Location: Grape Genetics Research Unit (GGRU)Title: Kinetics of winter deacclimation in response to temperature determines dormancy status in grapevines (Vitis spp.)
|KOVALESKI, ALISSON - Cornell University - New York|
|REISCH, BRUCE - Cornell University - New York|
Submitted to: AoB Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2018
Publication Date: 10/8/2019
Citation: Kovaleski, A.P., Reisch, B.I., Londo, J.P. 2019. Kinetics of winter deacclimation in response to temperature determines dormancy status in grapevines (Vitis spp.). Journal of Experimental Botany. 1.
Interpretive Summary: Grapes are one of the most economically important fruit crops worldwide, with the vast majority of production derived from a single, Mediterranean species, Vitis vinifera. Grapes, like many other temperate fruit crops, survive the stress of freezing that occurs during the winter season by halting their growth in the fall and entering dormancy. Once grapes become dormant, they still must survive temperatures below freezing without suffering lethal damage. In the dormant bud, the freezing point of water is suppressed such that the buds don't freeze, even when temperatures are low. Using this defense, the buds can survive winter temperatures as low as -25°C for cultivated varieties and -35°C for wild grape species. In this study we looked at this ability to survive freezing and the effect warm temperatures have on maintaining this defense. As the buds are exposed to warm temperatures, they gradually lose their ability to survive freezing. This study demonstrated that depending on the dormancy state (early winter versus late winter), warm temperatures have different impacts on freeze resistance. These differences in rate of loss can now be used to refine prediction models for winter survival for grapevine. Additionally, this method should also be of use for other temperate fruit crop species that use the same freeze suppression mechanism. This will allow other crop researchers to better model freeze resistance in their fruit species and help farmers understand the status of their crops during the dormancy season.
Technical Abstract: Bud dormancy and cold hardiness are critical adaptations for surviving winter cold stress for temperate perennial plant species, with shifting temperature-based responses during the winter. The objective of this study was to uncover the relationship between dormancy transition (chilling requirement) and temperature on the loss of cold hardiness. Dormant cuttings of European grapevine cultivars (Vitis vinifera; 'Cabernet Franc', 'Cabernet Sauvignon', 'Riesling', and 'Sauvignon blanc') and wild grapevine species (V. aestivalis, V. amurensis, and V. riparia) were examined to determine the relationship between chilling requirement and temperature on rate of deacclimation (kdeacc). Differential thermal analysis was used to determine kdeacc using mean low temperature exotherms. Effect of chill was evaluated as the deacclimation potential, which was the change in kdeacc due to chill accumulation. Results indicate that deacclimation potential varies dependent on dormancy state, following a logarithmic response to chill accumulation. The effect of temperature on kdeacc was exponential at low and logarithmic at high temperatures. The combination of deacclimation potential and kdeacc resulted in good prediction of deacclimation, demonstrating that kdeacc can be used as a quantitative determinant of dormancy transition. This information can be used to refine models predicting effects of climate change on dormancy and cold hardiness in grapevine.