UPSC Prelims 2002 Q32: Science & Technology – Biology
Consider the following plants:
1. Bougainvillea
2. Carnations
3. Cocoa
4. Grapes
Which of these plants are propagated by stem cuttings?
- (a) 1 and 2
- (b) 2, 3 and 4
- (c) 1, 3 and 4
- (d) 1, 2, 3 and 4
Answer: (d) 1, 2, 3 and 4
Explanation
Plants propagated by stem cuttings
| Plant | Propagation by stem cuttings |
|---|---|
| Bougainvillea | Yes — hardwood stem cuttings root easily |
| Carnation | Yes — stem cuttings from side shoots |
| Cocoa | Yes — rooted stem cuttings (apart from seeds and budding) |
| Grapes | Yes — hardwood stem cuttings are the standard method |
All four plants — bougainvillea, carnations, cocoa and grapes — can be propagated by stem cuttings, so the stored key (d) is right. Cocoa is usually raised from seed or budding too, but stem cuttings are a recognised method.
Answer: (d) 1, 2, 3 and 4.
Why each option is right or wrong
- (a) Incorrect. It leaves out cocoa and grapes, which can also be raised from stem cuttings.
- (b) Incorrect. It leaves out bougainvillea, which is a classic stem-cutting plant.
- (c) Incorrect. It leaves out carnations, which are raised from stem cuttings.
- (d) CORRECT. All four plants can be propagated by stem cuttings.
Key point
Vegetative propagation: cuttings (grapes, rose, bougainvillea), layering, grafting (mango), budding (citrus, cocoa).
Remember
Stem cuttings: bougainvillea, carnation, grape, cocoa, rose.
Common mistakes
- Excluding cocoa because it is usually grown from seed.
- Excluding carnations as a seed-grown flower.
- Treating grapes as a plant that can only be grafted.
Exam tip
Garden shrubs and vines (bougainvillea, grapes) are almost always raised from cuttings.
Sources
- NCERT Class XII Biology — Sexual Reproduction in Flowering Plants (vegetative propagation)
- Indian Council of Agricultural Research — Handbook of Horticulture