Location: Horticultural Crops ResearchTitle: Dormancy and cold hardiness transitions in wine grape cultivars Chardonnay and Cabernet Sauvignon
|Cragin, Jacob - Boise State University|
|Serpe, Marcelo - Boise State University|
|Keller, Markus - Washington State University|
Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2016
Publication Date: 1/6/2017
Citation: Cragin, J., Serpe, M., Keller, M., Shellie, K. 2017. Dormancy and cold hardiness transitions in wine grape cultivars Chardonnay and Cabernet Sauvignon. American Journal of Enology and Viticulture. 68:195-202. doi: 10.5344/ajev.2016.16078.
Interpretive Summary: Wine grape is a perennial crop that requires an exposure to cold before growth can resume in the spring. However, wine grapes are also easily injured by exposure to low temperature and cold injury is a major cause of economic loss in high latitude growing regions. Exposure to cold weather events usually occurs when vines are dormant. Throughout the winter, the stage and depth of dormancy of the vine changes and progression through dormancy differs by the type of grape. The objectives of this study were to compare dormancy and cold hardiness transitions in wine grape cultivars considered more (Chardonnay) or less (Cabernet Sauvignon) cold hardy. Results from the study showed that cold hardiness is acquired before fulfillment of chilling and steadily increases after the chilling requirement has been fulfilled. The chilling requirement was fulfilled earlier and cold hardiness progressed more rapidly in Chardonnay than Cabernet Sauvignon. Resistance to deacclimation after fulfillment of chilling was associated with the level of cold hardiness and the elapsed time since fulfillment of chilling. The influence of temperature on dormancy and cold hardiness transitions and resistance to deacclimation observed in this study has important implications for changing global climates. Temperature events in autumn influence subsequent susceptibility to injury during midwinter warming events by influencing the timing of the fulfillment of chilling. Weather conditions after fulfillment of chilling influence the level of acquired cold hardiness. Cold temperature events in autumn and mid-winter increase risk of cold injury in the event of a mid-winter warming by decreasing the resistance to deacclimation. The differences observed in this study between cultivars in effective temperatures for fulfillment of chilling show an opportunity to mitigate potential cold injury through better matching the type of grape with dormancy and hardiness transitions that compliment the pattern of weather events at potential site locations.
Technical Abstract: Dormancy and cold hardiness influence grapevine (Vitis vinifera L.) susceptibility to cold injury, which is a major cause of economic loss in high latitude growing regions. The objectives of this study were to compare dormancy and cold hardiness transitions in wine grape cultivars considered more (Chardonnay) or less (Cabernet Sauvignon) cold hardy. Cold hardiness was measured by differential thermal analysis, and a bud forcing bioassay was used to measure stage and depth of dormancy. Canes were repeatedly sampled from field-grown grapevines in Parma, ID, over two consecutive years. Both cultivars transitioned into endodormancy when day length was ~12.5 hr. Cold acclimation began during endodormancy. Bud cold hardiness steadily increased during ecodormancy. Low temperatures in autumn were associated with earlier transition to ecodormancy. Ecodormancy occurred earlier and cold hardiness increased more rapidly in Chardonnay than Cabernet Sauvignon. Among the temperatures evaluated in this study, release from endodormancy was most rapid at -3 °C in Chardonnay and 3 °C in Cabernet Sauvignon. The average number of days to bud-break steadily increased during endodormancy and decreased during ecodormancy, suggesting that capacity to resume growth increased during ecodormancy. Resistance to deacclimation during ecodormancy was inversely related to the level of bud cold hardiness and the duration of time in ecodormancy. This is suggestive of an interaction between mechanisms that impart hardiness with those involved in resumption of growth. The influence of autumn temperatures on dormancy and cold hardiness transitions and resistance to deacclimation has important implications for changing global climates. The differences observed in this study between cultivars in dormancy and cold hardiness transitions can be used to enhance cultivar and site selection.