Discuss asexual risks for crop production
Separate shared susceptibility, infected planting material and propagation costs.
Exam scope and assessment notes
Mapped to the named 0973 section using teaching from the corresponding single-science course. A 0973-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade. This qualification reports two grades on the 9–1 scale; confirm the entry route for your zone and exam series.
Before you begin
- Recall cells, DNA, inherited characteristics and the distinction between growth of an organism and production of offspring.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Does a clone label prove pathogen-free stock?
What you will learn
- Explain different disease and uniformity mechanisms
- Weigh practical costs and controls
Discuss asexual risks for crop production
| Feature | Meaning |
|---|---|
| Genetic mechanism | Many plants may share susceptibility |
| Infection mechanism | Pathogens can be carried with donor tissue |
| Resources | Labour, space, suitable conditions and establishment losses |
| Controls and limit | Healthy sources and hygiene can reduce risk, not guarantee zero disease |
Explain different disease and uniformity mechanisms
A crop planted with one clone genotype can share inherited susceptibility to a particular pathogen or environmental stress. If that susceptibility is important under the conditions, a large part of the crop may be affected. Connect the risk to common inherited traits rather than treating all disease as caused by cloning or assuming every genetically uniform crop is doomed.
Propagating material from an infected donor can carry a pathogen into daughter plants. This is a different mechanism from shared genetic susceptibility: one concerns pathogen transfer, the other concerns how a host genotype responds. A clone could be uninfected but susceptible, or infected despite useful inherited traits. Genetic identity alone does not certify pathogen-free planting material.
Weigh practical costs and controls
Growers can reduce some risks through suitable healthy source material, hygiene, monitoring and appropriate separation or diversity of stock, but these actions do not guarantee zero disease. Specialised tissue-culture methods can sometimes produce disease-free plants under suitable procedures; simply taking an ordinary cutting is not that certificate. The school discussion does not prescribe chemical treatments or certify a nursery process.
Propagation also needs suitable tissue, labour, containers, space and establishment conditions; losses can occur before planting out. A crop decision weighs these costs and risks against retaining valuable inherited traits and production predictability. State the grower’s goal and environment before judging the tradeoff, and avoid an absolute ranking of all seed and vegetative methods.
Sources for this lesson
Pause and explain
Which pair describes separate risks?
Worked example
Distinguish disease carried from an infected donor from inherited susceptibility in a uniform crop.
Show the worked solution
- Transferred pathogens establish infection status.
- Shared genotype can give similar responses to a pathogen.
Answer Pathogen transfer and shared inherited susceptibility are separate mechanisms; clone identity proves neither infection nor disease freedom.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Explain one shared-genotype risk for a uniform crop.
Give me a hint
Use a particular pathogen or stress rather than every possible threat.
Compare my reasoning
- Many plants share inherited traits.
- A stress affecting those traits may affect many plants.
Many plants may share susceptibility to a particular pathogen or stress, creating a common risk under those conditions.
Look for these in your work
- Link uniformity and susceptibility
- Use a conditional threat
Why is pathogen transfer from a donor different from inherited susceptibility?
Give me a hint
Separate what is carried from how the plant responds.
Compare my reasoning
- A pathogen can be carried in infected tissue.
- Genotype influences response but does not alone establish infection.
Donor material can carry a pathogen; inherited susceptibility concerns the host response. The mechanisms differ, and clone identity alone proves neither infection nor disease freedom.
Look for these in your work
- Distinguish both mechanisms
- Reject genotype-only health proof
Discuss whether ordinary cuttings guarantee disease-free cheap planting stock.
Give me a hint
Give benefits, costs and limits rather than a universal answer.
Compare my reasoning
- They can preserve a useful donor genotype.
- Donor infection, shared risk and establishment costs remain.
No guarantee follows. Cuttings can retain useful traits, but infected material, common susceptibility, labour and establishment losses need consideration; disease-free status requires separate evidence.
Look for these in your work
- Give a balanced judgment
- Include health and resource limits
Common mistakes
- Merging infection status and inherited susceptibility.
- Treating every cutting as certified disease-free.
What can you explain now?
Which pair describes separate risks?
Compare with the explanation
Shared inherited susceptibility and pathogen transfer from donor material
These mechanisms are distinct.
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Make it stick
Distinguish inherited susceptibility from transferred infection and give a balanced crop-production judgment.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.