Influence of plant growth regulators and water deficit on cv. Krissy table grape

Abstract

Context and purpose of the study. The quality of table grape clusters significantly affects consumer perception and market value, with berry size, texture, color, and overall appearance playing key roles. In warmer climates, poor color development in red grapes is a recurring challenge, reducing production efficiency. This coloration is largely determined by anthocyanins, the pigments that give grapes their blue, purple, and red hues. To enhance color and other quality characteristics, plant growth regulators (PGRs) are often employed to promote anthocyanin accumulation during ripening.

Material and methods. This study, conducted over the 2022 and 2023 growing seasons, examined the effects of abscisic acid (ABA) and ethephon (ETH)—applied individually and in combination (ABA + ETH)—on ‘Krissy’ table grapes under both water deficit (SDI) and non-deficit conditions. Data on stem water potential, gas exchange, berry ripening, yield, and berry quality at harvest were collected to assess treatment effects.

Results. Results indicated significant differences in stem water potential between water deficit and non-deficit treatments. Specifically, ABA application under water deficit conditions produced distinct effects compared to non-deficit treatments. Total soluble solids (TSS) analysis in late July showed statistically significant differences among treatments. While the 2022 season’s initial harvest revealed no significant yield differences across treatments, the second harvest indicated significant differences, notably between ETH under water deficit and ABA + ETH under non-deficit conditions. For the 2023 season, however, production weight was not significantly affected by any treatments.