Selection when traits have different genetic and phenotypic variances in different environments

Area of Science:

• Quantitative genetics
• Animal breeding

Background:

• Falconer's concept posits that performance in different environments represents distinct traits.
• Understanding genotype-environment interactions is crucial for effective animal breeding programs.

Purpose of the Study:

• To provide a framework for calculating expected genetic responses in one environment based on selection in another.
• To develop methods for optimizing selection strategies when animals are evaluated and selected across multiple environments.

Main Methods:

• Utilizing Falconer's concept to model direct and correlated responses to selection.
• Calculating expected responses based on heritability, phenotypic variance, genetic covariance, and selection intensity.
• Developing a weighted average approach to determine optimal selection fractions (p1, p2) when selecting from multiple environments.

Main Results:

• Formulas are presented for calculating expected responses in environment 2 from selection in environment 1, and vice versa.
• The study demonstrates that selection fractions (p1, p2) influence the direct and correlated responses.
• A method for optimizing selection fractions by calculating weighted average responses is proposed.

Conclusions:

• Falconer's concept provides a robust method for predicting cross-environment genetic gains in animal breeding.
• Optimizing selection strategies requires careful consideration of selection fractions across environments to maximize overall genetic response.
• The proposed approach allows for the calculation of optimal selection strategies in multi-environment breeding programs.