Soybean is a dual-purpose crop, as it serves as pulse and fodder. Legumes like soybeans have a distinctive characteristic of nodule formation. Nitrogen fixation enhancement can succeed by inoculation of soybeans with specific strains of rhizobia, ensuring adequate levels of healthy bacteria near the seed. The presented study materialized during 2018–2020 at the University of Agriculture, Faisalabad, and Ayub Agricultural Research Institute, Faisalabad, Pakistan. Two strains of Bradyrhizobium japonicum—S377 and S379—were treatments for inoculating 80 soybean accessions collected from the National Agriculture Research Center, Islamabad. Sowing 10 inoculated seeds per genotype and two seeds for control continued in a randomized complete block design (RCBD). Fresh root and shoot weights, dried root and shoot weights, nodule dry weight, grain and biomass yield, protein, and oil content increased significantly after inoculating seeds with rhizobial strains. These traits also showed significant genotypic correlations. The protein content, followed by the fresh shoot weight, directly affected nodule formation, increasing nitrogen fixation.
Bradyrhizobium japonicum, correlation, path analysis, nitrogen fixation, nodule formation, soybean
Eighty accessions inoculated with two strains of B. japonicum showed significant improvement in fresh root and shoot weights, nodule dry weight, protein, and oil content. The protein content and fresh shoot weight directly affected nodule formation, predicting the opportunity to improve yield by precisely selecting these traits in future breeding programs.