Fig. 1.

Schematic example of the regression of four genotypes (coloured lines) across a common factor, ‘x’ in a FA model. The vertical black lines represent the variation in GEBVs for the common factor ‘x’ at the average of the positive and negative loadings (or average contrasts). In a, the average negative and positive loading are − 0.15 and 0.7 units, respectively, and in b, − 0.7 and 0.7 units respectively