POTENCIAL DO ÓLEO DE PEQUI NA SOBREVIVÊNCIA DE INOCULANTES EM SEMENTES DE SOJA EM CONDIÇÕES DE ARMAZENAMENTO

Abstract

Biological nitrogen fixation and plant growth promotion via bioinputs are essential for the sustainability of soybean cultivation, but the survival of microorganisms on seeds still represents a technical challenge. This study aimed to evaluate the influence of pequi oil (Caryocar coriaceum) as a protective agent on the viability of microbial inoculants (Bradyrhizobium japonicum and Azospirillum brasilense) and its effects on the initial development of soybean (Glycine max (L.) Merrill) subjected to different pre-sowing storage periods. The experiment was conducted at the Instituto Federal Goiano – Campus Posse, using a Completely Randomized Design (CRD) in a 4x4 factorial scheme, testing four storage times (0, 7, 14, and 21 days) and four oil doses (0; 0.4; 0.8; and 1.6 mL). At 35 days after emergence, the germination percentage, number of nodules, and dry mass of roots and shoots were evaluated. The results demonstrated that storage for up to 14 days had no deleterious effect on germination and crop development. At 21 days, a severe reduction in the germination rate was observed due to the formation of a hydrophobic barrier imposed by the highest oil doses (1.6 mL), causing physical restriction and phytotoxicity. In contrast, at this same time, the 0.4 mL dose showed a significant osmoprotective effect on the viability of Azospirillum brasilense, resulting in the highest means of root and shoot biomass in the surviving plants. The application of the oil did not statistically alter nodulation, which was governed by the native soil microbiota. It is concluded that pequi oil has biotechnological potential for maintaining bacterial viability in prolonged storage, requiring adjustments in seed coating technology to mitigate physical damage to the seed.