Sex Determination Genetics

Sex determination in cannabis is a genetic trait controlled primarily by chromosomal factors, with the XY sex determination system being the most common model in dioecious varieties. Most modern cannabis cultivars express either male (XY) or female (XX) phenotypes, though hermaphroditic expressions occur when environmental stress or genetic predisposition triggers both reproductive organs. Breeders distinguish between genotypic sex (chromosomal composition) and phenotypic sex (expressed reproductive organs), as environmental factors like photoperiod, temperature, and nutrient stress can influence which organs develop. Feminized seed lines were developed by deliberately inducing hermaphroditism in female plants, then collecting pollen to create XX-only offspring. Understanding sex determination mechanisms remains foundational to breeding programs seeking stable flowering times, consistent

Breeders working in this category use sex determination genetics to produce feminized seeds, stabilize breeding lines, and eliminate unwanted male plants from cultivation environments. Consistent phenotypic expression of female plants improves crop uniformity and allows targeted selection for desired traits across stable genetic backgrounds.