Extra: saving time and money
MAS scheme for early generation selection in a typical breeding program for disease resistance. A susceptible (S) parent is crossed with a resistant (R) parent and the F1 plant is self-pollinated to produce an F2 population.
In this example, a robust SNP marker (allele T) has been developed for a major effect QTL contributing to disease resistance. By using a marker to assist selection, plant breeders may significantly reduce the size of field trials by eliminating many unwanted genotypes (marker genotypes CC and CT) and retain only those plants possessing the desirable homozygous genotypes for this locus (highlighted cells in the F2).
Note that 75% of the plants may be discarded after one cycle of MAS. This is important because plant breeders typically use large populations (e.g. 200 to 800 F2 plants per crossing combination) and hundreds of crossing combination in a single year.