response of marigold flower yield and yield components to water deficit stress and nitrogen fertilizer

in order to study the effect of water deficit stress and different nitrogen levels on flower yield, yield components and water use efficiency of calendula officinalis l., an experiment was conducted as split plot based on randomized complete block design with three replications, at research field of islamic azad university, birjand branch in 2009. in this experiment, irrigation treatments (irrigation after 60, 120 and 180 mm cumulative evaporation from pan class a) set as main plots and nitrogen rates (0, 60,120 and 180 kg n ha-1) set as sub plots. the results showed that increasing irrigation interval from 60 to 180 mm cumulative evaporation reduced flower number per m-2, biomass yield and plant height 65.6, 69.3 and 8.3%, respectively. also in comparison with control, irrigation after 120 and 180 mm evaporation reduced flower dry yield 16.2 and 72%, respectively. however, the highest wue was related to irrigation after 120 mm evaporation (0.161 and 0.788 kg m-3 for dry flower and biomass, respectively). nitrogen fertilizer utilization significantly increased flower yield, flower number, biological yield, wue and plant height, but there was not any significant difference between 120 and 180 kg n ha-1 treatments. interaction of irrigation and nitrogen on all traits was not significant. totally, the results indicated that treatment of irrigation after 120 mm evaporation with 120 kg n ha-1 application is suitable for marigold cultivation in birjand