Genetics & Breeding
F1, F2 Segregation & Selection
Crossing genetically different parents creates an F1 population whose descendants can segregate widely in the F2. The amount and pattern of variation depend on the parents, loci involved, dominance, linkage, and population size.
Key concepts
- F1 uniformity depends on parental genetic structure
- F2 populations reveal recombined allele combinations
- Rare combinations require larger populations to observe reliably
- Selection changes which individuals contribute to the next generation
What to measure or observe
- Preserve parent and family identity
- Score traits consistently across the full population
- Record population size and selection count
- Retain data on rejected as well as selected individuals when feasible
Common mistakes
- Expecting every F1 from seed to be identical
- Evaluating only selected plants
- Calling an F2 stabilized after one generation
- Ignoring population size when searching for rare combinations
Visuals this lesson still needs
- P1-F1-F2 generation diagram
- Segregation example grid
- Population-size probability concept
- Selection funnel