Аңдатпа
The walnut ( Juglans regia L .) is one of the most widely cultivated tree nuts globally, valued for its nutritional, economic, and ecological significance. Understanding genetic diversity and population structure is crucial for conservation and breeding efforts. We analyzed 253,307 single-nucleotide polymorphism (SNP) markers using the Axiom™ J. regia 700K SNP genotyping array in 173 walnut samples, including wild trees, local varieties of unknown origin, and commercially cultivars from Moldova, France, Hungary, Romania, Ukraine, China, and Uzbekistan grown in Kazakhstan. Our results revealed that wild walnut populations in Kazakhstan form distinct genetic clusters, reflecting historical isolation and adaptation, while cultivars exhibit a more dispersed genetic profile, indicative of admixture and artificial selection. Observed heterozygosity ( H O ) ranged from 0.29 in wild populations to 0.39 in French commercial varieties, with Chinese walnuts exhibiting the highest genetic diversity (0.48). Inbreeding coefficients ( F ) were highest in wild Kazakh walnuts (0.17), indicating genetic bottlenecks and habitat fragmentation, whereas local genotypes showed lower inbreeding levels (0.08), suggesting a more diverse genetic background. Principal Component Analysis (PCA) and ADMIXTURE analysis revealed an east–west genetic differentiation, positioning Kazakh walnuts as an intermediate genetic bridge between Chinese and European populations. These findings underscore the unique genetic heritage of Kazakhstan’s wild walnuts and their potential role in breeding programs aimed at enhancing resilience to environmental stressors and preserving genetic resources.