A breeder crosses disease-resistant wheat with high-yielding wheat. Only some offspring have both characteristics. The breeder then allows every offspring plant to reproduce.
Why is this unlikely to be the most effective breeding programme?
Crossing the original varieties makes further selection unnecessary in their offspring.
Plants with the desired combination cannot pass both characteristics to offspring.
Crossing the original varieties prevents their offspring from showing inherited variation.
Plants lacking the desired combination also contribute genes to the next generation.
44 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.