Efficiency and response of corn cultivars to nitrogen, associated or not with Azospirillum brasilense

Green corn is an economic and social alternative for small and medium-sized farmers. However, the high cost of the insums, especially in relation to the use of nitrogen, has advanced studies with nitrogen-fixing bacteria. This study evaluated commercial maize cultivars for the production of green ears, responsive and efficient to nitrogen use, with and without application in Azospirillum brasilense seeds. Two trials were installed in the agricultural years 2019/20 and 2020/21 in soweds carried out on 12/04/2019 and 10/12/2020 in this order, at the Federal University of Tocantins, Palmas-TO. In each trial, the experimental design was randomized blocks, with three replications, being the treatments arranged in subdivided plots, where the treatments involving the processes with inoculation of seeds with the bacterium Azospirillum (C Az) and without inoculation of seeds (S Az) were allocated in the plots, two doses of nitrogen (30 and 120 kg ha-1 N, considered as low and high N, respectively) and in the subplots eight corn cultivars were allocated in the subplots. Joint variance analysis was performed for each of the seed inoculation processes (C Az and S Az) and then the efficiency and response of corn cultivars were studied for the use of N for each process. The inoculation of seeds with the bacterium promoted changes in the efficiency and response of cultivars regarding the use of nitrogen. The cultivar BRS-3046 was the most important for the cultivation of green ears, since it was efficient and responsive to the use of nitrogen with Azospirillum brasilense.