Influence of some climatic and soil conditions on essential oil quantity and quality of different Thymus daenensis Celak subsp. daenensis ecotypes

Thymus daenensis Celak subsp. daenensis, an endemic medicinal plant in Iran, belongs to Lamiaceae family that has a high essential oil content and high Thymol in essential oil. Evaluations of different ecotypes of this species in order to identify the paramount ecotype with the highest essential oil percentage and Thymol content and also correlations of edaphic and climate conditions with essential oil quantity and quality in order to identify the best conditions for domestication of this species were the aims of this study. In this study, essential oils of plants referred to eight natural habitat (Malayer 1, Malayer 2, Jovzan, Arak, Khane miran e bala, Khane miran e paien, Shazand and Zaghe) of this species extracted and measured (v/w%) and then compositions of essential oils were determined by GG and GC/MS instruments. Soil and climatic characteristics were identified and their correlations to essential oil content and compositions were calculated. Results showed that the ecotypes had significant difference in essential oil percentage. The highest and the lowest essential oil percentage were obtained in Arak (5%) and Malayer 2 (2.5%) ecotypes, respectively. Thymol was dominant component of essential oils of all ecotypes. The highest (78.88%) and the lowest (67.16%) amounts of Thymol were observed in ecotypes of Jovzan and Malayer 1, respectively. Positive correlations between the essential oil percentage with mean daily temperature, clay, silt and soil lime were found. These correlations explained that edaphic and climatic conditions had a significant effect on the quantity and quality of essential oil and could help us to identify the second culture conditions for domestication of this plant.