QTL Mapping Of Nitrogen And Phosphorus Translocation Efficiency With Yield And Quality Traits In Soybean

Soybean is an important grain,oil and commercial crop.As a vital grain crops in China’s food security system,soybean occupies an important position in the food structure in China.Improving soybean yield and quality is the main goal in soybean breeding.Nitrogen（N）and phosphorus（P）are essential for crop yield and quality in agriculture.With the growth and development of soybean,plant nutrients accumulate into the grain,especially nutrients in the leaves are mostly transferred to the seeds for oil and protein synthesis after podding.Therefore,N and P translocation efficiency in soybean is essential for soybean yield and quality.It is of great significance to investigation genetic mechanism of soybean yield and quality in the context of N and P translocation efficiency.In this study,Jidou 17（JD17）,Huachun 6（HC6）and their derived RIL populations were used to construct a high-density genetic map,and conduct genetic analysis and QTL mapping for the nitrogen and phosphorus translocation efficiency（NTE/PTE）,yield and quality traits of RIL populations.The main research results are as follows:（1）Seed weight per plant HC6 was significantly higher than JD17（P≤0.05）.The protein content of HC6 was significantly higher than that of JD17（P≤0.05）,and the oil content of JD17 was significantly higher than HC6（P≤0.05）.The NTE/PTE of HC6 was significantly higher（P≤0.05）than JD17.（2）Correlation analysis showed that the Pearson correlation coefficient between N,P nutrient traits in leaves and yield,quality traits at full podding stage was-0.45～0.96,indicating that N and P nutrient in leaves were correlated with yield and quality traits.The correlation coefficients between N and P translocation efficiency and quality traits in grains ranged from-0.12 to 0.36,indicating that N and P translocation efficiency were correlated with protein and oil contents.（3）The genetic analysis showed that the yield and quality traits of two parents were between the maximum and minimum values of the yield and quality traits of the RIL population,showing bidirectional superparent separation.The skewness and kurtosis values ranged from-0.18 to 0.90,which approximately matched the normal distribution,suggesting that these traits belonged to the quantitative traits with heritability ranging from 0.59 to 0.90.The translocation efficiency of N and P showed superparent separation,the skewness and kurtosis values was-1.49～2.75,and the heritability was 0.73～0.74.The results showed that N and P translocation efficiency,yield and quality traits of soybean were regulated by environment and heredity.（4）13 QTL loci were identified with QTL mapping regulating yield and quality traits,with LOD values ranging from 2.6 to 9.01,which explained 6.7%to 21.2%of phenotypic variations.The LOD values of 30 loci regulating N and P concentrations in leaves and grains ranged from 2.62 to 9.88,which explained 6.60%to 22.9%of variations.11 genetic loci regulating NTE/PTE had LOD values ranging from 2.51 to 6.32,and phenotypic variations ranged from 6.8%to 16.2%.Co-localization results showed that q NWP06 regulated nutrient,yield and quality traits,q Nu10 regulated N and P translocation efficiency,and q NP20regulated nutrient and quality traits.（5）Near-isogenic lines（NILs）were further employed to verified q NP20.The results showed that the N and P translocation efficiency in NIL^JD17 was significantly lower than that of NIL^HC6（P≤0.05）,and the protein content of NIL^HC6 was significantly higher than that of NIL^JD17（P≤0.05）,indicating that q NP20 is an important genetic locus regulating nutrient translocation efficiency and soybean protein content.In summary,this study investigated N and P translocation efficiency in soybean,results suggest that N and P translocation efficiency of soybean plants were closely related to the formation of soybean yield and quality traits.A candidate site q NP20 was identified for regulating P translocation efficiency and protein content in soybean.The results provide theoretical basis and genetic resources for breeding new soybean varieties with high yield,high quality and high nutrient efficiency.