Go through the following statement regarding nectarless cottn varieties and choose correct one:

Options

A. They do not attract stem sawfly
B. They are produced by mutation breeding
C. They do not attract bollworms
D. They attract cereal leaf beetle

Answer

### Step-by-Step Solution:

1. **Understanding Nectarless Cotton Varieties**:
- Nectarless cotton varieties are those that do not possess nectaries, which are glands that produce nectar. Nectar typically attracts pollinators such as bees, moths, and other insects.

2. **Role of Nectaries**:
- Nectaries are important for attracting pollinators, which can aid in the process of pollination, including cross-pollination. Without nectaries, these varieties are less likely to attract such insects.

3. **Impact of Absence of Nectaries**:
- Since nectarless cotton varieties lack nectaries, they do not produce the sweet scent that attracts pollinators and pests. This leads to a reduced attraction of certain insects, including bollworms.

4. **Evaluating the Statements**:
- **Statement 1**: "They do not attract stems of fly."
- There is no specific information to support this claim, so we cannot consider it correct.
- **Statement 2**: "They are produced by mutation breeding."
- This statement is incorrect as nectarless cotton varieties are not developed through mutation breeding.
- **Statement 3**: "They do not attract bollworms."
- This statement is correct because the absence of nectaries means there is nothing to attract bollworms.
- **Statement 4**: "They attract cereal leaf beetle."
- This statement is also incorrect, as nectarless varieties do not attract pests due to the lack of nectar.

5. **Conclusion**:
- After evaluating all the statements, the correct statement regarding nectarless cotton varieties is that they do not attract bollworms.

### Final Answer:
- The correct statement is: **They do not attract bollworms.**