Current changes of ecoclimatic indicators may cause significant variation in grapevine phenology and grape ripening. Climate change modifies several abiotic factors (e.g. temperature, sunlight radiation, water availability) during the grapevine growth cycle, having a direct impact on the phenological stages of the grapevine, modulating the metabolic profile of berries and activating the synthesis and accumulation of diverse compounds in the skin of berries, with consequences on the composition of the grapes. The increase in average and extreme temperatures of summer months, as a major consequence of climate change, as well as changes of rainfall patterns during the ripening phase, leads to a higher concentration of sugar and a general change of the acidic profile of grapes, but also to the modification of secondary metabolites profiles (De Orduna, 2010; van Leeuwen and Darriet, 2016; Asproudi et al., 2018).

Therefore, in several viticulture areas, ripening occurs, when both colour and aroma profile can be adversely affected (Mori et al., 2007; Asproudi et al., 2016) which in wine is translated to a loss of typicity and terroir expression (Leeuwen et al., 2020). Due to climate change, a mismatch is also noted between the different parameters of technological, phenolic, and aromatic quality as they are regulated by different biosynthetic pathways and therefore are influenced differently.Significant variations observed in temperature and rainfall patterns or conditions of limited water availability and high temperature, that lately are characterizing the second part of berry development may cause the rapid development of individual berries during the hottest part of the season, which can adversely affect may affect the secondary metabolites that detrmine color and aroma thus grape and wine quality. 

Solutions

Radiation and temperature

Flavonoids were amongst the most affected compounds by higher levels of radiation. The fruit environment strongly regulates the production of flavonoids and early exposure has been found to have a greater impact on their concentrations than treatments performed at or after véraison.

Whilst higher carotenoids, flavonoids and selected free aroma compounds were observed in defoliated treatments thus in higher radition conditions, higher temperatures appear to have been detrimental to the adaptation of berries by limiting production of these compounds and increasing their rate of degradation, which further stresses the need to perform activities such as defoliation when temperatures are still mild.

Previous research indicated that microclimate conditions, which vary according to vintage, vineyard aspect and vine vigour may affect the timing of the peak concentration of norisoprenoid precursors whereas high temperature during the last stages of grape ripening, evidently leads to a decrease of the total norisoprenoids.

References

Mori, K., Goto-Yamamoto, N., Kitayama, M., and Hashizume, K. (2007). Loss of anthocyanins in red-wine grape under high temperature. Journal of experimental botany 58, 1935–1945.

De Orduna, R. M. (2010). Climate change associated effects on grape and wine quality and production. Food Research International 43, 1844–1855.

van Leeuwen, C., and Darriet, P. (2016). The impact of climate change on viticulture and wine quality. Journal of Wine Economics 11, 150–167.

Asproudi, A., Petrozziello, M., Cavalletto, S., and Guidoni, S. (2016). Grape aroma precursors in cv. Nebbiolo as affected by vine microclimate. Food chemistry 211, 947–956.

Asproudi, A., Ferrandino, A., Bonello, F., Vaudano, E., Pollon, M., and Petrozziello, M. (2018). Key norisoprenoid compounds in wines from early-harvested grapes in view of climate change. Food Chemistry 268, 143–152. doi: 10.1016/j.foodchem.2018.06.069.

van Leeuwen, C., Barbe, J.-C., Darriet, P., Geffroy, O., Gomès, E., Guillaumie, S., et al. (2020). Recent advancements in understanding the terroir effect on aromas in grapes and wines. OENO One 54, 985. doi: 10.20870/oeno-one.2020.54.4.3983.

Written by Andriani Asproudi

This is a work in progress