Cannabinoid Ratio

Cannabinoid ratio refers to the proportional balance between major cannabinoids—primarily THC and CBD—within a cannabis plant's chemotype. This ratio is determined by genetic expression and inherited alleles controlling cannabinoid synthase enzymes, not by terpenes themselves, though the term is often used in strain classification. Ratios range from THC-dominant (10:1 or higher) to balanced (1:1) to CBD-dominant (1:10 or higher). Understanding cannabinoid ratios is foundational to cannabis genetics because it defines chemotype categories and influences breeding strategies across commercial and research programs. Lineage records frequently document these ratios as primary identifiers, alongside cannabinoid acid profiles (THCA, CBDA) measured pre-decarboxylation.

Breeders select for specific cannabinoid ratios by tracking parental chemotypes and screening offspring through early testing. Ratio stability depends on homozygosity at cannabinoid-synthase loci; F1 hybrids often show segregation, requiring multiple generations to fix desired ratios in pure lines.