17 Mehmet Ugur YILDIRIM Ahmet IZMIRLI Journal of Animal and Plant Sciences JAPS 20232023/06/18 33 3 708-714 1018-7081 https://doi.org/10.36899/JAPS.2023.3.0663 <p>Lavender (<em>Lavandula angustifolia</em>&nbsp;Mill. family Lamiaceae) is a perennial and highly drought tolerant plant species. It grows well on calcareous slopes, and produces a fragrant essential oil. The aim of study was to evaluate foliar application of gibberellic acid (GA₃) and delaying harvesting for different durations on essential oil and components of English lavender after foliar treatment with 0, 200, 400 and 600 mg l^-1&nbsp;gibberellic acid (GA₃). Clevenger apparatus-based water-vapor distillation method was used to determine essential oil and its components by GC-MS. The experiment was established in split plots in randomized complete block design with two factors and 3 replications. The main plots were formed at harvest time and the sub-plots were created by GA₃&nbsp;applications. Statistical analyzes were made using MSTAT-C package program. When the GA₃&nbsp;doses and harvest times interaction were evaluated together, the average essential oil yield of the harvested lavender flowers ranged 6.20 to 8.20 % showing the prominent influence of the concentration of GA₃&nbsp;and delay in harvesting (in hours) on concentrartration of alkaloids. More than 50 components were identified, the most important among these was 1.8-cineole, linalool, camphor, borneol, lavandulol, and terpinene-4-ol. The amount of linalool, which improves the quality of the essential oil ranged 34.49-38.75%. The minimum and the maximum essential oil values were noted from the flowers harvested after 30 hours (control treatments), and 54 hours from 400 mg l-1 GA₃&nbsp;treated plants in the same order. However, essential oil contents showed a slight decrease at higher GA₃&nbsp;treatments and prolonging duration of harvest after respective GA₃&nbsp;treatments. GA₃&nbsp;treatments enhanced the quantity of essential oil substantially, and the optimal dose was determined as 400 mg l^-1&nbsp;GA₃ on samples harvested after 54 hours following application. The results further showed that the quantities of essential oil's primary components varied according to harvest time.</p> Aromatic plant, camphor, flower, linalool, plant growth regulator Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2022-JAPS-66