University of Tehran, College of Aburaihan International Journal of Horticultural Science and Technology 2322-1461 6 2 2019 12 01 Essential oil Content and Composition of Dracocephalum Moldavica under Different Irrigation Regimes 167 175 73957 10.22059/ijhst.2019.280572.294 EN Shima Alaei Department of Agronomy and Plant Breeding, Faculty of Agriculture, Kermanshah branch, Islamic Azad University, Kermanshah, Iran. Journal Article 2019 05 04 <em>Dracocephalum moldavica</em> L. is an annual species of Lamiacea family whose essential oil is widely used in medicinal, food, cosmetic and health industries. Drought stress is a major factor limiting plants growth and yield. The main objective of this study was to evaluate the influence of irrigation regime on essential oil content and composition of <em>D. moldavica</em> L. The Irrigation regimes were 100%, 85%, 75% and 55% of field capacity (FC). The results showed that 53 essential oil components were identified in different irrigation regimes. Thirty-six, twenty-two, twenty and thirty components were identified at 100%, 85%, 75% and 55% of FC, respectively. The amounts of identified components were 99.4%, 96.6%, 97.8% and 99.9% at 100%, 85%, 75% and 55% of FC, respectively. The highest of main components were geranyl acetate, geraniol and geranial in all the irrigation regimes. The amount of oxygen-containing monoterpenes of essential oil were 81.6%, 94.5%, 91.8% and 92.0% at 100%, 85%, 75% and 55% of FC, respectively. Our results showed that essential oil content increased significantly by 3.4%, 13.8% and 27.6% at 85%, 75% and 55% of FC, respectively. Furthermore, the amount of oxygen-containing monoterpenes of <em>D. moldavicum</em> increased by 15.8%, 12.5% and 12.7% at 85%, 75% and 55% of FC, respectively, but oxygen-containing sesquiterpenes decreased by increasing the level of drought. In conclusion, our results indicated the advantage of drought for increasing essential oil content and oxygen-containing monoterpenes (OM), especially geranyl acetate, geraniol and geranial in <em>D. moldavica</em>. https://ijhst.ut.ac.ir/article_73957_2d152fd943ffb875d77645ebdfeab58e.pdf