Effects of Different Levels of Salinity Stress on the Morphological Traits of Damask Rose (Rosa damascene Mill)

Damask rose (Rosa damascene Mill) is one of the most important and economical rose species in Iran. After drought, salinity is the second most common environmental stress limiting agricultural production. In order to investigate the effect of salinity stress on Damask rose, an experiment was conducted based on a completely randomized design with three replications in the lysimeter condition at the Research Greenhouse of National Salinity Research Center during 2018-2019 growing season. The treatments were four levels of salinity stress (2.8, 5, 8 and 11 dS m‒1). The results indicated that the effect of different levels of salinity were significant for all traits except the number of branches per plant and the number of petals. The plants treated with the salinity levels of 2.8, 5 and 8 dS m‒1 had a significantly larger number of flowers per plant, flower weight, petal weight, yield flower and essential oil yield, compared to salinity level of 11 dS m‒1. Increasing the salinity level from 2.8 to 11 dS m‒1 caused the reduction in height (41.4%), 11 flowers per plant (47.8%), 0.77 g flower (39.9%), petal weight (18.3%), flower yield (62.4%), and essential oil yield (53.9%). Overall, the results showed that the salinity tolerance threshold of Damask rose of Mahalat was 8 dS m‒1.