A heterozygous round seeded plant (Rr) is crossed with a homozygous round seeded plant (RR)

Question

What will the punnett square look like?
What percentage of the offspring will be homozygous (RR)

Answer 1

To create a Punnett square for the cross between a heterozygous round-seeded plant (Rr) and a homozygous round-seeded plant (RR), we start by identifying the alleles involved:

• The heterozygous plant (Rr) can pass on either the dominant allele \(R\) or the recessive allele \(r\).
• The homozygous plant (RR) can only pass on the dominant allele \(R\).

Here's how the Punnett square will look:

          R      |      R
       -------------------
    R |   RR    |   RR
       -------------------
    r |   Rr    |   Rr

From the Punnett square, we can see the possible combinations of the alleles for the offspring:

1. \(RR\) (homozygous dominant)
2. \(RR\) (homozygous dominant)
3. \(Rr\) (heterozygous)
4. \(Rr\) (heterozygous)

Now, let's calculate the percentages of the offspring:

• Homozygous (RR): 2 out of 4 squares = 50%
• Heterozygous (Rr): 2 out of 4 squares = 50%

Thus, 50% of the offspring will be homozygous (RR).