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چکیده
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Sunflower is one of the most important oilseed crops worldwide, cultivated extensively across diverse regions. To enhance oil quality and yield, plant breeders have developed new sunflower cultivars over time. This study assessed the genetic diversity, polymorphism, and population structure of various sunflower cultivars using molecular markers. Genomic DNA was extracted via the CTAB protocol and amplified using selected genetic diversity primers. Data analysis revealed substantial variation among cultivars, with cultivar 3 exhibiting the highest number of different alleles and polymorphic loci, and cultivar 13 the lowest. Cultivar 3 also showed the highest values for effective allele number, Shannon’s information index, and expected heterozygosity, indicating considerable intra-cultivar genetic variability, while cultivar 5 showed the lowest diversity. Principal coordinate analysis (PCoA) corroborated these results, demonstrating wide dispersion of individuals in cultivar 3 and tight clustering in cultivar 5. The Ewens-Watterson neutrality test indicated a predominantly neutral evolutionary pattern, though a few loci suggested possible selection. AMOVA revealed significant genetic differentiation, with 56% of variation among cultivars and 44% within. High genetic differentiation and low gene flow emphasized limited gene exchange between cultivars. STRUCTURE analysis identified five distinct genetic clusters, and UPGMA alongside Nei’s genetic distance analysis confirmed close genetic relationships between cultivars 12 and 13 and marked divergence between cultivars 8 and 15. These results provide valuable insights for sunflower breeding and conservation, supporting efforts to maintain and enhance genetic diversity.
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