Polygenic Trait Expression

Polygenic trait expression refers to characteristics controlled by multiple genes rather than a single locus, resulting in continuous variation across a population. In cannabis breeding, traits like plant height, flowering time, cannabinoid ratios, and terpene profiles are commonly attributed to polygenic inheritance patterns. This multi-gene control creates a spectrum of phenotypes rather than discrete categories, making these traits difficult to reliably predict or stabilize across generations. Understanding polygenic expression is essential for breeders selecting for consistent chemotypes or morphologies, as environmental factors often interact with genetic architecture to produce final phenotypes. Stabilizing polygenic traits typically requires multi-generational selection and larger population sizes compared to single-gene traits.

Breeders working with polygenic traits employ phenotypic selection across multiple generations and often track progeny performance to identify individuals carrying favorable allele combinations. Population-level analysis and test crosses help clarify the number of genes involved and their relative contribution to trait variation.