Diversity and potential use of rhizobia from nodules of Gliricidia sepium

Abstract

Research involving the selection of N₂ fixing rhizobia for inoculation of forage legumes can contribute to improve the nutritional quality, and promote the management and conservation of pastures. Thus, the aim of this study was to analyze the morphological, phenotypic and symbiotic diversity of rhizobia derived from 30 root nodules of legume Gliricidia sepium. Thirty three bacterial isolates were obtained in medium 79, of which eight were selected for tolerance studies in different conditions of acidity and salinity and the symbiotic properties in G. sepium legumes, Phaseolus vulgaris and Crotalaria spectabilis. Bacterial isolates showed similar morphological characteristics, but differed in regard to phenotypic and symbiotic properties. Regarding G. sepium, all isolates inoculated including inoculant strain, BR 8802, showed similar ability to provide nitrogen for plant growth. However, some of the isolates showed greater ability to survive in different pH and salinity compared to BR 8802, suggesting that these should be selected for further studies.