Response of damask rose (Rosa damascena Mill.) to foliar application of magnesium (Mg), copper (Cu) and zinc (Zn) sulphate under western Himalayas

• Foliar fertilization effect was studied in damask rose.
• ZnSO4 @ 2% recorded 21.9% higher numbers of flower and 21.3% flower yield per plant than control.
• Essential oil composition was significantly affected by foliar application of different nutrients.
• MgSO4 + ZnSO4 @ 1% recorded 26.4% higher citronellol + nerol content (37.79 ± 1.4%) than control.

Foliar application of nutrients plays a vital role in plant metabolism. Very little research has been carried out with foliar spray of nutrients on growth, yield, essential oil content and composition of damask rose (Rosa damascena Mill.) under western Himalayas, hence the experiments were conducted from December 2012 to May 2014, to study the effect of foliar application of MgSO4, CuSO4 and ZnSO4 alone and in combinations at different concentrations for the first time. Eleven treatments, either single or mixture of salts were applied through foliar spray to damask rose plants according to experimental layout. Results of the study revealed that foliar application of ZnSO4 @ 2% recorded 21.9% and 21.3% higher numbers of flower/plant and flower yield/plant than control, respectively. Individual flower weight, essential oil content, chlorophyll content index and number of branches/plant were not affected by different treatments. However, essential oil composition was significantly affected by foliar application of different nutrients. Total 25 compounds were identified which accounted for 92.73 ± 0.8% to 95.64 ± 0.8% in different treatments. Application of MgSO4 @ 1% + ZnSO4 @ 1% recorded 26.4% higher citronellol + nerol (37.79 ± 1.4%) content than control. Essential oil produced from the flowers in which plants were treated with ZnSo4 @ 1% recorded significantly higher composition of Z-rose oxide (2.25%), E-geraniol (26.53%) and lower composition of nonadecene (1.53%), nonadecane (6.81%), docosane (0.58%) and heneicosane (2.60%) as compared with other treatments.