Variability in essential oil content and constituent profile of damask rose (Rosa damascena Mill.) at altered intervals of harvest in the Indian Western Himalaya

The cultivation of essential oil-bearing damask rose (Rosa damascena Mill.) is majorly focused on enhancing the essential oil content and quality. The current study aims to investigate the variability in the essential oil level and component makeup of damask rose at different harvests at regular intervals during the flowering season. The study consists of two vegetation years i.e. 2021 and 2022 with five harvesting dates, viz., April 6, April 13, April 20, April 27, and May 4 during both years. The damask rose variety ‘Jwala’ was used for the experiment and plants taken for flower harvest were 6 and 7 years old during 2021 and 2022, respectively. The essential oil content of damask rose fresh flowers was significantly higher in the first vegetation year (0.044%) and April 20 (0.048%) harvest and decreased with delay in harvesting after that. GC-MS profiling displayed citronellol and geraniol as major contributors to essential oil area percentage but quantitative variations were observed with variability in temperature and precipitation. The highest percentage of citronellol was recorded on the May 4 harvest. The highest geraniol content was recorded from April 27 than other dates of harvests but remained statistically analogous with April 13 and April 20. Essential oil decreased at both delayed and early harvests. Throughout the crop harvest season, harvesting on April 20 harvest date produced the highest essential oil content compared to early and late flush harvest. This suggests that the middle of the flowering season is suitable for procuring the highest essential oil yield under the mid-hill conditions of the western Himalayan region. These findings could have significant economic implications for the market demand and pricing for damask rose essential oil.