Evaluate the Effect of Varying Amounts of Super Absorbent under Different Irrigation Regimes on Growth and Water Deficit Tolerance of German Chamomile (Matricaria Chamomilla), as a Second Crop

To evaluate the effect of water deficit stress on yield, yield components, chlorophyll and osmolytes in Matricaria chamomilla, and the effect of super absorbent polymers on reduction of drought stress, a factorial experiment was conducted based on randomized complete block design with three replications in Faculty of Agriculture of Urmia University on 2008. Treatments included water deficit stress (irrigation after 50, 100, 150 and 200 mm evaporation from pan class A) and varying amounts of super absorbent polymer (0, 60, 120, 180, 240 and 300 kg/ha). Results of Analysis of Variance (ANOVA) showed the significant effect of irrigation on dried flower, the numbers of capitol per plant, capitol diameter and receptacle height, and non significant effect on single capitol weight and leaf soluble carbohydrates. While, the effect of super absorbent polymer on was non significant dried flower, the numbers of capitol per plant, capitol diameter, receptacle height, single capitol weight and leaf soluble carbohydrates Interaction effect between water deficit and polymer was significant on the yield of biomass, chlorophyll a, b, total chlorophyll and proline. The highest and lowest yield of dried flower (116.83 and 75.98 kg/ha), capitol diameter (0.544 and 0.497 cm) and receptacle height (0.676 and 0.568 cm) were obtained from irrigation after 50 and 200 mm evaporation from pan class A, respectively. But, the maximum and minimum numbers of capitol per plant (199.22 and 91.22) were obtained from 100 and 150 mm evaporation from pan, respectively. The highest yield of biomass (1215.55 kg/ha) was obtained from irrigation after 50 mm evaporation and 0 kg/ha of polymer application, and the lowest yield (164.44 kg/ha) was obtained from irrigation after 200 mm evaporation by using 120 kg/ha of polymer. In this research, chlorophyll a and b had the reducing trend from irrigation after 100 mm evaporation from pan. The greatest proline accumulation (4.001 mg/g dry weight) belonged to irrigation after 200 mm evaporation with 120 kg/ha of polymer, and the minimum leaf proline content (0.748 mg/g dry weight) was observed at irrigation after 100 mm evaporation with 300 kg/ha of polymer. In general, German chamomile tolerance to drought stress was through osmotic regulation of proline, and the yield of biomass was improved by super absorbent application.