Sex Determination Genetics

Sex determination genetics in cannabis refers to the biological mechanisms that establish phenotypic sex expression in dioecious plants. Cannabis species produce distinct male, female, and intersex phenotypes, determined primarily by chromosomal sex factors (XY system in most populations) and environmental stress conditions. Understanding these genetics is foundational for breeding programs seeking stable female lines, studying pollen production in males, or developing feminized seed technology. Environmental factors—light stress, temperature extremes, nutrient imbalance—can trigger intersex expression even in genetically female plants, complicating predictability. Breeders use sex determination knowledge to stabilize traits, select for female-only populations, and develop consistent seed stocks.

Breeders working in sex determination use this trait to isolate reliable female-only lines through repeated selection and to create feminized seed stocks by inducing female plants to produce viable pollen. Understanding sex genetics also helps identify and eliminate unwanted male or hermaphroditic plants early in breeding cycles, improving crop consistency.