Impact of 2100-Projected Air Temperature, Carbon Dioxide, and Water Scarcity on Grape Primary and Secondary Metabolites of Different Vitis vinifera cv. Tempranillo Clones

The exploration of the grapevine (Vitis vinifera L.) intra-varietal diversity can be an interesting approach for the adaptation of viticulture to climate change. We evaluated the response of four Tempranillo clones to simulated year-2100-expected air temperature, CO₂, and relative humidity (RH) conditions: climate change (CC; 28 °C/18 °C, 700 μmol mol^–1 CO₂, and 35%/53% RH) vs current situation conditions (CS; 24 °C/14 °C, 400 μmol mol^–1 CO₂, and 45%/63% RH), under two irrigation regimes, “well-watered” (WW) vs “water deficit” (WD). The treatments were applied to fruit-bearing cuttings grown under research-oriented greenhouse controlled conditions. CC increased sugar accumulation and hastened grape phenology, an effect that was mitigated by water deficit. Both CC and water deficit modified amino acid concentrations and accumulation profiles with different intensities, depending on the clone. Combined CC and water deficit decreased anthocyanins and the anthocyanin to total soluble solids (TSS) ratio. The results suggest differences in the response of the clones to the 2100-projected conditions, which are not always solely explained by differences observed in the ripening dynamics. Among the clones studied, RJ43 and CL306 were the most affected by CC/WD conditions; meanwhile, 1084 was globally less affected than the other clones.