Allelopathic effect of Thymus kotschyanus on seed germination and initial growth of Bromus inermis and Agropyron elongatum

The allelopathic influence of aqueous extracts of Thymus kotschyanus on Bromus inermis and Agropyron elongatum germination (%)، germination speed and seedling growth was examined. In other to this، at first extract from shoot and roots of Thymus kotschyanus was prepared. The extract was diluted by adding distilled water to 5، 25، 50 and 75 percent. The effect of the above concentrations، as well as distilled water as control were studied on seed germination using a completely randomized design. Results indicate that there were significant differences among the treatment for germination percentage and speed، length of root، length of shoot، length seedling and vigority index (p<1% and p<5%). Comparison of means indicated that the most amounts of germination speed and percentage and other studied indices related to control treatment and the lowest amounts belonged to treatment with 75 concentration percentage of Thymus kotschyanus. The increasing of concentration of the Thymus kotschyanus extract significantly decreased germination and seedling growth in both species and Bromus inermis had more sensibility than Agropyron elongatumin related to allelopathic effect of Thymus kotschyanus.