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2026 Student Flash Talks Viticulture
June 17, 2026 – 5:00 pm – 5:30 pm
VITICULTURE
Select presentation title to view abstract.
Some student authors have been assigned oral, 3-minute Flash Talks. These “flash” presentations will provide additional opportunities for interaction between conference attendees and student researchers.
Flash Talks will take place on Wednesday, June 17, 5:00 pm – 5:30 pm, at the Boise Centre, Boise, Idaho
Moderator:
To be announced
Speakers:
Rachel Ciccone | Alexandra Gunn | Dave Liscombe | Jim Willwerth*
Effect of Exogenous Tetralone Abscisic Acid Applications on the Hormone and Metabolite Profile of Merlot Buds
Rachel Ciccone, Alexandra Gunn, Dave Liscombe, and Jim Willwerth*
*Brock University, 1812 Sir Isaac Brock Way, L2S 3A1, Canada, jwillwerth@brocku.ca
Many winegrape cultivars are vulnerable to freeze injury, leading to vine damage and crop loss. Cold hardiness is influenced by genotype, environment, and viticultural practices. Abscisic acid (ABA), a key phytohormone involved in dormancy and stress responses, has been shown to promote cold acclimation. However, its rapid degradation in plant tissues limits ABA’s use as a plant growth regulator. To improve persistence, ABA analogues such as tetralone ABA have been developed to resist enzymatic degradation. Tetralone ABA contains a tetralone ring that prevents cyclization after oxidation of the 8’‑methyl group, extending molecule activity. Previous work identified tetralone ABA as a promoter of cold hardiness. This study examined its effects on dormancy, cold hardiness, and metabolite and hormone profiles in multiple Vitis genotypes. Tetralone ABA was applied to canopies at two rates (0.5, 1.0 g/L) postharvest to Marquette, Merlot, and Riesling grapevines and compared to S‑ABA and untreated controls. Bud water content and cold hardiness were monitored throughout dormancy. Bud tissue samples were prepared and hormone profiling was conducted using liquid chromatography-selective reaction monitoring (LC-SRM) analyses to quantify tetralone ABA and ABA catabolites. Buds were also analyzed using UPLC-qTOF-MS equipped with a BEH C18 column for analysis of semipolar metabolites to assess broader metabolic responses through untargeted metabolomics. Some increases in hardiness were observed late in dormancy with tetralone ABA treatments but were not consistent across cultivars or rates of application. In Merlot, phaseic acid and dihydrophaseic acid levels differed significantly on occasions, coinciding with increased bud water content. Tetralone ABA catabolites were low through most of dormancy and inconsistently detected. Metabolomics results revealed several features of interest elevated by tetralone ABA, including p‑coumaryl flavonoid glycosides, flavonoid dimers, and monoterpene glycosides; many associated with phenylpropanoid pathway activity. These findings indicate metabolic shifts that warrant further investigation.
Funding Support: Canadian Grapevine Certification Network, Ontario Grape and Wine Research Inc., Agriculture and Agri-Food Canada Sustainable CAP
Delaney Dyer | Arran Rumbaugh* | Francesco Maioli | Ben Montpetit | Marion Hervé | Anne Humbert-Goffard | Tatiana Svinartchuk | Aziz Kocnogullari | Graham McGrath | Max Shulaker
Leveraging Volatile Sensing for Rapid Detection of Smoke-Derived Signatures in Grapes and Wines
Delaney Dyer, Arran Rumbaugh,* Francesco Maioli, Ben Montpetit, Marion Hervé, Anne Humbert-Goffard, Tatiana Svinartchuk, Aziz Kocnogullari, Graham McGrath, and Max Shulaker
*USDA-ARS, 595 Hilgard Lane, RMI North Room 3156, Davis, CA, 95616, arran.rumbaugh@usda.gov
