Symbiotic efficiency of indigenous common bean rhizobia isolated from Northwestern Croatia

Abstract

The strains of nodule bacteria differ greatly in their symbiotic properties and efficiency in nitrogen fixation and therefore, the selection of highly effective strains is of great importance when attempting to achieve a successful pre-sowing inoculation of common bean. The aim of this study was to determine the nodulation ability of indigenous rhizobial strains and to evaluate their compatibility and symbiotic efficacy with two common bean cultivars. A two-factorial pot experiment (12 indigenous rhizobial strains and two common bean cultivars) was set up in the greenhouse. In the full blossom phase, dry nodule biomass, shoot dry weight and N content in dry shoot was determined. The research revealed significant differences depending on the strain of nodule bacteria and common bean cultivars. The compatibility of indigenous and reference strains on the examined common bean cultivars was also observed. The cultivar Tresnjevac was significantly better than Slavonski zeleni in all measured parameters. The results revealed that the indigenous common bean rhizobial strains considerable differ in their symbiotic efficiency. The highest dry nodule biomass was determined when strain HO12 was applied, and the highest shoot dry weight with strains MB1 and DE7. The application of strain DE7 revealed the highest N content in dry shoot. The results indicate that these indigenous strains of common bean nodulating bacteria are characterized by the highest symbiotic efficiency and could be used for the pre-sowing inoculation of common bean after testing in field scale experiment.

Keywords

• rhizobium spp.
• symbiotic nitrogen fixation
• trešnjevac
• slavonski zeleni
• greenhouse experiment