In what ratiothe parental phenotypes will appear in `F_(2)` generatio of dihybride cross

Options

A. `3//16:3//16`
B. `4//16:4//16`
C. `9//16 :1//16`
D. `12//16 : 4//16`

Answer

To determine the ratio in which parental phenotypes will appear in the F2 generation of a dihybrid cross, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Dihybrid Cross**: A dihybrid cross involves two traits, each represented by two alleles. For example, let's consider two traits: seed shape (Round 'R' dominant over Wrinkled 'r') and seed color (Yellow 'Y' dominant over Green 'y').

2. **Parental Generation (P)**: We start with two parental plants. One plant is homozygous dominant for both traits (RRYY) and the other is homozygous recessive for both traits (rryy).

3. **F1 Generation**: When we cross these two parents, all offspring in the F1 generation will be heterozygous for both traits (RrYy). The phenotype of all F1 offspring will be Round and Yellow since both traits are dominant.

4. **F2 Generation**: To obtain the F2 generation, we self-fertilize the F1 generation (RrYy x RrYy).

5. **Punnett Square**: We can use a Punnett square to determine the genotypic and phenotypic ratios in the F2 generation. The Punnett square for a dihybrid cross will have 16 boxes (4 for each trait).

6. **Phenotypic Ratio**: The phenotypic ratio for a dihybrid cross is typically 9:3:3:1. This means:
- 9 Round Yellow (parental phenotype)
- 3 Round Green
- 3 Wrinkled Yellow
- 1 Wrinkled Green (the other parental phenotype)

7. **Identify Parental Phenotypes**: In this case, the parental phenotypes are Round Yellow and Wrinkled Green.

8. **Calculate the Ratio of Parental Phenotypes**:
- Round Yellow (parental phenotype) appears 9 times.
- Wrinkled Green (parental phenotype) appears 1 time.
- Therefore, the ratio of parental phenotypes in the F2 generation is 9:1.

### Final Answer:
The parental phenotypes will appear in the ratio of **9:1** in the F2 generation of a dihybrid cross.

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