Effects of Irrigation Water Salinity on Yield Quantity and Quality and Water Use Efficiency of Damask Rose in Pot Conditions

In order to investigate the effect of salinity stress on applied water, yield and water use efficiency of Damask rose, an experiment was conducted based on completely randomized design with three replications and four levels of water salinity including 2.8, 5, 8 and 11 dS.m-1 at Research Greenhouse of National Salinity Research Center, during 10 Oct 2018 to 30 Sep 2019. In this study, volume of applied water and drainage water, evapotranspiration, flower yield, essential oil yield, and water use efficiency (based on flower yield) were determined. The results showed that the average of applied water, evapotranspiration and drainage water in each irrigation were 14.3, 8.4 and 5.9 L per plant for all treatments, respectively. Also, sum of applied water, evapotranspiration and drainage water volume during the experiment were equal to 616, 363 and 253 L per plant, respectively. The sum of irrigation water volume was 619, 625, 610 and 610 L per plant in 2.8, 5, 8 and 11 dS.m-1 treatments, respectively. Flower yield in 2.8, 5 and 8 dS.m-1 treatments were 60.3, 55.8 and 57.1 g/plant and had no significant difference, such that plants treated with 5 and 8 dS.m-1 had a decrease of 7.46% and 5.25% compared to the 2.8 dS.m-1 treatment, respectively. However, treatment of 11 dS.m-1 had the lowest flower yield (22.66 g/plant) with a decrease of 62.42% compared to the treatment 2.8 dS.m-1. The results showed that the highest water use efficiency of Damask rose was obtained in treatments 2.8, 5, and 8 dS.m-1 (0.09, 0.08 and 0.09 kg/m3) and the lowest (0.03 kg/m3) was in salinity of 11 dS.m-1. Salinity stress levels of 8 and 11 dS/m caused the highest percentage of essential oil (0.025% and 0.027%, respectively) and salinity of 2.8 and 5 dS/m caused the lowest percentage of essential oil (0.022% and 0.021%, respectively).