Effects of deficit irrigation on essential oil composition and yield of fennel (Foeniculum vulgare Mill) in a high-altitude environment

ABSTRACT

Successful fennel (Foeniculum vulgare Mill) production in semi-arid environments depends largely on irrigation applications. Deficit irrigation studies on fennel are lacking or very limited, particularly in high-altitude environments. This study was conducted to determine the effects of deficit irrigation levels on the essential oil content, essential oil yield, and chemical composition of fennel. The experiment was carried out in 2014 and included four deficit irrigation levels: 100% (I₁), 80% (I₂), 60% (I₃), and 40% (I₄) of Class A pan evaporation. All parameters were significantly affected by deficit irrigation applications. Essential oil content tended to increase under increased water deficit conditions with the range of 2.21% to 2.42%. Anethole (90.71–91.62%) was the major compound in the fennel fruit oil, followed by estragole (3.60–4.02%), limonene (2.19–3.24%), and fenchone (0.96–1.55%), respectively. Essential oil yield showed an increase with increased irrigation amounts.

KEYWORDS:

• Fennel
• Foeniculum vulgare
• irrigation
• essential oil
• anethole
• water use efficiency

Acknowledgments

The authors would like to thank Michael OH, who is a member of Ecohydrology Lab at Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, Canada for proofreading of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by Ataturk University [Project BAP n. 2012/215].