Genetic Diversity of Greek Rye (Secale cereale L.) Germplasm Revealed by ISSR, SCoT and Exon-Based Molecular Markers

Rye (Secale cereale L.) is a small-grain cereal traditionally cultivated under low-input conditions, where locally adapted populations have contributed substantially to the maintenance of genetic diversity. Despite this importance, Greek rye germplasm has received limited attention at the molecular level. In the present study, 33 rye accessions, including gene bank landraces, locally cultivated populations and one commercial variety, were analyzed using inter-simple sequence repeat (ISSR), start codon-targeted (SCoT), and exon-based amplified polymorphism (EBAP) markers. All three marker systems generated high proportions of polymorphic loci and comparable estimates of expected heterozygosity, indicating considerable genetic variability within the studied material. Multivariate analyses revealed moderate population structuring and consistently identified a small number of genetically divergent accessions, most notably T-492, K-163, and K-166. No clear clustering according to geographical origin was detected, as in most cases of landraces or local populations. Taken together, the results provide a detailed molecular overview of Greek rye germplasm—which has never been performed before for Greek rye genetic material—and offer a useful basis for conservation priorities and future pre-breeding efforts.