What percentage of progenies would have broad leaves and pink flower i `F_(2)` generation of Snapdragon if first trait follow law of dominance and the other shows incomplete dominance ?

Options

A. 0.375
B. 0.5625
C. 0.625
D. 0.125

Answer

To solve the question regarding the percentage of progenies with broad leaves and pink flowers in the F2 generation of Snapdragon, we will follow these steps:

### Step 1: Understand the Traits
- **Broad Leaves**: This trait follows the law of dominance. The genotypes are:
- BB (homozygous dominant) - Broad leaves
- Bb (heterozygous) - Broad leaves
- bb (homozygous recessive) - Narrow leaves

- **Flower Color**: This trait shows incomplete dominance. The genotypes are:
- RR (homozygous dominant) - Red flowers
- Rr (heterozygous) - Pink flowers
- rr (homozygous recessive) - White flowers

### Step 2: Set Up the Cross
We will perform a dihybrid cross between the parents:
- Parent 1: BbRR (broad leaves and red flowers)
- Parent 2: Bbrr (broad leaves and white flowers)

### Step 3: Determine Gametes
From the parents, we can determine the possible gametes:
- BbRR can produce: BR, Br
- Bbrr can produce: Br, br

### Step 4: Create a Punnett Square
We will create a Punnett square with the gametes:
```
BR Br
----------------
Br | BbRR BbRr
----------------
br | BbRr Bbrr
```

### Step 5: Analyze the Offspring
Now we analyze the offspring phenotypes:
1. BbRR - Broad leaves, Red flowers
2. BbRr - Broad leaves, Pink flowers
3. BbRr - Broad leaves, Pink flowers
4. Bbrr - Broad leaves, White flowers

### Step 6: Count the Phenotypes
From the Punnett square, we have:
- Broad leaves and Red flowers: 1 (BbRR)
- Broad leaves and Pink flowers: 2 (BbRr)
- Broad leaves and White flowers: 1 (Bbrr)

Total broad leaves = 1 (Red) + 2 (Pink) + 1 (White) = 4

### Step 7: Calculate the Percentage
Now we need to find the percentage of progenies with broad leaves and pink flowers:
- Total broad leaves = 4
- Broad and Pink = 2

Percentage of broad leaves and pink flowers = (Number of broad and pink / Total broad leaves) * 100
= (2 / 4) * 100 = 50%

### Final Answer
The percentage of progenies with broad leaves and pink flowers in the F2 generation of Snapdragon is **50%**.

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