Microrganismos associados à adubação na promoção de crescimento em plantas de milho crioulo (Zea mays L.)

Abstract

In the Amazon region, corn (Zea mays L.), belonging to the Poaceae family, is considered a cereal of great importance for human consumption, animal feed and obtaining biofuels, such as ethanol and biodiesel. It is, particularly, a crop with a high requirement of macronutrients, such as nitrogen, phosphorus and potassium, essential for the development of vegetables, enabling more sustainable and economical alternatives. It is believed that the reduction in the amount of fertilization associated with biofertilizers, such as the fungi native to the Amazon, can positively influence the promotion of growth, gas exchange, economic viability and productivity, similar to the standard with 100% of the fertilization recommended for the crop. In this sense, the objective of this study was to evaluate the use of entomopathogenic fungi and biological control agents in plant diseases Metarhizium anisoplie, Beauveria bassiana and the mix of Trichoderma asperellum (isolates UFRAT06, T09, T12 and T52) associated with 50% of the recommended fertilization on biometric, physiological, and anatomical parameters of Creole corn plants. The experiment was carried out in a greenhouse, with a completely randomized design; six treatments and six replications. The treatments were: T1- without fertilization and fungi (Control), T2 - 50% of the recommended fertilization for culture, T3- Beauveria bassaiana + 50% fertilization, T4- Metarhizium anisopliae + 50% fertilization, T5- Trichoderma asperellum Mix (Isolates UFRAT06, T09, T12 and T52) + 50% fertilization and T6- 100% fertilization (Recommended standard treatment). All treatments with microorganisms promoted greater growth of corn plants, with the most efficient being T5 for all variables analyzed. Plants inoculated with M. anisopliae and fertilization and with the mix of T. Asperellum and fertilization showed higher values in the parameters of net photosynthesis (A), stomatal conductance (gs), transpiration (E) and carboxylation efficiency (A/Ci), compared to the control treatment. For the intercellular CO2 (Ci) variable, the T4 and T5 treatments stood out. In the anatomical analyses of the fungi, the best treatments were T4 and T5. Biochemically, all microorganisms evaluated showed satisfactory results for phosphate solubilization, siderophore production and indoleacetic acid (IAA) production. It is concluded that the microorganisms M. anisopliae and T. asperellum, associated with half of the fertilization recommended for creole corn, are efficient and maximize the biometric, physiological and anatomical parameters of the crop.