Plant & Animal Genome VI Conference

P43

DETECTION OF GENETICALLY RELATED GROUPS IN MAIZE ELITE GERMPLASM USING MOLECULAR MARKER DATA

1. Department of Biological Sciences and Plant Molecular Biology Center, Northern Illinois University, DeKalb IL 60115
2. Cargill Hybrid Seeds, 2600 W. Galena Blvd, Aurora IL 60506

Commercial maize germplasm is divided into groups based on patterns of heterotic behavior. Members of partially inbred groups, such as heterotic groups, should be detectable by their genetic relatedness. We have examined 48 commercial maize genotypes from the US Corn Belt using 78 polymorphic RAPD bands and 116 microsatellite primers. Genetic distances between the genotypes were determined from the molecular marker data, and cluster analysis was used to find groups of related genotypes. Multidimensional scaling (MDS) was used to visualize relationships between the genotypes. The clusters found with molecular markers closely resemble the heterotic groups to which the 48 genotypes belonged. The stability of group assignments was assessed using bootstrap samples of the data. Similar groups were detected despite differences in marker type and genetic distance method used. Seed-line clustering, a variant on the UPGMA algorithm, was found to produce more stable groups and to identify peripheral and hard-to-classify genotypes more clearly than standard UPGMA trees.