Identification Of Shade Tolerance Of Soybean Germplasm Resources And Screening Of Shade Tolerance Varieties

Soybean is a kind of light and temperature-preferring crop,while maize soybean intercropping is a planting method that can achieve,the most utilization of agricultural resources in consequence increases the production.In the meantime,this planting method can make full use of space resources in a three-dimensional manner in turn,increase the utilization efficiency of light,soil nutrients and water,and thus improve the output efficiency per unit area.However,when soybean is intercropped with corn,low light level can affect the morphological characteristics and yield of soybean due to competition for light,water,and nutrients between the soybean and corn where soybeans at a disadvantage position during their growth process,seriously affecting their growth and development,leading to overgrowth or lodging of vines,reduced pod setting and branching of soybeans,and thus having a serious impact on the formation of soybean yield.Therefore,selecting and screening soybean varieties with good shade tolerance is one of the important means for increasing soybean yield.This study analyzed the basic performance of soybean germplasm resources of different genotypes under shading stress and normal light conditions to select soybean varieties with stable and high yield,and strong shade tolerance under intercropping conditions.The results are as follows.(1)Identification of Shade Tolerance of Soybean Germplasm ResourcesUsing 180 soybean germplasm resources as materials,9 agronomic traits and the yield of soybean were analyzed and evaluated using shading and natural light treatment,respectively.The results showed that under shading treatment and normal natural lighting conditions,there were certain differences in the comparison of plant height,number of main stem nodes,plant biomass,internode length,stem diameter,number of pods per plant,number of seeds per plant,the weight of 100 seeds,and weight of seeds per plant among the test materials.Based on the weight and membership function values of the comprehensive indicators of soybean varieties,the comprehensive shade tolerance D value of each soybean variety was calculated and arranged.According to the shade tolerance of soybean varieties,180 soybean materials were divided into four categories: strong shade tolerance type,moderate shade tolerance type,weak shade tolerance type,and weak shade tolerance type.Under shading treatment,soybean with strong shade tolerance increased the number of main stem nodes;shortened internode length;decreased plant height;increased stem diameter and pods per plant,and increased the number of grains per plant,plant biomass,100 grain weight,and yield per plant.Preliminary screening of suitable tolerant shade-tolerant soybean germplasm resources for maize soybean intercropping has been conducted.The experiment adopted a field maize soybean intercropping model to screen shade tolerant soybeans.Using 10 soybean germplasm resources as materials,statistics and analysis were conducted based on the agronomic traits of each variety,such as plant height,bottom pod height,stem diameter,number of main stem nodes,number of pods per plant,number of grains per plant,and 100 grain weight.Plant biomass,plant weight balance point,and yield were also analyzed;Analyze the correlation between the lodging level of soybean varieties and various traits of soybean varieties.The correlation analysis results show that the lodging level of soybean is significantly positively correlated with its plant height,bottom pod height,number of main stem nodes,and plant weight balance point,while it is significantly negatively correlated with its stem diameter,100 grain weight,number of pods per plant,number of grains per plant,plant biomass,and yield.According to the grading standards for lodging in the field,15 soybean varieties were classified into different lodging levels.Among them,Liaodou 102,Liaodou 103,and Liaodou14Q078-2 had the lowest lodging level and had more pods per plant,more grains per plant,more branches,heavy grains per hundred,and high yield.Therefore,Liaodou 102,Liaodou 103,and Liaodou 14Q078-2 were preliminarily screened for their strong shade tolerance and suitability for intercropping with corn.