Hybrid vigour is due to :

Options

A. homozygosity
B. linkage
C. emasculation
D. heterozygosity

Answer

**Step-by-Step Solution:**

1. **Understanding Hybrid Vigour**: Hybrid vigour, also known as heterosis, refers to the phenomenon where the offspring (hybrids) exhibit superior qualities compared to their parents. This can include increased growth rates, higher yields, and improved resistance to diseases.

2. **Identifying the Causes**: The question presents four options: homozygosity, linkage, emasculation, and heterozygosity. We need to determine which of these is responsible for hybrid vigour.

3. **Evaluating Homozygosity**: Homozygosity refers to having identical alleles for a particular gene. In the context of hybrid vigour, homozygosity would not lead to variation or superior traits since both alleles are the same. Thus, it cannot be the cause of hybrid vigour.

4. **Considering Linkage**: Linkage involves genes that are located close to each other on the same chromosome. While linkage can affect inheritance patterns, it does not directly contribute to hybrid vigour. Therefore, linkage is not the correct answer.

5. **Examining Emasculation**: Emasculation is the process of removing anthers from a flower to prevent self-pollination. This technique is used in breeding but does not directly relate to the concept of hybrid vigour itself. Hence, emasculation is not the cause of hybrid vigour.

6. **Identifying Heterozygosity**: Heterozygosity occurs when an organism has two different alleles for a particular gene (e.g., one dominant and one recessive). This genetic variation is crucial for hybrid vigour, as it allows for the expression of superior traits from both parent organisms. Therefore, heterozygosity is the correct answer.

7. **Conclusion**: The correct answer to the question "Hybrid vigour is due to:" is **heterozygosity**.

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