Effect of season on essential oil content and composition of Palmarosa [Cymbopogon martini (Roxb.) Will. Watson] cultivated in the mid-hill conditions of the Western Himalayas

Abstract

Palmarosa [Cymbopogon martini (Roxb.) Will. Watson] is an aromatic grass that is grown for the extraction of its valuable essential oil because it has extensive applications in various industries. A study was conducted in the Western Himalayan region from 2022 to 2023 to investigate the effects of different harvest seasons and dates on the quantity and quality of essential oil. The research spanned three phenological seasons: Summer, Autumn, and Winter. This study aims to address the existing gap in the literature regarding essential oil profiles under these environmental conditions. The highest essential oil yield was observed during summer (June 4). GC/GC-MS analysis identified seven compounds in the essential oil during chemical profiling. Amongst them, the major chemical compound was geraniol, which attained the highest percentage (93.48%) on January 21 during the winter season; this can be attributed to the maturity, quality stages of the plant, and polar nature of oxygenated compounds, which resulted in higher solubility in condensate water. In contrast, the rainy season led to a dilution of essential oil concentrations, adversely affecting key compounds like geraniol while also increasing the risk of fungal diseases. This study revealed that palmarosa can be harvested in the mature stage to increase the quality and quantity of essential oil in the Western Himalayas.