Answer :
To find the expected ratio of red-to-white flowering plants in the phenotypes of the F2 generation, we need to consider the Punnett square and the genetics of the plant crosses.
1. Alleles and Dominance:
- The letter 'R' represents the dominant allele for red flowers.
- The letter 'r' represents the recessive allele for white flowers.
2. Cross the F1 Generation:
This cross involves two plants that both carry one dominant allele for red flowers (R) and one recessive allele for white flowers (r). Therefore, both are heterozygous (Rr).
3. Punnett Square:
The Punnett square for this cross looks like this:
[tex]\[
\begin{array}{|c|c|c|}
\hline
& R & r \\
\hline
R & RR & Rr \\
\hline
r & Rr & rr \\
\hline
\end{array}
\][/tex]
4. Possible Genotypes:
- RR: Red flowering.
- Rr: Red flowering (because the presence of one 'R' allele is enough for the flower to be red).
- rr: White flowering (since both alleles are recessive).
5. Calculate the Phenotype Ratio:
- RR appears once (1 out of 4 possibilities).
- Rr appears twice (2 out of 4 possibilities, from the boxes Rr and Rr).
- rr appears once (1 out of 4 possibilities).
6. Phenotype Outcomes:
- Red flowering plants (RR and Rr combined) = 1 + 2 = 3 parts.
- White flowering plants (rr) = 1 part.
7. Ratio of Red to White Flowering Plants:
- The ratio of red to white flowering plants is 3:1.
This means the horticulturalist can expect to see a 3 red to 1 white ratio in the phenotypes of the F2 generation.
1. Alleles and Dominance:
- The letter 'R' represents the dominant allele for red flowers.
- The letter 'r' represents the recessive allele for white flowers.
2. Cross the F1 Generation:
This cross involves two plants that both carry one dominant allele for red flowers (R) and one recessive allele for white flowers (r). Therefore, both are heterozygous (Rr).
3. Punnett Square:
The Punnett square for this cross looks like this:
[tex]\[
\begin{array}{|c|c|c|}
\hline
& R & r \\
\hline
R & RR & Rr \\
\hline
r & Rr & rr \\
\hline
\end{array}
\][/tex]
4. Possible Genotypes:
- RR: Red flowering.
- Rr: Red flowering (because the presence of one 'R' allele is enough for the flower to be red).
- rr: White flowering (since both alleles are recessive).
5. Calculate the Phenotype Ratio:
- RR appears once (1 out of 4 possibilities).
- Rr appears twice (2 out of 4 possibilities, from the boxes Rr and Rr).
- rr appears once (1 out of 4 possibilities).
6. Phenotype Outcomes:
- Red flowering plants (RR and Rr combined) = 1 + 2 = 3 parts.
- White flowering plants (rr) = 1 part.
7. Ratio of Red to White Flowering Plants:
- The ratio of red to white flowering plants is 3:1.
This means the horticulturalist can expect to see a 3 red to 1 white ratio in the phenotypes of the F2 generation.
