Effects of water deficit stress and application of nitrogen on yield physiological indices of Calendula (Calendula officinalis L.)

The effects of water deficit stress and nitrogen on yield physiological indices of Calendula (Calendula officinalis L.), The experiment were carried out in a split plot design based on completely randomized block design with 4 replications. Treatments were three levels of stress and irrigation after 40, 80 and 120 mm water evaporation from evaporation pan, and consumption of 0, 30, 60 and 90 kg/ha nitrogen. The results indicated that water deficit stress had significant effect on harvest index 50% flowering, flower weight to plant ratio 50% flowering, productivity effort 50% flowering, harvest index 100% flowering, productivity effort 100% flowering, harvest index 100% second flowering, flower weight to plant ratio 100% second flowering, productivity effort 100% second flowering, harvest index, flower weight to plant ratio, productivity effort. The highest harvest index (18.85), flower weight to plant ratio (13.15) and productivity effort (21.26) with irrigation after 40 mm evaporation. Nitrogen had signification effect on harvest index 50% flowering, flower weight to plant ratio 50% flowering, productivity effort 50% flowering, harvest index 100% flowering, productivity effort 100% flowering, harvest index 100% second flowering, flower weight to plant ratio 100% second flowering, productivity effort 100% second flowering, harvest index, flower weight to plant ratio, productivity effort. In water deficit stress nitrogen had significant effect on flower weight to plant ratio 100% flowering. The results indicated that the best time for harvest in Calendula is when 100 percent flowering irrigation after 40 mm evaporation and 90 kg/ha nitrogen. Also the best time for seed harvest in the last stage is irrigation after 40 mm evaporation and 90 kg/ha nitrogen.