Genetics & Breeding
Heritability, Repeatability & Trait Selection
A trait can be strongly influenced by genetics, environment, or both. Heritability is population- and environment-specific and should not be interpreted as a universal percentage describing one individual plant.
Key concepts
- Heritability describes variation within a defined population and environment
- High environmental noise makes phenotypic selection less reliable
- Repeated measurements can improve confidence for variable traits
- Correlated traits can respond together under selection
What to measure or observe
- Define the population and environment
- Use repeatable trait measurements
- Record replicate or family data when possible
- Separate measurement error from biological variation
Common mistakes
- Applying a published heritability value to every population
- Using one subjective score for a complex trait
- Ignoring environment-by-genotype interactions
- Assuming a heritable trait is easy to select visually
Visuals this lesson still needs
- Genetic-versus-environmental variation diagram
- Repeatability example
- Trait measurement noise graphic
- Selection response concept