Abstract

One of the most prominent strategies to increase maize grain yield with a higher benefit/cost ratio and a lower environmental impact is the inoculation of plant growth-promoting bacteria. Among other factors, the success of the interaction plant-microorganism depends on genetic traits, therefore, selection of plant genotypes compatible with this association is extremely important to the viability of this technology. This article presents an innovative study that investigates the interactions between Azospirillum brasilense Ab-V5 and 27 genotypes of maize, including 24 experimental hybrids from a partial diallel (denotated H_ij as a result of the crosses among the parental inbred lines L_i and the tester breeding lines T_j), the variety ST0509 from UEL and the commercial hybrids DKB390 and DKB390H from Monsanto. The plots consisted of treatments with or without inoculation in three replicates and the 27 maize genotypes were randomly distributed in the sub-plots. The inbred lines L₂, L₃, L₆, L₁₁, T₂ and T₃ present the highest general combining ability, producing the best hybrid combinations. The additive effects of genes are more important than the non-additive effects for all traits evaluated. The most promising experimental hybrids are H_{2 3’,} H_{3 2’}, H_{11 2’,} H_{11 3’} and H_{12 3’}. Significant effect for inoculum was not verified when performed at the seedling stage in the experimental conditions of this study.

Key words: Zea mays L., Azospirillum brasilense, inoculation, biological nitrogen fixation, combining ability.