Plant Breeding with Genomic Selection: Gain per Unit Time and Cost

ABSTRACTAdvancements in Lorenz, USDA-ARS, R.W. Holley Center for Agriculture and Health, genotyping are rapidly decreasing Cornell Univ., Ithaca, NY 14853. Received 9 Nov. 2009. *Corremarker costs and increasing genome coverage. This is facilitating the use of marker-assisted selection (MAS) in plant breeding. Commonly employed MAS strategies, however, are not well suited for agronomically important complex traits, requiring extra time for !eld-based phenotyping to identify agro-nomically superior lines. Genomic selection (GS) is an emerging alternative to MAS that uses all marker information to calculate genomic esti-mated breeding values (GEBVs) for complex traits. Selections are made directly on GEBV without further phenotyping. We developed an analytical framework to (i) compare gains from MAS and GS for complex traits and (ii) provide a plant breeding context for interpreting results from studies on GEBV accuracy. We designed MAS and GS breeding strategies with equal budgets for a high-investment maize (Zea mays L.) program and a low-investment winter wheat (Triticum aestivum L.) program. Results indicate that GS can outperform MAS on a per-year basis even at low GEBV accuracies. Using a previ-ously reported GEBV accuracy of 0.53 for net merit in dairy cattle, expected annual gain from GS exceeded that of MAS by about threefold for maize and twofold for winter wheat. We con-clude that if moderate selection accuracies can be achieved, GS could dramatically accelerate genetic gain through its shorter breeding"cycle.E.L. He-ner and M.E. Sorrells, Cornell Univ., Dep. of Plant Breeding and Genetics, Emerson Hall, Ithaca, NY 14853; J.-L. Jannink and A.J. -sponding author (mes12@cornell.edu).