Increase of the productivity of the soybean crop with the application of biostimulants

Abstract

The use of biostimulants increases plant development although few studies relate this practice to the physiological aspects of the plant. An experiment was carried out to evaluate the use of a biostimulant (cytokinin, indolebutyric acid, gibberellic acid), applied on soybean seeds and leaves at different phenological growth stages for a conventional variety (Conquista) and a genetically modified (Valiosa RR). The treatments were constituted by cultivars, applications of 6 mL of the commercial product per kilogram of seeds, and of 025 L ha-1 on leaves at the stages V5, R1 and R5, and combination of these factors, comprising a total of 30 treatments. The experimental design was a randomized block with 4 replications. The height of plants, insertion of the first pod, number of branches per plant, number of pods per plant, and number of grains per pod were evaluated. The conventional variety was more productive than the genetically modified variety. The use of the biostimulant increased the number of pods per plant and seed yield although the application via seeds and on leaves was similar. The biostimulant increased grain yield by 37% compared to the control. Plant growth provides increase in the number of pods per plant and grain yield in both applications the leaves and seeds, confirming the hypothesis of this study. However, higher productivity is not related to increased shoot growth, considering the plant height, branches per plant, height of first pod. Regarding to the increase in g the productivity plant growth, biostimulant is more, effective when applied during the reproductive growth stage.