Agronomic efficiency of selected rhizobia strains and diversity of native nodulating populations in Perdoes (MG-Brazil). II - Beans

Common bean (Phaseolus vulgaris L.) is an economically and socially highly relevant staple food and an excellent protein source for the Brazilian population. Symbiosis of beans and N-2 fixing bacteria can increase yields and decrease yield costs. The first aim of this study was to evaluate the agronomic efficiency of previously selected rhizobia strains compared to the recommended strain (CIAT 899). Phenotypic diversity of rhizobia native populations was evaluated by cultural characteristics and analysis of total protein profiles by polyacrilamide gel electrophoresis (SDS-PAGE). Field inoculations with strains UFLA 02-100, UFLA 02-86 and UFLA 02-127 increased grain yields similarly to the control with 70 kg ha(-1) N-urea and strain CIAT 899, compared to the control without inoculation and mineral N. No relation was observed between the phenotypic grouping according to cultural characteristics or protein profiles. Native bean-nodulating populations are quite diverse and do not include strains similar to the strains introduced as inoculants.