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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #421315
Research Project: Resilient, Sustainable Production Strategies for Low-Input Environments

Location: Crops Pathology and Genetics Research

Title: Irrigation timing affects grape berry cell death and late-season dehydration

Author
item RITTER-JENKINS, ALEXANDER - University Of California, Davis
item SERRANO, A. SERGIO - Regional Institute Of Agri-Food And Forestry Research And Development Of Castilla-la Mancha (iriaf
item CORELLA CABALLERO, ROLANDO - Universidad De Panama
item GAO, TIANLE - University Of California, Davis
item KNIPFER, THORSTEN - University Of British Columbia
item SHACKEL, KENNETH - University Of California, Davis
item McElrone, Andrew
item CANTU, DARIO - University Of California, Davis
item BARTLETT, MEGAN - University Of California, Davis

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2026
Publication Date: 4/2/2026
Citation: Ritter-Jenkins, A., Serrano, A., Corella Caballero, R.I., Gao, T., Knipfer, T., Shackel, K., McElrone, A.J., Cantu, D., Bartlett, M. 2026. Irrigation timing affects grape berry cell death and late-season dehydration. American Journal of Enology and Viticulture. 77. Article 0770007. https://doi.org/10.5344/ajev.2026.25048.
DOI: https://doi.org/10.5344/ajev.2026.25048

Interpretive Summary: Cells in grape berries start to die naturally towards the end of the groing season. This cell death causes shrinkage of berries prior to harvest especially during hot and dry periods. We found that irrigation applied late in the season, helps to reduce berry cell death and berry shrivel prior to harvest. Dialing in the timing of irrigation to prevent berry cell death can help maintain crop yields that can be negatively impacted by berry shrinkage.

Technical Abstract: Hot, dry conditions can exacerbate late-season berry dehydration, reducing yield and wine quality. Late-season dehydration occurs as mesocarp cells die, releasing water that is lost to berry transpiration or backflow to the canopy. We tested whether short pulses of increased irrigation reduce late-season dehydration by interrupting stress-induced signals for cell death. We compared conventional irrigation to an early- and a late-pulse treatment, where irrigation was increased by ~40% in the 2 weeks immediately before or after the expected onset of cell death (~90 days after anthesis). We measured Cabernet Sauvignon in an experimental vineyard in Davis, California in an atypically hot (2022) and cool (2023) growing season. We monitored vine water stress, berry cell death and shrivel index, and concentrations of putative signals for cell death (i.e., H2O2) and markers of cellular damage. The late-pulse treatment significantly reduced the rate of cell death, and the magnitude of berry shrivel at harvest, but only in the hot season (p <0.05). Conversely, the early-pulse treatment did not impact the rate or date of onset for cell death or shrivel (p >0.05). H2O2 levels increased with cell death, but were not impacted by irrigation, indicating other mechanisms produced the treatment effects on cell death. These findings suggest the onset of cell death is robust to water status, but a short pulse of supplemental irrigation soon after onset can slow the rate of cell death and mitigate late-season dehydration under hot growing conditions.