A breeder wants to produce a variety of garden plant that has large flowers and is resistant to a disease.
Four plants were grown under the same environmental conditions. The breeder measured the mean flower diameter and exposed each plant to the disease.
The breeder will only select plants with a mean flower diameter greater than 9.5 cm and with at least 80% of their leaves remaining healthy.
| Plant | Mean flower diameter in cm | Leaves remaining healthy in % |
|---|---|---|
| P | 8.7 | 94 |
| Q | 10.8 | 35 |
| R | 9.9 | 88 |
| S | 10.2 | 84 |
Give the letters of the two plants the breeder should select.
Describe how the breeder should continue the selective breeding programme after the selected plants have produced offspring.
Explain why using only closely related plants in every generation could make the new variety vulnerable to a different disease.
80 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.