Application of doubled haploids for target gene fixation in backcross programmes of maize

With 2 figures Abstract Application of molecular markers in backcross (BC) programmes is well established. A combination of foreground and background selection is used to tag donor alleles and to accelerate BC programmes. Similarly, doubled haploid (DH) lines are increasingly used in maize and various other crops to speed up breeding programmes. The DH technology cannot accelerate the BC procedure, but it is beneficial for the final step in BC programmes. For the fixation of target gene(s), smaller population sizes are required in case of DHs compared with progeny produced by self-pollination. The objectives of this study were to determine the usefulness of DH compared with BCnF2 populations in the final step of BC programmes in relation to (i) the number of target genes and (ii) the genetic distance of a pair of target genes, linked in repulsion phase. We found that the relative advantage of using DH compared with self-pollinated progeny increases rapidly with the number of independently segregating target genes in BC programmes, and in particular in case of close linkage (recombination fraction r < 0.05).