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United States Department of Agriculture

Agricultural Research Service

Research Project: RESEARCH TO DEVELOP STRATEGIES AND TECHNOLOGIES FOR PRESERVING PLANT GENETIC DIVERSITY IN EX SITU GENEBANKS

Location: Plant Germplasm Preservation Research Unit

Title: Identification of historic apple trees in the Southwestern United States and implications for conservation

Authors
item Routson, Kanin - ROUTSON UNIV. OF AZ
item Reilley, Ann
item Henk, Adam
item Volk, Gayle

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 1, 2009
Publication Date: June 1, 2009
Citation: Routson, K., Reilley, A., Henk, A.D., Volk, G.M. 2009. Identification of historic apple trees in the Southwestern United States and implications for conservation. HortScience 44:589-594.

Interpretive Summary: The diversity of landrace and heirloom fruit varieties has declined worldwide over the past century. Abandoned farmsteads and historic orchards harbor considerable agrobiodiversity, but the extent and location of that diversity is poorly understood. We assessed the genetic diversity of 280 historic apple (Malus Xdomestica) trees growing in 43 abandoned farmstead and orchard sites in Arizona, Utah, and New Mexico. Genetic markers allowed us to compare the historic trees to 109 heirloom varieties that were available to homesteads in the Southwest in the late 19th and early 20th centuries. Genetic analysis revealed that 144 varieties were represented in the 280 field samples. We identified 34 of these 144 varieties as named heirloom varieties brought to the region by Stark Brothers Nursery and by USDA as well as agricultural experiment stations. One hundred and twenty of the total samples (43%) had DNA fingerprints that suggested that they were representative of these 34 named varieties. The remaining 160 samples—representing 110 varieties—had unique fingerprints that did not match any of the named varieties. The results of this study confirm for the first time that a high diversity of historic apple varieties remain in homestead orchards on and near the Colorado Plateau. Future efforts targeting orchards in the Southwest should focus on conserving the unique genotypes as a means to sustain both cultural heritage and biological genetic diversity.

Technical Abstract: The diversity of landrace and heirloom fruit varieties has declined worldwide over the past century. Abandoned farmsteads and historic orchards harbor considerable agrobiodiversity, but the extent and location of that diversity is poorly understood. We assessed the genetic diversity of 280 historic apple (Malus Xdomestica) trees growing in 43 abandoned farmstead and orchard sites in Arizona, Utah, and New Mexico using seven microsatellite markers. We compared the historic “unknowns” to 109 heirloom varieties introduced into the Southwest in the late 19th and early 20th centuries. Genetic analysis revealed that 144 varieties were represented in the 280 field samples. We identified 34 of these 144 varieties as named heirloom varieties brought to the region by Stark Brothers Nursery and by USDA as well as agricultural experiment stations. One hundred and twenty of the total samples (43%) had DNA fingerprints that suggested that they were representative of these 34 named varieties. The remaining 160 samples—representing 110 varieties—had unique fingerprints that did not match any of the named varieties. The results of this study confirm for the first time that a high diversity of historic apple varieties remain in homestead orchards on and near the Colorado Plateau. Future efforts targeting orchards in the Southwest should focus on conservation for all unique genotypes as a means to sustain both cultural heritage and biological genetic diversity.

Last Modified: 8/27/2014
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