Gamete stripping and spawning

9 Genetic improyement traits, breeding values and application of genomic resources 

The selected traits in aquaculture are divided into two categories, depending on the parentage relationship of fish on which the measurements are performed. The highest accuracy of selection can be made for traits measured on the candidates, but, as can be seen in Table 2.5, other important traits cannot be measured on the selection candidates, so the information for those traits is recorded on sibs of the candidates. The heritability, reported in Table 2.5, is the parameter which calculates for each trait the ratio of the genetic variation over the total phenotypic variation (genetic and environmental) in a population. For example, for a trait like growth. 

There are several statistical packages that can be used to calculate traditional and genomic BLUP breeding values and the variance components of the traits that are needed for the breeding values. The most commonly used are ASREML (Gilmour et al., 2006), DMU (Madsen and Jensen, 2007) and VCE (Groeneveld et al, 2008). 

The number of breeders effectively contributing to the next generation, the so-called effective population size Ne, is of particular importance as it 

The design of a genetic improvement program has the purpose of structuring groups of (test) individuals in the population such that accurate breeding values for the traits under selection can be obtained and ensuring 

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