Evaluación a campo de Bacillus velezensis EM-A8, potencial biocontrolador del patógeno foliar Exserohilum turcicum en maíz.

FIAMMA GROSSI; MELINA SARTORI; BARROS GERMÁN; FRANCISCO GIORDANINO; ANDREA NESCI; GARCÍA, D

Tucumán

Congreso; XL REUNIÓN ANUAL DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2022

SOCIEDAD DE BIOLOGIA DE CUYO

Maize is one of the most important cereals worldwide. Northern corn leaf blight, caused by the pathogen Exserohilum turcicum, is among the diseases that threat maize yield. In order to find a biological alternative to traditional chemical management of the disease, two formulations with the antagonist Bacillus velezensis EM-A8 were developed. Previously, antagonist ability of the bacteria was determined in vitro and maize physiological response to bacteria and pathogen was evaluated in greenhouse conditions. To assess disease control ability under natural conditions, a trial was performed in the south of Córdoba province, Argentina. Biocontrol bacteria was applied in both nutritive broth (B) and enriched nutritive broth (EB) in late sowing maize at V8 phenological stage, in natural incidence of the disease. Every ten days salicylic acid foliar concentration, proline foliar concentration, disease severity and number of affected leaves were quantified, and yield and its components- number of rows per ear, number of kernels per row and weight of thousand kernels (g)- were measured after physiological maturity. Visual estimation of severity and number of affected leaves resulted in high values in all of the treatments, although the biocontroller aid in maintaining lower values than the control. Proline (15.57±3.96 μMol.g-1 FW) and salicylic acid (32.04±10.47 nMol.g-1 FW) levels did not differ among treatments. However, yields were significantly superior in plots treated with EB (8711.88±1790.29 kg.ha-1) and B (8450.12±2579.32 kg.ha-1) compared to the control (7463.67±1812.76 kg.ha-1). Number of kernels per row was also higher in EB treated maize (29.28±4.64). Although b did not differed from the control in this trait (27.78±4.89 and 27.52±5.48, respectively), kernel weight was higher in B (216±9.61 g) and EB (214.89±23.17 g) treated plots compared to the control (194.67±5.66 g). Further studies are necessary to determine the mechanisms by which B. velezensis EM-A8 enhances maize yield and clarify if this occurs due to its antagonistic activity or rather to its influence on the plant’s tolerance.