Satureja bachtiarica Bunge is an endemic species plant widely distributed in Iran. Phenotypic and chemical characterization of this species from different natural regions of Iran was evaluated. Twenty-six morphological traits analyzed showed significant differences among and within populations. The samples were phenotypically diverse, which stem weight, total weight and leaf and flower weight were characteristics with the highest variation. Leaf dimensions were in significant correlation with flower and inflorescence characteristics and also plant height showed significant positive correlation with characteristics related to inflorescence and weight. Clustering from morphological data allocated samples into two main clusters with high variability. Thirty-four components were identified in the essential oils, so that carvacrol, thymol, γ-terpinene and p-cymene were the major components of all samples and showed the high eigenvalues variance according to principal component analysis. Among populations, Ilam population showed the highest essential oil content, p-cymene, γ-terpinene and thymol and Yazd population had the highest carvacrol. Carvacrol was negatively correlated with p-cymene, γ-terpinene, borneol and thymol. Multiple regression analysis (MRA) revealed that phytochemical compositions as dependent variable, showed statistically significant correlation and in association with leaf and flower traits as independent variable, especially variables sepal and petal trichomes, indicating a main role of leaf and flower on production of these compounds. The high morphological differences and high value of the essential oil composition within and among S. bachtiarica populations could provide useful information for conservation and selection of cross-parents in breeding programs.
