Identificação e inoculação de bactérias promotoras de crescimento no cultivo de grão-de-bico

Abstract

The use of plant growth-promoting bacteria in combination with organic fertilization represents a strategic biotechnological approach for the sustainable intensification of agriculture, especially in legumes of nutritional and economic importance, such as chickpea (Cicer arietinum L.). Several studies have highlighted the potential of these bacteria, including Bradyrhizobium, Bacillus, Azospirillum, Klebsiella variicola, Mesorhizobium sp., Kosakonia radicincitans, among others, in promoting plant growth through mechanisms such as biological nitrogen fixation, nutrient solubilization, phytohormone synthesis, and improved resource use efficiency. In this study, native microorganisms from tropical soils were identified, along with individual analyses of their plant growth-promoting effects. In addition, biological inoculants were developed and tested under both controlled and field conditions. For the first time in Brazil, we identified a bacterium of the genus Mesorhizobium sp1, native to tropical soils, which could establish symbiosis with chickpea by forming viable root nodules and fixing atmospheric nitrogen. The results demonstrated that inoculation and co-inoculation with multiple bacterial strains resulted in synergistic effects on the physiological and agronomic performance of chickpea, promoting significant increases in biomass, nodule number and weight, chlorophyll content in leaves, and nitrogen, phosphorus, and potassium accumulation. Furthermore, the studies showed that chickpea cultivars respond differently to combinations with microorganisms, highlighting the need for integrated approaches adapted to regional edaphoclimatic conditions, particularly in semiarid environments.