Determination of optimal harvesting time for essential oil and estragole yield in bitter fennel (Foeniculum vulgare Mill.) growing in culture conditions

This study was carried out in order to determine the most suitable harvest period for high essential oil and estragole yield in perennial fennel plants grown under culture conditions. Fennel plants were harvested at 4 different periods, vegetative development (1st and 2nd vegetative stage), pre-flowering stage and full flow-ering stage with 20-day intervals. Plants were dried in the shade, and essential oils were obtained by Cle-venger-type hydro distillation system. Fresh and dry weight, essential oil content, essential oil yield, essential oil components and estragole yield were determined. Harvestings made at the 2nd vegetative and pre-flowering periods had the higher fresh and dry weight. The highest estragole yield were obtained from the pre-flowering period. Essential oil yield was lower in the harvests made in the 1st vegetative period than in other growing stages. Estragole was the main component of fennel essential oil in all growing stages, and the essential oil components differed in terms of number and ratio depending on the stages. In this study, essential oil and estragole production in cultivated perennial fennel plants varied significantly depending on the development stages of the plants, and the most suitable harvesting period in terms of essential oil and estragole yield was the period before flowering.(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.