Effect of Salinity Tolerant Rhizobial Strains on Growth, Nodulation and Yield of Groundnut in Pot Condition

Abstract

Background: Soil salinity is a major abiotic stress that severely limits global crop production, particularly in arid and semi-arid regions. Groundnut (Arachis hypogaea L.), a vital oilseed and legume crop, is moderately sensitive to salt stress, which negatively impacts its growth, nodulation efficiency, and final yield. Aims: This pot experiment was conducted to evaluate the efficacy of salinity-tolerant rhizobial strains as a sustainable strategy to mitigate the detrimental effects of salt stress on groundnut. Method: The experiment was conducted in glass house of the Soil Science Division of BINA in the year 2025 at the Rabi-Kharif-1 season with CRD and three replications. An experimental pot filled up with 5 kg of sterilized sand, and we used Binachinabadam-8 as a crop variety. One groundnut cultivar Binachinabadam-8 was grown in a pot-culture which was set up under varying levels of induced salinity (2-7 dS saline water), with treatments  including T1(uninoculated control), and inoculation with selected superior salt-tolerant rhizobial isolates (T2: STGN-1, T3: STGN-3, T4: STGN-4, T5: STGN-5, T6: STGN-6, T7: STGN-7, T8: STGN-9, T9: STGN-10), which demonstrated high tolerance to saline water in preliminary in vitro screening. Results: The results indicated that increasing salinity levels significantly reduced all measured parameters in the uninoculated and inoculated treatments, including shoot dry weight, root dry weight, nodule number, effective nodule, nodule dry weight, and pod yield. However, inoculation with the salinity-tolerant strains STGN-4 was found to be the best performer and STGN-9 and STGN-10 better while STGN-1, STGN-3, and STGN-6 performing well, respectively. Plants inoculated with STGN-4 showed an increase in effective nodule (25.00), total nodule (53.00), root length (11.00) cm, number of branches (5.33) and STGN-10 pod plant-1 (18.67) and grain yield plant-1 (29.4 gm) over the control. These superior results are attributed to the enhanced biological nitrogen fixation (BNF) capacity and potential plant growth-promoting (PGP) activities of the salt-tolerant strains, which likely supported better root colonization and function under osmotic stress. Conclusion: The findings demonstrated that inoculating groundnut with carefully selected, salinity-tolerant rhizobial strains is a highly effective, eco-friendly, and economical approach to enhancing growth, improving nodulation, and securing economically viable yields of groundnut in saline-affected soils.