In quantitative inheritance `F_(2)` ratio obtained in a dihybrid cross is

Options

A. `1:4:6:4:1`
B. `9:7`
C. `15:1`
D. `12:3:1`

Answer

### Step-by-Step Solution:

1. **Understanding Quantitative Inheritance**:
- Quantitative inheritance, also known as polygenic inheritance, refers to a type of inheritance where a single trait is controlled by multiple genes. This results in a continuous range of phenotypes rather than discrete categories.

2. **Dihybrid Cross in Quantitative Inheritance**:
- In a dihybrid cross involving two traits, each trait is controlled by two alleles from two different genes. When these genes are involved in quantitative inheritance, the phenotypic ratio can be determined based on the combination of alleles.

3. **Phenotypic Ratio in F2 Generation**:
- In the F2 generation of a dihybrid cross under quantitative inheritance, the phenotypic ratio is typically expressed as 1:4:6:4:1. This ratio indicates the distribution of phenotypes resulting from the combination of alleles from both parents.

4. **Analyzing Other Options**:
- To confirm that 1:4:6:4:1 is the correct answer, we can analyze other potential ratios:
- **9:7 Ratio**: This ratio is associated with complementary gene interaction, not quantitative inheritance.
- **15:1 Ratio**: This ratio is indicative of non-allelic gene interaction, which also does not apply to quantitative inheritance.
- **12:3:1 Ratio**: This ratio is characteristic of dominant epistasis, which is again not relevant to quantitative inheritance.

5. **Conclusion**:
- After analyzing the ratios, we conclude that the correct phenotypic ratio for the F2 generation in a dihybrid cross under quantitative inheritance is indeed 1:4:6:4:1.

### Final Answer:
In quantitative inheritance, the F2 ratio obtained in a dihybrid cross is **1:4:6:4:1**.

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