effects of jasmonic acid on essential oil yield and chemical compositions of two iranian landraces of basil (ocimum basilicum) under reduced irrigation

background & aim: sweet basil (ocimum basilicum), a plant that is extensively cultivated in some countries, is used to enhance the flavour of salads, sauces, pasta, confectioneries and other products as both a fresh and dried herb. the effect of foliar application of jasmonic acid and reduced irrigation on essential oil yield and chemical components of two iranian landrace of basil (ocimum basilicum) were investigated. experimental: treatments comprised control, 0.0, 200 and 400 µl jasmonic acid applied to plants under normal irrigation and stressed conditions (30 and 60% f.c) based on a completely randomized design with three replications. the essential oils from the aerial parts of basil were analyzed by gc-fid and gc/ms. results & discussion: results indicated that the different levels of jasmonic acid and irrigation had significant effects on oil yield and some main components of the essential oil. the highest value of oil content was obtained from application of 400 µl ja. percentage of some chemical constituents in the essential oil extracted from the plants under stress was higher than non-stressed plants. foliar application of jasmonic acid significantly improved methyl chavicol in the oils, but reduced germacrene- d, α-cadinol and δ-cadinene amounts. industrial and practical recommendations: since, essential oil of basil, particularly methyl chavicol component, have many application in pharmaceutical and perfumery industry and has health benefits such as antiviral, antibacterial and antispasmodic activity, we can use jasmonic acid elicitor to enhance the therapeutic properties of basil and also essential oil content and methyl chavicol of plant.