Discuss sexual reproduction benefits for crop breeding
Connect new combinations, selection and a stated grower goal.
Section 16.2 · Sexual reproduction
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall DNA, inherited characteristics, nuclei and the distinction between growth and reproduction.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which aim can sexual crossing support?
What you will learn
- Explain why variation can help breeding
- Separate creating combinations from choosing useful plants
Discuss sexual reproduction benefits for crop breeding
| Feature | Meaning |
|---|---|
| Crossing | Combines inherited contributions |
| Variation | Provides breeding candidates |
| Selection | Chooses plants meeting the goal |
| Limit | Testing and conditions still matter |
Explain why variation can help breeding
Crossing plants can bring inherited contributions together and produce new combinations among offspring. A grower seeking to combine useful traits from selected stock can use that variation as material for breeding. The sexual route therefore serves a different aim from copying one already selected donor genotype through cuttings. Name the breeding goal before comparing the methods.
Not every offspring will show the desired combination. The grower must observe or test relevant traits and select suitable plants. Crossing and selection are separate steps: one generates possible combinations, while the other chooses plants that meet the goal. Later testing under suitable conditions may be needed to judge performance, stability and unintended tradeoffs.
Separate creating combinations from choosing useful plants
Genetic variation among crop plants may also leave some suited to a specified environmental challenge. This possible benefit is conditional on useful inherited differences and the growing environment. It does not mean every diverse crop resists all pathogens, yields more or ripens together. A desired trait in one situation can be less useful in another.
For suitable species, sexually produced seeds may provide convenient planting, storage or dispersal material, but the advantage depends on seed type, viability and handling conditions. Do not claim every crop seed stores indefinitely or gives disease-free stock. A complete discussion links benefits to the crop and goal while weighing unpredictable trait combinations and production costs.
Pause and explain
Is selecting a useful offspring the same event as fertilisation?
Worked example
A grower wants useful inherited characteristics from two selected lines in offspring. Why can a cross help?
Show the worked solution
- Both lines contribute inherited information.
- Offspring can provide new combinations for selection.
Answer Crossing can produce combinations that the grower can evaluate and select.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
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 sexual-reproduction benefit for a grower seeking new trait combinations.
Give me a hint
Link gamete contributions with a breeding goal.
Compare my reasoning
- A cross combines inherited contributions.
- Offspring variation provides candidates for selection.
Sexual crossing can produce new inherited combinations that a grower can assess and select for the stated breeding goal.
Look for these in your work
- Name new combinations
- Link variation to selection
Why must useful offspring be selected and tested rather than assuming every cross is an improvement?
Give me a hint
Variation includes different outcomes.
Compare my reasoning
- Offspring combinations vary.
- Meeting the desired performance goal needs evidence.
Not every combination meets the goal; offspring need evaluation and selection, with suitable testing of performance and tradeoffs.
Look for these in your work
- Retain varied outcomes
- Require goal-specific evidence
Compare a grower seeking new combinations with one wanting to preserve an existing donor genotype.
Give me a hint
Match the route to the aim.
Compare my reasoning
- Crossing generates combinations for selection.
- Vegetative copying preserves an existing genotype in the model.
Crossing can support new combinations for selection; vegetative copying can preserve an already selected donor genotype. Neither aim establishes a universally best method.
Look for these in your work
- Address both goals
- Give a conditional comparison
Common mistakes
- Saying every cross automatically creates the best plant.
- Treating crossing and selection as the same step.
What can you explain now?
Is selecting a useful offspring the same event as fertilisation?
Compare with the explanation
No; selection judges the resulting plants
The origin event and later choice differ.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Explain a breeding benefit and separate crossing from later selection.
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.