Skip to main content
ARS Home » Research » Publications at this Location » Publication #346615
Title: Identification of unknown apple cultivars demonstrates the impact of local breeding program on cultivar diversity

Author
item GROSS, BRIANA - University Of Minnesota
item MARTINEZ, MARLYN - University Of Minnesota
item WEDGER, MARSHALL - Washington University
item Volk, Gayle
item HALE, CINDY - Clover Valley Farms

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2018
Publication Date: 3/27/2018
Citation: Gross, B.L., Martinez, M., Wedger, M.J., Volk, G.M., Hale, C. 2018. Identification of unknown apple cultivars demonstrates the impact of local breeding program on cultivar diversity. Genetic Resources and Crop Evolution. 65:1317-1327.

Interpretive Summary: Apple trees, either abandoned or cared for, are common on the North American landscape. These trees can live for decades, and therefore represent a record of large- and small-scale agricultural practices through time. Here, we assessed the genetic diversity and identity of 330 unknown apple trees in northern Minnesota using the USDA-ARS National Plant Germplasm System (NPGS) apple collection maintained in Geneva, NY as the reference set. Genetic markers (simple sequence repeat) were used to compare the unknown, mostly historic trees in the Duluth, Minnesota region to >1000 named apple cultivars in the USDA-NPGS collection. Overall, the 330 unknown trees had high levels of genetic diversity and consisted of 264 unique genotypes. A total of 76 of the unknown trees were matched to 20 different name cultivars, and these cultivars were mainly derived from either the local breeding program at the University of Minnesota, or were Russian cultivars imported for horticulture in the northern Great Plains. This study demonstrates the importance of local breeding programs, and also the challenges associated with identifying clones in a genetically diverse crop like apple. In addition, it demonstrates the value of the USDA-NPGS plant collections for use in identifying unknown plant materials that once played important roles in American agriculture. Through the USDA-NPGS, these cultivars continue to remain available today.

Technical Abstract: Apple trees, either abandoned or cared for, are common on the North American landscape. These trees can live for decades, and therefore represent a record of large- and small-scale agricultural practices through time. Here, we assessed the genetic diversity and identity of 330 unknown apple trees in northern Minnesota with 9 simple sequence repeat (SSR) markers. The unknown trees were compared to >1,000 named cultivars in the U.S. Department of Agriculture Plant Genetic Resources Unit Malus collection and also to each other to identify repeated genotypes. Overall, the 330 unknown trees had high diversity (average He = 0.747), and consisted of 264 unique genotypes. A total of 76 of the unknown trees were matched to 20 different name cultivars, and these cultivars were mainly derived from either the local breeding program at the University of Minnesota, or were Russian cultivars imported for horticulture in the northern Great Plains. This study demonstrates the importance of local breeding programs, and also the challenges associated with identifying clones in a genetically diverse crop like apple.