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Changes in climate are influencing the quality of wine grapes worldwide. The impact of extreme climate events over short periods is increasingly recognised as a serious risk to grape quality and yield quantity. In this study, the mitigation effects of a pulsed water spray treatment on vine canopy during heatwave (HW) events were evaluated in relation to vine condition during the growing season and grape quality. In the UNCuyo experimental vineyard, vines of the three cultivars Malbec (ML), Bonarda (BO) and Syrah (SY) were treated with an overhead pulsed water spray. Heatwaves were defined as days with a minimum temperature of 21 °C and a maximum temperature of 35 °C. Two heat waves were identified during the growing season. Samples were collected at weekly intervals from veraison to harvest. On five sample dates, Leaf and Stem Water Potential (LWP, SWP), Stomatal Conductance (gs), Leaf Temperature (LT), Berry Temperature (BT), Chlorophyll Content (CC), Fluorescence (Fv/Fm) and Performance Index (PI) were recorded at several time points during the day to evaluate the physiological responses of the vine. Berries were collected on each sample date and at harvest. Berry weight, soluble solid content and pH were recorded. In the treated vines (Trt), LWP, SWP, Fv/Fm, PI and gs were significantly higher and LT was lower than in the control vines (Ctl) during the second heatwave, which was longer and more intense than the first one. One week after the more severe heatwave, LWP, SWP and gs remained significantly higher in Trt than in Ctl, displaying reduced physiological stress in Trt. At harvest, the anthocyanin profile, total polyphenol index (TPI), fruit yield, number of bunches and their average weight, berry weight, soluble solid content and pH were also recorded. Bunch weight was significantly higher in Trt for all cultivars. No differences were found in total anthocyanin concentration. These findings indicate that the vines subjected to targeted overhead water treatment during heatwaves underwent less physiological stress and yielded higher grape production, without increasing the risk of potential fungus diseases, in the Mendoza climate. Consequently, this practice could serve as a valuable strategy for mitigating the adverse effects of heatwaves.

In addition to winemaking techniques, wine’s quality and typicity are linked to the place where the grapes are grown. Climate, soil and the cultivar are major drivers of the terroir’s expression. Moreover, climate change is affecting the distribution of grapevine varieties in different wine-growing regions because changes in climatic conditions over the past years is affecting grape production. This study investigated the influence of some terroir parameters on the volatile composition of Cabernet Sauvignon wines. Eight wines from vineyards sited in Argentina, Spain and Portugal with altitudes between 2400 and 77 m above sea level (a.s.l.) with different soils and climatic conditions were selected. The results suggested that the vineyard’s place significantly modified the volatile composition of Cabernet Sauvignon wines because all chemical groups of volatiles quantified were affected. Volatile acids, C6 compounds, aldehydes, esters and terpenes showed the highest concentrations at 2400 m a.s.l., where the highest thermal amplitude was observed. In Portugal, where the vineyard studies were sited at lower altitudes (77 m a.s.l.) and under warm climatic conditions, high concentrations of alcohols and lactones were observed. Alcohols also showed high concentrations in wines from vineyards sited at 413 and 155 m a.s.l. (Spain). Principal component analysis showed the positive correlation of Cabernet Sauvignon wines located at higher altitudes with terpenes. On the contrary, wines from grapes grown at lower altitude conditions exhibited a correlation with alcohols and lactones.