Phytochemical characteristics of Roselle (Hibiscus sabdariffa L.) under different fertilizer systems and irrigation water

In order to evaluate the effects of different fertilizer systems and irrigation water on some phytochemical characteristics of Roselle (Hibiscus sabdariffa L.), a field experiment was conducted at the University of Jiroft during 2013 and 2014. The study was conducted as split plot based on a randomized complete blocks design with three replications. Three irrigation levels (100%, 80% and 60% of crop water requirement) were assigned as main plot factor. Four fertilizers including mycorrhiza, vermicompost, cow manure, and chemical fertilizer (NPK) were allocated as sub plot factor. The results indicated that fertilizer treatments and different irrigation water levels had significant effect on total phenol, anthocyanin, acidity of calyx, seed protein and seed oil. The highest and lowest anthocyanin (3.05 and 2.78 ml.gr-1), total phenol (12.52 and 12.90 ml.gr-1) and acidity of calyx (0.81 and 0.87 gr.100 gr dry weight) belonged to vermicompost and cow manure. Also, 60% and 100% crop water requirement produced the highest and lowest anthocyanin (3 and 2.19 ml.gr-1), total phenol (13.04 and 10.81 ml.gr-1) and seed protein (20.90% and 20.01%). Furthermore, the interaction effect of fertilizer systems and irrigation levels had a significant effect on anthocyanin content. The interaction effect of irrigation levels and year had a significant effect on oil seed. Vitamin C was not affected by experimental treatments.