Location: Horticultural Crops Production and Genetic Improvement Research Unit
Project Number: 2072-30500-002-014-A
Project Type: Cooperative Agreement
Start Date: Apr 1, 2026
End Date: Mar 31, 2030
Objective:
Determine dose-response relationships between wildfire smoke exposure and changes in grape berry physiology, fruit composition, and wine composition across wine grape cultivars that differ in ripening time. The Cooperator will expose grape clusters from 12 cultivars to five levels of smoke just prior to harvest, with applications timed separately for early- and late-ripening cultivar groups so that exposure occurs at the same phenological stage. The Cooperator will quantify effects of smoke level on berry physiology through differential gene expression analysis of key genes involved in carbohydrate and lipid metabolism at multiple time points after smoke exposure. The project will also evaluate treatment effects on fruit composition and support production of small-lot wines so that smoke-related volatile compounds can be measured in both grapes and wines. Resulting data will be used to identify exposure thresholds associated with physiological disruption and compositional changes relevant to fruit and wine quality.
Approach:
The Cooperator will conduct a field experiment using custom-built smoke dosing chambers to expose grape clusters to controlled smoke treatments during ripening. Twelve wine grape cultivars will be included and organized into early- and late-ripening groups. Smoke will be applied at one biologically equivalent time point for each group, specifically just prior to harvest, so that all cultivars are treated at a comparable phenological stage. Five smoke exposure levels will be imposed to generate dose-response data across a broad range of conditions relevant to wildfire events. Chambers will be equipped and managed to maintain target smoke concentrations, and appropriate controls will be included to distinguish smoke effects from chamber effects.
Following treatment, the Cooperator will collect berry samples at multiple time points to evaluate short-term physiological and molecular responses to smoke. Analyses will focus on differential gene expression of selected genes associated with carbohydrate metabolism and lipid metabolism in order to better understand how smoke exposure at different doses influences berry physiological processes. Additional fruit samples will be collected for compositional analyses and for quantification of free and bound smoke-related volatile compounds. Small-lot wines will be produced from treatment fruit so that the same classes of smoke-related compounds can be measured in finished wines.
Data generated through this work will be used to develop dose-response relationships linking smoke exposure level with berry molecular responses, fruit composition, and wine composition across cultivars differing in ripening time. These results will improve understanding of cultivar-specific sensitivity to smoke exposure and provide information useful for risk assessment, research prioritization, and management decisions related to wildfire smoke impacts on wine grape production.