Variability in Essential Oil Content and Composition of Achillea tenuifolia Lam. Populations in Field Conditions

Achillea tenuifolia Lam. belongs to the Asteraceae family that is one of the most popular aromatic plants in Iran with great variation in both morphology and essential oil components. The aim of this study was determination of essential oil content and composition of A. tenuifolia populations in field condition. Seeds of 17 populations of A. tenuifolia collected from their natural habitats were cultivated under the same environmental conditions in the research farm of Alborz Research Station, Karaj, Iran. The aerial parts of the plants were collected at full flowering stage and dried in shade (room temperature) and their essential oils were obtained by hydro-distillation. The oils were analyzed by GC and GC/MS. Based on the results, the oil yield varied from 0.16 to 1.59% (w/w dried weight). Populations from Divandareh with 1.59% and Khoy2 with 0.16% had the highest and lowest oil yield, respectively. According to the cluster analysis, the populations were placed in two clusters. Germacrene D was the main compound in all oils, but the essential oils of populations in cluster 1 contained higher amount of germacrene D (up to 64.5% in Semnan population). α-Humulene (up to 15%) and 1,8-cineole (up to 11.7%) were the other major components in the oil of cluster 1 populations. The lower amounts of these three compounds (in addition to E-β-farnesene and piperitone) and higher amount of more volatile compounds like p-cymene, β-phellandrene, camphor, and α-thujone and presence or absence of other minor compounds placed the other populations in cluster 2. Each cluster divided in two groups because of different percentages of some component such as cubenol, viridiflorol, methyl hexadecanoate and phytol. Therefore, based on the demand for processing, the proper population can be chosen for vast cultivation.