Smoke-exposed grapes accumulate volatile organic compounds (VOCs) and their glycoconjugate precursors that can be released during fermentation and impart unpleasant, smoky, and ashy flavors to wines, complicating harvest decisions and potentially compromising wine quality. Current diagnostic methods rely on gas chromatography-mass spectrometry/liquid chromatography-mass spectrometry (GC-MS/LC-MS) analyses and small-scale fermentations that are time-consuming and costly. As smoke events continue to affect the California wine industry, there is a growing need for rapid, cost-effective methods to assess smoke impact risk in grapes and wine. This study explores the use of a novel, commercially available signature analysis machine (SAM) that leverages differential sensing and data models to classify samples rapidly based on VOC signatures. Using wines across various cultivars from the 2020 and 2021 vintages, the SAM was able to differentiate smoke-affected wines from non-affected wines with classification driven by smoke exposure rather than variety or vintage. GC-MS and LC-MS chemical analyses were performed as validation for all samples to quantify smoke-derived volatile phenols and their glycoconjugates, respectively. Use of SAM for the detection of smoke impact is currently being extended to grape samples collected from Napa Valley appellations affected by the Pickett Fire in 2025. Results suggest that rapid VOC fingerprinting may enable detection and classification of smoke-derived signatures. Continued integration of VOC signals with chemical and sensory data to construct a library of validated smoke exposure signatures may enable rapid screening of grape samples and risk assessment. Similar approaches are also being explored for the detection of fresh mushroom aroma (FMA) in France, supporting the broader applicability of this strategy to vineyard-derived sensory risks.
Funding Support: Research was jointly funded through USDA-ARS, UC Davis, Moët Hennessy, and Analog Devices.
Bijaya Ghimire | Sarah Lowder*
Effect of Vine Spacing and Boron Application on Yield, Fruit Chemistry, and Vine Nutrition of Muscadine Cultivar Paulk
Bijaya Ghimire and Sarah Lowder*
*University of Georgia, 1111 Miller Plant Sciences, 120 Carlton Street, Athens, GA, 30602, sarah.lowder@uga.edu
Muscadines (Vitis rotundifolia) are relatively pest- and disease-resistant grape species native to the southeastern United States. The region’s soil is often deficient in boron (B) and mineral nutrient application is often overlooked. Furthermore, limited research has explored planting densities for commercial muscadine production. In late summer 2024, leaf blade and petiole analysis of the muscadine cultivar Paulk reported B deficiency. This study evaluated the effect of four B application strategies (spring soil application; prebloom foliar application; fall foliar application after harvest, all at 0.22 kg/ha; and an untreated control) and three vine spacings (3, 4.6, and 6 m) on vine productivity, primary fruit chemistry, and tissue nutrient composition of 6-yr-old B deficient Paulk vines. B application strategies and vine spacings had no effect on yield per ha, berry weight, berry diameter, or primary fruit chemistry (total soluble solids, titratable acidity, and pH). Previous trials on the vines reported higher yield per ha at closer spacing, indicating size advantage for the vines diminishes as the vines age. Vine spacing did have a significant effect on yield per vine, with vines spaced at 6 m producing 6 kg and 15 kg more fruit than those spaced at 4.6 m and 3 m, respectively. B treatments differed in leaf blade (p < 0.001) and petiole (p < 0.001) B concentration at bloom and leaf blade B concentration at veraison (p < 0.001). All vines, treated or untreated, had B tissue concentration within or above the sufficiency range (15 to 25 ppm), contrary to 2024, where all tissues were deficient. Pruning weights are being collected to understand how these treatments influence the balance between vegetative growth and yield. In conclusion, B application may not improve yield and quality within a season, but it can improve the tissue B concentrations. Closer spacings may benefit growers in initial years; however, the benefit may not continue as the vines mature.
