Question

In a certain plant, tall stems (t) are dominant to short stems (t). a farmer crosses a short-stemmed plant with a heterozygous long-stemmed plant. what are the expected genotypes, phenotypes, genotypic ratios, and phenotypic ratios? (be sure to show how you got your answer --- punnett square!) trait: answers

Answer 1

The answers would be:

Genotype                Phenotype

     Tt                      Tall stemmed

     tt                       Short stemmed

Genotypic ratio : 2:2 or 1:1

Phenotypic ratio: 2:2  or 1:1  

You can read on to see how this was done:

Tall stems (T) are dominant to short stems (t).

First figure out the genotypes of the parents. We have a short-stemmed plant and a heterozygous long-stemmed plant cross.

For short stem to occur, you need 2 pairs of short alleles. So the first parent would have a genotype of tt.

Heterozygous long-stemmed means that the parent has one of each allele. So the genotype of the second parent would be, Tt.

Now we can make our Punnett Square.

tt x Tt

      t        t  

T |  Tt  |   Tt

t  |   tt  |   tt

Let's list down the genotypes and phenotypic results.

Genotype        no.         Phenotype

     Tt                 2           Tall stemmed

     tt                  2           Short stemmed

So from that we can answer the other questions:

Genotypic ratio : 2:2 or 1:1

Phenotypic ratio: 2:2  or 1:1