Question

Name the first transgenic crop which has repellent effect in insect:

• A. Smartstax maize
• B. Spring Wheat strain Cadenza
• C. Asian mega rice variety PSBRc82
• D. "Flavr Savr" a delayed ripening tomato

Hint:

Remember: Wheat Cadenza was modified to release \((E)\)-\(\beta\)-farnesene (aphid alarm pheromone), acting as a natural repellent to pests and an attractant to beneficial natural enemies.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
While many transgenic crops are engineered with insecticidal endotoxins (like Bt crops), some have been engineered to emit volatile organic compounds that act as natural repellents or alarm pheromones to deter pests.

Step 2: Detailed Explanation:
The Spring Wheat strain Cadenza was genetically engineered by researchers at Rothamsted Research (UK) to produce the aphid alarm pheromone, \((E)\)-\(\beta\)-farnesene.
This volatile compound repels aphids from feeding on the wheat plants while simultaneously attracting their natural insect predators (such as parasitic wasps).
This was a significant milestone in engineering behavioral-deterrence traits in major cereals.

Step 3: Final Answer:
The first transgenic crop with a repellent effect on insects is Spring Wheat strain Cadenza, matching option (B).