The phenomenon of reducing fertility and productivity due to repeated inbreedings is called

Options

A. inbreeding vigour
B. heterosis
C. inbreeding depression
D. hybridization

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the phenomenon that leads to reduced fertility and productivity due to repeated inbreeding.

2. **Identifying Key Terms**:
- **Inbreeding Vigor**: This refers to the hybrid vigor or heterosis, which is the opposite of what is being asked.
- **Heterosis**: This is the phenomenon where hybrid offspring exhibit superior qualities compared to their parents, not reduced fertility.
- **Hybridization**: This is the process of crossing two different species or breeds, which typically aims to enhance productivity and fertility.
- **Inbreeding Depression**: This is the reduction in fertility and productivity that occurs when closely related individuals are bred over several generations.

3. **Analyzing Each Option**:
- **Inbreeding Vigor**: Incorrect, as it refers to the benefits gained from inbreeding, not the drawbacks.
- **Heterosis**: Incorrect, as it denotes the advantages of hybrid offspring.
- **Hybridization**: Incorrect, as it aims to improve traits and does not cause reduced fertility.
- **Inbreeding Depression**: Correct, as it specifically refers to the decline in fertility and productivity due to repeated inbreeding.

4. **Conclusion**: The correct answer to the question is **Inbreeding Depression**.