Exploring genetic diversity and population structure of Turkish Dactylis glomerata L. germplasm using Start Codon Targeted (SCoT) marker system

BACKGROUND: Dactylis glomerata L. (Orchard grass) is a widely cultivated forage crop known for its rich nutritional value, making it an ideal daily feed for livestock. This study assessed the genetic diversity and population structure of 180 orchard grass accessions using 12 highly polymorphic Start Codon Targeted (SCoT) primers. RESULTS: A total of 244 reproducible bands were generated with an average polymorphism rate of 85.47%, and the number of polymorphic bands per primer ranged from 11 to 29, with an average of 17.42 bands. Genetic diversity values varied, with the highest (0.389) recorded for SCoT 8 and the lowest (0.253) for SCoT 4. Shannon's information index averaged 0.47 and the mean PIC value was 0.70. The highest genetic distance of 0.81 was observed between Yozgat1 and Çanakkale3, identifying them as the most genetically divergent genotypes in the germplasm. STRUCTURE analysis classified the evaluated germplasm into two populations (Population A and Population B), which was consistent with The Neighbor-Joining tree, Principal Coordinate Analysis (PCoA) supported this pattern, showing a general separation of accessions with some degree of substructuring. CONCLUSIONS: The identified genetic variability, distinct accessions, and two genetically distant genotypes (Yozgat1 and Çanakkale3) provide valuable genomic resources for breeding programs aimed at enhancing the adaptability and productivity of orchard grass.