Symbiotic efficiency of Vicia spp. from Pampean semiarid region

DALMASSO R; CASTAÑO C; PAGLIERO F; LORDA G; MONTECCHIA MS; GARCÍA P

Mendoza

Congreso; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Sociedad de Biología de Cuyo

Biological N2-fixation through symbiotic interaction between rhizobia and legumes is a major source of N input into the terrestrial ecosystem and therefore of great agricultural and ecological significance. However, an efficient symbiotic association is required for the successful use of rhizobia as inoculants. Thus, the purpose of this study was to select native rhizobial strains nodulating Vicia spp. adapted to the environmental conditions of the Pampean semiarid region for inoculant production. A collection of 160 rhizobial isolates from field-grown Vicia spp. Plants were characterized by BOX-PCR genomic fingerprinting to distinguish isolates at the strain level and the assessment of genotypic diversity. Cluster analysis of fingerprints revealed 4 groups among isolates at 70% similarity level related with their geographical origin. Within each cluster, isolates showed highly similar fingerprints, thus, we chose one representative strain of each group to evaluate their symbiotic efficiency on Vicia sp. In greenhouse inoculation assays, the native strain named 25b and Rhizobium leguminosarum D70, the strain commonly used as seed inoculant, showed the best performance among all treatments. Plants inoculated with 25b or D70 strains showed a significantly increase in N content (53 and 61%, respectively) when compared to N-fertilized treatments. The use of native strain 25b as inoculant, adapted to the soil characteristics and environmental conditions of Pampean semiarid region, will maximize the benefits of symbiotic N2-fixation and contribute to the success of inoculants for Vicia spp. for this region.