Question

Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis Bt is resistant to:

• A. Plant nematodes
• B. Insect predators
• C. Insect pests
• D. Fungal diseases

Answer 1

The correct option is C

Insect pests

The correct option is the C.

Explanation for the correct option:

1. Bt cotton variety was developed by the introduction of the toxin-producing gene of Bacillus thuringiensis bacteria.
2. Bt is resistant to insect pests.
3. Bt cotton plant is a genetically modified plant that was developed by the introduction of the toxin-producing gene of the bacteria Bacillus thuringiensis.
4. These bacteria produce protein crystals during a specific phase of their growth cycle.
5. These crystals carry a toxic insecticidal protein.
6. It is got activated inside the pest intestine.

Explanation for the incorrect options:

Option A:

1. Bt does not act on plant nematodes.
2. They act on external part of the plant and cause necrosis.

Option B:

1. Bt does not affect the insect predator because it kills only those who eat Bt protein present in plant.
2. But insect predator eat insect only.

Option C:

1. Bt kills pest by forming hole in its gut, but fungal disease is not resisted by Bt protein because fungus infect the plant by its hyphae.

Final Answer: Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis Bt is resistant to insect pests.