Essential oil yield, composition and quality at different harvesting times in three prevalent cultivars of rose-scented geranium

Geranium is an economically important aromatic plant for its highly priced essential oil. The essential oil yield and composition is influenced by genetic, agronomical and environmental factors but at maturity, the right harvesting time during the day without affecting the quality is not clear. Present study was undertaken to study the change in essential oil yield and composition at different harvesting time during a day in three geranium cultivars i.e., Bourbon, Bio-G-171, and CIM-Pawan. Randomised samples from three cultivars were harvested at crop maturity stage to obtain oil yield and composition of essential oil at different times (06 A.M., 10 A.M., 02 P.M., and 06 P.M.) during the day. Results indicated that essential oil yield increased significantly from 06 A.M. (0.18 %) to 06 P.M. (0.40 %) in Bourbon only and not in Bio-G-171 and CIM-Pawan. With respect to quality of essential oils, no significant quantitative variations in marker compounds was recorded. Citronellol/geraniol ratio is a quality criteria as per industry need and results unveiled high ratio in Bourbon (1.85) and CIM-Pawan (1.73) in afternoon and in Bio-G-171 (1.78) during forenoon, compared with other harvesting time during the day. The study revealed that essential oil significantly increased in cultivar Bourbon during the day but not in Bio-G-171 and CIM-Pawan cultivars. With respect to quality, considering C/G ratio, one can go for harvesting in cultivar Bourbon and CIM-Pawan in the afternoon and for cultivar Bio-G-171, harvesting in forenoon is advisable.