Effect of nitrogen on some quantitative and qualitative traits of Dracocephalum ‎kotschyi Boiss

In order to investigate the effects of nitrogen fertilizer on quantitative and qualitative traits of Dracocephalum kotschyi Boiss, a field experiment was conducted in the Research Field of Tarbiat Modares University during 2018 growing season. The experiment was performed at three replications in a completely randomized blocks design. The experimental treatments included eight nitrogen fertilizer amounts (0, 50, 100, 150, 200, 250, 300 and 350 kg Nitrogen/ha). Urea as nitrogen fertilizer and the seedling of Fereydun Shahr as ecotype were used. The results showed that the maximum height (29.63 cm) was obtained from the application of 136.6 kg N ha-1. The highest total fresh weight was observed with 2966 kg ha-1 from the application of 126.8 kg N ha-1. The highest stems and leaves fresh weight was produced by using 112.69 and 162.69 kgNha-1, respectively. Application of 112.69 and 126.5 kg N ha-1 had the highest total flavonoid (7.69 μmol/g of fresh leaf weight) and essential oil yield respectively. Because the purpose of cultivating medicinal plants to produce essential oil yields, therefore, the recommended amount of nitrogen to achieve maximum essential oil yield for D. kotschyi is 126.5 kg ha-1.