Abstract
Enhancing color development in red table grapes is a significant challenge for growers worldwide due to its direct impact on marketability and economic returns. This study investigated the efficacy of abscisic acid (ABA) and ethephon, applied individually and in combination, on berry quality parameters and maturation advancement in ‘Red Globe’ seeded grapes. A total of 12 treatments comprising various concentrations of ABA (200, 400, and 600 ppm) and ethephon (100 and 200 ppm), applied alone or in combination at veraison and 10 days postveraison, were evaluated during the 2022–2023 fruiting season at the ICAR-National Research Centre for Grapes, Pune. The application of ABA at 400 ppm significantly accelerated ripening by 8 days compared to the control while maintaining optimal berry firmness (58.26%). The highest bunch weight (442.63 g) was recorded with ABA at 600 ppm plus ethephon at 200 ppm. Notably, ABA at 400 ppm resulted in the highest marketable yield (12.67 kg/vine), representing a 28.4% increase over the control, while having minimal negative impact on physiological weight loss (5.23%) during postharvest storage. The highest total soluble solids (18.9°B) and lowest acidity (0.71%) were achieved with ABA at 600 ppm plus ethephon at 200 ppm. While higher concentrations of both plant growth regulators enhanced coloration and total soluble solids (TSS) accumulation, they also reduced berry firmness, potentially affecting postharvest quality. This study demonstrates that strategic application of ABA at moderate concentrations (400 ppm) represents an optimal balance between early ripening, marketable yield enhancement, and maintenance of postharvest quality parameters in ‘Red Globe’ grapes.