Two-Season Evaluation of Maize Hybrids Across Plant Densities Under Mineral Fertilization and a Bacterial Consortium

Selecting maize hybrids for a given planting density requires knowing whether their yield responses to nutrition programmes persist across seasons. A two-season factorial randomized complete block experiment in Karacabey, Türkiye, compared ten commercial hybrids at three target densities under mineral fertilization (NPK) or a plant growth-promoting bacterial consortium (PGPB) without mineral fertilizer. Grain yield was standardized to 15% moisture. Across seasons, NPK and PGPB averaged 1578.73 and 1554.70 kg da−1, respectively. The PGPB-NPK difference was −24.02 kg da−1 (heteroscedasticity-robust 95% confidence interval: −40.95 to −7.10). The PGPB-NPK difference for P2105 at 9500 plants da−1 was positive in both seasons but was not significant after adjustment for multiple comparisons. The results identify hybrid-density combinations for further testing and do not establish yield equivalence or support replacing mineral fertilizer. P2105 at 9500 plants da−1 is a candidate for independent validation under comparable conditions. These findings show that recommendations for the bacterial nutrition programme should account for maize hybrid, target planting density and growing season.