Path Analysis in Soybean Cultivars Grown under Foliar Spraying and Furrow Inoculation with Azospirillum brasilense

The objective of this study was to evaluate, through path analysis, the influence of agronomic characters as a function of foliar spraying and furrow inoculation by Azospirillum brasilense on soybean yield. Two experiments were conducted in the crop years of 2013/14 and 2014/15, grown in Lavras, Minas Gerais. In the first experiment, the experimental design was a randomized block in a factorial 4 × 6, four cultivars (Anta 82 RR®, BRS Favorita RR®, BRS 780 RR®, BRS 820 RR®) and six doses of A. brasilense (0, 300, 400, 500, 600, 700 mL ha-1), with three replications. In the second experiment, the experimental design was a randomized block design, arranged in a 4 × 2 factorial scheme, four cultivars (Anta 82 RR®, BRS Favorita RR®, BRS 780 RR®, BRS 820 RR®) and two treatments with A. brasilense (inoculated and non-inoculated) with three replications. For both experiments, it was established plant height, phytomass of the aerial part, plant height at harvest, first legume insertion, number of legumes, number of grains per legume, mass of one thousand grains and grain yield. In the study with foliar spraying of soybean with A. brasilense, plant height at harvest was the only variable that had a direct effect on soybean grain yield. As such, in the study with furrow inoculation of A. brasilense in soybean, plant height at harvest and number of vegetables were the variables with the greatest direct effects on soybean grain yield.