Genetic diversity of cornelian cherry (Cornus mas L.) cultivars from Eastern Europe based on SSR markers

• Analysis of 50 cornelian cherry accessions using nine SSR markers revealed 85 alleles, with high polymorphism (PIC: 0.39–0.86). • Bayesian STRUCTURE analysis, principal coordinate analysis and neighbor joining clustering identified genetic groups linked to geographic and cultivar origins. • Yellow-fruited cultivars consistently formed a separate genetic group across all analyses. • Hungarian landraces exhibited notable genetic diversity, valuable for local breeding programs. • Cultivars like ‘Macrocarpa’ and ‘Variegata' showed genetic differences despite similar historical names. This study aimed to evaluate the genetic diversity and relationships among 50 cornelian cherry ( Cornus mas ) accessions using nine Simple Sequence Repeats markers. Successful amplification yielded a total of 85 alleles, with allele sizes consistent with previous studies ranging between 130 and 275 base pairs. The number of alleles per locus ranged from 3 to 16, with an average of 9.78. Genetic indices showed high polymorphism, with Polymorphic Information Content values ranging from 0.39 to 0.86 with an average of 0.72. The average observed heterozygosity value was 0.56 while the average expected heterozygosity value was 0.7 Bayesian STRUCTURE analysis distinguished three major genetic clusters corresponding to geographic and cultivar origins. Neighbor-joining clustering grouped the accessions into two primary clusters, with subgroups reflecting geographic origin, including Bulgarian, Ukrainian, Slovakian, Polish, and Hungarian genotypes, as well as distinct clusters for yellow-fruited cultivars. Principal coordinate analysis supported these clusters, explaining 29.17 % of the total variation. Yellow-fruited cultivars clustered separately from other genotypes in all analyses, suggesting distinct genetic characteristics. The study highlighted the genetic diversity within Hungarian landraces and emphasized the potential value of these genotypes in breeding programs. Differences among cultivars with shared historical names, such as the ‘Macrocarpa’ and ‘Variegata' types, suggest that historical naming conventions may mask significant genetic variability. The findings underscore the utility of microsatellite markers in cornelian cherry cultivar identification and genetic fingerprinting, providing essential insights for breeding and conservation efforts.