Changes in thermal resources and limitations for Georgian viticulture

Abstract

Background and Aims The growth and development of grapevine is constrained by temperature, affecting the bulk of physiological processes of the plant. The aim of this study was to evaluate the effects of climate change on thermal resources and limitations in the context of Georgia, one of the oldest viticultural areas in the world. Methods and Results The analysis on daily series of temperature for the time period 1974–2013 for the main viticultural areas of Georgia shows that an abrupt change to warmer temperature occurred in 1994, leading to a decline in low temperature stress and an increase in high temperature stress, associated with more frequent heat waves. The availability of thermal resources for grapevine growth remained unchanged. Conclusions In Georgia, the shift to warmer temperature did not affect the availability of thermal resources for grapegrowing. Although some attention should be paid to possible damage due to an earlier budburst and increased frost risk. Furthermore, it is important to highlight the strong increase of summer heatwaves with potential negative impacts on grape composition and phenolic maturity, when combined with severe water stress. Significance of the Study Quantitative studies of the effects of climate change on Georgian viticulture are essential to develop adaptation strategies based on either germplasm (e.g. rootstocks and cultivars) and agronomical practices (e.g. pruning, trellis systems, soil and water management).

The effects of leaf removal and artificial shading on the composition of Chardonnay and Pinot noir grapes

“…PCA effectively discriminated the differences among years, while the correlation matrix revealed a positive relationship between GDD and HHH and a negative relationship between NHH and HHH. This is in agreement with the definition of GDD, HHH and NHH (Amerine and Winkler, 1944;Cola et al, 2020), which associates increases in temperatures with an HHH increase at the expense of NHH. The good correlation showed by NHH and HHH regarding the ripening process suggests that the adopted response curve can provide a synthetic representation of the process.…”

“…-NHH -Normal Heat Hour Index, which represents the accumulation of hourly thermal resources useful for berry maturation (Cola et al, 2020), cumulated from fruit set to physiological maturity;…”

Georgian Grapevine Cultivars: Ancient Biodiversity for Future Viticulture

“…vines was recorded at the end of March, and, thus, a higher susceptibility to spring frost is expected when compared to the other cultivars that sprouted in April (Maghradze et al, 2014). Global warming generally resulted in the increase of cases of temperature above the optimal range (24-26 • C) during summer and in particular during grape ripening (Cola et al, 2020). A delay in the maturation process, obtained through the selection of late-ripening cultivars, could ensure thermal conditions during ripening more suitable for berry metabolism.…”

Climate Change Impacts on Plant Phenology: Grapevine (Vitis vinifera) Bud Break in Wintertime in Southern Italy

“…Frosts are strongly related to specific circulation patterns and show a high interannual variability. This, together with the increase in active temperature availability and the consequent advance of phenology, exposes grapevine to a higher risk of damage [40,[50][51][52][53][54][55]. In fact, as underlined by several authors [14,51,56], the early start of the vegetative growth increases the risk of damages induced by spring frosts, due to the high susceptibility of the plants.…”

“…This, together with the increase in active temperature availability and the consequent advance of phenology, exposes grapevine to a higher risk of damage [40,[50][51][52][53][54][55]. In fact, as underlined by several authors [14,51,56], the early start of the vegetative growth increases the risk of damages induced by spring frosts, due to the high susceptibility of the plants. In fact, the peculiar conditions of the 2019/2020 vintage that cannot be considered a singular event (see the maximum values recorded during the last decades and the standard deviation of the data) resulted in an early and anomalous bud break.…”