Co-inoculation with Bacillus sp CECT 450 improves nodulation in Phaseolus vulgaris L.

The strain Bacillus sp. CECT 450 increased nodulation on bean (Phaseolus vu lgaris L.) when co-inoculated with Rhizobium tropici CIAT 899. This positiv e effect occured under controlled conditions on perlite-vermiculite, sand, or in a mixture of soil and sand. This increase was also observed in a fiel d assay. Nodulation kinetic studies suggested that the synergistic effect i s pronounced during the latter stages of cultivation. In contrast, the same bacteria co-inoculated with Bradyrhizobium japonicum USDA 110 reduced nodu lation on soybean (Glycine max (L.) Merr.). Inoculation with Bacillus sp. C ECT 450 alone had no effect on bean plants, but reduced root growth in soyb ean. The survival of Bacillus sp. CECT 450 on inoculated seeds was high, ev en when inoculated seeds were maintained for several months at room tempera ture.