SNP Genotyping Dataset (hmp format) of 85 Iranian Walnut (Juglans regia) Genotypes for Leafing Date GWAS

This dataset contains SNP genotyping data in HapMap (hmp) format for 85 Iranian walnut (Juglans regia) genotypes and commercial cultivars. The dataset was generated using genotyping-by-sequencing (GBS) and comprises approximately 68K high-quality SNPs. These data were used to perform genome-wide association studies (GWAS) to identify candidate loci associated with leafing date, a key adaptive trait for climate resilience in walnut. Population structure analysis revealed three major genetic clusters corresponding to geographic origin, highlighting the evolutionary history of Iranian walnut germplasm. GWAS consistently identified significant loci on chromosomes 1, 4, 6, 8, 11, and 13. A validated marker on chromosome 4 (JRgwLDch4pos20189439) showed strong discrimination between early- and late-leafing phenotypes across populations. This dataset provides a valuable genomic resource for marker-assisted selection (MAS) and breeding of climate-resilient walnut cultivars. File format: hmp. File size: 68 KB.