Study on essential oil quantity and quality of Thymus kotschyanus Boiss. & Hohen. cultivated in Yazd, Iran

Thymuskotschyanus Boiss. & Hohen. is a perennial medicinal shrub growing wild in some regions of Iran including Yazd province. This research was carried out in order to analyze oil quantity and quality of cultivated Thymuskotschyanus in the Medicinal Plants Farm, Yazd, Iran. The seeds of 19 accessions collected from natural habitats were sown in a greenhouse and the seedlings were planted in the farm. Shoots were harvested at 50% flowering stage in the second year and dried under shadow. Essential oil was extracted with water distillation method and oil components were identified after determining oil content. The highest amounts of oil content respectively were related to accessions TK7 (3.42%), TK12 (3.22%), TK17 (2.66%) and the lowest amount was observed in accession TK6 (0.79%). The highest amounts of oil production respectively were recorded in accessions TK5 (38.3kg/ha), TK7 (36.4kg/ha) and TK12
(36.1 kg/ha) and the lowest amount was related to TK1 (1.3 kg/ha). Cluster analysis based on eleven oil components classified the accessions into three groups. The first group, (TK2, TK6, TK13, TK18, TK16, TK19), was rich for thymol-p-cymene, the scond group (TK1, TK3, TK4, TK5, TK7, TK11, TK14, TK15, TK17) for carvacrol-thymol and the 3rd group (TK8, TK9, TK10, TK12) was rich for Geraniol-linalool. In general, accessions TK7, with 3.42% oil content, 36.4 kg/ha oil production and 63.8% carvacrol; TK14, with 2.2% oil content 35.5 kg/ha oil production and 47.2% carvacrol and thymol, TK5 with 2.4% oil content, 38.3 kg/ha oil production and 57% thymol and carvacrol are proposed as superior accessions.