Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2010
Publication Date: 3/1/2011
Publication URL: http://hdl.handle.net/10113/48756
Citation: Kisha, T.J., Cramer, C.S. 2011. Determining redundancy of short-day onion accessions in a germplasm collection using microsatellite and targeted region amplified polymorphic markers. Journal of the American Society for Horticultural Science. 136(2):129-134. Interpretive Summary: This research demonstrates the utility of microsatellite and targeted region amplified polymorphism molecular markers for assisting germplasm curators in determining differences and redundancies among accessions of onion (Allium cepa L.). While the results established the validity of marker assisted determination of germplasm diversity, it also called attention to the need for field studies to collaborate the results, especially among closely related germplasm which may differ by one or a few genes.
Technical Abstract: The U.S. National Plant Germplasm System is one of the world’s largest national genebank networks focusing on preserving the genetic diversity of plants by acquiring, preserving, evaluat- ing, documenting and distributing crop-related germplasm to researchers worldwide. Maintaining viable germplasm collections is essential to world food security, but comes at a cost. Redundancy within the collection can incur needless expense and occurs as a result of donations of similar material under different names from different donors. Alternatively, similarly named accessions from different donors can actually be genetically distinct. We evaluated 38 short-day onion accessions using microsatellite and targeted region amplified polymorphic molecular markers to compare newly acquired germplasm with existing accessions in the collection to determine differences and redundancies and to compare the utility of each marker type in distinguishing the onion accessions. Both marker types distinguished differences and found similarities, but the results didn’t always agree. Discriminating among closely related accessions using molecular markers can require a large number of random marker loci, especially when differences may be limited to a single trait. TRAP markers were more efficient, uncovering about 10 random polymorphic loci per primer pair, while microsatellite markers each uncovered differences at a single locus.