A gardener uses a single healthy potato plant to produce a large number of new potato plants by cutting sections of the potato tuber and planting each section separately. Explain why this method of reproduction makes the entire crop vulnerable to being destroyed by a single pathogen.

Cambridge International IGCSE Biology (0610) — 16.1 Asexual reproduction · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Asexual reproduction produces genetically identical offspring (clones). All the new potato plants are therefore genetically the same and share the same susceptibility to any given pathogen. Because there is no genetic variation or diversity in the crop, none of the plants have a different resistance trait that could survive infection. Consequently, a single pathogen that can infect one plant can potentially destroy the entire crop.

Examiner tips

  • Use the term ‘clones’ to show understanding of asexual reproduction.
  • Explain that identical genetics means identical susceptibility.
  • Mention lack of genetic diversity as the key vulnerability.
  • Conclude that a single pathogen can wipe out the whole crop.

Common mistakes

  • Confusing asexual with sexual reproduction; not mentioning clones.
  • Failing to link identical genetics to shared susceptibility.
  • Overlooking the role of genetic diversity in resistance.

Mark scheme (4 marks)

  1. The method described is asexual reproduction, producing genetically identical offspring (clones)
  2. Because all plants are genetically identical, they all share the same susceptibility to a given pathogen / none have genetic resistance
  3. There is no genetic variation / diversity in the population
  4. Therefore the whole population / entire crop can be destroyed by one pathogen

Key terms in this question

pathogen

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