Aplicações de Azospirillum brasilense na cultura da soja

Abstract

The growth promoting bacteria of the genus Azospirillum brasilense have great agronomic potential due to their beneficial physiological effects during the plant growth. In order to verify these potential four studies were performed. In the first study the objective was to evaluate the inoculation effect of different doses of Bradyrhizobium japonicum and Azospirillum brasilense in the morphophysiological development and soybean nodulation. The experiment was performed in design the completely randomized, with four replications, in a 5 x 2 factorial, with five doses of Azospirillum brasilense (0, 0.5, 1.0, 1.5 and 2.0 mL per kg -1 of seed ) and two doses of Bradyrhizobium japonicum (0 and 3.0 mL per kg -1 of seed), both transmitted via seeds. Doses of isolated Azospirillum brasilense and coinoculation did not promote influences on the evaluated parameters. In the second study the objective was to evaluate the inoculation of Azospirillum brasilense associated with Bradyrhizobium japonicum in agronomic traits and soybean yield. The experiment was performed in randomized blocks in a 4 x 2 factorial, with four cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRSMG 780RR ® and BRSMG 820RR ® ) and two treatments with Azospirillum brasilense (inoculated seed and non inoculated) with three replications in two crop years. The inoculation or not of Azospirillum brasilense associated with Bradyrhizobium japonicum does not affect the agronomic traits and grain yield in RR ® soybean cultivars. In the third study the objective was to evaluate the agronomic traits and grain yield in soybeans due to Azospirillum brasilense doses applied by spraying the leaves. The experiment was performed in randomized blocks in a 4 x 6 factorial, with four cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRSMG 780RR ® and BRSMG 820RR ® ) and six doses of Azospirillum brasilense (0, 300 , 400, 500, 600 and 700 mL ha -1 ) with three replications in two crop years. The spraying leaves in doses of Azospirillum brasilense does not affect the agronomic traits and grain yield in RR ® soybean cultivars. In the fourth study the objective was to evaluate the yield and quality of soybean seeds produced under the effect of different doses of bacteria Azospirillum brasilense applied to the leaves. Seeds of four soybean cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRSMG 780RR ® and BRSMG 820RR ® ) were produced in 2013/2014 crop year in Lavras, Minas Gerais, Brazil, with the application of six doses of inoculants based of Azospirillum brasilense (0, 300, 400, 500, 600 and 700 mL ha -1 ) of the strains (AbV5 and AbV6). The application of the inoculant with Azospirillum brasilense bacteria did not affect the studied variables.