بررسی تاثیر کشت و اهلی کردن بر رشد و مواد موثره تعدادی از گونه های آویشن ‭(Thymus sp.) ‬در استان اصفهان

In order to study natural habitat of Thymus species, T. daenensis and T. carmanicus, and study the effect of domestication and cultivation of them in agro ecosystems in Esfahan province, two separated experiments were conducted during 2005-2008 in habitat and field conditions respectively. At the first experiment by referring to T. daenensis and T. carmanicus habitats, Eskandari and Gardaneh Khansar respectively, using quadrate, recording of some characters and gathering seeds and cuttings were done. Then the native species were cultivated in Fozveh and Gahiz stations in cutting and seed forms. In the field condition an alien species, T vulgaris, was used for comprising. Treatments concluded different harvesting stages. The statistical design was RCBD with 3 replications. The results combined over the years and analyzed. Results showed that T. daenensis typical station had cold semiarid climate, 2180 m altitude and 0.7% slope. Coverage percentage was 7 and density was 0.3. Soil was semi deep, clay- loam with PH= 6.7 and Ec= 0.77. Dominant plants in thyme community were Phelomis persica and Bromus tomentelus. Typical station of T. carmanicus had cold semiarid climate, 3200 m altitude and 3.0% slope. Coverage percentage was 8.33 and density was 0.5. Soil was low deep, loamy with PH= 6.7 and Ec= 0.88. Dominant plants in thyme community were Astragallus spp. and Grasses. Combined analysis of variance on T. daenensis in different harvesting stages under two planting conditions in Fozveh station showed that year and different harvesting stages had significant effects on dry yield, dry weight /fresh weigth ratio, essential oil percentage and essential oil yield. Combined analysis of variance on T. daenensis in different harvesting stages under two planting conditions in Gahiz station showed that year had significant effect only on essential oil yield. The essential oil in second year of experiment was higher than the first year. Comparison of means for different harvesting stages showed that the highest essential oil percentage was occurred at middle of flowering. Also the highest dry weight per hectare observed at the end of flowering and seed formation stage. Based on the results it was cleared that the optimum stage for producing the highest essential oil yield in this species, is the end of flowering stage. Results of chemical components for T. daenensis essential oil showed that the thyme was the major component and the highest amount of this component exists at the beginning to end of flowering. Combined analysis of variance on T. carmanicus in different harvesting stages under two planting conditions in Fozveh and Gahiz stations showed that year and different harvesting stages had significant effects on all of the measured parameters. Based on the dry weight and essential oil yield in two stations, it was concluded that this species didn t have suitable adaptation and dry weight and essential oil yield in the second year was lower than the first year. Average of studied traits in different harvesting stages revealed that the optimum harvesting stages for this species is at the end of flowering and seed formation stages. Analysis of variance for essential oil components in this species showed that there were significant differences between different harvesting stages. The major chemical component was Carvacrol and the highest amount of it observed at the middle of flowering. For T.vulgaris results showed that year had significant effects on dry weight and dry weight/fresh weight ratio, but no significant effects on essential oil percentage and yield were observed. Also the maximum essential oil percentage and yield occurred at seed formation stages. It is recommended that the best time for harvesting is at the end of flowering and beginning of seed formation. Thymol was the major component in this species and had the highest amount at the beginning of flowering. The results of physiological indices showed that T. daenensis, T. carmanicus and T.vulgaris respectively needed 768, 538 and 595 GDD for beginning of flowering, 976, 707 and 776 GDD for middle of flowering, 1186, 908 and 976 GDD for end of flowering and 1414, 1044 and 1114 GDD for seed formation stage. The dry matter accumulation had sigmoid pattern. The maximum of leaf area in T. daenensis was in the end of flowering stage; in T. carmanicus was in the middle of flowering and in T.vulgaris was in the beginning of budding. T. daenensis had slower RGR and higher CGR. Key words: Thymus, habitat, cultivation and domestication, growth physiological indices, essential oil, Esfahan province.