Effects of Ontogenetic Variability on Yield of Some Labiatae Family (Mentha spicata L., Origanum onites L., Melissa officinalis L., Lavandula angustifolia Mill.) Plants

In this study, it was aimed to investigate the effect of ontogenetic variability on yield of some plants belonging to Labiatae family (Mentha spicata L., Origanum onites L., Melissa officinalis L. and Lavandula angustifolia Mill.). The study was conducted for two years at Bafra plain of Central Black Sea Region in Turkey. In this study, three different harvesting periods (before flowering, 50% flowering and 100% flowering) are considered as research subjects. According to the results of the research, plant height values of M. spicata, O. onites, L. angustifolia and M. officinalis plants varied between 47.50-103.67 cm, 25.00-49.47 cm, 30.00-40.60 and 56.90-96.60 cm, respectively; the highest values were measured at 50% flowering in M. spicata, and at full flowering on other plants. Harvesting cycles significantly affected the fresh herba, drog herba and essential oil yields in all plants examined, drog leaf yield in M. spicata, O. onites and M. officinalis species and drog flower yield in L. angustifolia. According to the data obtained, it is recommended that M. spicata and M. officinalis plants should be harvested at 50% flowering period, and L. angustifolia and O. onites plants should be harvested at 100% flowering period