Use of certain chemicals and radiation to change the base sequences of genes of crop plants is termed

Options

A. recombinant DNA technology
B. transgenic mechanism
C. mutations breeding
D. gene therapy

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the process of using chemicals and radiation to change the base sequences of genes in crop plants.

2. **Identifying Key Terms**: The key terms in the question are "chemicals," "radiation," "change the base sequences," and "crop plants."

3. **Analyzing the Options**:
- **Recombinant DNA Technology**: This involves combining DNA from different sources to create new genetic combinations. This does not fit the description in the question.
- **Transgenic Mechanism**: This refers to the introduction of foreign genes into a plant. Again, this does not match the question since it focuses on altering existing genes rather than introducing new ones.
- **Mutation Breeding**: This involves using chemicals or radiation (mutagens) to induce mutations in the plant's DNA, thereby changing the base sequences. This matches the description given in the question.
- **Gene Therapy**: This is a medical approach to treat diseases by altering genes, which is not relevant to crop plants.

4. **Conclusion**: Based on the analysis, the correct answer is **Mutation Breeding**. This process uses mutagens (chemicals or radiation) to induce mutations that can lead to desirable traits in crop plants.

**Final Answer**: Mutation Breeding

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