Wheat cultivars submitted to seed inoculation with Azospirillum brasilense and nitrogen application in different environments

Abstract

The response of wheat to seed inoculation with Azospirillum brasilense is variable, depending on factors related to the interaction of the bacterium with the genotype, growing environment and nitrogen availability. The objective of this work was to evaluate the response of wheat cultivars to seed inoculation with two strains of A. brasilense  (Ab-V5 and Ab-V6) and to application of nitrogen (N) doses in two environments. The experiments were conducted under field conditions in Eldorado do Sul (RS) and Itapiranga (SC), in the 2012 and 2013 growing seasons, under a randomized block design, in a 3 x 2 x 3 factorial arrangement, with three N doses (0, 50 and 100 kg ha^-1), with and without seed inoculation with A. brasilense, and three wheat cultivars (Mirante, Quartzo and TBIO Pioneiro). Nitrogen application increased wheat growth and grain yield, mainly in Eldorado do Sul (RS), where the soil of the experimental site shows lower fertility levels. Wheat seeds inoculation with two strains of      A. brasilense showed variable responses in the growth and grain yield according to the cultivar, growing season and experimental site. Positive responses to seed inoculation were more consistent for the cultivar Mirante, in Eldorado do Sul (RS).