Impact on Grape Juice Quality and Phenolic Composition of Greek Autochthonous Grapevine Variety Mouhtaro Under Abscisic Acid Biostimulation

Sustainable viticulture practices could be useful tools for ensuring grape and wine quality, especially in the context of climate change. A promising and innovating approach is the use of bioelicitors in order to stimulate productivity and metabolite biosynthesis in an environmentally friendly way. However, the result depends on the variety, the phenological stage, concentration of the biomolecule applied, and climate conditions. The present study examined the impact of the plant hormone abscisic acid on the phenolic compound accumulation in the autochthonous, red-colored Greek grapevine variety Mouhtaro. During 2018 and 2019 vintages berry quality characteristics, and metabolome were evaluated at three stages: véraison, beginning and mid, and harvest. Abscisic acid (ABA) was given at doses of 0.04% w / v and 0.08% w / v during the véraison stage. According to the results, the ABA-treated grape berries were smaller and exhibited lower total soluble solid levels and increased titratable acidity compared to the control. Although no significant differences were observed in amino acids or anthocyanin and stilbene accumulation upon ABA treatment, application of ABA at the higher dose resulted in increased concentrations of phenolic acids, flavan-3-ols, and flavonols. Therefore, the application of ABA could be considered as a promising method for improving the grape quality characteristics of Mouhtaro.