Evaluation of genetic diversity in fifteen Rosa damascena Mill. genotypes based on morphologic and yield traits

Damask rose is a valuable oil bearing species whose various products are widely used in food, cosmetics and pharmaceuticals. In this study, fifteen genotypes from different regions of Iran were cultivated in a randomized complete block design with 3 replications and 3 plants per plot. During two crop years, the morphological traits, flower yield and yield components were measured. The essential oils (EOs) extracted using a modified clevenger system according to British Pharmacopoeia (1993). The EO content (percentage) and EO yield were calculated for each of the R. damascena (DR) genotypes. The data were analyzed by univariate and multivariate analysis. The results showed a significant difference (p<0.01) between the years and the genotypes for all the traits except the essential oil percentage. The highest flower fresh yields (7383.8 kg.ha-1) were obtained in Fars1 and then 6016 (kg.ha-1) in Isfahan5 and the lowest yield (2566.1 kg) was obtained in LOR1. The highest content of EO (%) was obtained in Kermanshah9 genotype (0.048%) and in Isfahan9 (0.044%), respectively, and the lowest content of EO (%) was obtained in Fars1 (0.024%). The highest EO yields (2.25 kg.ha-1) were observed in Isfahan5 and (2.18 kg.ha-1) in Isfahan9, respectively, and the lowest EO yields was observed in Lorestan1 (0.81 kg.ha-1) and Azarbaijan-e-gharbi1 (0.92 kg.ha-1). The cluster analysis classified the genotypes into four group. The results of PCA showed that Fars1 had the highest flower yield and Isfahan8 had the highest EO yield.