In sweet peas, genes C and P are necessary for colour in flowers . The flowers are white in the absence of either or both the genes . What will be the percentage of coloured flowers in the offspring of the cross Ccpp × ccPp ?

Options

A. 1
B. 0.75
C. 0.25
D. 0.5

Answer

To solve the problem, we need to analyze the genetics of the sweet pea flower color based on the given parental genotypes and the genes involved.

### Step-by-Step Solution:

1. **Identify the Genotypes of Parents:**
- The first parent is **Ccpp** (homozygous for C and homozygous recessive for P).
- The second parent is **ccPp** (homozygous recessive for C and heterozygous for P).

2. **Determine the Gametes:**
- For **Ccpp**, the only gamete produced will be **Cp** (since it can only contribute C and p).
- For **ccPp**, the possible gametes produced will be **cP** and **cp** (since it can contribute either c and P or c and p).

3. **Set Up the Punnett Square:**
- We can set up a Punnett square to visualize the potential offspring from the gametes:
```
| | cP | cp |
|---|----|----|
| Cp| CcP | Ccpp |
```

4. **Analyze the Offspring:**
- From the Punnett square, we have:
- **CcP**: This genotype will produce colored flowers (since it has both dominant alleles C and P).
- **Ccpp**: This genotype will produce white flowers (since it has a recessive p and only one dominant C).

5. **Calculate the Ratios:**
- The offspring genotypes are:
- 1 CcP (colored)
- 1 Ccpp (white)
- This gives us a ratio of 1 colored flower (CcP) to 1 white flower (Ccpp).

6. **Calculate the Percentage of Colored Flowers:**
- Out of 2 total offspring, 1 is colored.
- Therefore, the percentage of colored flowers = (Number of colored flowers / Total number of flowers) × 100 = (1/2) × 100 = **50%**.

### Final Answer:
The percentage of colored flowers in the offspring of the cross Ccpp × ccPp is **50%**.