Polygenic Expression

Polygenic expression refers to traits in cannabis determined by multiple genes rather than a single dominant or recessive locus. Height, flowering time, cannabinoid ratios, and terpene profiles are commonly polygenic, meaning each contributing gene adds small, cumulative effects to the final phenotype. This genetic architecture explains why offspring from the same parents often display a range of phenotypes rather than discrete categories. Breeders working with polygenic traits typically require larger population sizes and multiple generations to isolate and stabilize desired combinations. Environmental factors also influence polygenic expression, making phenotype prediction more complex than simple Mendelian inheritance.

Understanding polygenic inheritance helps breeders set realistic timelines for trait stabilization and explains phenotypic variance within F1 and F2 generations. Selection pressure applied consistently across multiple generations can gradually shift population means toward target characteristics, though complete predictability remains limited.