When Mendel crossed a true-breeding tall with a true-breeding dwarf plant,all of the F₁ generation was tall.Therefore we may conclude that the allele for dwarfism in the pea plant is:
A)recessive
B)codominant
C)dominant
D)intermediate in expression

Question

Quizplus · Accepted Answer

If all of the offspring in the F₁ generation were tall, it means that they all received at least one dominant allele for tallness from the tall parent. Since the dwarf plant was true-breeding, it means it could only contribute two recessive alleles for dwarfism. Therefore, the allele for dwarfism must be recessive.

When Mendel Crossed a True-Breeding Tall with a True-Breeding Dwarf