The objective of this study was to use 21 SSR loci to evaluate genetic diversity in 87 accessions of American hazelnut (Corylus americana) and 68 hybrids between American and European hazelnuts representing a wide geographic range from the USDA-ARS NCGR National collection, OSU hazelnut breeding collection and Arbor Day Foundation. The results of this study were published in Genetic Resources and Crop Evolution DOI 10.1007/s10722-011-9743-0.