Effect of genotypes-Rhizobium-environment interaction on nodulation and productivity of common bean (Phaseolus vulgaris L.) in eastern Ethiopia

Background: Effectiveness of Rhizobium inoculation is determined by common bean genotypes. Environmental factors also affect common bean genotypes-Rhizobium-symbiosis. The effect of common bean genotypes-Rhizobium strains-environment interaction on nodulation and common bean production is not well studied. Three genotypes (Dursitu, Gofta, and Kufanzik) and eight selected isolates of common bean nodulating-rhizobia with N-fertilized and control check were used for field experiments at four locations (Babile, Fedis, Haramaya, and Hirna) to evaluate the effect of genotypes-Rhizobium strains-environment interaction on the nodulation, yield and yield traits of common bean. The treatments were laid out in a randomized complete block design with three replications. Results: This study revealed that Rhizobium inoculation, the genotypes, environment and their interaction significantly (P ≤ 0.05) affected all investigated traits of common bean. Common bean genotypes Rhizobium inoculation and experimental locations significantly affected nodule number (NN) and nodule dry weight (NDW). The highest NN and NDW as compared to the uninoculated control across locations were recorded with the genotype Dursitu in all inoculation treatments. However, the result revealed the lowest mean total biomass (TBY) and grain yield (GY) over locations with the same genotype Dursitu. The highest mean grain yields of 3358.89, 3257.82, 1499.25 and 2204.82 kg ha−1 across the treatments were recorded at Haramaya, Hirna, Babile and Fedis sites, respectively, with the genotype Gofta, thereby implying that there was none specificity between common bean genotypes × locations in the study locations of eastern Ethiopia with tested common bean genotypes. None of the tested isolates produced statistically better NN, NDW, TBY, GY and total plant N accumulation consistently in all locations with all tested common bean genotypes, indicating the presence of Rhizobium strains × location specificity. Conclusion: Therefore, the result showed the need for a specific strain of Rhizobium development for common bean production in different locations.