Monday, November 5, 2007 - 11:15 AM
55-7

Patterns of Linkage Disequilibrium and Haplotype Diversity in Historical Elite Malting Barley Lines.

Carol A. Powers, University of Minnesota, Department of Agronomy and Plant Genetics, 411 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, MN 55108-6026, Federico Condón, Recursos Genéticos INIA La Estanzuela, CC39173 Rta 50 Km 11, Colonia, Uruguay, and Kevin Smith, University of Minnesota, 411 Borlaug Hall Univ. of MN, 1991 Upper Buford Circle, St. Paul, MN 55108.

Identification of quantitative trait loci (QTL) that are suitable for marker assisted selection is time and labor intensive. Association mapping can leverage pedigree, phenotypic and genotypic data generated by breeding programs to identify QTL. This approach relies on the innate linkage disequilibrium (LD) and informative haplotype diversity in a population of interest. To determine the feasibility of association mapping within a single barley breeding program, we investigated the pattern of LD in historical and elite contemporary germplasm from the University of Minnesota. Ninety six varieties /breeding lines were genotyped with 1,536 single nucleotide polymorphisms (SNPs); 67% of the SNPs had a minor allele frequency of >1%. While the average extent of LD in cultivated barley has been observed to be 2 – 5 cM, we observed variable patterns of LD across the genome.  Different patterns of LD between the founding parent population and more elite germplasm indicates that breeding has shaped LD.  In some cases, known genomic regions of high recombination or regions that were apparently under selection were associated with changes in LD.  Understanding the pattern of LD in this germplasm will provide a foundation for studying larger populations of contemporary breeding germplasm through the USDA Barley Coordinated Agricultural Project.