Morpho-physiological variation and essential oil content of Iranian populations in Thymus kotschyanus Boiss. & Hohen grown under similar condition

Abstract

Thymus kotschyanus Boiss. & Hohen is one of the medicinal herbs native of Iran. According to the economic importance of thyme, identify of morphological characteristics and essential oil content is important in different populations. We studied the pattern of variation of 33 morphological and physiological characteristics of T. kotschyanus in 15 Iranian populations experimentally grown under similar conditions. The results showed that in important traits, the highest mean of flowering stem length was related to Zanjan-I population, the most number of shoots pre plant was in Azarbayejangharbi-IV population, the highest leaf’s length and width respectively, belonged to Tehran and Lorestan population, the highest plant height was in Zanjan-I population, the most fresh and dry weight was related to Azarbayejangharbi-II population and the longest inflorescence was observed in Qazvin-II population. Cluster analysis of quantitative traits divided three main groups in thymus populations and Azarbayejangharbi populations were separated partially. Based on the qualitative traits, populations were classified in five main groups. As such, Zanjan and Qazvin populations were in separate groups. The results showed that the most content of essential oil and the highest mean of the most morphological traits were belonged to Azarbayejangharbi-I, IV and Tehran populations. Therefore, the morphophysiological characteristics of medicinal plants have many effects on essential oil’s content. Thus, the planting of diverse population in the equal environmental conditions will reduce the environmental impacts on incidence of vegetative traits, also better reveals the diversity of genetical differences between populations.