Efeitos da inoculação de Biomaphos® Bacillus megaterium (BRM119) e Bacillus subtilis (BRM2084) no crescimento de mudas de açaí (Euterpe precatoria Mart.)

The production of seedlings with better aerial and root growth characteristics is extremely important for the success of commercial crops. The use of phosphate-solubilizing bacteria of the genus Bacillus has been a promising strategy for optimizing seedling production, due to the increased availability of nutrients such as phosphorus, in addition to promoting plant growth through other mechanisms. In this context, Euterpe precatoria Mart., known as açaí-solteiro, a palm tree of great socioeconomic, food, and environmental importance in the Amazon, stands out. Given this, the present study aimed to evaluate the effects of Bacillus spp. inoculation on promoting the growth of açaí seedlings (E. precatoria) in order to contribute to the sustainable production of seedlings and strengthen the açaí production chain in the Amazon. The experiment was conducted in a greenhouse, in a completely randomized design, with 10 replicates. Different doses (0, 1, 3, and 4 mL) were tested with the following concentrations: 0; 4; 12; and 16×108 CFU. mL-1, respectively, of the commercial inoculant Biomaphos® (Bacillus subtilis and Bacillus megaterium). At 180 days after transfer to pots, the following variables were evaluated: aerial part variables (plant height, collar diameter, number of leaves, leaf area, and dry aerial part mass) and root variables (dry mass, volume, surface area, and diameter). Inoculation with Bacillus spp. promoted an increase in the aboveground variables, except for plant height. For the root, inoculation increased the volume, surface area, and dry root mass, while the diameter showed a linear reduction. Inoculation with Biomaphos® promotes the growth of açaí seedlings under greenhouse conditions. In the aerial part variables, it was possible to evaluate the best doses, and in the root variables, the doses that initiated growth.