These bacterial strains are Plant Growth Promoting Rhizobacteria (PGPR) possess a Competitive Advantage, improved on the colonization of leguminous plants, and increase the overall performance of growth of leguminous Plant.Also, it reveals a method to SIFT and select bacterial strains that possess the beneficial characteristics just mentioned.Claim 1: a Biologically Pure Culture of bradyrhizobia japonicum selected from the group consisting of: ECA Deposited with the Access Number 50592 Strain NRRL B -； Deposited with the Access Number 50593 Strain NRRL B -； Deposited with the Access Number 50586 Strain NRRL B -； d Epositada the Access Number 50588 Strain NRRL B -； Deposited with the accession Number NRRL B - 50587； LTo access the number of Deposited with Strain NRRL B - 50589； ECA Deposited with the Access Number 50591 Strain NRRL B -； Deposited with the accession Number 50590 Strain NRRL B -； Deposited with the Access Number 50594 Strain NRRL B -； Deposited with the accession Number NRRL B - 50726 the strain； Positada the Access Number 50727 Strain NRRL B -； Deposited with the accession Number NRRL B - 50728；Deposited with the accession Number Strain NRRL B - He； and ECA Deposited with the accession Number NRRL B - 50730. Claim 2: Bradyrhizobium strains according to claim 1, wherein Said strains are able to stimulate nitrogen fixation in a Plant.Estas cepas bacterianas son rhizobacterias promotoras del crecimiento de plantas (PGPR, por sus siglas en inglés), poseen una ventaja competitiva mejorada respecto de la colonización de plantas leguminosas, e incrementan el desempeño general del crecimiento de una planta leguminosa. También, se revela un método para tamizar y seleccionar cepas bacterianas que poseen las características beneficiosas recién mencionadas.Reivindicación 1: Un cultivo biológicamente puro de Bradyrhizobia japonicum seleccionado del grupo integrado por: la cepa depositada con el número de acceso NRRL B-50592； la cepa depositada con el número de acc
