Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Association Breeding Strategies For Improvement Of Self-Pollinated Crops

Mark E. Sorrells¹ , Elliot L. Heffner¹ , Jean-Luc Jannink²

¹  Cornell University, Department of Plant Breeding and Genetics, Ithaca, NY 14853, USA

²  USDA-ARS, R.W. Holley Center for Agriculture and Health, Cornell University, Ithaca, NY, USA

Association breeding strategies utilize phenotypic and genotypic information to increase gain from selection and reduce selection cycle time. Three approaches will be elaborated that utilize molecular marker information for crop improvement: 1) association breeding: crossing/ selection/ testing program, 2) marker-assisted recurrent selection (MARS), and 3) genomic selection (GS). Plant breeders frequently introduce new germplasm into their breeding programs and discard undesirable materials. Consequently, marker / phenotype relationships must be evaluated frequently. Association breeding and MARS are are based on the selection of significant marker-trait associations. Genotypic data can be combined with phenotypic data from routine screening and variety trial evaluations to identify significant markers and facilitate selection for low heritability traits. Novel alleles can be identified and the relative allelic value can be assessed as often as necessary. In contrast, genomic selection incorporates all marker information in a breeding value prediction model, thereby avoiding biased marker effect estimates and capturing more of the variation due to small effect QTL. Genomic selection predicts the breeding values of lines in a population by analyzing their phenotypes and high-density marker scores. Because GS incorporates all marker information in the prediction model, it minimizes biased marker effect estimates and captures more of the variation due to small effect QTL. Increasingly efficient breeding methods will continue to be developed for identifying and evaluating allelic effects on a large scale so that breeders can assemble desirable alleles in superior varieties.