The core purpose of this project is to revolutionize the way apple orchards confront and adapt to the increasing threat of freeze-induced crop losses due to shifting climatic patterns

Recognizing the limitations of traditional critical temperature-phenology charts, which lack comprehensive coverage during pivotal periods such as fall acclimation and spring deacclimation, and fail to account for the dynamic interplay between BUD hardiness and temperature fluctuations throughout dormancy, this project endeavors to develop sophisticated models that transcend these constraints. These models will accurately predict key transitions in apple dormancy and link these transitions to the lethal temperatures for flower buds and wood at various developmental stages. Crucially, this project seeks to establish a robust framework that can simultaneously predict tree development and lethal temperature thresholds. This dual-predictive capability is a game-changer, offering growers a powerful tool that can be synergistically used with weather forecasting to make informed and timely decisions for frost protection. The project s activities include: a) comprehensive studies of BUD dormancy and phenology using popular apple cultivars such as honeycrisp, gala, and fuji across different climates b) development of critical temperature-development models to determine lethal temperatures for apple floral buds c) enhancement of predictive models for BUD development based on temperature responses d) testing the efficacy of plant growth regulators in inducing early defoliation and cold acclimation and e) widespread dissemination of research findings through various channels including webinars, grower meetings, and publications. The expected outcomes of this project are multifold. They include advanced models for predicting developmental stages and lethal temperature limits in apple trees, a deeper understanding of dormancy dynamics and BUD hardiness, and the development of effective orchard management practices to improve winter hardiness, fruit set, and production. This project s beneficiaries extend beyond the applicant organization. They include apple growers, especially in the major apple-producing states, extension agents and specialists who will receive enhanced tools and knowledge, and consumers who will benefit from a consistent supply and quality of apples. Key partners and collaborators, including universities in WA, MI, NC, VA, extension services, agricultural technology firms, and industry stakeholders, play a vital role. Their expertise in horticulture, tree physiology, and dormancy research, combined with their ability to facilitate experimental setups, data collection, and extension education, will bridge the GAP between research findings, practical applications, and data dissemination. In summary, this project aims not only to equip apple growers and stakeholders with more precise and actionable information but also to provide them with tools to navigate the complexities of a changing climate effectively. This initiative marks a significant step in safeguarding the future of apple production, ensuring sustainable yields and long-term market stability.