大豆苗期耐低磷指标筛选与耐低磷品种鉴定OA

[Objective]Study was carried out to study the low-phosphorus tolerance characteristics of different soybean varieties during the seedling stage,clarify the evaluation indicators for identifying low-phosphorus tolerance in soybean seedlings under low-phosphorus stress,and screen out low-phosphorus-tolerant varieties.[Method]Using 318 soybean varieties as the experimental materials,low-phosphorus stress treatment(LP,0.05 mmol·L-1 KH2PO4)and normal phosphorus treatment(NP,0.5 mmol·L-1 KH2PO4)were set up at the seedling stage.Nine indicators including plant height,main root length,above-ground dry weight,root dry weight,total root length,root surface area,root volume,root average diameter,and root tip number were measured.The low-phosphorus tolerance coefficients of each indicator were calculated.Variability analysis,correlation analysis,principal component analysis,and cluster analysis were conducted to analyze the characteristics of the indicators.The membership function method was combined to comprehensively evaluate the low-phosphorus-related indicators and low-phosphorus tolerance of different soybean varieties.[Result]There were extremely significant differences among the varieties for all 9 indicators.Except for the main root length and root tip number,there were significant differences in the other 7 indicators between the phosphorus treatments.The low-phosphorus tolerance coefficients of the 9 indicators could be simplified to 5 principal components.The cumulative contribution rate in the LP treatment reached 88.07%.A regression equation for evaluating the low-phosphorus tolerance characteristics of soybean seedlings was established:D=-0.454+0.221X1+0.320X2+0.247X5+0.073X8+0.058X9,R2=0.998(P＜0.01).The first-level evaluation indicators under the LP treatment were X1(plant height),X2(main root length),X5(total root length),X8(root average diameter),and X9(root tip number).Among the 318 soybean materials,61 materials belonged to low-phosphorus sensitive types,102 materials belonged to low-phosphorus moderately sensitive types,95 materials belonged to moderately tolerant types,and 60 materials belonged to tolerant types.[Conclusion]Five low-phosphorus tolerance indicators at soybean seedling stage,namely plant height,main root length,total root length,root average diameter,and root tip number were selected.60 soybean varieties were identified as low-phosphorus-tolerant.The research results provide scientific methods for the identification and selection of soybean low-phosphorus-tolerant varieties,and also provide theoretical basis and material foundation for the exploration of low-phosphorus tolerance functional genes in soybeans and efficient utilization of phosphorus nutrition.