Sex Chromosomes

Sex chromosomes in cannabis determine whether plants develop as males, females, or hermaphrodites. Cannabis is a dioecious species with an XY sex determination system, where female plants carry XX chromosomes and males carry XY. Environmental stress, genetics, and epigenetic factors can influence sex expression, sometimes causing phenotypic variation from the expected genotype. Understanding sex chromosome inheritance is fundamental to breeding programs, as female plants are cultivated for cannabinoid and terpene production while males are selectively bred or eliminated depending on breeding objectives. Seed producers rely on sex chromosome knowledge to generate reliable female-only seeds through feminization techniques or traditional male-female crosses.

Breeders use sex chromosome understanding to develop feminized seed lines, maintain stable dioecious populations, and select for desired phenotypes in male pollinators. Knowledge of sex determination also helps breeders predict offspring ratios and troubleshoot unexpected hermaphroditism in breeding projects.