In Mirabilis, red flowered plant crossed with white flowered one resulted in all pink flowered plants. What are the chances of appearance of red flowered plant in a cross between pink and white flowered plant?

Options

A. (a) Zero
B. (b) 0.25
C. (c) 0.5
D. (d) 0.75

Answer

**Step-by-Step Solution:**

1. **Understanding the Genetics of Mirabilis:**
- In Mirabilis, there are two flower color traits: red and white. Red is dominant (R) and white is recessive (r).
- When a red-flowered plant (RR) is crossed with a white-flowered plant (rr), all offspring are pink (Rr) due to incomplete dominance.

2. **Identifying the Genotypes:**
- The genotypes of the plants involved are:
- Red flowered plant: RR
- White flowered plant: rr
- Pink flowered plant: Rr

3. **Crossing Pink and White Flowered Plants:**
- We need to determine the outcome of a cross between a pink flowered plant (Rr) and a white flowered plant (rr).
- Set up a Punnett square to visualize the possible offspring.

4. **Setting Up the Punnett Square:**
- The alleles of the pink flowered parent (Rr) are placed on one side, and the alleles of the white flowered parent (rr) are placed on the other side:
```
R r
---------
r | Rr | rr |
---------
r | Rr | rr |
```

5. **Analyzing the Offspring:**
- From the Punnett square, we can see the possible genotypes of the offspring:
- 50% Rr (pink flowers)
- 50% rr (white flowers)
- There are no offspring with the genotype RR (red flowers).

6. **Conclusion:**
- Since there are no red flowered plants (RR) produced from the cross between pink (Rr) and white (rr), the chances of appearance of red flowered plants in this cross is **0%**.

**Final Answer:**
The chances of appearance of red flowered plants in a cross between pink and white flowered plants is **0**.

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