Efecto de cepas de Azospirillum brasilense en el crecimiento y rendimiento de grano del maíz

Auxin production in vitro of three strains (CBG-180, CBG-181, CBG-497) of the plant growth-promoting rhizobacteria Azospirillum brasilense native of northern Tamaulipas, México, was evaluated regarding their effects on biomass, grain and forage production of maize (Zea mays L.). Strain CBG-497 (from the Río Bravo county) produced more auxins in vitro than strains CBG-180 and CBG-181 (from the Díaz Ordaz county). In greenhouse, the strain CBG-497 significantly increased biomass production (20 to 90 %) in three maize hybrids ('Garst-8222', 'Dekalb-2003' and 'Asgrow-Tigre') compared to the non inoculated control. Under field conditions grain and forage yields were not different between biofertilizers based on A. brasilense native strains and chemical fertilization, but the application of biofertilizers increased the profitability of maize (36 % in average) due the reduction of fertilization costs.