Field Evaluation of Iron and Zinc Chelates Foliar Application on ‎Morphological Characteristics, Yield, and Essential Oil Content of Native and ‎Improved Fennel ‎

Foeniculum vulgare Mill. is one of the medicinal plants, which is widely used in pharmaceutical and food industries. Due to the effective role of micronutrients in the quantitative and qualitative yield of medicinal plants, the effect of foliar application of iron chelate (0, 1.5 and 3 g/L) and zinc chelate (0, 1.5 and 3 g/L) on the functional properties and essential oil content of native and improved (cv. Soroksari) fennel was evaluated. The experiment was conducted as a split-split plot, based on RCB design with three replications during 2018 at the University of Kurdistan. Simple effects of iron chelate, the interaction iron chelate and cultivar, as well as the interaction iron chelate, zinc chelate and cultivar type, had no significant effect on measured traits. Zinc chelate significantly affected most of the studied traits, so that the highest of essential oil content (5.06%) and yield (35.07 L/ha) were belonged to 3 g/L treatment, while the highest seed yield (884.2 kg/ha) was obtained in zero treatment of zinc chelate. The interaction of iron chelate and zinc chelate as well as the interaction of zinc chelate and cultivar had only a significant effect on seed width and number of umbels, respectively. The impact of cultivar had a significant effect, on the number of umbels per plant, seed yield, and essential oil yield, so that the highest average of mentioned traits (25.29, 765.26 kg/ha and 34.27 L/ha, respectively) were belonged to native fennel. Generally, among the fertilizer treatments, 3 g/L zinc chelate and between the two types of fennel, native fennels were recognized as superior.