UPSC Prelims 2011 Q29: Science & Technology – Biotechnology & Genetics
A genetically engineered form of brinjal, known as the Bt - brinjal, has been developed. The
objective of this is
- (a) To make it pest - resistant
- (b) To improve its taste and nutritive qualities
- (c) To make it drought - resistant
- (d) To make its shelf - life longer
Answer: (a) To make it pest - resistant
Explanation
Why Bt-brinjal was developed
Bt-brinjal is genetically engineered to carry a gene from the soil bacterium *Bacillus thuringiensis* (Bt).
| Option | Verdict | Reason |
|---|---|---|
| (a) To make it pest-resistant | Correct | The Bt gene produces a protein toxic to specific insect pests (like the fruit and shoot borer), protecting the plant without broad chemical pesticide spraying |
| (b) To improve taste and nutritive qualities | Incorrect | Bt-brinjal's modification targets pest resistance, not taste or nutrition |
| (c) To make it drought-resistant | Incorrect | The Bt trait is about insect resistance, unrelated to water stress tolerance |
| (d) To make its shelf-life longer | Incorrect | Shelf-life engineering (as in some other GM crops) is a different trait altogether |
Bt technology in brief:
| Point | Detail |
|---|---|
| Gene source | Soil bacterium *Bacillus thuringiensis* |
| Mechanism | Produces a protein toxic to specific insect larvae that eat the plant |
| Other Bt crops in India | Bt cotton (approved); Bt brinjal's commercial release was put on moratorium in 2010 |
Answer: (a) To make it pest-resistant.
Why each option is right or wrong
- (a) CORRECT. The Bt gene gives the plant resistance to specific insect pests.
- (b) Incorrect. Bt technology is about pest resistance, not taste or nutrition.
- (c) Incorrect. Drought resistance is a separate trait, unrelated to the Bt gene's function.
- (d) Incorrect. Shelf-life extension is a different kind of genetic modification, not what Bt does.
Key point
Bt-brinjal: carries a gene from Bacillus thuringiensis, making the plant produce a toxin against specific insect pests; its goal is pest resistance, not taste, drought tolerance or shelf-life.
Remember
Bt-brinjal = pest-resistant, via the Bacillus thuringiensis gene.
Common mistakes
- Confusing Bt (pest-resistance) technology with traits like drought tolerance or shelf-life.
- Not knowing the Bt gene's source: the bacterium Bacillus thuringiensis.
- Forgetting that Bt-brinjal's commercial release in India was put on a moratorium in 2010.
Exam tip
Any crop named 'Bt-something' always means pest/insect resistance, from the Bacillus thuringiensis gene.
Sources
- Ministry of Environment and Forests, Government of India — Decision on Commercialisation of Bt Brinjal (9 February 2010)
- Genetic Engineering Approval Committee — Bt Brinjal (Event EE-1): minutes of the 97th meeting (14 October 2009)