Genetic characterization of Rosa damascena species growing in different regions of Syria and its relationship to the quality of the essential oils

Seven Rosa damascena samples and two check samples were collected and studied for both of the chemical oil and the molecular genetics composition. Results of oil chemical analyses of the different samples showed a great deal of resemblance among essential oils resultant from rose samples collected from the same region. The molecular genetics analyses for the same samples using both RAPD and ISSR techniques showed the same trend in the dendrogram. When the data were combined and put into one tree, the samples fell into two main clusters: The first combined samples 1 and 2 (Damascus) as the most closely genetically related followed by 3 and 5, and lastly the two checks were entered 4 (Rosa centifolia) and then 9 (Crataegus). And the second cluster contained three samples: the two closely related 7 and 8 (Aleppo) followed by the most distant sample of all 6. The study concluded that there were a high degree of conformity between the two dendrograms based on the chemical composition of essential oil on one hand and on the DNA level on the other hand, stressing the role of environment (mostly annual rainfall) on oil characteristics quality. On the other hand, based on these results, the authors suggest that sample 6 may not belong to Rosa damascena but to another species, and this needs further confirmation using cytoplasmic DNA techniques that target the variability at the species level.