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 genetic cross between the two given parents and determine the percentage of colored flowers in their offspring.

### Step 1: Identify the Genotypes of the Parents
The genotypes of the parents are:
- Parent 1: Ccpp (C is dominant for color, c is recessive; p is recessive)
- Parent 2: ccPp (c is recessive; P is dominant for color, p is recessive)

### Step 2: Determine the Gametes Produced by Each Parent
Each parent will produce gametes based on their genotype:
- Parent 1 (Ccpp) can produce two types of gametes: Cp and cp.
- Parent 2 (ccPp) can produce two types of gametes: cP and cp.

### Step 3: Create a Punnett Square
Now we will create a Punnett square to visualize the possible combinations of gametes from both parents.

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

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

### Step 5: Determine the Phenotypes
Now we will determine the phenotypes based on the genotypes:
- CcPp: Colored (both C and P are dominant)
- Ccpp: White (C is dominant, but P is recessive)
- ccPp: Colored (C is recessive, but P is dominant)
- ccpp: White (both C and P are recessive)

### Step 6: Count the Colored and White Flowers
Out of the four possible offspring:
- 2 are colored (CcPp and ccPp)
- 2 are white (Ccpp and ccpp)

### Step 7: Calculate the Percentage of Colored Flowers
To find the percentage of colored flowers:
- Number of colored flowers = 2
- Total number of flowers = 4
- Percentage of colored flowers = (Number of colored flowers / Total number of flowers) × 100
= (2 / 4) × 100 = 50%

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