Fig. 1 Optimal number of replications for different investments, (I₀, abscissa) and different individual heritabilities, (h²_i, ordinate), for phenotypic selection (graph a) and marker-assisted selection with R_C value equal to 1 (graph b), 4 (graph c), and 8 (graph d). We assumed that 10 individuals are selected and that the determinism of the trait implies an equivalent number of 5 QTLs