Allelopathy is a phenomenon of direct or indirect, beneficial or adverse effects of a plant on its own or another plant through the release of chemicals into the environment. The experiment was designed to determine the allelopathic effects of Thymus kotchyanus on seed germination and initial growth characteristic of Sanguisorba minor. Tissues of T. kotchyanus in addition to seeds of S. minor were collected from Bijar rangelands and collected materials of T. kotchyanus were dried and powder. The research was performed at the greenhouse condition. The treatments included 5, 10, 15, 20 and 25 weight percentage of above mentioned powders. The tests were made in a completely randomized blocks with a factorial arrangement with four replications for 4 weeks. Germination seeds were counted and recorded daily. Germination properties included: germination percentage, mean germination time, germination speed and inhibitory percentage. At the end of study period, radicle and stem length were measured. The analysis of their variance was performed with the use of MSTAT-C soft ware, and the Excel soft ware was used to draw the required charts, and the Duncan test was used to compare the data average. The results indicated that allelopathic effect of T. Kotchyanus had negative effects on germination properties of S.minor. It was noted that powder had a considerable inhibitory effect on target plant germination and the effect at 15gr, 20gr and 25gr of powder was found to be significantly higher than that at lower amount powder (5gr and 10gr) and control treatment (without powder). The effect of 5gr powder of T.kotchyanus on germination properties and initial growth of S.minor was almost better than control treatment and effect of 10gr powder of T. Kotchyanus was similar to control treatment. The lowest germination percentage and seedling growth resulted from 25gr powder of T. Kotchyanus.
