FOLIAR MICRONUTRIENTS SHAPE SEED COAT QUALITY IN VEGETABLE SOYBEAN

Abstract

The present study investigated the response of vegetable soybean seed-coat properties to foliar application of ferrous sulfate (FeSO₄) and zinc sulfate (ZnSO₄). The experiment was conducted during Kharif 2023 at the University of Agricultural Sciences, GKVK, Bengaluru, using vegetable soybean (Glycine max (L.) Merr.) cv. Karune (KBVS-1). Nine treatments were evaluated in a randomized block design with three replications. Among the treatments, 0.2% ZnSO₄ consistently recorded the highest values for the principal measured physical and biochemical attributes, including seed-coat thickness (0.83 mm), rupture force (69.59 N), total phenolics (0.39 mg g⁻¹), flavonoids (0.64 mg g⁻¹), proanthocyanidins (0.35 mg g⁻¹) and tannins (0.41 mg g⁻¹). Peroxidase-assay absorbance at 450 nm also reached its maximum under this treatment (2.77). Scanning electron microscopy showed comparatively greater apparent continuity among seed-coat tissue regions, while energy-dispersive X-ray spectroscopy revealed localized variation in the reported elemental composition. Collectively, the findings establish 0.2% ZnSO₄ as the most promising treatment among those tested for modifying vegetable soybean seed-coat properties.