Extraction of DNA from leaf and dormant bud tissues was carried out as described in . Dormant buds were collected as described in  and stored at −70 °C until used for DNA extractions. For the 514 samples, DNA quality and quantity was tested before submitting for genotyping. Approximately 20 K SNPs, originating from EST transcriptome assemblies, were submitted for design scores and 16 K of these were selected for inclusion on an Affymetrix Axiom™ Genome-Wide 1.5 K - 50 K array (Santa Clara, CA). Genotypes were successfully determined for 506 of the 514 samples and were used in downstream analysis with an initial call rate of 97% or greater.