Exogenous Application of 1-Aminocyclopropane-1-carboxylic Acid as a New Strategy to Trigger the Color Development of Table Grapes Grown in Subtropics

Abstract

This study aimed to assess, for the first time, the exogenous application of a new formulation of 1-aminocyclopropane-1-carboxylic acid (ACC) developed for agricultural use at different concentrations as a strategy to trigger color development in table grapes grown in the subtropics. Trials were conducted in commercial vineyards of ‘Benitaka’ and ‘Rubi’ grapes located in a subtropical area in the South of Brazil. For each cultivar, a randomized block design with seven treatments and four replications was used as the statistical model. Treatments included various concentrations of a formulation containing 400 g kg−1 of ACC: 0, 25, 50, 75, 100, and 125 g 100 L−1, as well as a standard concentration of a formulation containing 100 g L−1 of abscisic acid (S-ABA): 3.2 L ha−1. Treatments were exogenously applied at véraison, and for each cultivar, two trials were conducted independently, including two methods of application: to the entire canopy of the vines or only to the bunches, totaling four independent trials. The concentration of total anthocyanins and the color index of the berries were assessed weekly, whereas visual sensory analysis of the color coverage of the berries was performed at harvest. The data were subjected to analysis of variance, and means were compared by Tukey’s test at 5% significance using R-Studio software. A single exogenous application of ACC, ranging from 75 g 100 L−1 to 125 g 100 L−1, intensified berry color by increasing the total anthocyanin concentration in berry skins. For ‘Benitaka’ grape, applications of ACC to the entire canopy of vines or only to bunches ranging from 75 g 100 L−1 to 100 g 100 L−1 resulted in enough color coverage, while for ‘Rubi’, ACC at 100 g 100 L−1 was enough to intensify and to uniform the red color of berries, as well as the application of S-ABA at 3.2 L ha−1, with no negative impact to the bunches or vines.