Environmental and developmental factors affect essential oil production and quality of Lavandula angustifolia during flowering period

The world demand for lavender essential oil is still increasing. Despite of growing interest and the commercial importance of lavender oil it is not clear how environmental and developmental factors influence the optimum period of harvesting lavender flowers for essential oil production. In this report, it was evaluated how the quality and quantity of Lavandula angustifolia cv. Etherio essential oil (EO) is influenced during blooming by environmental factors. It was examined if lavender EO is correlated with gene expression during blooming, targeting to manage the optimum EO harvesting time. The EO content was positively regulated by temperature and flowering stage development while it was negatively affected by rainfall during flowering period. The quality of EO and specifically linalool content was influenced by temperature, flower development, LaLINS expression and rainfall. Although rainfalls remarkably decrease linalool production, the quality of lavender oil was recovered after ten days, suggesting that linalool biosynthesis is regulated during flowering period by both environmental and developmental cues. It is suggested, that the optimum harvesting period to obtain valuable lavender essential oil is when flowering reaches at 60%, ambient temperature is over 26 °C and no precipitations were occurred ten days before harvesting.