Selection of efficient rhizobia in lines of common bean (Phaseolus vulgaris L.) drought tolerant

Abstract

Common bean (Phaseolus vulgaris L.) yield is limited by prolonged drought conditions and nutrients scarcity in the soil. The Colombian Agricultural Research Corporation (AGROSAVIA) selected five common bean genotypes for presenting biofortification characteristics, good grain size and water deficit tolerance, however, sustainable techniques are required that contribute to the adaptation of these genotypes, and mitigate the impact of drought and nutrient scarcity on the crop production. Plant growth promoting rhizobacteria is an alternative to improve nutrients absorption and plants adaptation to adverse conditions. In this work, the efficiency of rhizobia in biological nitrogen fixation (BNF) in selected common bean genotypes was evaluated. Soil samples were taken in the rhizosphere and roots of the five bean genotypes at the Motilonia Research Center, as well as two alternative samplings in other areas of the Cesar department. Bean seeds were used as a trap to obtain nodules in the laboratory. The nodulation and biological nitrogen fixation of 11 strains from the AGROSAVIA bank in five bean genotypes were evaluated and the symbiotic efficiency of 7 of the strains in four of the genotypes was measured. Three isolates with rhizobia characteristics, symbionts of the 77-SMG22 genotype, were obtained. The most efficient strains in BNF were P17 and P22 in genotype 45-HTA10-2, strains C229 and P37 in 48-HTA14-1, in genotype 56-DAB295 all symbiont strains were efficient (C229, P03, P22 and P37), and in the 77-SMG22 genotype the most efficient treatment was the commercial inoculant Rhizobiol®. Therefore, the strains from the AGROSAVIA bank promote the development of some common bean genotypes reflected in the growth of the plants.