Homozygosity Heterozygosity

Homozygosity and heterozygosity describe the genetic state of alleles at a given locus in a cannabis plant. A homozygous individual carries two identical alleles (AA or aa), while a heterozygous individual carries two different alleles (Aa). These states directly influence trait expression, stability, and heritability in breeding programs. Understanding the homozygous/heterozygous balance is fundamental to predicting phenotypic outcomes and designing stable cultivars. Breeders often track these genetic compositions across multiple loci to develop uniform, reliable seed lines or to maintain hybrid vigor in F1 crosses.

Breeders pursue homozygosity in selfed or inbred lines to achieve trait stability and create true-breeding varieties, while heterozygosity is leveraged in hybrid breeding to produce uniform F1 generations with desired phenotypes. The ratio of fixed versus segregating loci determines whether a cultivar will breed true or produce variable offspring.