Effect of Irrigation Interval and Nitrogen Fertilizer on Seed Yield and Pigment Contents in Dill

In order to determine the optimum irrigation interval and nitrogen fertilizer rate for dill in Kermanshah climate conditions, an experiment was conducted as split plot design with three replications at Research Farm, Razi University in 2013. The Main plot and irrigation interval, included three levels (irrigation interval of 4, 6 and 8–day). The Split plot, nitrogen fertilizer, included four levels (nitrogen rate of 0, 100, 200 and 300 kg ha-1). The Studied traits included seed yield, biological yield, leaf and stem yield, umbel number per plant, umbellate number per umbel, 1000-seed weight, harvest index, plant height, stem diameter, leaf relative water content, chlorophyll-a, chlorophyll-b, total chlorophyll and carotenoides content. Leaf chlorophyll was measured by spectrophotometer. Results showed that the urea application of 300 kg ha-1 with the irrigation interval of 4-day produced the highest seed yield. Irrigation interval and nitrogen fertilizer had no significant effect on umbel number per plant, umbellate number per umbel, biological yield, stem and leaf yield, plant height and stem diameter. The nitrogen fertilizer application of 300 kg ha-1 had the highest harvest index. The irrigation interval of 8-day with the urea application of 200 kg ha-1 had the highestchlorophyll-a, chlorophyll-b and total chlorophyll content among major treatments. For the research is required to talk in to account the study of drought at different growth stages in dill.