Exogenous phytohormones and growth-promoting microorganisms in Basilisk grass cultivation

The use of plant growth-promoting bio-inputs has been widely disseminated as a means to optimise pasture production processes. This study was conducted to evaluate the effects of applying exogenous phytohormones along with different microorganisms on the productive characteristics of Basilisk grass (Urochloa decumbens). The experiment was conducted in a 4×2 factorial design, in a completely randomised layout, evaluating four microorganism inoculations (no inoculation; Azospirillum brasilense + Pseudomonas fluorescens; Rhizophagus intraradices; A. brasilense + P. fluorescens + R. intraradices), combined or not with an exogenous phytohormone based on cytokinin, gibberellin and auxin. The results showed that inoculation with plant growth-promoting microorganisms stimulated an increase in root volume. In addition, the presence of the microorganisms increased the concentration of chlorophyll pigments, resulting in a 14% increase in the crude protein content of Basilisk grass compared with the control. The use of exogenous phytohormones also resulted in higher concentrations of total chlorophyll pigments and crude protein content, with increase in 25% and 9.7% respectively. The combined use of bacteria and mycorrhizal fungi, along with exogenous phytohormones, increased the accumulation of forage mass and leaf biomass. The combination enhanced carbohydrate accumulation in the leaves of Basilisk grass, thereby improving its nutritional quality. Therefore, considering the evidence found in this research, it becomes evident that the application of exogenous phytohormones, when combined with the inoculation of A. brasilense, P. fluorescens, and R. intraradices, represents a strategy to enhance the productivity of Basilisk grass.