In sweet peas genes C and P are necessary for colour in flowers. The flowers are while 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. `75%`
B. `25%`
C. `100%`
D. `50%`

Answer

To solve the problem, we need to analyze the genetic cross between the two given genotypes: Ccpp and ccPp. We will follow these steps:

### Step 1: Identify the Genotypes of the Parents
- Parent 1 (P1): Ccpp
- Parent 2 (P2): ccPp

### Step 2: Determine the Gametes Produced by Each Parent
- For Parent 1 (Ccpp), the possible gametes are:
- C (dominant allele for gene C)
- p (recessive allele for gene P)

So, the gametes from P1 are: Cp and cp.

- For Parent 2 (ccPp), the possible gametes are:
- c (recessive allele for gene C)
- P (dominant allele for gene P)

So, the gametes from P2 are: cP and cp.

### Step 3: Create a Punnett Square
Now, we will create a Punnett square to determine the possible combinations of the offspring.

| | cP | cp |
|---------|------|------|
| **Cp** | CcPp | Ccpp |
| **cp** | ccPp | ccpp |

### Step 4: Analyze the Offspring Genotypes
From the Punnett square, we can see the following genotypes for the offspring:
1. CcPp (colored flower)
2. Ccpp (white flower)
3. ccPp (white flower)
4. ccpp (white flower)

### Step 5: Determine the Phenotypes
- CcPp: Colored flower (both genes are dominant)
- Ccpp: White flower (gene P is recessive)
- ccPp: White flower (gene C is recessive)
- ccpp: White flower (both genes are recessive)

### Step 6: Calculate the Percentage of Colored Flowers
Out of the 4 possible offspring:
- 1 offspring (CcPp) is colored.
- 3 offspring (Ccpp, ccPp, ccpp) are white.

The percentage of colored flowers is:
\[ \text{Percentage of colored flowers} = \left( \frac{1}{4} \right) \times 100 = 25\% \]

### Final Answer
The percentage of colored flowers in the offspring of the cross Ccpp and ccPp is **25%**.

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