Caracterização e seleção de rizóbios de mucuna

Abstract

The objective of this study was to characterize and to select rhizobia from mucuna to be used as inoculants. A first trial was set in the dependencies of Embrapa Agrobiologia, in pots with samples from eight soils collected in SIPA (System of Integrated Agroecological Production) for nodules of mucuna for subsequent isolation and characterization. The design was completely randomized with two replications. With the nodules collected, the isolation and morphological characterization of green manure was made, resulting in a dendrogram of similarity. Representatives of these groups were characterized by ARDRA, using three restriction enzymes (Msp I, I and HinfI DDE). With isolates obtained from nodules it was carried up the nodulation test for pre-selection of most promising isolates, and evaluated: number of nodules, dry weight of nodules and dry weight of shoot. In the five most promising strains from the efficiency test, it was assessed: nodules dry weight, fresh and dry weight of shoot, dry mass of root and shoot, and total N content. The test was conducted in a greenhouse, the design of randomized blocks with four replications and two samplings. The time of growth and change of pH were determinants of the formation of morphological groups from mucuna isolates. In general, the rhizobia strains showed similar results to the control strain and the control for nitrogen. There was wide diversity of rhizobia from mucuna in the performed genotypic and phenotypic characterizations, which may indicate existence of new rhizobia species.