Consider the following techniques/phenomena : 1. Budding and grafting in fruit plants 2. Cytoplasmic male sterility 3. Gene silencing Which of the above is/are used to create transgenic crops?
- (a) 1 only
- (b) 2 and 3 ✓ UPSC's answer
- (c) 1 and 3
- (d) None
Why the answer is (b)
• Transgenic crops carry genes inserted by genetic engineering.
• Gene silencing (3), via RNA interference, is a transgenic technique — e.g. virus-resistant papaya and the non-browning Arctic apple; cytoplasmic male sterility (2), though natural, is engineered transgenically in crops like GM mustard (barnase–barstar) to produce hybrids — the official key counts both.
• Budding and grafting (1) are conventional vegetative propagation methods that do not alter genes.
• Hence 2 and 3, option (b).
Why the other options are wrong
- (a) 1 only
- Grafting does not create transgenic crops.
- (c) 1 and 3
- Grafting is conventional; CMS engineering is transgenic.
- (d) None
- Gene silencing and engineered CMS are transgenic techniques.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2014, held on 24 August 2014. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.