The lack and/or inconsistent behavior of results found in literature have limited Azospirillum use in maize crops. In this regard, this study aimed at evaluating the performance and chlorophyll a fluorescence of maize hybrids inoculated with Azospirillum brasilense under different nitrogen levels and protected crop conditions with nutrient solution. The experiment was conducted in a greenhouse at Instituto Federal Goiano, Rio Verde Campus. Adapted jars from "Leonard" were used in the experiment. For each bottle, 1.5 kg of substrate with washed sand and vermiculite in a proportion of 1:1 and nutrient solution of Sarruge was used. The experiment was conducted in a completely randomized design in a 4 × 2 × 2 factorial arrangement with four replications, totaling 160 treatments: four maize hybrids: simple hybrid– H1 (NS 90); modified simple hybrid– H2 (AS 1581); double hybrid– H3 (DKB 310); triple hybrid– H4 (ATL 310); with absence and presence of N (NP and NA) and absence and presence of inoculation (IP and IA). Physiological evaluations of chlorophyll a fluorescence using a modulated portable fluorometer, MINI-PAM model were performed at the end of the experiment. Initial fluorescence (F0), maximum fluorescence (Fm), potential quantum yield (Fv/Fm) variable fluorescence/maximum fluorescence), effective quantum yield (ΔF/Fm’), photochemical dissipation (qp), non-photochemical dissipation (qn and NPQ) and electron transport rate (ETR) were determined. On average, there was a difference in ETR of about 34% between treatments. For H4, it was observed that Fv/Fm was lower with inoculant when compared with plants without inoculation, a difference of approximately 11%, on average, was observed in value of Fv/Fm ratio. Due to better efficiency in absorption and utilization of nitrogen promoted by bacteria (A. brasilense), inoculated maize hybrids showed a good photosynthetic performance.
Key words: biological nitrogen fixation, nitrogen economy, maize hybrids.