Plant Genome III Conference

UPDATE ON NORTH AMERICAN BARLEY MAPPING PROJECT

The North American Barley Genome Mapping Project (NABGMP) has constructed molecular marker-based linkage maps in two doubled haploid populations and a third map is under construction. Most markers are RFLPS. The merging of the NABGMP and BAZ (Germany) maps is discussed in the poster by Liu et al. at this meeting. Cumulatively, these maps provide satisfactory genome coverage, with an average marker density of 3.0 cM. However, significant gaps remain in these maps. QTLs for a number of economically important traits have been mapped in these populations. The results are summarized in the poster by Hayes et al. at this meeting. Alternative marker strategies may assist in expanding the catalog of available markers and in saturating key regions of the genome. We have found abundant microsatellite, or simple sequence repeat (SSR) polymorphism in wild and cultivated barley. Up to 37 alleles have been detected per SSR locus. The high level of polymorphism and ease of assaying large numbers of individuals for SSR variation, especially through multiplex PCR and/or multiple loadings of single gels, make SSRs an attractive class of marker for germplasm characterization and marker- assisted selection in barley. Based on synteny relationships, the abundant markers mapped in rice may be readily transferred to barley maps. A number of markers have been transferred between the rice and barley maps. A rice/barley synteny map will make the ever-growing cereal molecular and genetic information available to the barley scientific community.