Improving Cuticle Thickness and Quality Traits in Table Grape cv. 'Italia' Using Pre-Harvest Treatments

Table grape viticulture, due to the impact of climate change, will have to face many challenges in the coming decades, including resistance to pathogens and physiological disorders. Our attention was focused on fruit cracking due to its ubiquitous presence in several species. This study explores the effects of three different treatments on the epidermis and cuticle of table grape berries by evaluating the impact of the girdling technique on various fruit quality parameters, including cuticle thickness, sugar content, acidity, color, bunch weight, and rheological properties. The treatments were (1) calcium chloride (CaCl₂), (2) calcium chloride + salicylic acid (CaCl₂ + SA), and (3) calcium chloride + Ascophyllum nodosum (CaCl₂ + AN), with and without girdling, plus an untreated control. This research was conducted over the 2021-2022 growing season in a commercial vineyard in Licodia Eubea, Sicily, Italy. The results indicate significant variations in cuticle thickness and other qualitative traits throughout the growth and ripening phases, with notable differences depending on the treatment used. This study's findings suggest that specific treatments can influence the structural integrity of the grape cuticle, potentially impacting the fruit's susceptibility to cracking and overall marketability. The findings provide valuable insights into the role of chemical treatments and cultural techniques in enhancing fruit quality and resistance to environmental stresses in table grape cultivation.