Study on some ecological factors, morphological traits, essential oil productivity and ploidy levels of Thymus eriocalyx (Ronniger) Jalas in Iran

In order to evaluate several ecological factors, morphological traits, essential oil productivity and ploidy levels of Thymus eriocalyx (Ronniger) Jalas with uses of DSS method ten natural habitats were selected  in Lorestan, Markazi, Hamadan, Kermanshah and Kurdestan provinces  in Iran. To study and evaluate morphological characters, five complete plant samples and flowering branches were collected from each locality at flowering stage for essential oil extraction in spring season of 2008. Ecological data of ten localities were also recorded. Vegetative and reproductive traits and essential oil quantity of each population were studied. Seeds were also collected in the seed production season to study seed characters, chromosome counting and ploidy level. At least 10 mitotic cells of each population were studied to determine chromosome numbers and ploidy levels. All populations were classified in 4 groups. Results revealed that specimens from "Te9 population" had the highest average length and width of inflorescence leaf, inflorescence leaf length to width ratio, stem leaf length to width ratio, petiole length, calyx tube length, corolla length and the highest average length and width of bracteole. The results of chromosome counting showed that specimens of Te1, Te2, Te3, Te4, Te5, Te6 and Te8 populations were diploid (2n=2x=30) and specimens of Te7, Te9 and Te10 populations were tetraploid (2n=4x=60). The highest essential oil production belonged to Te5 population (3.04%).