Funding Support: UGA foundation
Jenna Goddard | Brent Arnoldussen* | Kynady Thomas | Elayna Stirn | Joseph Dvorak
High-Throughput Cold Hardiness Assessment of Muscadine Grape (Vitis rotundafolia Michx.) Cane and Reproductive Tissue
Jenna Goddard, Brent Arnoldussen,* Kynady Thomas, Elayna Stirn, and Joseph Dvorak
*University of Kentucky, 318N Agricultural Science Building North, Lexington, KY, 40546, brent.arnoldussen@uky.edu
Muscadine grapes (Vitis rotundifolia) exhibit limited cold hardiness, restricting their production range and motivating breeding efforts to improve winter survival in Muscadine cultivars and hybrids. Cold hardiness screening is therefore a critical component of selection. In contrast to Vitis vinifera and other cultivated grapes, where dormant bud injury is often the primary concern, Muscadines typically sustain injury to canes prior to buds, reducing the utility of high-throughput, bud-focused methods such as differential thermal analysis (DTA). To address this limitation, we developed a reverse low-temperature exposure (RLTE) system consisting of independently controlled, insulated heating pods operated within a -40°C freezer. The system interfaces with a computer for real-time temperature monitoring, data logging, and setpoint adjustment, and uses programmable ramp/soak profiles to maintain stable and accurate temperature regulation. We compared cold hardiness estimates of dormant Muscadine tissues obtained using the RLTE system with those generated using a conventional DTA approach. Ten cane and bud samples each of Supreme and Carlos were evaluated in both systems. In the DTA assay, all samples were cooled to a common target temperature of -20°C, while in the RLTE system, pods were cooled along a 5°C gradient from 5 to -20°C. After exposure, DTA data were analyzed for low-temperature exotherm peaks, while RLTE samples were assessed for oxidative browning under a dissecting microscope. Both systems exposed cane and bud tissues to lethal temperatures. DTA produced interpretable exotherm peaks for bud tissue, but cane peaks were less distinct. The RLTE system identified lethal temperatures for both tissues, although oxidative browning responses were not always consistent and warrant further refinement.
Funding Support: USDA SCRI
Daniela Menendez | Andrew Harner* | Amanda Stewart | Demetra M. Perry
Preliminary Insights Assessing the Effects of Controlled Adult Spotted Lanternfly Infestations on Cabernet franc
Daniela Menendez, Andrew Harner,* Amanda Stewart, and Demetra M. Perry
*Virginia Polytechnic Institute and State University, 595 Laurel Grove Road, Winchester, VA, 22602, dharner@vt.edu
The spotted lanternfly (Lycorma delicatula, SLF) is an invasive sap-feeding planthopper that has emerged as a significant threat to winegrape production in Virginia and the eastern United States. While grape producers primarily apply insecticides to control adult SLF populations, more information is needed to optimize standard practices and develop targeted density-specific management strategies. For this study, 21 6-yr-old Cabernet franc (Vitis vinifera) vines grafted onto 420-A rootstocks (Vitis berlandieri × Vitis riparia) were caged with exclusion netting at the Alson H. Smith Jr. Agricultural Research and Extension Center in Winchester, VA. Vines were randomly assigned to different infestation density treatments (0, 5 adult SLF per shoot, and 10 adult SLF per shoot) and different infestation timings (at veraison, 3 wk after veraison, or both times). Vines were infested at each time point for a week before SLFs were removed. At harvest, yield parameters (yield/vine, cluster weight) were quantified and berry samples were collected to assess the effects on berry weight and juice chemistry parameters (total soluble solids, pH, titratable acidity, yeast assimilable nitrogen). Buds were collected in winter to assess effects on cold tolerance. The first year of data suggests that the density and timing of adult SLF infestations had no significant effect on measured Cabernet franc fruit chemistry parameters, yield parameters, or bud cold hardiness. Additionally, preliminary results seem to indicate that experimental vines tolerated the imposed infestation length and densities without incurring effects on measured traits. Data will be collected in the spring to evaluate effects on fruit from sequential harvests. Additional analyses looking at fruit total phenolics and volatile composition will be critical to understand holistic effects on grapevine and fruit chemistry. Finally, these treatments will be implemented for a second year to evaluate the effect of consecutive feeding events across seasons.
