Monday, November 5, 2007
59-3
Increasing Genetic Gain in Maize with Doubled Haploids and Marker-Assisted Recurrent Selection.
Patricio Mayor and Rex Bernardo. Agronomy and Plant Genetics, University of Minnesota, 411 Bourlaug Hall, 1991 Upper Buford Cir, St. Paul, MN 55108
Marker-assisted recurrent selection (MARS) increases the gain per unit time in maize (Zea mays L.). The use of doubled haploids (DH) instead of F2 plants may permit a better estimation of effects associated with markers. Our objectives were to determine if the genetic gain from MARS in maize is greater in DH populations than in F2 populations. We simulated a DH population and an F2 population from the same cross between two inbreds and studied genetic models defined by the population size (N = 100, 250, 450), number of loci (20, 60, 100) controlling the trait, and trait heritability (0.20, 0.50, 0.80). The number of selected individuals was constant (Nsel =6). In Cycle 1 of MARS, the response to selection was always greater with a DH population than with an F2 population. No gain from selection was expected with DH in Cycle 2. By the end of MARS (Cycle 3), the response to selection when heritability was low was 11 to 41% greater with a DH population than with an F2 population. The advantage of using a DH population in MARS decreased as heritability and population size increased. Further analyses and field validation of these results is being conducted.