Cannabis sativa: Dioecious into Monoecious Plants influencing Sex Determination

Cannabis sativa: Dioecious into Monoecious Plants influencing Sex Determination

Ravindra B. Malabadi1*, Kiran P. Kolkar2, Raju K. Chalannavar1, Antonia Neidilê Ribeiro Munhoz3, Gholamreza Abdi4, Himansu Baijnath5
1Department of Applied Botany, Mangalore University, Mangalagangotri-574199, Mangalore, Karnataka State, India
2Department of Botany, Karnatak Science College, Dharwad-580003, Karnataka State, India
3Department of Chemistry, Environment and Food, Federal Institute of Amazonas, Campus Manaus Centro, Amazonas, Brazil- 69020-120
4Department of Biotechnology, Persian Gulf Research Institute, Persian Gulf University, Bushehr, 75169, Iran
5Ward Herbarium, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
*Corresponding Author: rbmalabadi_b3g@yahoo.com
DOI: https://doi.org/10.51584/IJRIAS.2023.8409
Received: 04 July 2023; Accepted: 12 July 2023; Published: 03 August 2023

Abstract: This review paper highlights about sex determination and conversion of dioecious into monoecious plants by applying exogenous growth regulators or chemicals. Cannabis sativa L. (Cannabaceae) is a dioecious plant, producing male and female flowers on separate unisexual individuals. Although both male and female plants are capable of producing cannabinoids in equal concentrations, female plants produce greater floral biomass than male plants and thus are exclusively used in commercial Medical Cannabis sativa (drug or marijuana) production facilities. In commercial production, marijuana plants are all genetically unfertilized female plants and, male plants are destroyed as seed formation reduces flower quality. One male Cannabis plant can ruin the entire female plant crop due to uncontrolled pollination and crop is designated as contaminated. Moreover, after pollination, female plants alter their relative investment in phytochemicals by reducing the production of secondary metabolites like cannabinoids, flavonoids, and terpenoids. Therefore, early diagnosis of sex is very important to both breeders and farmers for Cannabis crop improvement or production purposes. Cannabis sex determination could be modified by applying exogenous growth regulators or chemicals, which can influence the ratio of endogenous hormones and hence the incidence of sex organs. Silver compounds such as silver nitrate (AgNO3) or silver thiosulfate (Ag2S2O3; STS) have been found to have masculine effects in many plant species including Cannabis. A gap in the literature highlighting Cannabis sex determination has been updated in this review paper.

Key Words: Cannabis sativa, Dioecious, Feminized seeds, Hermaphrodites, Phytocannabinoids, Sex determination, Silver compounds

I. Introduction

The important characteristic of Cannabis sativa L. is the production of phytocannabinoids in abundance which are present in their acidic form in plant tissue (1-17). Phytocannabinoids are produced as a part of defensive mechanism in the trichomes on flower bracts of female inflorescences (1-17, 61). In recent years, the medicinal applications of Cannabis sativa L. have gained wider attention worldwide (1-20, 61-62). Cannabis sativa L., is classified into two types as Industrial Cannabis sativa, hemp or Medical Cannabis sativa (drug or marijuana) based on its THC content (1-45). Medical Cannabis sativa (drug or marijuana) contains very high levels of THC (1 to 35% of dry weight). On the other hand Industrial Cannabis sativa (Hemp) contains very low levels of THC (0 to 0.3% of dry weight) (1-40, 61, 62). However, due to the presence of psychoactive molecules, Λ9-tetrahydrocannabinol (Λ9-THC) and Λ8-tetrahydrocannabinol (Λ8-THC), Cannabis cultivation and its use is restricted/regulated in many countries (1-17, 61, 62). Medical Cannabis sativa (drug or marijuana) plants are grown commercially for their psychoactive compounds, which are produced in the trichomes that develop on flower bracts in female inflorescences (1-35, 61-62). Although the classification between hemp and marijuana is based on legal convention, different studies indicated that the discrimination between these varieties is not limited to Cannabinoid biosynthesis but can be monitored across the whole genome (1-17). Cannabis sativa L. (hemp, marijuana) produces male and female inflorescences on different plants (dioecious) (1-40, 61-62). Therefore, the plants are obligatory out-crossers. In commercial production, marijuana plants are all genetically female. The male plants are destroyed as seed formation reduces flower quality (1-35, 61, 62).