Funding Support: Virginia Wine Board, Virginia Agricultural Council, Virginia Tech College of Agriculture and Life Sciences
Gwendolyn Richards* | Sonia Lemonier | Nicholas Baham | Casey Fison | Cristina Lazcano | Charlotte Decock
Assessing Carbon Storage Potential of Regeneratively Managed Vineyard Soils
Gwendolyn Richards,* Sonia Lemonier, Nicholas Baham, Casey Fison, Cristina Lazcano, and Charlotte Decock
*Cal Poly San Luis Obispo, 1 Grande Ave, San Luis Obispo, CA, 93401, gwendolynarichards@gmail.com
Soil carbon storage is widely recognized as essential to both reducing atmospheric CO₂ levels and improving soil health. To optimize soil carbon storage, it is important to understand both its potential and limitations. This study focuses on two key carbon pools: particulate organic carbon (POC), which is quick to decompose, and mineral-associated organic carbon (MAOC), which is stable and remains in the soil long-term. Both pools play critical roles in carbon stabilization. While POC content is influenced by multiple factors beyond soil texture, MAOC is almost entirely dependent on the presence of fine particles, which suggests a saturation point for carbon storage. This research aims to identify these MAOC saturation points in regeneratively managed soils by sampling vineyards across California. Soil fractionation techniques are used to isolate POC and MAOC, and carbon content is measured using an elemental analyzer. By determining the MAOC saturation threshold, we can better predict a soil’s capacity for long-term carbon storage based on properties like soil texture and management practices. Preliminary data show an exponential increase in POC and a logarithmic increase in MAOC with increasing SOC, suggesting that carbon saturation may be occurring in high SOC vineyards within the data set and that soils with a high fine fraction content and large carbon deficit offer the greatest potential for long-term carbon storage. Together, these results provide a way for growers to match regenerative practices to site-specific capacity, enabling more efficient, targeted, and durable long-term carbon storage in vineyard systems.
Funding Support: Foundation for Food and Agriculture Research
Guadalupe Partida | Leticia Fazio | Marco Saldivar | Xavier Rideout | Luca Brillante*
Evaluating Foliar-Applied Functional Compounds to Mitigate Heat and Water Stress in Cabernet Sauvignon Grapevines
Guadalupe Partida, Leticia Fazio, Marco Saldivar, Xavier Rideout, Luca Brillante*
*Department of Viticulture & Enology, California State University Fresno, Fresno, CA, USA lucabrillante@csufresno.edu
Climate change-driven heat and water stress have increasingly threatened grapevine physiology, fruit composition, and yield in warm-climate viticultural regions such as California’s Central Valley. This study evaluated the effectiveness of foliar-applied functional compounds as sustainable strategies to mitigate heat and water stress in Cabernet Sauvignon grapevines while maintaining photosynthetic efficiency and fruit quality. Over two growing seasons, field trials were conducted to evaluate three categories of compounds: particle film (diatomaceous earth and calcium carbonate), film-forming biopolymers (di-1-p-menthene (pinolene), starch, xanthan gum), and plant growth regulators (abscisic acid, ethephon, salicylic acid). Treatments were applied at bunch closure and veraison for particle films and biopolymers, and at veraison for plant growth regulators within a randomized complete block design. Vine water status, gas exchange, and fruit composition were measured throughout the season, while yield components were assessed at harvest. Across seasons, several treatments improved vine water status and intrinsic water use efficiency, with particle films and select biopolymers moderating vine water status and improving gas exchange under high temperatures, while maintaining fruit composition and ripening dynamics. Calcium carbonate and diatomaceous earth reduced stress indicators while maintaining fruit ripening dynamics. Starch and xanthan gum demonstrated potential as a biodegradable alternative to conventional film-forming biopolymers. Among the compounds evaluated, some plant growth regulators improved ripening behavior, while others reduced transpiration. Overall, results indicate that foliar-applied functional compounds differ substantially in their physiological tradeoffs, while particle films and film forming biopolymers offer a promising and sustainable strategy to improve resilience in warm viticultural regions.
