In two genes inheritance, number of the offspring in F2 generation matched with parental phenotype is/are

Options

A. 10
B. 9
C. 3
D. 1

Answer

To solve the question regarding the number of offspring in the F2 generation that match the parental phenotype in a two-gene inheritance scenario, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Parental Traits**:
- We have two traits: seed shape (round vs. wrinkled) and seed color (yellow vs. green).
- Round shape is dominant (allele R) and wrinkled shape is recessive (allele r).
- Yellow color is dominant (allele Y) and green color is recessive (allele y).

2. **Determine the Genotypes of the Parents**:
- The parental generation consists of pure breeding individuals:
- Round yellow parent: RRYY
- Wrinkled green parent: rryy

3. **Cross the Parents to Form the F1 Generation**:
- The F1 generation will be a hybrid of the two parents:
- F1 genotype: RrYy (all offspring will be round and yellow because both traits are dominant).

4. **Self-Cross the F1 Generation to Form the F2 Generation**:
- The F2 generation results from crossing two F1 individuals:
- F2 cross: RrYy x RrYy

5. **Determine the Phenotypic Ratio in the F2 Generation**:
- Using a dihybrid cross, the phenotypic ratio can be determined:
- The phenotypic ratio is 9:3:3:1.
- This means:
- 9 offspring will be round yellow (RRYY, RRYy, RrYY, RrYy).
- 3 offspring will be round green (Rryy).
- 3 offspring will be wrinkled yellow (rrYY, rrYy).
- 1 offspring will be wrinkled green (rryy).

6. **Count the Offspring Matching Parental Phenotypes**:
- The parental phenotypes are round yellow and wrinkled green.
- From the phenotypic ratio:
- Round yellow: 9 offspring
- Wrinkled green: 1 offspring
- Total offspring matching parental phenotypes = 9 (round yellow) + 1 (wrinkled green) = 10.

### Final Answer:
The number of offspring in the F2 generation that match the parental phenotype is **10**.

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