Does Natural Boron Application Increase Yarrow (Achillea millefolium L.) Essential Oil Yield?

This study investigated the impact of different boron doses (Boron-free, 80 L/ha, and 10 L/ha) on the yield and components of yarrow essential oil. The study utilized a randomized block trial design with three replicated field studies conducted between 2017 and 2018 in the Kütahya-Gediz region of Turkey. The essential oil of this species was extracted using the hydro-distillation procedure. The essential oil ratios were 0.66-0.59% in the plants grown without boron, 0.82-0.81% in the plants grown with the 80 L/ha boron dose, and 0.70-0.69% in the plants grown with the 10 L/ha boron dose, based on examinations conducted on dry flowers in 2017-2018. Employing GC-MS/FID analysis, 20 components of the yarrow essential oils were identified. 19 components were detected in the boron-free dose, while 18 were found in the dose 80 L/ha and 10 L/ha of boron. The main components of the essential oil (EO) based on boron doses were determined as follows: α-pinene at 16.25%, 20.50%, and 17.38%; Chrysanthenone at 16.54%, 19.29%, and 20.05%; cis-chrysanthenyl acetate at 11.33%, 15.26%, and 13.29%; and Filifolone at 10.00%, 11.46%, and 11.30%. The ratios of yarrow essential oil and its constituents were influenced positively by the applications of 80 L/ha and 10 L/ha natural boron supplementation. We can recommend applying 80 L/ha boron to the yarrow plant grown for its essential oil to obtain a high essential oil yield.