Abstract
Peach (Prunus persica), a model species in the Rosaceae family and a globally significant temperate fruit, requires advanced genotyping tools to accelerate genomics-assisted breeding. To address this need, we developed the PeachSNP170K array and genotyped 489 peach accessions, generating a high-resolution SNP-based kinship framework that surpasses the limitations of traditional pedigree analysis. This approach enabled the identification of genomic regions underlying key phenotypic variations. Genome-wide association studies (GWAS) uncovered 1202 SNPs linked to sugar and acid content, as well as flowering time, including identified loci associated with citrate content and flowering time. Notably, we identified PpNHX1 (sodium/proton antiporter 1) within a citrate-associated locus, which influences citrate accumulation in peach fruit. Additionally, haplotype analysis revealed a highly selected haplotype, Hap3, within a major flowering-time locus, contributing to low-latitude adaptation. These findings establish the PeachSNP170K array as a powerful tool for high-throughput genomic analysis, providing valuable resources for peach research and breeding.