Raman Spectroscopy Enables Highly Accurate Differentiation Between Young Male and Female Hemp Plants

Abstract

Determination of hemp (Cannabis sativa) sexuality is an integral part of the hemp industry. Current methods of analysis can be costly and invasive. Genetic testing is most often required which involves sending leaf samples to a laboratory for results. These wet laboratory methods require taking samples from immature hemp plants which can pose a risk due to the sensitivity of the young plants. Not only can collecting leaf samples damage the plant but the wait time to see results of genetic testing can take valuable time. This issue in the hemp industry can be solved by the emerging technology of Raman spectroscopy. Raman spectroscopy provides a way to accurately and non-invasively differentiate between young male and female hemp plants. A portable, hand-held Resolve Agilent Raman spectrometer was used as our instrument of analysis which does not disturb the plants in any way. Highly accurate and nonintrusive hemp differentiation is exceedingly important to hemp growers due to the preference for female hemp. Female hemp plants have a higher concentration of cannabinoids than male plants. Current efforts to minimize cross-pollination are not as effective as predetermining males or females. Hemp producers seeking higher cannabinoid concentrations desire fields that contain 100% female plants. If a male plant is within the field, it can unwantedly cross-pollinate female plants thus not allowing for the desired amount of cannabinoid production. Our results show that through Raman Spectroscopy, mature male and female hemp can be distinguished with an accuracy of 94% and even more importantly, that young hemp plants can be differentiated with 90% accuracy. In conclusion, our findings will allow hemp growers to save valuable time and expenses. This discovery broadens the many applications of Raman spectroscopy and can expand how plant sex determination is being conducted.