Question

In tomatoes, red fruit (R) is dominant over yellow fruit (r). A plant that is heterozygous for red fruit is crossed with a plant that has yellow fruit. What will be the genotype ratio of the offspring be?

Answer 1

To determine the genotype ratio of the offspring when a heterozygous red fruit plant (Rr) is crossed with a yellow fruit plant (rr), we can set up a simple Punnett square.

The possible gametes from each parent are:
- The heterozygous red fruit plant (Rr) can produce two types of gametes: R and r.
- The yellow fruit plant (rr) can only produce one type of gamete: r.

When we combine these gametes in a Punnett square, we have:

\[
\begin{array}{c|c|c}
& r & r \\
\hline
R & Rr & Rr \\
\hline
r & rr & rr \\
\end{array}
\]

From this Punnett square, the potential genotypes of the offspring are:
- 2 Rr (heterozygous red fruit)
- 2 rr (homozygous yellow fruit)

Now, let's determine the genotype ratio:
- **Rr**: 2
- **rr**: 2

Thus, the genotype ratio of the offspring is:
- 2 Rr : 2 rr, which simplifies to 1 Rr : 1 rr.

So, the final genotype ratio of the offspring will be **1:1**.