Question

What are the possible genotypes of the offspring resulting from a cross between a purebred tall pea plant and a hybrid tall plant, using (T) for tall and (t) for short?

Answer 1

The offspring of a cross between a purebred tall pea plant (TT) and a hybrid tall plant (Tt) will have two possible genotypes: TT (homozygous dominant) and Tt (heterozygous). Both genotypes result in the tall phenotype since tall is the dominant trait.

Step-by-step explanation:

The possible genotypes of the offspring resulting from a cross between a purebred tall pea plant (TT) and a hybrid tall plant (Tt) can be determined using a Punnett square. A plant with TT genotype is homozygous dominant and will always be tall, whereas a plant with Tt genotype is heterozygous but will also display the tall phenotype because the dominant trait T for tallness masks the recessive trait t for shortness.

When a TT plant is crossed with a Tt plant, the offspring can have the following genotypes: TT or Tt. The TT offspring arise when the T allele from the purebred parent pairs with the T allele from the hybrid parent. The Tt offspring result when the T allele from the purebred parent pairs with the t allele from the hybrid parent. Since there are no tt combinations possible from this cross, all offspring will phenotypically be tall.

Thus, the two possible genotypes are:

1. TT (homozygous dominant)
2. Tt (heterozygous)

However, the phenotypic outcome will be the same for both genotypes, leading to tall plants.