Effect of rhizobia inoculation on growth and yield of selected soybean (Glycine max L.) varieties under salt stress

Abstract

Salinity stress is among the factors that limits biological nitrogen fixation (BNF), growth and yield of soybean. Effects of different rhizobia inoculations on the growth and yield of soybean (Glycine max) varieties under salt stress condition were determined in a screen house. Five improved varieties of soybean (TGX1987-62F, TGX1987-10F, TGX1835-10E, TGX1951-3F and TGX1904-6F) and one local variety (Silba) were tested. The experiment was laid out in a Completely Randomized Design (CRD) with three replications. Different levels of rhizobia inoculation were prepared at 0 g/kg, 5 g/kg, 10 g/kg, 15 g/kg, 20 g/kg and 25 g/kg while salinity was maintained at 75 mM NaCl. Data were collected on root and shoot biomass, leaf area, relative water contents of leaf, relative growth rate, seed number, seed weight, chlorophyll contents and number of nodules, and analyzed using One-way Analysis of Variance at 5% significant level. Variety TGX1987-10F recorded the highest leaf area (1.78 cm2 at 32 DAS and 2.58 cm2 at 66 DAS), seed number (74.61) and seed weight (8.36 g) while varieties TGX1835-10E and TGX1987-62F recorded the lowest leaf area (1.41 cm2 and 4.21 cm2), shoot biomass (12.23 g and 21.75 g) chlorophyll content (32.69, 43.22, 34.99) at 23, 46 & 63 DAS with 0.0056 RGR. Higher inoculation level of the rhizobia (25 g per kg of soybean) was found to increases leaf area, LRWC, shoot biomass, chlorophyll content and yield of varieties TGX1987-10F and TGX1904-6F under salinity condition. Inoculation with rhizobia is effective in improving growth, BNF, yield and yield components of soybean varieties in a saline soil. Soybean varieties TGX1987-10F and TGX1904-6F inoculation with rhizobia are recommended for cultivation in saline area while TGX1835-10E and Silba are highly salinity sensitive.