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…

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.