Efficiency of marker-assisted selection compared with conventional selection

Marker-assisted selection (MAS) has received extensive attention in the past ten years. Two main strategies of MAS have been proposed: the use of markers to control the introgression of gene or QTL (quantitative trait locus), and the use of markers to predict breeding values in a population under selection, Theoretical and experimental results published on the interest of these two strategies are presented, focusing on the preliminary results of a MAS experiment performed on a maize population. From these results it appears that markers can be very efficient to quickly fix favorable alleles at target genes. Nevertheless, potential interactions between QTL (or genes) and environmental conditions or genetic background can reduce the efficiency of MAS. Further work is needed to optimize the use of markers in selection.