main results are as follows:(1)The seminal root length,total root length per plant,total root surface area,total root volume and number of root tips of different genotypes of wheat showed a linear increase trend with time,while the average root diameter showed a linear decrease the trend of.The coefficients of variation of total root length,total root surface area,total root volume and number of root tips per plant are larger.According to the morphological quantitative traits of the main radicle,the main radicle can be divided into two types,and there are significant differences between the two types,except for the average root diameter.(2)Different nitrogen levels have different effects on wheat seedling stage.Compared with normal nitrogen level,low nitrogen level significantly promotes the elongation of the main radicle and the ratio of root to shoot,and significantly reduces the aerial part;high nitrogen level is different from normal nitrogen Compared with the level,the root length and root shoot ratio of the main radicle were significantly reduced.The average root length,total root surface area and total root volume per plant at normal levels are 1.92,1.89 and 1.83 times the low nitrogen level and 1.89,1.66 and 1.46 times the high nitrogen concentration,while the root tips appear low nitrogen Level>Normal nitrogen level>High nitrogen level changes.(3)Under different nitrogen levels,the dry weight of wheat roots,dry weight of aerial parts and dry weight of plants were significantly or extremely significantly positively correlated with the total root length,total root surface area,and total root volume,respectively,with a correlation coefficient of 0.584~0.899;The root nitrogen accumulation,shoot nitrogen accumulation and plant nitrogen accumulation in wheat seedling stage were significantly or extremely significantly positively correlated with total root length,total root surface area and total root volume,and the correlation coefficient was 0.471~0.830,the correlation between the average root diameter and wheat nitrogen accumulation is not strong.Root morphological parameters such as total root length,total root surface area,total root volume,and number of root tips can be used as evaluation indicators for evaluating wheat seedling nitrogen.Through the principal component analysis and the membership function method to calculate the comprehensive value,the comprehensive value under different nitrogen levels can be divided into three categories.(4)The coefficients of variation of infertile small crust number,spikelet number,thousand kernel weight,soluble sugar content and amylose were larger.The number of seed larvae and the number of spikes per spike were significantly positively correlated with the total root length of wheat seedlings,while the average root diameter was significantly negatively correlated.Grain amylopectin content is more closely related to total starch content and root morphology at seedling stage.Grain amylopectin is significantly positively correlated with total root length,total root surface area and total root volume,while total starch is only related to total root surface area and total root the volume was significantly positively correlated;the soluble sugar content of the grain was close to the root-to-root ratio of wheat,and was significantly negatively correlated with it.