The predominance of subtropical climatic condition in the Southem Brazil, makes the summer legumes cultivation in this region an option for animal feeding and soil management programs. These plants can gradually improve the chemical, physical and biological soil conditions as well as being a low cost protein source due to its symbiotic nitrogem fixation ability. Due to the potential species arising, to the expansion of the legume cultivated areas and to the new genotype released, several species and even cultivars have showed defficient symbiosis, using both native and early selected rhizobia as inoculants. So, in order to meet rhizobia requirements of each legume in each place, new rhizobia strains should be selected from native populations and the available stocks should be continuousiy screened against the newly released legume cultivars.
summer legumes; symbiosis; specificity; soil management
