Thc Dominant Expression

THC-dominant expression describes cannabis plants that accumulate significantly higher cannabinoid percentages as tetrahydrocannabinol (THC) relative to cannabidiol (CBD) and other minor cannabinoids. This trait results from specific genetic polymorphisms in the CBDA synthase gene, which determines the enzymatic pathway flowers follow during cannabinoid synthesis. Lineage records frequently report THC-dominant phenotypes emerging from cultivars originally developed in regions with selective breeding histories favoring potency metrics. The expression pattern is polygenic, meaning multiple genes influence final cannabinoid ratios, and environmental factors including light intensity, temperature, and harvest timing can modulate final ratios within genetically predetermined ranges.

Breeders working to develop THC-dominant cultivars typically select parent plants showing consistent high-THC cannabinoid profiles across multiple generations, then cross-test offspring for stability. Understanding the genetic basis allows breeders to predictably work with THC-dominant lines while maintaining other desired traits like terpene profiles or growth structure.