Homozygous Homozygous Heterozygous

Homozygous-Homozygous-Heterozygous (HHh) describes a tri-locus genotype pattern where two trait loci are fixed (homozygous) and one segregates (heterozygous). This configuration is common in stabilized breeding lines that retain some intentional genetic variation. Breeders working in this category often use HHh genotypes as intermediate steps between F1 hybrids and fully stable IBL (inbred line) material. The heterozygous locus may control morphology, terpene expression, or vigor traits, allowing phenotypic exploration while maintaining consistency at two critical loci. Understanding HHh structures helps predict segregation ratios in subsequent generations and informs breeding decisions around trait fixation.

HHh genotypes are strategically deployed in cultivar stabilization protocols to balance uniformity with genetic diversity. Breeders use them to evaluate whether a third trait should be fixed or maintained as segregating variation in commercial or research lines.