Percentage of the pea plants which would be homozygous recessive in `F_(1)` generation when tall `F_(1)` heterozygous pea plants are selfed will be:

Options

A. `25% `
B. `50% `
C. `100% `
D. `60%`

Explanation

To determine the percentage of homozygous recessive pea plants in the F2 generation when tall F1 heterozygous pea plants are selfed, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Parent Genotypes**:
- We have two types of parent plants: one tall (dominant trait) and one dwarf (recessive trait).
- Let's denote the tall allele as 'T' (dominant) and the dwarf allele as 't' (recessive).
- The tall parent will be homozygous (TT) and the dwarf parent will be homozygous recessive (tt).

2. **Perform the F1 Cross**:
- When we cross the tall parent (TT) with the dwarf parent (tt), all offspring (F1 generation) will be heterozygous (Tt) because they inherit one allele from each parent.

3. **Selfing the F1 Generation**:
- Now, we self the F1 heterozygous plants (Tt x Tt).
- This is a monohybrid cross, where we are looking at one trait (height) with two alleles.

4. **Gamete Formation**:
- Each Tt plant can produce two types of gametes: T and t.

5. **Punnett Square**:
- We can set up a Punnett square to visualize the possible combinations of alleles from the selfing of Tt x Tt:
```
T t
----------------
T | TT | Tt |
----------------
t | Tt | tt |
----------------
```
- From the Punnett square, we can see the possible genotypes of the offspring:
- 1 TT (homozygous dominant)
- 2 Tt (heterozygous)
- 1 tt (homozygous recessive)

6. **Count the Homozygous Recessive Offspring**:
- Out of a total of 4 offspring (1 TT + 2 Tt + 1 tt), only 1 is homozygous recessive (tt).

7. **Calculate the Percentage**:
- To find the percentage of homozygous recessive plants, we use the formula:
\[ \text{Percentage of homozygous recessive} = \left( \frac{\text{Number of homozygous recessive}}{\text{Total number of offspring}} \right) \times 100 \]
- Substituting the values:
\[ \text{Percentage} = \left( \frac{1}{4} \right) \times 100 = 25\% \]

### Final Answer:
The percentage of the pea plants which would be homozygous recessive in the F2 generation when tall F1 heterozygous pea plants are selfed is **25%**.

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