Question

In tomatoes, red fruit (R) is dominant over yellow fruit (r). A plant that is homozygous for red fruit is crossed with a plant that has yellow fruit. What would be the genotype and phenotype of the F1 offspring?​

Answer 1

The genotype and phenotype of the F1 offspring are as follows:

Genotype - RR : Rr : rr = 1 : 2 : 1

Phenotype - Red fruit : Yellow fruit = 3 : 1

It is given that red fruit is dominant over yellow fruit in tomatoes.

A plant with homozygous red fruit (RR) is crossed with the plant having yellow fruit (rr).

The F1 offspring is given below with the help of Punnett's square-

$RR \times rr$

      R      R

r      Rr      Rr

r     Rr      Rr

Thus, all four offsprings will be having heterozygous red fruit.

Now, crossing them again, we will get,

$Rr \times Rr$

      R      r

R     RR      Rr

r      Rr      rr

Thus, the genotype of the F2 generation will be  RR : Rr : rr = 1 : 2 : 1

and the phenotype will be- 75% of plants will be having red fruit while 25% will be having yellow fruit.

Answer 2

Explanation:

red fruit would be 100% for the F1 offspring.