terclim by ICS banner
IVES 9 IVES Conference Series 9 GiESCO 9 Heatwaves impacts on grapevine physiology, berry chemistry & wine quality

Heatwaves impacts on grapevine physiology, berry chemistry & wine quality


Context and purpose of the study – Climate change impacts on both yields and quality have increased over the past decades, with the effects of extreme climate events having the most dramatic and obvious impacts. Increasing length and intensity of heatwaves associated with increased water stress necessitates a reevaluation of climate change responses of grapevine and, ultimately, a reconsideration of vineyard management practices under future conditions. Here we summarize results from a three-year field trial manipulating irrigation prior to and during heatwave events to assess impacts of water application rates on vine health and physiology, berry chemistry, and wine quality. We also highlight potential mitigation strategies for extreme heat, both in terms of water application, as well as other cultural practices that could be widely applicable.

Material and methods – A three-year experimental study consisting of manipulating irrigation prior to and during heatwave events was conducted in a commercial vineyard of Cabernet Sauvignon on 1103P rootstock.  To evaluate the use of irrigation applied prior to and during heat waves (HWs), and its effect on grapevine physiology and berry composition, we exposed Vitis vinifera cv. Cabernet Sauvignon vines in an established vineyard to three differential irrigation treatments. The baseline treatment was under water deficit (60% ET), while the 2x baseline ET and 3x baseline ET treatments had double and triple the irrigation of the baseline, respectively. Differential irrigation started one to two days prior to a HW and continued until the last day of the HW.  Vine physiology, berry chemistry, transcriptomic data, yield and wine chemistry were collected for all seasons, and the carbohydrate status of the different vine organs were assessed at the end of the study.

Results – The amount of irrigation applied before and during heatwaves had significant effects on yield, primary and second chemistry, as well as sensory properties of the resulting wine. Throughout HWs there was a significant reduction in gas exchange, an increase in leaf temperature, and lower evaporative cooling in the baseline treatment, while no differences were observed between 2x and 3x treatments. However, after HWs the baseline treatment showed signs of recovery from physiological stress. Skin tannin and anthocyanin content, the onset of anthocyanin synthesis, pH, and acidity were affected negatively by underwatering (60% ET) or overwatering (3x). Additionally, the baseline treatment had the highest total soluble solids (TSS), and the lowest yield. There were no significant impacts on carbohydrate status of the vine after three years of treatment. Despite distinct weather patterns each year of the study, impacts were Our study highlights the detrimental effects of insufficient or excess water applications during heat waves on grapevine physiology, berry composition, and wine quality, and emphasizes the need for a broader understanding of how different mitigation strategies for extreme heat impact vines and wine.


Publication date: July 17, 2023

Issue: GiESCO 2023

Type: Article


Elisabeth FORRESTEL1*, Martina GALEANO1, James CAMPBELL1, Sophia BAGSHAW2, Morgan FURZE3, Luis SANCHEZ4, Nick DOKOOZLIAN4, Annegret CANTU1, Andrew GAL5, Mallika NOCCO5, Andrew McELRONE1,2

1Department of Viticulture and Enology, University of California Davis
2USDA-ARS, Davis, California
3Department of Botany and Plant Pathology, Purdue University
4 E. & J. Gallo Winery, Modesto CA
5Department of Land Air & Water Resources, University of California Davis

Contact the author*


Grapevine health, heatwaves, climate change, irrigation, water stress, carbohydrate storage, berry chemistry, wine quality


GIESCO 2023 | IVES Conference Series


Related articles…

Methodological advances in relating deep root activity to whole vine physiology

Full understanding of grapevine responses to variable soil resources requires
assessing the grapevine root system. Grapevine root systems are expansive and examining deep roots (i.e., >40 cm)
is particularly important in conditions where grapevines increase reliance on deep soil resources, such as drought
or plant competition. Traditional methods of assessing roots rely on morphological traits associated specific
functions (e.g., root color, diameter, length), while recent methodological advances allow for estimating root
function more directly (e.g., omics). Yet, the potential of applying refined methods remains underexplored for roots
at deep depths.

The impacts of frozen material-other-than-grapes (MOG) on aroma compounds of red wine varieties

An undesirable note called “floral taint” has been observed in red wines by winemakers in the Niagara region caused by large volumes of frozen leaves and petioles [materials-other-than-grapes (MOG)] introduced during mechanical harvest and subsequent winemaking late in the season. The volatiles, which we hypothesized are responsible, are primarily terpenes, norisoprenoids, and specific esters in frozen leaves and petioles. The purpose of this study was to investigate the volatile compounds which may cause the floral taint problem and explore how much of them (thresholds) may lead to the problem. Also, the glycosidic precursors of some of these compounds were analyzed to see the changes happening during frost events.

Aromatic profile of six different clones of Chardonnay grape berries in Minas Gerais (Brazil)

Aromas are one of the key points in food analysis since they are related to character, quality and consequently consumer acceptance. It is not different in the winery industry, where the aromatic profile is a combination of viticultural and oenological practices. Based on the development of more aromatic clones and on the potential to produce sparkling wines at Caldas, in the southern region of Minas Gerais (Brazil) (21°55´S and 46°23´W, altitude 1,100m), the aim of this work was the determination of volatile compounds in six different clones of Chardonnay grape berries to better understand which compounds add bouquet to the wine, and additionally comprehend the impacts of the edaphoclimatic and annual conditions on the improvement of grape-growing and winemaking practices.

Improving stilbenes in vitis Labrusca L. Grapes through methyl jasmonate applications

Grapes (Vitis sp.) are considered a major source of phenolic compounds such as flavonols, anthocyanins and stilbenes. Studies related to the beneficial effects of these compounds on health have encouraged research aimed at increasing their concentration in fruits. On this behalf, several plant growth regulators such as jasmonic acid and its volatile ester, methyl-jasmonate (MeJa), have demonstrated promising results in many fruits. However, Brazilian subtropical climate might interfere on treatment response. The present study aims to evaluate the application of MeJa in the pre-harvest period in Concord and Isabel Precoce grapes (Vitis labrusca L.).

Service crop effects on grapevine water and nitrogen status and yield under Mediterranean climate

Service crops in vineyard can provide multiple ecosystem services but they can also lead to competition with the grapevine for soil resources in the Mediterranean region due to potential severe droughts (Garcia et al., 2018). One of the levers of action to manage this competition is the choice of species adapted in terms of growth dynamics and water and nutrients’ needs. The objectives of this study were to determine the effect of temporary service crops on grapevine water and nitrogen status and grapevine yield and yield components in a Mediterranean vineyard.