Abstract

Bacteria of the Azospirillum genus have considerable potential for application in agricultural systems, either in co-inoculation and foliar application to increase crop yields, due to its role in the production of phytohormones. The objective of this research was to evaluate the yield and quality of soybean seeds produced under the effect of different doses of Azospirillum brasilense bacteria applied to the leaves. Seeds of four soybean cultivars (Anta 82 RR^®, BRS Favorita RR^®, BRS 780 RR^® and BRS 820 RR^®) were produced in the 2013/2014 crop year in Lavras, Minas Gerais, Brazil, with application of six doses of inoculants based on A. brasilense (0, 300, 400, 500, 600 and 700 mL ha^-1) of the strains, AbV₅ and AbV₆. Besides the yield, the mass of a thousand seeds, moisture content, germination, emergence at 7 and 15 days after sowing, emergence speed index, accelerated aging, strength, viability and mechanical damage were evaluated by tetrazolium and the hypochlorite test. Regardless of the soybean cultivar, application of up to 700 mLha^-1 of A. brasilense innoculant at v₃ stage (second open trefoil) of the plants, the yield, physiological potential and seeds were not affected.

Key words: Glycine max (L.) Merrill, growth promoting bacteria, emergency, viability, vigor.