Do fungicides induce biostimulation in soybean cultivation? A multivariate approach

Abstract

Some fungicides have demonstrated not only protective effects but also biostimulatory responses in crop physiology. Thus, the objective was to assess soybean responses to the application of fungicide groups on morphophysiological dynamics at three reproductive stages. The trial was conducted under field conditions in Gurupi, TO – Brazil. The experimental design was randomized blocks, comprising seven chemical groups of fungicides and one control, with three repeated measurements over time and four replications. Fungicides were applied at the beginning of R1, R3, and R5 stages of the crop. Five days after each application, composite samples of leaf area, specific leaf area, shoots dry mass, leaf percentage, relative growth rate, average grain weight, and leaf contents of N, P, and K were evaluated. The results were analyzed through canonical correlation. Leaf area and specific leaf area were the most sensitive variables to treatments, while thousand grain weight did not respond to treatments. The chemical groups TRI (Azoxystrobin+Tebuconazole+Mancozeb),ATI(Pyraclostrobin+Epoxiconazole+Fluxapyroxad), OXI (Fluxapyroxad+Oxychloride), and SPOT (Dimoxystrobin+Boscalid) were the major contributors to discriminant function formation. These were strongly associated with physiological responses at the three reproductive stages.