The effects of different leaf-applied elicitors on yield and quality characteristics of Turkish oregano (origanum onites L.)

This study was conducted to investigate the effects of different foliar applied elicitors on yield and quality traits of Origanum onites L. (Turkish Oregano). Field trials related to the study were conducted under Adana conditions over a two-year period during the years of 2021-2023 . The effects of phenylalanine, pectin, chitosan, and salicylic acid, and their different doses (control, 50, 100, 200, and 400 mg/l-1) applied to the leaves of Origanum onites L. (Izmir Thyme) were investigated. In the research, depending on different elicitors and their dosage, plant height changed from 40.6 to 80.4 cm, green herbage yield from 406.3 to 2231 kg/da, dry herbage yield from 146.7 to 1006 kg/da, drug leaf ratio was from 49.73 % to 63.04%, drug leaf yield from 86.67 to 540.3 kg/da, essential oil ratio from 4.13 % to 5.13%, essential oil yield from 3.46 to 27.73 kg/da. The ratios of carvacrol, p-cymene, γ-terpinen, which are main essential oil components, varied 47.96-69.06%, 15.5-76.27% and 6.64-9.08%, respectively. Essential oil antioxidant ratio varied between 82.34 % and 98.17%, hydrosol antioxidant ratio between 82.34% and 98.17%, essential oil antioxidant ratio between % 82.34 and 98.17. It was determined that phenol concentrations ranged from 48.51 to 97.53GAE/mL, and hydrosol total phenol concentrations ranged from 25.15 to 90.93GAE/mL. Research results showed that elicitor applications play an important role in the morphological development and essential oil production of Origanum onites. In particular, 200 mg/l salicylic acid consistently yielded the best results in terms of essential oil yield, antioxidant capacity, phenol content, and overall plant yield, while 400 mg/l chitosan showed a strong effect on vegetative growth and essential oil yield. Based on the research findings, it was concluded that different elicitors can activate different physiological and biochemical pathways in the plant, and therefore, elicitor selection should be optimized based on the intended use.