Genetic fingerprinting identifies apple (Malus domestica Borkh.) fruit cultivars in historic orchards on public lands

Authors: Volk, Gayle; MCCARDLE, KEVIN - National Park Service; SERIN, JORDAN - National Park Service; MAGBY, JONATHAN - Washington State University; MAZUR, RACHEL - National Park Service

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2021
Publication Date: 3/24/2021
Citation: Volk, G.M., McCardle, K., Serin, J., Magby, J., Mazur, R. 2021. Genetic fingerprinting identifies apple (Malus domestica Borkh.) fruit cultivars in historic orchards on public lands. Genetic Resources and Crop Evolution. https://doi.org/10.1007/s10722-021-01175-8.
DOI: https://doi.org/10.1007/s10722-021-01175-8

Interpretive Summary: Many federal lands have historic homesteads and orchards which must be evaluated for potential significance, according to the National Historic Preservation Act of 1966. It is difficult to determine accurate cultivar names using appearance and taste information. The availability of genetic data for apple cultivars in the USDA National Plant Germplasm System as well as other heritage apple orchards has facilitated the development of a reference cultivar dataset for the genetic fingerprints of apple cultivars. A total of 86 historic apple trees in Redwood National and State Parks and Eldorado National Forest were genotyped and compared to this reference cultivar dataset to determine their cultivar identities. Cultivar information will be considered as the determination of the historic significance of orchards on these public lands is determined.

Technical Abstract: The National Historic Preservation Act of 1966 mandates that historic resources, including orchards, on federal lands be evaluated for potential significance. Evaluations include assessments and documentation of an orchard’s layout and location, as well as the forms, ages, conditions, and cultivars of the trees. These factors may reveal an orchard’s history and uniqueness and determine an orchard’s historic significance. Fruit tree cultivar identities are a key piece of this puzzle. They reveal information about an orchards’ use, origin, and uniqueness. In the past, historic preservationists relied on pomologists to identify cultivars based primarily on the physical traits of the tree. DNA fingerprinting technologies, in combination with high-quality reference cultivar collections, have dramatically improved the accuracy of heritage cultivar identification. We demonstrate the utility of using DNA technologies for cultivar identifications on federal lands using examples from trees in orchards of Redwood National and State Parks and the Eldorado National Forest. A total of 86 historic apple trees from these locations were genotyped and cultivar names were determined for 35 trees, using a reference set of 1634 apple cultivars from the USDA National Plant Germplasm System, Washington State University, and Seed Savers Exchange. The unidentified trees are likely a combination of cultivars that are not in the reference set or are unique trees derived from seeds. The information derived from genetic fingerprinting analyses will aid in the determination of the historic significance of orchards on public lands.