A breeder used selective breeding to increase the seed yield of sunflower plants. Plants from each generation were grown under the same conditions.
The plants were exposed to a fungal disease that had not previously affected the breeding population. Plants that did not survive produced no seeds.
| Generation | Mean mass of seeds produced per surviving plant in g | Plants surviving the fungal disease in % |
|---|---|---|
| 0 | 82 | 84 |
| 4 | 101 | 75 |
| 8 | 122 | 58 |
| 12 | 139 | 43 |
Calculate the difference between the expected total mass of seeds produced by 100 generation 0 plants and by 100 generation 12 plants after exposure to the fungal disease.
Give your answer in grams.
Another breeder proposes this procedure.
The breeder chooses some high-yield plants from generation 12 and breeds them together. All their offspring are then allowed to breed, without their seed yield being measured. This is repeated for several generations.
Explain why this procedure is unlikely to produce a continued increase in seed yield.
Suggest how the procedure should be corrected.
Suggest whether the breeder should continue selecting only for greater seed yield.
Use the information in the table and your knowledge of selective breeding.
100 exam-style questions on Edexcel GCSE Biology 4.3 Selective breeding and genetic modification, covering 4.3.1 Selective breeding and its impact, 4.3.2 Tissue culture, 4.3.3 Genetic engineering overview, 4.3.4 Main stages of genetic engineering, 4.3.5 Advantages and disadvantages of GM organisms, 4.3.6 Agricultural solutions for a growing population, and 4.3.7 Evaluating genetic engineering and breeding. Each one has a worked solution and a mark scheme showing where the marks go.