MARKER-ASSISTED SELECTION IN AUTOGAMOUS RIL POPULATIONS - A SIMULATION STUDY

Molecular markers may enable plant breeders to select indirectly for g enes affecting quantitative traits by selecting for molecular markers closely linked to these genes (marker-assisted selection, MAS). We hav e assessed the effectiveness of MAS compared to phenotypic selection. Key variables in this assessment were: trait heritability, selection i ntensity, genetic architecture and uncertainty in QTL mapping. Simulat ion studies showed that the application of MAS in autogamous crops, wi th the objective of obtaining transgressive genotypes, can improve sel ection results when compared to conventional selection procedures. Mar ker-assisted selection appears particularly promising when dominant al leles at quantitative trait loci are present and linked in coupling ph ase. Uncertainty in estimated QTL map positions reduces the benefits o f marker-assisted selection, but this reduction remains limited in mos t cases.