Heterozygous Homozygous

Heterozygous and homozygous refer to the genetic composition at specific loci in cannabis plants. A heterozygous locus carries two different alleles (one from each parent), while a homozygous locus carries identical alleles. Understanding these states is foundational to breeding stable lines and predicting offspring phenotypes. Cannabis breeders track these conditions across multiple traits—cannabinoid production, morphology, terpene expression—to establish breeding stock and F1 hybrids. Homozygous lines tend toward phenotypic consistency across generations, whereas heterozygous plants may segregate variable traits in subsequent generations, a principle central to both line-breeding and hybrid seed production.

Breeders selectively homozygose desirable traits through repeated self-fertilization or sibling crosses to create stable cultivars. Conversely, F1 hybrids leverage heterozygosity to express vigor and uniform phenotypes, then revert to segregating populations in F2 if not backcrossed or stabilized.