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.

High Temperature and Elevated Carbon Dioxide Modify Berry Composition of Different Clones of Grapevine (Vitis vinifera L.) cv. Tempranillo.

Tempranillo is a grapevine (Vitis vinifera L.) variety extensively used for world wine production which is expected to be affected by environmental parameters modified by ongoing global climate changes, i.e., increases in average air temperature and rise of atmospheric CO2 levels. Apart from determining their effects on grape development and biochemical characteristics, this paper considers the intravarietal diversity of the cultivar Tempranillo as a tool to develop future adaptive strategies to face the impact of climate change on grapevine. Fruit-bearing cuttings of five clones (RJ43, CL306, T3, VN31, and 1084) were grown in temperature gradient greenhouses (TGGs), from fruit set to maturity, under two temperature regimes (ambient temperature vs. ambient temperature plus 4°C) and two CO2 levels (ambient, ca. 400 ppm, vs. elevated, 700 ppm). Treatments were applied separately or in combination. The analyses carried out included berry phenological development, the evolution in the concentration of must compounds (organic acids, sugars, and amino acids), and total skin anthocyanins. Elevated temperature hastened berry ripening, sugar accumulation, and malic acid breakdown, especially when combined with high CO2. Climate change conditions reduced the amino acid content 2 weeks after mid-veraison and seemed to delay amino acidic maturity. Elevated CO2 reduced the decoupling effect of temperature on the anthocyanin to sugar ratio. The impact of these factors, taken individually or combined, was dependent on the clone analyzed, thus indicating certain intravarietal variability in the response of Tempranillo to these climate change-related factors.

Growth performance and carbon partitioning of grapevine Tempranillo clones under simulated climate change scenarios: Elevated CO2 and temperature.

Atmospheric CO2 levels and global temperatures are expected to rise in the next decades, and viticulture must face these changes. Within this context, exploiting the intra-varietal diversity of grapevine (Vitis vinifera L.) can be a useful tool for the adaptation of this crop to climate change. The aim of the present work was to study the effect of elevated temperature and elevated levels of atmospheric CO2, both individually and combined, on the growth, phenology and carbon partitioning of five clones of the cultivar Tempranillo (RJ43, CL306, T3, VN31 and 1084). The hypothesis that clones within the same variety that differ in their phenological development may respond in a different manner to the above mentioned environmental factors from a physiological point of view was tested. Grapevine fruit-bearing cuttings were grown from fruit set to maturity under two temperature regimes: ambient (T) vs elevated (ambient + 4°C, T + 4), combined with two CO2 levels: ambient (ca. 400 ppm, ACO2) vs elevated (700 ppm, ECO2), in temperature-gradient greenhouses (TGGs). Considering all the clones, elevated temperature hastened grape development and increased vegetative growth, but reduced grape production, the later most likely associated with the heat waves recorded during the experiment. Plants in the elevated CO2 treatments showed a higher photosynthetic activity at veraison and an increased vegetative growth, but they showed signs of photosynthetic acclimation to ECO2 at maturity according to the C:N ratio, especially when combined with high temperature. The combination of ECO2 and T + 4, mimicking climate change environmental conditions, showed additive effects in some of the parameters analyzed. The clones showed differences in their phenological development, which conditioned some responses to elevated CO2 and temperature in terms of vegetative production and C partitioning into different organs. The work adds new knowledge on the use of different grapevine clones, that can be useful to improve the viticultural efficiency in future climate change scenarios.