In Mirabills jalapa , the homozygous white(rr) and Red (RR) flower colour produces pink (Rr) flower colour. When a pink flower is crossed with red flower, the ratio will be

Options

A. 25% white : 50% pink : 25% red
B. 50% pink : 50% red
C. 50% pink : 50% white
D. 50% red : 50% white

Answer

To solve the problem regarding the flower color inheritance in Mirabilis jalapa, we will follow these steps:

### Step 1: Understand the Genotypes
- Homozygous white flowers are represented as **rr**.
- Homozygous red flowers are represented as **RR**.
- The heterozygous pink flowers are represented as **Rr**.

### Step 2: Identify the Cross
We need to perform a cross between a pink flower (Rr) and a red flower (RR).

### Step 3: Set Up the Punnett Square
To visualize the genetic cross, we can use a Punnett square. The alleles from one parent will be placed on the top and the alleles from the other parent on the side.

```
R R
----------------
R | Rr Rr
r | rr rr
```

### Step 4: Fill in the Punnett Square
- The top row represents the alleles from the red flower (RR).
- The left column represents the alleles from the pink flower (Rr).
- Fill in the squares:
- The first column (R from RR and R from Rr) gives us **Rr** (pink).
- The second column (R from RR and r from Rr) gives us **Rr** (pink).

### Step 5: Analyze the Results
From the Punnett square, we can see:
- 2 squares show **Rr** (pink flowers).
- 2 squares show **RR** (red flowers).

### Step 6: Determine the Ratio
The resulting ratio of flower colors from this cross is:
- 2 Red (RR) : 2 Pink (Rr)
- This simplifies to a ratio of **1 Red : 1 Pink**.

### Conclusion
When a pink flower (Rr) is crossed with a red flower (RR), the ratio of the resulting flower colors will be **1 Red : 1 Pink**.

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