A plant of genotype RRTt (red fruits, tall ) is crossed with a plant of genotype rrtt ( white furits, dwarf). What is percentage of tall plants with red fruits in next generation ?

Options

A. 1
B. 0.75
C. 0.25
D. 0.5

Answer

To solve the problem, we will follow these steps:

### Step 1: Identify the Genotypes and Phenotypes
- The first plant has the genotype **RRTt** (red fruits, tall).
- The second plant has the genotype **rrtt** (white fruits, dwarf).
- Here, **R** (red fruits) is dominant over **r** (white fruits), and **T** (tall) is dominant over **t** (dwarf).

### Step 2: Determine the F1 Generation
- When we cross the two plants (RRTt x rrtt), we can determine the gametes produced by each parent:
- The first parent (RRTt) can produce gametes: **RT** and **Rt**.
- The second parent (rrtt) can only produce gametes: **rt**.

- The F1 generation will consist of the following combinations:
- **RT x rt** → **RrTt** (red fruits, tall)
- **Rt x rt** → **Rrtt** (red fruits, dwarf)

### Step 3: Analyze the F1 Generation
- The F1 generation will have two genotypes:
- **RrTt** (red fruits, tall)
- **Rrtt** (red fruits, dwarf)

### Step 4: Determine the F2 Generation
- To find the F2 generation, we will cross the F1 plants (RrTt and Rrtt):
- The gametes from **RrTt** can be: **RT, Rt, rT, rt**.
- The gametes from **Rrtt** can be: **Rt, rt**.

- We can set up a Punnett square to determine the possible combinations in the F2 generation.

### Step 5: Create a Punnett Square
- The Punnett square will look like this:

```
Rt rt
----------------
RT | RrTt | Rrtt |
-------------------------
Rt | RrTt | Rrtt |
-------------------------
```

### Step 6: Analyze the Results
- From the Punnett square, we can see the following combinations:
- **RrTt** (red fruits, tall) - 2 occurrences
- **Rrtt** (red fruits, dwarf) - 2 occurrences

### Step 7: Calculate the Percentage of Tall Plants with Red Fruits
- Out of a total of 4 plants (2 RrTt and 2 Rrtt):
- The percentage of tall plants with red fruits (RrTt) is:
\[ \text{Percentage} = \left( \frac{\text{Number of RrTt}}{\text{Total Number of Plants}} \right) \times 100 = \left( \frac{2}{4} \right) \times 100 = 50\% \]

### Final Answer
The percentage of tall plants with red fruits in the next generation is **50%**.

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