Which of the following statements is correct regarding nectarless cotton varieties?

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

Explanation

### Step-by-Step Solution:

1. **Understanding Nectarless Cotton Varieties**:
- Nectarless cotton varieties are genetically modified or selectively bred cotton plants that do not produce nectar. Nectar is a sugary liquid that can attract certain pests.

2. **Analyzing the Options**:
- **Option A**: "They do not attract stem shrub leaf."
- This statement is vague and does not specifically relate to the known characteristics of nectarless cotton.
- **Option B**: "They are produced by mutation breeding."
- This statement is partially true, as some nectarless varieties can be developed through mutation breeding, but it is not the primary characteristic that defines them.
- **Option C**: "They do not attract ball worms."
- This is a significant characteristic of nectarless cotton. By not producing nectar, these varieties are less attractive to certain pests, including bollworms, which are harmful to cotton plants.
- **Option D**: "They attract green leaf bitter."
- This statement is incorrect, as nectarless cotton varieties do not attract pests due to the absence of nectar.

3. **Identifying the Correct Statement**:
- From the analysis, **Option C** ("They do not attract ball worms") is the correct statement regarding nectarless cotton varieties. This characteristic helps in reducing pest infestations, making these varieties more resilient.

### Final Answer:
- The correct statement regarding nectarless cotton varieties is: **They do not attract ball worms.**

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