Dihybrid Cross Calculator – Punnett Square by Mark Dihybrid Cross Punnett Square Calculator Calculate genotype and phenotype ratios for a dihybrid cross. Parent 1 – Trait 1 Genotype ? Select genotype for Trait 1 (e.g., AA, Aa, aa). AA (Homozygous Dominant) Aa (Heterozygous) aa (Homozygous Recessive) Parent 1 – Trait 2 Genotype ? Select genotype for Trait 2 (e.g., BB, Bb, bb). BB (Homozygous Dominant) Bb (Heterozygous) bb (Homozygous Recessive) Parent 2 – Trait 1 Genotype ? Select genotype for Trait 1 (e.g., AA, Aa, aa). AA (Homozygous Dominant) Aa (Heterozygous) aa (Homozygous Recessive) Parent 2 – Trait 2 Genotype ? Select genotype for Trait 2 (e.g., BB, Bb, bb). BB (Homozygous Dominant) Bb (Heterozygous) bb (Homozygous Recessive) Calculate Reset Select genotypes, then click “Calculate”. JavaScript is disabled. Please enable it to use the calculator.