Effect of the Pruning System and P-Fertilizer on Growth and Productivity of Rosa damascena mill. var.

Getting the highest flower yield with high-quality volatile oil of Rosa damascena Miller var. trigintipetala Dieck through good agricultural practices is one of the main challenges for oil production. Despite the critical role of pruning and P-fertilizer which strongly improve the flower productivity, their impacts on growth, flower yield, volatile oil and some physiological and biochemical processes are still poorly investigated on damask rose. Thus, in this experiment, two pruning levels i.e. 80 and 100 cm from ground level and three rates of P-fertilizer (0, 15 and 30 kg P2O5 ha-1, respectively) were examined. The tallest plants were observed in response to the combined treatment of pruning level at 100 cm and P-fertilizer at 30 kg ha-1. However application of the same P-fertlizer level with pruning at 80 cm resulted in the highest new shoots number/hill, flower yield components, oil content, relative water content, chlorophyll content, stomatal conductance, total soluble sugars, and N, P and K percentages relative to the other treatments. The flower yield was increased by 23.52 % when plants pruned at 80 cm and fertilized with P at 30 kg ha-1 compared to the pruning at 100 cm withought P addition. Decreasing pruning level and increasing P-fertilizer enhanced the protein content while reduced the free amino acids content. Conclusevelly, to obtain higher flower yield and volatile oil productivity, pruning damask rose plants at 80 cm and P-fetilizet at 30 kg ha-1 is recommended.