Plant & Animal Genomes XV Conference

January 13-17, 2007
Town & Country Convention Center
San Diego, CA

Population Genetic Sub-Structure Within The USDA Pisum Core Collection And Its Potential As A Platform For Association Mapping.

Allan F. Brown¹ , Gail Timmerman-Vaughan² , Clarice J. Coyne¹

¹  USDA-ARS Western Regional Plant Introduction, Washington State University, 59 Johnson Hall, Pullman Wa, USA 99164

²  New Zealand Institute for Crop and Food Research Canterbury Agriculture & Science Centre Gerald St Lincoln, NZ 7608

Population genetic sub-structure (PGS) and genetic diversity within the USDA Pisum core collection (305 accessions) is described using multiple techniques (Bayesian structure analysis, principle component analysis, and hierarchical cluster analysis). Analysis was conducted using fifteen microsatellite primer pairs, thirty-seven RAPD loci and forty-four agronomic or morphological traits. The analysis of the PGS using the microsatellite data identified three sub-populations within the Pisum core collection. The first and second sub-populations constituted 48% and 35% of the Pisum core, respectively. The third sub-population, approximately 17% of the collection consisted of the wild P. s. ssp. elatius and P. s. ssp. abyssinicum and the Asian highland accessions. In Pisum, these three sub-populations appear to follow the pattern of spring seeded garden (SSG), winter seeded field (WSF), and wild/unadapted (WUA) germplasm in a manner analogous to what has been observed in maize where the population structure (Iowa stiff stalk, non-stiff stalk and tropical) has been influenced by selection on adaptive traits. The principle component analysis using both the microsatellite and RAPD data demonstrated the genetic distance of the two wild ssp. and the Asian highland accessions from the bulk of the core and from each other. The hierarchical cluster analysis using a combined dataset identified four clusters that correspond with the Asian highland accessions, the bulk of the core collection and the sub-species P. s. ssp. elatius and P. s. ssp. abyssinicum. Within the bulk of the core finer distinctions could be visualized that corresponded to sub-populations 1 and 2.