Abstract
Recurrent backcrossing is used to transfer the genes underlying agronomically important traits from a donor into the genetic background of a recipient genotype, usually an inbred line (Allard 1960). In a backcross program, molecular markers can be used for indirect selection for the presence of a favorable allele (Tanksey 1983) and for selection against the undesired genetic background of the donor genotype (Tanksley et al. 1989). Selection against the genetic background of the donor (‘background selection’) allows us to reduce the number of backcross generations required for gene introgression from six to three (Frisch et al. 1999a). Due to this time saving and the possibility to monitor the donor genome content of the converted line, background selection has become a standard tool in plant breeding, as demonstrated by the example of the introgression of a gene coding for the Bacillus thuringiensis toxin into a maize inbred line (Ragot et al. 1995). However, the cost of a breeding program applying background selection is determined by an optimum allocation of resources, because the price of marker analyses is still high. In this chapter, principles for the optimum design of backcross programs for introgression of qualitatively inherited traits with markerassisted background selection are described. Considered topics are (1) introgression of a dominant gene, (2) introgression of a recessive gene, and (3) simultaneous introgression of two genes.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call