Answer :
To solve this problem, we need to analyze the Punnett square provided in the question. The Punnett square shows the possible genotypes from crossing two geraniums from the F1 generation. Here’s a step-by-step explanation of how to determine the expected ratio of red-to-white flowering plants:
1. Identify the Alleles:
- The allele for red flowers is represented by 'R'.
- The allele for white flowers is represented by 'r'.
- Red flowers are produced when at least one 'R' is present (i.e., genotypes RR or Rr).
- White flowers are produced only with the genotype 'rr'.
2. Analyze the Punnett Square:
The construction of the Punnett square from the question is as follows:
```
| R | r |
--------------
R | RR | Rr |
--------------
R | Rr | rr |
```
3. List the Possible Genotypes:
From the Punnett square, the possible genotypes and their frequency of occurrence are:
- RR: 1 occurrence
- Rr: 2 occurrences (there are two Rr combinations)
- rr: 1 occurrence
4. Determine the Phenotypes:
- Red-flowering genotypes are RR and Rr.
- White-flowering genotype is rr.
- From the genotypes, we have:
- 3 potential red-flowering plants (1 RR and 2 Rr)
- 1 potential white-flowering plant (1 rr)
5. Calculate the Phenotypic Ratio:
- The ratio of red-flowering to white-flowering plants is 3 red : 1 white.
Therefore, the expected ratio of red-to-white flowering plants in the F2 generation is 3 red: 1 white.
1. Identify the Alleles:
- The allele for red flowers is represented by 'R'.
- The allele for white flowers is represented by 'r'.
- Red flowers are produced when at least one 'R' is present (i.e., genotypes RR or Rr).
- White flowers are produced only with the genotype 'rr'.
2. Analyze the Punnett Square:
The construction of the Punnett square from the question is as follows:
```
| R | r |
--------------
R | RR | Rr |
--------------
R | Rr | rr |
```
3. List the Possible Genotypes:
From the Punnett square, the possible genotypes and their frequency of occurrence are:
- RR: 1 occurrence
- Rr: 2 occurrences (there are two Rr combinations)
- rr: 1 occurrence
4. Determine the Phenotypes:
- Red-flowering genotypes are RR and Rr.
- White-flowering genotype is rr.
- From the genotypes, we have:
- 3 potential red-flowering plants (1 RR and 2 Rr)
- 1 potential white-flowering plant (1 rr)
5. Calculate the Phenotypic Ratio:
- The ratio of red-flowering to white-flowering plants is 3 red : 1 white.
Therefore, the expected ratio of red-to-white flowering plants in the F2 generation is 3 red: 1 white.