Genetic Diversity of Ecotypes of Horse Mint (Mentha longifolia) in Southwest of Iran using Morphological Traits

Horse mint (Mentha longifolia syn. Mentha sylvestris) is one of the valuable medicinal and aromatic plants belongs to Lamiaceae family. To evaluate diversity of horse mint in southwest of Iran, 35 ecotypes from six provinces of Lorestan, Fars, Khuzestan, Isfahan, Kohgilouye va Boyerahmad and Charmahal va Bakhtiari were examined. To assess the morphological traits at flowering stage, ten plants were selected in each habitat and 17 qualitative and quantitative morphological traits for each ecotype were assessed. The results showed that there was a vast diversity among the ecotypes. Cluster analysis divided ecotypes into four groups. Factor analysis classified traits into four major components which justified 81.5 percent of the total of variance. Number of branches, number of flowering shoots, number of nodes and leaf number were the first component. Plant height had a significantly positive correlation with main shoot diameter and number of nodes. Generally, the results of this study showed that ecotypes no. 6 and 13 (Lorestan and Fars) due to good characteristics and high amount of essential oil have good potential for domestication of this species.