A farmer wants to grow a variety of rose that produces exceptionally fragrant flowers. He knows that seeds from this rose may not reliably produce plants with the same fragrance. Which method of propagation should he use, and why would it better guarantee the desired trait in the new plants?
Generated by claude-sonnet-4-6 · 2026-06-26 01:05 · grounding rag
Model Answer
The farmer should use vegetative propagation (such as grafting or layering).
Why it guarantees the desired trait:
In vegetative propagation, new plants are grown from parts of the parent plant (stem, root, or leaf) rather than from seeds. Since sexual reproduction involves combination of DNA from two individuals, seeds may produce offspring with varying traits. Vegetative propagation produces plants that are genetically identical to the parent, ensuring all new plants inherit the same fragrance. It also allows plants to bear flowers earlier than seed-grown plants.
Source: Chapter 7, Section 7.2.5 — Vegetative Propagation
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Explanation
- Key concept tested: Difference between sexual (seed) and asexual (vegetative) reproduction in terms of genetic consistency.
- Examiners want: (1) correct method named, (2) reason seeds are unreliable (genetic variation from sexual reproduction), (3) reason vegetative propagation is reliable (genetic similarity to parent).
- Mention a specific technique (grafting/layering) to score full marks — don't just say "vegetative propagation."
- The phrase "genetically similar to the parent" is directly from the textbook and is a scoring keyword.