Effects of foliar application of gibberellic acid on growth, yield, and postharvest quality of beetroot (Beta vulgaris L.)

Abstract

A pot experiment was conducted at the Horticulture Farm, Bangladesh Agricultural University, Mymensingh, during the Rabi season of 2023-2024 to evaluate the effect of gibberellic acid (GA₃) with different concentrations on the growth, yield, and postharvest quality of two beetroot (Beta vulgaris L.) varieties when applied as foliar spray. The experiment was laid out in a completely randomized design (CRD) with three replications, comprising two varieties Red Baby (V₁) and Heart Beet (V₂) and four GA₃ concentrations: 0 ppm (T₀), 100 ppm (T₁), 200 ppm (T₂), and 300 ppm (T₃). Results revealed that GA₃ application significantly enhanced growth and yield parameters compared to the control. The 200 ppm GA₃ treatment (T₂) produced the maximum leaf length (37.22 cm), leaf breadth (8.00 cm), root diameter (5.02 cm), root weight (58.17 g), and yield (5.81 t ha^-1). Postharvest weight loss was lowest (32.26%) at 200 ppm GA₃, indicating improved shelf life. Among the varieties, Heart Beet (V₂) outperformed Red Baby (V₁) in most growth and yield attributes, while Red Baby exhibited higher anthocyanin content (0.055 µmol m^-2) and total soluble solids (21.00 %). The findings suggested that Heart Beet is more suitable for yield-focused production, especially with 200 ppm GA₃, while Red Baby with 100 ppm GA₃ is better for enhanced sweetness and nutritional quality. Overall, foliar application of GA₃ at 200 ppm proved optimal for improving growth, productivity, and postharvest quality of beetroot.