The effect of different irrigation water levels on yield and quality characteristics of purple basil (Ocimum basilicum L.)

► As a result of two-year field study, increasing water stress increased the essential oil ratio while decreased the plant height and yield. ► The highest essential oil ratio was found to be 1.10% at the I50 treatment. ► Highest plant height (38.6 cm) and green herb yield (2269.4 kg da−1), drug herb yield (417.2 kg da−1), drug leaves yield (300.6 kg da−1) were determined at the I125 treatment. ► The main components of essential oil were linalool, eugenol and methyl chavicol. ► Since the yields changed in parallel with the amount of irrigation water applied, irrigation water use efficiencies were not significantly different.