2019 ASHS Annual Conference

The United States is among the leaders in fresh apple production. Increased volatility in temperatures will create less predictable snow packs, hotter summers, and changes to seasonal patterns that will affect orchard productivity and quality. High yields and reduced losses to disorders will be required to maintain profitability and to increase sustainability of production under these changing environments. Irrigated regions of the Western United States rely on a steady supply of water from melting snowpack in nearby mountain regions. In these areas, decreased summer water flows will require the development of water savings practices that do not negatively impact productivity or quality. Earlier bud break and later frosts will change dormancy and chilling patterns and change frost risk for most apple production regions in the country. Lastly, higher summer temperatures and earlier fruit maturity will increase the risk of sun-related damage that currently account for significant amounts of losses to the apple industry in Washington State. These losses may increase in areas traditionally unaffected by heat related disorders. All of these impacts will require changes to management practices that combine to conserve resources while still maintaining quality and productivity standards to ensure the profitability of tree fruit production in the United States. While some cropping regions have experienced recent drought events that have necessitated water conservation research, irrigated apple production systems have not suffered widespread impacts and as such, are not as well equipped to implement strategies to navigate changes in climate. Here, we highlight several strategies to mitigate the impacts of climate change and conserve water resources in apple production regions. These include the use of protective netting to optimize the light environment to reduce heat related losses while also conserving water through reduced evapotranspiration and reduction in evaporative cooling use. Other strategies include irrigation decisions that reduce postharvest losses due to heat and nutrient imbalances in susceptible cultivars. Lastly, we highlight the need for more research to better understand the plasticity of tree fruit species to develop cultivars that are better equipped to withstand the changing environmental pressures that are being experienced in traditional production regions. These combined strategies will better guide mitigation and adaption strategies that will help maintain apple production in the future.