Quantitative Genetics

Quantitative genetics refers to the inheritance patterns of cannabis traits controlled by multiple genes rather than single dominant/recessive alleles. In cannabis breeding, traits like plant height, leaf width, terpene production levels, and cannabinoid ratios typically show quantitative inheritance, meaning phenotypic expression exists on a spectrum rather than in discrete categories. Breeders working in this category use selective breeding across generations to shift population averages toward desired trait combinations. Understanding quantitative trait loci (QTL) helps explain why identical genetics can produce variable results across environments and why stabilizing specific phenotypes requires consistent selection pressure. This polygenic model contrasts with single-gene traits like leaf shape variants or certain pigmentation markers that follow Mendelian inheritance patterns.

Breeders leverage quantitative genetics principles to develop stable F1 hybrids and inbred lines by selecting parents that demonstrate the desired trait range. Genomic selection tools increasingly help identify individuals carrying favorable allelic combinations at multiple loci, accelerating polygenic trait improvement without waiting for full phenotypic expression.