Which of the following is not a true statement with respect to Bt cotton?

Options

A. Bt toxin is produced by a bacterium Bacillus thuringiensis
B. It is an example of biopesticide
C. Bt toxin gene has been cloned in plants to provide resistance to insects
D. Bt cotton could increase the amount of pesticide used

Answer

To determine which statement about Bt cotton is not true, we will analyze each statement provided in the question step by step.

### Step-by-Step Solution:

1. **Statement 1: Bt toxin is produced by a bacterium Bacillus thuringiensis.**
- **Analysis:** This statement is true. Bacillus thuringiensis (Bt) is a soil bacterium that produces a protein toxin (Bt toxin) which is harmful to certain insects.

2. **Statement 2: It is an example of biopesticide.**
- **Analysis:** This statement is also true. Bt is considered a biopesticide because it is derived from a natural organism (the bacterium) and specifically targets insect pests, making it a microbial biopesticide.

3. **Statement 3: Bt toxin gene has been cloned in plants to provide resistance to insects.**
- **Analysis:** This statement is true as well. The gene responsible for producing the Bt toxin has been successfully cloned and inserted into various crops, including cotton, to confer resistance against insect pests without the need for chemical insecticides.

4. **Statement 4: Bt cotton could increase the amount of pesticide use.**
- **Analysis:** This statement is false. Bt cotton is designed to reduce the need for chemical pesticides because it produces its own insecticidal protein. Therefore, the use of chemical pesticides is generally decreased with the cultivation of Bt cotton.

### Conclusion:
The statement that is not true with respect to Bt cotton is: **"Bt cotton could increase the amount of pesticide use."**

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