Improving Freezing Tolerance of Cold-Sensitive Grape Cultivars Using Abscisic Acid

Thanks to my advisor Dr. Imed Dami, my SAC members: Dr. Michelle Jones and Dr. Joshua Blakeslee. Thanks for the support from all my previous and current lab mates.Grape and wine industries in colder regions such as Ohio have been expanding rapidly and demand for premium wine grapes has also increased. However, several popular cultivars are sensitive to freezing temperatures below -20°C. The goal of this study was to improve freezing tolerance of sensitive grape cultivars using abscisic acid (ABA). The objectives of this research are to: 1) evaluate the response of greenhouse- and field-grown wine grape cultivars to exogenous ABA, 2) characterize the changes of freezing tolerance, water content, and soluble sugars in bud tissues of greenhouse- and field-grown vines in response to exogenous ABA. In the field, we evaluated the effect of exogenous ABA on freezing tolerance and optimum timing of ABA application of Vitis vinifera ‘Pinot gris’. ‘Pinot gris’ grapevines were treated with 400mg/L ABA at different stages of development (veraison, post-veraison and post-harvest). The application of ABA did not affect yield components or fruit composition, but caused early leaf abscission, advanced bud dormancy, decreased bud water content, and eventually increased freezing tolerance. Greenhouse experiments showed that ABA caused desiccation of buds which was associated with increased freezing tolerance. Ultimately, the findings of this project are valuable to grape producers to provide another tool for freeze protection and to the scientific community for better understanding of the mechanisms of freezing tolerance.SCRI ProjectOhio Grape Industries ProgramDepartment of Horticulture & Crop Science, OARDC, OS