Q. Chromosomal doubling for producing polyploid plants is carried out by

Options

A. a) PEG
B. b) NAA
C. c) Mutagen
D. d) Fusogen

Answer

**Step-by-Step Solution:**

1. **Understanding Polyploidy:**
- Polyploidy refers to the condition of having more than two complete sets of chromosomes. It is common in plants, particularly in the Liliaceae family.

2. **Identifying the Role of Mutagens:**
- Mutagens are agents that cause changes in the DNA sequence. In the context of inducing polyploidy, certain mutagens can interfere with normal cell division processes.

3. **Colchicine as a Mutagen:**
- Colchicine is a specific type of mutagen that is known to induce polyploidy. It works by inhibiting the formation of spindle fibers during cell division.

4. **Mechanism of Action:**
- Colchicine disrupts the assembly of microtubules, which are essential for chromosome segregation during mitosis. As a result, cells can end up with doubled chromosome numbers because the chromosomes do not separate properly.

5. **Conclusion:**
- Since colchicine is a mutagen that effectively induces polyploidy by interfering with mitosis, the correct answer to the question is option C: Mutagen.

**Final Answer:**
- Chromosomal doubling for producing polyploid plants is carried out by **Mutagen (specifically colchicine)**.

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