Exploring factors affecting grapevine bud deacclimation to mitigate spring freeze injury
Restricted (Penn State Only)
- Author:
- Guilbault, Emma
- Graduate Program:
- Agricultural and Environmental Plant Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- October 14, 2024
- Committee Members:
- Michela Centinari, Thesis Advisor/Co-Advisor
Misha T Kwasniewski, Committee Member
Surinder Chopra, Professor in Charge/Director of Graduate Studies
Luis O Duque, Committee Member
Jason P Londo, Special Signatory - Keywords:
- grapevine
deacclimation
abscisic acid
dormancy
cold hardiness
spring freeze damage
delayed budbreak - Abstract:
- Spring freeze events are a major challenge faced by North American vineyards. Spring freezes are capable of damaging or killing fragile tissues, especially surrounding budbreak, which can result in yield losses and changes in juice chemistry that can in turn impact wine production. Shifts in seasonal temperatures may result in earlier budbreak times for perennial crops such as grapevines, thus extending the amount of time during which new bud and shoot tissues are at risk of being exposed to spring freeze events. Budbreak timing occurs after grapevines gradually exit their dormant states and lose cold hardiness in a complex process called “deacclimation,” aspects of which are not well understood at this time. Chapter 2 explores the relationship between deacclimation and “chill accumulation,” or the amount of time perennial crops spend at certain low temperatures and evaluates whether this relationship changes at different vineyards across Pennsylvania over two consecutive years. The goal of this study is to contribute to a better understanding of deacclimation dynamics and the factors that influence them, which can be applied to help assess spring freeze damage risk for different regions. Additionally, while several spring freeze damage mitigation methods are currently in practice across North America, many of them come at costs that make them less accessible to vineyards. For this reason, identifying alternative strategies for freeze damage mitigation is critical to help growers protect their vines. Chapter 3 explores the application of a synthetic analog of the naturally produced plant hormone abscisic acid, to mitigate spring freeze damage by delaying budbreak timing. By delaying budbreak timing, the amount of time during which vulnerable tissues are at risk of exposure to a spring freeze event is shortened. Chapter 3 also evaluates other effects of the abscisic acid analog, such as yield components and natural hormone levels, to provide additional information about its potential impacts on grapevines.