Virus-free plants can be obtained by:

Options

A. Shoot tip culture
B. Haploid culture
C. Protoplast fusion
D. Embryo culture

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how virus-free plants can be obtained. This requires knowledge of plant tissue culture techniques that can eliminate viruses.

2. **Identifying the Options**: The options provided are:
- a. shoot tip culture
- b. haploid culture
- c. protoplast fusion
- d. embryo culture

3. **Evaluating Each Option**:
- **Shoot Tip Culture**: This technique involves taking the shoot tip of a plant, which contains meristematic cells. These cells are less likely to be infected by viruses because they are actively dividing and can regenerate healthy tissues.
- **Haploid Culture**: This involves producing haploid plants from pollen or ovules, but it does not specifically target virus elimination.
- **Protoplast Fusion**: This technique involves fusing plant cells without their cell walls, which is more about genetic manipulation than virus elimination.
- **Embryo Culture**: This technique involves culturing embryos but does not specifically address the removal of viruses.

4. **Conclusion**: Among the options, shoot tip culture is the most effective method for obtaining virus-free plants because it utilizes the meristematic tissue that is less likely to harbor viruses.

5. **Final Answer**: The correct answer is **a. shoot tip culture**.

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