Effect of Nitrogen and Cytokinin on Quantitative and Qualitative Yield of Thyme (Thymus vulgaris L.)

In order to investigate the effect of nitrogen and cytokinin on the quantitative and qualitative characteristics of thyme, a three-year factorial experiment was conducted at Razi University based on a randomized complete block design with 3 replications. Factors included nitrogen levels (0, 50 and 100 kg N/ha) and cytokinin concentrations (0, 100, 200 and 400 μM). The results of analysis of variance showed that the interaction effect of nitrogen × cytokinin on plant height, number of branches, leaf, stem and whole plant dry weights, essential oil percentage and yield was significant (p ≤0.01). With increasing the amount of nitrogen and cytokinin, all the studied traits (except harvest index) increased significantly compared to the control. The highest plant height and number of branches were obtained in the treatment of 100 kg N/ha × 400 μM cytokinin. The treatment of 100 kg N/ha × 100 μM cytokinin resulted the highest production of dry weights of leaf (3287 kg/ha), stem (3110 kg/ha) and whole plant (6398 kg/ha); aproximately 60.5, 59.8 and 60.9% more than the control treatment, respectively. Also, the highest percentage of essential oil (2.45 %) was obtained by applying 50 kg N/ha × 400 μM cytokinin. Application of 100 kg N/ha and foliar application of 200 μM resulted in the highest essential oil yield (77.60 kg/ha). In general, the results of this experiment showed that the quantitative and qualitative yield of thyme can be increased by consuming the appropriate amount of nitrogen and cytokinin.