Efficiency of seed inoculation with Azospirillum brasilense on agronomic characteristics and yield of wheat

► Inoculants containing bacteria that promote plant growth and increase grain yield of plants. ► Seed inoculation with Azospirillum brasilense makes possible the partial biological nitrogen. ► A. brasilense provides additional contributions of nitrogen. ► Estimates are that the saving resulting from replacement of nitrogen fertilizers by Azospirillum inoculants. The aim of this study was to evaluate the efficiency of seed inoculation with Azospirillum brasilense on the agronomic performance and yield of wheat. The experiment was conducted in randomized blocks design with six replications in a factorial scheme (3×3×2). The factors consisted of three doses of nitrogen (zero, half and full dose); seed inoculation with A. brasilense (without inoculant, liquid inoculant and peat inoculant); two doses of bioregulator (0 and 250mLha−1) in two growing seasons (2010 and 2011). At the point of harvest, the number of seeds per ear, thousand seed mass, hectoliter weight and yield were evaluated. It is inferred that the A. brasilense is efficient in performing partial nitrogen fixation supplemented by nitrogen fertilization; yield is positively influenced by nitrogen fertilization associated with inoculation, regardless of the type of inoculant.