A horticulturist wants to produce geraniums with specific characteristics. She knows that the trait of red flowers is governed by the allele [tex]\( R \)[/tex] ([tex]\( RR \)[/tex] and [tex]\( Rr \)[/tex]), and the trait of white flowers is governed by the allele [tex]\( r \)[/tex] ([tex]\( rr \)[/tex]).

The horticulturist crosses two geraniums from the F1 generation. Look at the Punnett square to see this cross.

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

Which ratio of red-to-white flowering plants would she expect to see in the phenotypes of the F2 generation?

A. 3 red: 1 white
B. All red
C. 2 red: 2 white
D. 1 red: 3 white

To determine the expected ratio of red-to-white flowering plants in the F2 generation when crossing geraniums, we can analyze the results of the given Punnett square.

1. Understanding the Cross:
- We have two parent plants, both heterozygous for flower color (Rr and Rr).
- The allele "R" is dominant for red flowers, and "r" is recessive for white flowers.

2. Punnett Square Analysis:
- The Punnett square outlines the possible genetic combinations in the offspring:
- Top row: 'R' and 'r' from one parent.
- Side column: 'R' and 'r' from the other parent.

[tex]\[
\begin{tabular}{|c|c|c|}
\hline
& R & r \\
\hline
R & RR & Rr \\
\hline
r & Rr & rr \\
\hline
\end{tabular}
\][/tex]

3. Counting the Genotypes:
- RR: One combination produces red flowers.
- Rr: Two combinations produce red flowers (since "R" is dominant, both "Rr" combinations result in red flowers).
- rr: One combination produces white flowers.

4. Phenotypic Outcome:
- Red Flowers: RR, Rr, Rr (3 possibilities)
- White Flowers: rr (1 possibility)

5. Ratio Calculation:
- From the table, we have 3 instances of red-flowered genotypes and 1 instance of white-flowered genotypes.
- Therefore, the expected ratio of red-to-white flowering plants in the F2 generation is 3:1.

Thus, in the F2 generation, you would expect the ratio of red flowering plants to white flowering plants to be 3:1.