Assessment of domestication and harvesting time on growth and concentrations of active ingredients of two thyme (Thymus L.) species in North Khorasan province of Iran

This research was aimed to evaluate the effect of cultivation and domestication of two thyme (Thymus L.) species، Khorasani (Thymu stranscaspicus) and garden (Thymus vulgaris)، on growth and yield components. The study was conducted in different agricultural ecosystems of North Khorasan province during 2005-2009. The main treatments consisted of harvesting time in a randomized complete block design with three replications. Results showed that the number، order and extent of the main chemical compounds in both species of thyme did not differ much. However، the quantitative properties measured in both species were affected by different stages of harvest in each year. The highest dry weight in both species was obtained at the end of flowering stage in all years. Harvesting time had different effects on species composition of essential oil in the studied years. The highest efficiency of essential oil was recorded in mid-flowering stage especially in third year. The quantity of essential oil is the economic indicator of thyme performance. Garden thyme (T. vulgaris) produced more essential oil as compared to Khorasani thyme (T. transcaspicus).