Influence of the Season on the Quantity and Chemical Composition of the Essential Oil and Synthesis of Secondary Metabolites in Cymbopogon martini (Roxb.) Wats.

Perennial aromatic crops' production, yield, and quality are significantly impacted by seasonal variations. Cymbopogon martinii (Roxb.) (Poaceae) is a perennial aromatic grass that produces valuable essential oil from the leaves and inflorescence containing high concentrations of geraniol and geranyl acetate. The current study intends to determine how seasonal changes (autumn, winter, and summer) affect the production of geraniol, geraniol acetate, and essential oils from various plant components, (leaves and inflorescence). The field study was conducted at the experimental farm of India's CSIR-Central Institute of Medicinal and Aromatic Plants for two years (May 2018 to May 2020). Four varieties viz. cv. Tripta, Trishna, PRC1, and CIMAP Harsh were grown, and harvesting was done in three entirely different seasons, i.e., autumn, winter, and summer, for two consecutive years; thus, a total of six harvests (two in each season) were obtained. The research findings revealed that under the sub-tropical climatic conditions, cv. CIMAP Harsh performs better in yield and productivity with maximum essential oil yield obtained in the summer, followed by autumn. Maximum geraniol (89.9% and 51.26 kg ha-1) and geraniol acetate (3.0% and 1.73 kg ha-1) yields in leaves were reported during the summer season. In contrast, in inflorescence, geraniol (76.8% and 12.77 kg ha-1) yields were recorded maximum during the autumn season, irrespective of variety. In terms of essential oil yield and quality of oil, harvesting during the winter months did not make any significant difference. Nevertheless, it is intriguing to notice that the CIMAP Harsh variety placed top for the traits N2, N3, N5, N6, N7, N8, N13, N15, N21, and N22 and second for N1. In the traits N2 to N8, N13, and N14, Trishna was the variety that placed second. Therefore, it is advised that these two palmarosa cultivars be grown commercially on a wide basis.