In pea plants, the allele for tall (T) is dominant to the allele for short (t).

Question

In pea plants, the allele for tall (T) is dominant to the allele for short (t). Which of the following is the percent of offspring that will be tall if a heterozygous plant (Tt) is crossed with a homozygous tall plant?

A. 100%

B. 75%

c. 50%

D. 25%

 

I think its either 100% or 75%.

Answer 1

Hi Dag,

 

Heterozygous pea plant would have two kinds of gametes: T and t.

 

Homozygous pea plant would have only one kind of gamete: T.

 

Based on punnet square, all F1 progeny would be either TT or Tt for their genotype. 

 

       T   l   t

T     TT  l  Tt

 

T     TT  l  Tt

 

I have made punnet square for your easy comprehension. 

 

Since T is dominant over  t, all F1 progeny will be tall, that is 100% tall in phenotype. 50% of this progeny would be homozygous tall and rest 50% would be heterozygous tall.

 

Hope this helps.