Cannabis sativa L. is a predominantly dioecious species, but sex expression is highly plastic and can be modified by genetic, hormonal, developmental, and environmental factors. This plasticity has major implications for commercial production because hermaphroditic expression in female plants can cause unintended pollination, seed formation, reduced floral quality, and losses in cannabinoid yield. This review summarizes current understanding of sex determination and sex-expression instability in C. sativa, with emphasis on hermaphroditism and its agronomic significance. We examine the genomic architecture of sex determination, the roles of ethylene and gibberellin signaling, and the effects of exogenous chemical treatments used to alter sexual phenotype. Particular attention is given to silver-based ethylene inhibitors, especially silver thiosulfate, which remain the most effective tools for induced masculinization and feminized seed production. We also assess the role of environmental stressors in sex instability and review current approaches for early detection, including visual inspection, Raman spectroscopy, and sex-linked molecular markers. Overall, the available evidence supports a multilayered and context-dependent model in which genotype, treatment regime, developmental stage, and environmental conditions interact to shape sexual phenotype. Improved understanding of these processes will be essential for reducing hermaphroditic risk, improving breeding strategies, and supporting stable, high-value cannabis production.
Richards et al. (Wed,) studied this question.