Comparison in essential oil of Rosa damascena Mill. during harvest period under calcareous soil conditions

Rosa damascena Mill. is the most important scented rose species which cultivated for essential oil production in the world. The objective of the present study was to understand how different harvest dates influenced the essential oil yields and chemical compounds in petals of Rosa damascena Mill. planted for the first time under calcareous soil conditions, Sa′adat Shahr region. In the current survey, flowers were collected four times with three replications from four years old plants between 05:00 and 06:00 AM (2nd, 9th, 16th and 23rd of May, 2020). The essential oils of samples were extracted by hydro-distillation system (Clevenger apparatus) and were analyzed by a combination of GC-FID and GC-MS techniques, to check for chemical variability. The essential oil content of flowers harvested at different times ranged from 0.046% to 0.082% (w/w). The number of identified compounds were 30, of which 21 were common. The highest content of citronellol + geraniol (60.9 %), which are the most important constituents of its essential oil, was observed when the flowers were harvested in the 2nd of May. However, the lowest content of them (40.6 %) was found in the flowers of the fourth week of harvesting. n-nonadecane and n-heneicosane continuously increased from the first week (17.4 %) to the fourth week (34.8 %) of the harvest. This experiment revealed that different harvest dates can significantly modify the performance and composition of Damask rose’ essential oil. Moreover, calcareous soil conditions could be used to obtain essential oil of Rosa damascena Mill.