Question

In Mendel's monohybrid cross with pea plants (TT × tt), what did the F₁ generation show?

Options

• All F₁ plants were short (tt) because the recessive allele dominated

• F₁ plants were of intermediate height, showing blending inheritance

• F₁ plants showed a mixture of both tall and short plants

• All F₁ plants were tall (Tt) because only the tall phenotype appeared

Answer 1

When Mendel crossed true-breeding tall (TT) plants with true-breeding dwarf (tt) plants, all F₁ offspring were heterozygous (Tt) and showed only the tall phenotype. This demonstrated that the tall allele was dominant and that no blending occurred—the recessive allele for dwarfism was present but not expressed in the heterozygous F₁ generation.