Date Received: 13-04-2018 / Date Accepted: 04-09-2018
Experiments were conducted to evaluate effects of salinity on germination, growth, physiology and yield of two soybean varieties DT84 and DT26. NaCl solution with 4 concentrations (0, 50, 100 and 150 mM) was used for treating soybean seeds in the germination experiment. In potted experiment, soybean plants were treated by adding different NaCl concentrations (0, 50 and 100 mM) to Hoagland solution from three weeks after germination to maturity stage. The results showed that the germination ratewas significantly reduced atNaCl concentration of 150 mMwith46.67%and 31.67% in DT84 and DT26,respectively.Increased salt concentration also decreasedroot and shoot length of seedlings, fresh weight of roots and shoots and high NaCl concentration (150 mM) significantlyinhibited seeding growth of both soybean varieties. In potted experiment, plant height, leaf area, dry matter, nodules, SPAD value, Fv/Fm ratio, yield and yield components decreased with increasing NaCl concentration, while the water saturation deficit and ion leakage increased. The individual yields of soybean under salinity stress at 50 and 100 mM NaCl reduced by 32.4% and 61.9% in DT84 variety and by 39.5% and 68.9% in DT26 variety, respectively. Evaluation of salinity susceptibility index (SSI) of two soybean varieties showed that DT84 variety was more salt tolerant than DT26 variety at both 50mM and100mM NaCl concentrations.
