Chilling requirement (CR) is an important agronomic trait in peach (Primus persica L.) to ensure adequate flowering and fruit set. To date, several CR quantitative trait loci (QTLs) have been mapped in peach. Despite being heavily researched, there are no validated DNA tests for this trait in the U.S. breeding germplasm. Breeders need a DNA tool to inform cross design and select hybrids with the targeted CRs for their particular environment. Therefore, we used 9K peach SNP array vl genotypic data from the U.S. peach germplasm (N=108) for haplotype construction in previously reported QTL regions for CR on chromosomes (Chr) 1, 4, and 7. Thirty-four unique haplotypes/alleles were detected within these three regions, with mean phenotypic CR between 200- 1,100 chill hours (CH). From all identified alleles, six were associated with low CR (850 CR; 1, 2, 4, 5 and 6 on Chrl; 7 on Chr4; 5 and 12 on Chr7), and the 20 remaining had moderate CR (500 to 800 CR). Application of these results in breeding is discussed.
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