Screening And Seedling Stage Identification Of Phosphorus High-efficient Soybean Varieties

Phosphorus（P）is one of the essential elements for plant growth and development.Soybean is one of preferable P crops.P deficiency in soil is one of the important factors limiting soybean yield.Screening high P efficient soybean varieties（lines）is one of the effective ways to achieve soybean sustainable production and solve the problem of "available" P deficiency.Breed selection is based on yield results.In order to reduce the workload,the index and method for rapid evaluation and identification of phosphorus efficiency at the early soybean growth stage were explored to improve the screening efficiency for phosphorus efficient germplasm resources.In this study,90 soybean varieties collected from Shenyang,Tieling and Jilin regions were used as experimental materials to identify phosphorus efficiency at seedling stage and maturity stage,and to study the physiological characteristics of phosphorus efficient varieties.The main results are as follows:1.A phosphorus efficient genotype soybean variety（line）:.09-13 and a phosphorus inefficient genotype soybean variety（line）:.09-5 was obtained by using yield and relative yield as screening indexes.2.The screening index of phosphorus efficiency at seedling stage was identified and verified by comparing with the screening results of yield.A method was developed to calculate the comprehensive score value（D value）of the three indexes of phosphorus utilization rate,relative value of phosphorus utilization rate and root volume under low phosphorus condition to screen the phosphorus efficient genotype soybean.3.Regression analysis was carried out on three indexes of phosphorus utilization rate（X₁）,relative value of phosphorus utilization rate（X₂）and root volume（X₃）under low phosphorus conditions,and the regression equation was established:D=1.218X1+0.320X2+0.007X3-0.664（P=0.001,R2=0.999）.The phosphorus efficiency of different soybean varieties（lines）can be evaluated directly according to the comprehensive score value（D value）.4.In this study,the activity of nutrient assimilation related enzymes in the root systems of No.12 and No.10 soybeans and the expression of four genes including Gm G3PT1 involved in phosphorus stress response were investigated.The results showed that the root response to low p stress was different from that of low P stress,but the specific pathway was still to be further studied.