Influence of Various Plant Spacing on Growth, Herbage Yield, Essential Oil Yield and Aroma Content of Palmarosa (Cymbopogon martinii Roxb.) at Different Harvest Under Agro-Climatic Condition of Doon Valley

Palmarosa oil is an essential oil bearing grass, rich in geraniol and geranyl acetate with abundant pharmacological activities. A field study was carried out during 2010 and 2011 at the Centre for Aromatic Plants (CAP), Dehradun, Uttarakhand, India to investigate the effect of plant spacing on growth, herbage yield, essential oil content, and composition of palmarosa oil at different harvest. The experiment consisted six treatments of various plant spacing viz., 30 cm x 30 cm, 45 cm x 30 cm, 60 cm x 30 cm, 45 cm x 45 cm, 60 cm x 45 cm, and 60 cm x 60 cm. The results revealed that maximum plant height (200.9 cm) and herbage yield (361.5 q/ha) of palmarosa were obtained from closer plant spacing as compared to wider plant spacing. However, no. of tillers (69.1 tillers/plant), dry matter accumulation (DMA) (494.0 g/plant), oil content (0.56 %) and oil yield (139.7 kg/ha) was found significantly higher under wider plant spacing as compared to closer spacing. The study revealed that the geraniol and geranyl acetate were found major aroma components of palmarosa oil, out of which geraniol accounted around 53.21-82.26 % and geranyl acetate approximately 3.90-13.05 %. However, the other components present in palmarosa oil were found very trace in amount. Therefore, based on the above findings it is concluded that cultivation of palmarosa crop with wider plant spacing produced the maximum and best quality of essential oil yield in the environment suitable for palmarosa in a Doon valley climate of the Himalayan region.