Fig. 1. Five breeding schemes (Breeding Plan 2 to 6) for marker-assisted introgression of two genes and a reference scheme (Breeding Plan 1) for introgression of two genes without background selection. DA and DB are the donor lines of the target genes, R is the recipient line. The symbols denote: | no selection, 
selection only for presence of the target gene(s), 
selection for presence of the target gene(s) and marker-assisted background selection, x crossing, and 
selfing, 
, 
, and 
indicate generations with crossing, backcrossing, and selfing, respectively.
