Chromosomal Architecture, Karyotype Profiling and Evolutionary Dynamics in Aleppo Oak (Quercus infectoria Oliv.)

Aleppo oak (Quercus infectoria) is among the most industrially and ecologically significant oak species, valued for its medicinal properties and considerable genetic importance. Cytogenetic analysis provides critical insight into evolutionary history, interspecific relationships, and karyotypic differentiation. This study investigated the chromosomal architecture and karyotypic diversity of five natural populations of this species in western Iran (Sardasht, Oramanat, Baneh, Paveh, and Marivan) using actively dividing root meristems and a high-resolution image-based cytogenetic system. All examined cells displayed a basic chromosome number of x = 12 and a diploid condition, and chromosome lengths ranged from 0.90 to 2.12 µm. ANOVA and mean comparisons of five chromosomal parameters (Long Arm, Short Arm and Total Length, Arm Ratio, and Centromeric Index) revealed significant interpopulation differences in chromosome length and arm dimensions. All populations shared the karyotype formula 12 m and were classified into Stebbins’ Category B, indicating a moderately symmetrical, relatively primitive cytogenetic structure. Principal component analysis reduced the dataset to two major axes explaining 99.93% of the total variance, predominantly influenced by SA and TL on PC1 and by LA, AR, and CI on PC2. Hierarchical clustering grouped the populations into three distinct lineages, with Sardasht–Oramanat–Baneh showing the greatest divergence. Biplot vector patterns further clarified trait correlations, highlighting genomic structuring and potential breeding utility.