The realised realized genetic trend is not always the same as the predicted genetic trend. In practice it generally is not higher than expected, but it can be lower. If it is lower than expected, as breeding organisation it is essential to find out why this is the case. We have already discussed the potential issues with difference between predicted and realised realized selection response. If these issues remain across generations, this will have an influence on the genetic trend. But there are a few additional reasons that we will discuss.
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