Inoculation with Plant Growth-Promoting Bacteria Improves the Sustainability of Tropical Pastures with Megathyrsus maximus

Brazil is the second-largest producer and first exporter of beef, with herds mainly raised in extensive pastures, where Megathyrsus maximus occupies over 30 Mha. About 70% pastures are under degradation, using plant growth-promoting bacteria (PGPB) may contribute to reversing this scenario. We investigated effects PGPB on growth six cultivars M. maximus—Tanzania-1, Massai, BRS Zuri, Mombaça, Tamani, Quênia—under greenhouse conditions. Plants were inoculated, or not, elite strains Azospirillum brasilense CNPSo 2083 + 2084, Bacillus subtilis 2657, Pseudomonas fluorescens 2719, Rhizobium tropici 103. At 35 days after emergence, plants evaluated for ten root traits, shoot dry weight, levels macro micronutrients accumulated shoots. Several traits increased due inoculation all genotypes, impacting nutrient uptake. Despite differences effectiveness, genotypes benefited from some degree, but Mombaça Zuri more responsive. Scanning electron microscopy indicated that bacterial species differed their capacity colonize seeds rootlets. The results show represent an important strategy sustainability pastures.