Effect of different water regimes and nitrogen applications on the growth, yield, essential oil content, and quality parameters of the oil rose (Rosa damascena Mill.)

Oil rose (Rosa damascena Mill.) is a great important aromatic and medicinal plant widely used in cosmetics, food processing, pharmaceuticals, and agrochemical industries. Water supply and nutrition are vital for plant growth and yield. Water stress causes plant growth, development, and yield loss at different levels. This study was conducted to investigate the effect of different water and nitrogen levels (N) on growth, yield, and quality parameters and determine the chemical composition of oil rose through gas chromatography coupled with mass spectrometry (GC/MS) analysis. The fieldwork for this research was conducted from March 2014 to June 2018. According to the results of study treatments, the highest fresh flower yield per plant was determined with the I-0.50, 80 kg ha(-1) treatment. In 2017 and 2018, as fertilizer level increased and irrigation level decreased, fresh flower yield, oil yield per plant, plant height, number of branches in plant, and leaf area values decreased. However, there was little tradeoff between reductions in applied water and fresh flower yield. Furthermore, the GC-MS results reveal little change in essential oil quality as water stress increases with diminished applied water. The yield response and essential oil quality are the direct result of the relatively invariant WUE.