For estimating breeding values two things are still required: phenotypic information and the regression coefficient of the true breeding value on the phenotypic superiority. Parent-offspring regression, which can be used to estimate the heritability as we have seen in the chapter on genetic models, in a way is estimating the breeding value of the offspring based on performance of the parents. In case of information on a single parent the regression coefficient equals half the heritability, where the half represents the additive genetic relationship between the single parent and the offspring. The EBV of the offspring thus can be calculated as:
EBVoffspring = bsingle parent-offspring * (Psingle parent - Pmean)
= ½ h2 * (Psingle parent - Pmean)
In case information on both parents is available the regression of the phenotype of the offspring on the mid-parent equals the heritability, the additive genetic relationship with both parents is 2*0.5 = 1, so the EBV becomes:
EBVoffspring = h2 * (Pmid-parent - Pmean)