In this chapter we begin by specifying the characteristics of quantitative traits.
The terms phenotype and genotype have been touched upon earlier. They are valid for both qualitative and quantitative traits. Now their definitions are repeated to get deeper into the substance.
The term ’breeding value’ is introduced, this is used a lot within animal breeding. Its main content is how many good genes an animal passes on to its offspring.
The breeding value can be equal to the genotype value. But it is not always so, because dominance conditions cannot be transferred to offspring.
The term additive variance is also introduced. It is the variance of the breeding values and it can be used to predict the mean value of the next generation. The additive variance is also a part of the definition of heritability. The heritability measures how much of the variation in a trait is caused by genetic factors and how much is caused by the environment.
