11.6.3 Four-way crosses (2024)
- Tessa Jacobs
- Kor Oldenbroek
Two-way cross females (F1’s) are crossed to crossbred males of a third and fourth breed. For their offspring, the second generation in the cross, the notation F2 is used. In this system, the full effect of heterosis in the crossbred dams (F1) and males (F1) can be utilized. Four-way crosses are widely used in commercial poultry breeding programs. All three reasons form the motivation for these four-way crosses in layer and broiler production: exploiting heterosis, combining ability of breeds and crosses and selection in breeds for traits that cannot be easily improved simultaneously in single breed. Besides, crossbreeding provides genetic protection of the pure lines for the breeding companies, as animals cannot be patented. In these poultry breeding programs, many (>25) traits are important; many of them are correlated (negatively or positively) to each other and/or have a low heritability. First, the selection for traits in specialized lines and then combining the traits of the lines by crossbreeding gives the full profit for heterosis.
