Morphological characterization and genetic diversity of mini core collection of Rosa damascena from Morocco

Damask rose (Rosa damascena Mill.) is a popular Rosa species cultivated for the industrial production of rose oil worldwide. In the current study, the morphological characteristics and genetic diversity among 12 populations of these species collected from Kelaat M'gouna in Morocco were examined to identify more variable traits and compare their genetic structure. Observations were recorded for a total of 24 morphological traits. The phenotypic variation coefficient (CV) of the studied traits varied from 4.79 % to 42.52 %, confirming the high phenotypic variation between accessions. Cluster analysis grouped accessions into two major clusters based on their morphological resemblance. For molecular investigations, nuclear DNA was amplified using 13 ISSR markers. Analysis of molecular variance (AMOVA) indicated that the highest proportion was within populations (87 %) rather than between them (13 %). Boutaghrar region recorded high values of genetic diversity (He = 0.237), percentage polymorphic loci (PPL = 67 %) and Shannon information index (I = 0.358) Clustering based on Jaccard similarity divided studied the accessions into three distinct clusters. STRUCTURE analysis and principal coordinate analysis (PCoA) were consistent with the genetic relationships derived from cluster analysis. Our study suggests that the wide genetic variation and haplotype observed in Moroccan Damascene roses are valuable for future improvement and conservation of rose programs, particularly for enhancing commercial traits, flower yield, and breeding stability.