Apple trees do not all respond to drought in the same way. The rootstock-the lower portion of a grafted tree-plays a significant role in determining how a tree tolerates water stress. Results of the study show that apple rootstocks vary considerably in their ability to tolerate prolonged drought. Differences were observed in water use efficiency, growth regulation, and physiological stress indicators as soil moisture declined. Some rootstocks maintained more stable performance under reduced irrigation, while others exhibited early stress responses as drought conditions intensified.
The findings highlight the importance of rootstock selection as a practical tool for managing orchards under limited water supplies. Threshold-based irrigation approaches used in the study demonstrate how growers may be able to conserve water while minimizing negative impacts on tree performance, particularly when paired with drought-tolerant rootstocks.
Led by Dr. Andrew M. Bierer and Dr. Lisa Tang, (with support from Virginia Tech collaborator Caroline Wolcott and Biological Science Aid intern Kamryn Viands) the project used an innovative approach that gradually imposed drought stress over six weeks using the open-source Open_Irr irrigation platform and soil-based conditions that more closely resemble orchard environments. Collaborators from Virginia Tech and USDA contributed expertise in soil science, plant physiology, and irrigation technology. The research provides practical, science-based information to guide growers in selecting rootstocks and managing irrigation under increasingly variable climate conditions.
As climate variability and water scarcity continue to challenge fruit production systems, this research contributes data-driven guidance for improving irrigation efficiency and sustaining apple production during periods of prolonged drought.
According to Dr. Bierer, "The work for (this study)began at USDA-ARS as a collaboration between the Soil (Dr. Andrew M. Bierer) and Horticulture (Dr. Lisa Tang) laboratories at the Appalachian Fruit Research Station in Kearneysville, WV. Lisa and I share an interest in abiotic stress plant response dynamics, so we had an intention of collaborating on the topic from our own perspectives. Lisa brings a wealth of experience in assessment of plant physiology while I offer an understanding of soil physical properties and microelectronics; these interests aligned well with the needs of the regional temperate fruit industry. In fact, the work was driven directly by stakeholder interest in modern apple rootstock response to drought stress, supported by the State Horticultural Association of Pennsylvania under Agreement 58-8080-3-004. The second driver of the work was the development of the open-source irrigation control system, Open_Irr, which facilitated drought imposition during the trial. The Open_Irr platform allows us to implement threshold water management in our research, which remains of high interest across the specialty crop industry."
Dr. Bierer is a research and soil scientist with the USDA Agricultural Research Service at the Appalachian Fruit Research Station in West Virginia. His work focuses on the development of new technologies & strategies for increasing Orchard industry resilience towards climatic patterns.
The full article can be found on the Journal of the American Society for Horticultural Science electronic journal website at: https://doi.org/10.21273/JASHS05526-25
Established in 1903, the American Society for Horticultural Science is recognized around the world as one of the most respected and influential professional societies for horticultural scientists. ASHS is committed to promoting and encouraging national and international interest in scientific research and education in all branches of horticulture.
Comprised of thousands of members worldwide, ASHS represents a broad cross-section of the horticultural community - scientists, educators, students, landscape and turf managers, government, extension agents and industry professionals. ASHS members focus on practices and problems in horticulture: breeding, propagation, production and management, harvesting, handling and storage, processing, marketing and use of horticultural plants and products. To learn more, visit ashs.org.