Funding Support: ARI USDA NIFA-NextGen
Grace E. Lilly | Patricia A. Skinkis*
Vine Nitrogen Dynamics: Rootstocks Alter Pinot noir Growth and Productivity More than Yeast Assimilable Nitrogen
Grace E. Lilly and Patricia A. Skinkis*
*Oregon State University, Department of Horticulture, Oregon Wine Research Institute, 2750 SW Campus Way, 4017 Ag & Life Sciences Bldg., Corvallis, OR, 97331, patricia.skinkis@oregonstate.edu
Nitrogen (N) is one of the most important macronutrients in grapevines that affects vine growth, productivity, and fermentation kinetics. Tissue N and yeast assimilable N (YAN) are indicators of vine and must N status used by grapegrowers and winemakers and can be influenced by rootstock. The most common rootstocks planted in Oregon are 3309C, 101-14, and Riparia Gloire, all vigor-reducing rootstocks that may limit N uptake and must N. A mature trial (27- to 28-yr-old) of Pinot noir grafted to eight rootstocks (1103P, 101-14, 3309C, 420A, 44-53, 5BB, Riparia Gloire, and Schwarzmann) and own-rooted vines was evaluated over 2 yr (2024 and 2025) to understand N dynamics under the non-fertilized, non-irrigated management common in Oregon’s Willamette Valley. There were differences by rootstock for vegetative growth, yield, vine and must N, and N utilization efficiency. Vines on 5BB, 420A, and 1103P were consistently high performers. These rootstocks had nearly two-fold vegetative growth and yield compared to vines on 3309C, 44-53, Riparia Gloire, and Schwarzmann (low performers). Vines on 5BB consistently had the highest N concentration in leaf blades at veraison. However, N utilization efficiency (yield/plant N) was consistently highest in the three high-performer rootstocks (1103P, 5BB and 420A). However, only 5BB had higher must YAN than all other rootstocks and own-rooted vines. While rootstock influenced vegetative and reproductive growth, the ratio of vine size-to-crop weight was also affected by rootstock. The high-performer vines on 5BB, 420A, and 1103P were balanced (yield: pruning wt: 7 to 9) while lower-performing vines on Riparia Gloire, 44-53, and Schwarzmann produced a higher proportion of yield relative to smaller canopies (yield: pruning wt: 12 to 15) and had lower N utilization efficiency. While rootstock can have a major impact on vine growth, yield, and N utilization efficiency, there is similar must N accumulation for Pinot noir.
Funding Support: Oregon Wine Board, Oregon Wine Research Institute
Riley Hibbard* | Brent Sams | Andrew McElrone | Nicolas Bambach | Mason Earles
Characterizing the Effects of Canopy Size on the Severity of Late-Season Dehydration in Sonoma County Cabernet Sauvignon
Riley Hibbard,* Brent Sams, Andrew McElrone, Nicolas Bambach, and Mason Earles
*GALLO, 3387 Dry Creek Rd, Healdsburg, CA, 95448, riley.hibbard@ejgallo.com
In recent years, extreme temperature fluctuations near grape harvest have made accurate yield prediction increasingly difficult. Late-season dehydration, a process that occurs after maximum berry weight is attained and concurrently with mesocarp cell vitality loss, plays a crucial role in concentrating sugars to achieve desired wine styles and defines this stage of uncertainty. Its extent depends largely on the vapor pressure deficit (VPD) around the berry, vine water stress, and time from onset to harvest. Recent studies have focused on methods to mitigate late-season dehydration, particularly in warmer years, yet to our knowledge, no research has examined the extent and drivers of differences within the same vineyard. In 2024, we conducted a yield variability trial comparing high- and low-vigor canopies that revealed a wide range of dehydration-related cluster weight change from veraison to harvest between +34% and -22%. Building on these preliminary observations, in 2025, five Cabernet Sauvignon vineyards in northern Sonoma County were classified as high- or low-vigor plots based on a histogram analysis of normalized difference vegetation index from mid-July 2024 Sentinel 2 satellite imagery, ensuring maximum canopy differences without manipulation. Fruit zone microclimate was monitored continuously from veraison until harvest, while berry weights were collected weekly. Destructive cluster weights were collected at veraison, maximum weight, and commercial harvest. A relatively cool season paired with several rain events in the late season reduced dehydration, and few significant differences were observed. However, statistically significant differences in fruit zone microclimate were found between vigor classes. An analysis of daily differences in fruit zone VPD showed that these rarely exceeded 1.0 kPa until ambient temperatures exceeded 35°C. This suggests that in future years, an accumulation of temperatures above 35°C in the late season may result in more significant differences in the rate and degree of dehydration.
Funding Support: GALLO
