Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/10/2010
Publication Date: 6/10/2010
Citation: Bonman, J.M., Gu, Y.Q., Coleman Derr, D., Jackson, E.W., Bockelman, H.E. 2010. Inferring geographic origin of barley accessions using molecular markers. Genetic Resources and Crop Evolution. DOI: 10.1007/s10722-010-9574-4. Interpretive Summary: Barley accessions from the National Small Grains Collection (NSGC) are useful to plant breeders as sources of genetic resistance to important diseases. These accessions have been collected over the past 100 year and previously we found that many accessions obtained from a nursery grown in the Ukraine in 1930 by N.I. Vavilov were resistant to more than one disease of barley. We refer to these accessions as having ‘multiple resistance’ (MR). Vavilov collected barleys from many areas worldwide and we do not know where he collected the MR accessions grown in the 1930 nursery. Within NSGC these barley accessions are listed as having unknown origin. Because MR is valuable for breeding new barley varieties, we sought to identify the origin of the MR accessions using molecular markers. We discovered that the MR accessions from the Vavilov nursery were probably originally from Ethiopia. In the future we will use molecular markers to better understand the genetic relationships among barley accessions within the NSGC. Such information will be useful in helping plant breeders generate more diverse and productive barley varieties.
Technical Abstract: The USDA Agricultural Research Service (ARS) National Small Grains Collection (NSGC) has 207 landrace barleys obtained from a nursery grown in the Ukraine in 1930 by N.I. Vavilov, many of which have multiple resistance (MR) to disease similar to accessions from Ethiopia. Vavilov collected germplasm across a wide geographic area and the original collection locations of the accessions from his nursery are unknown. The purpose of this study was to determine, using molecular markers, if the MR accessions of unknown origin from the Vavilov nursery are genetically related to MR accessions from Ethiopia. The genetic relatedness among susceptible accessions of unknown origin and among a selection of landrace accessions from the NSGC barley core subset was also assessed. Simple sequence repeat (SSR) and Diversity Array Technology PL (DArT) marker data were used to generate similarity matrices with Dice’s similarity coefficients. Cluster analysis from these results showed that the unknown-origin MR accessions grouped with accessions from Ethiopia. Susceptible accessions of unknown origin were genetically similar to accessions from western Asia, especially near the Caucasus, and from both southern and northern Europe. Based on similarity of marker profiles, some accessions from the core collection are likely duplicates. Future work will seek to identify the probable origin of the remainder of the unknown-origin accessions and to more thoroughly characterize the genetic diversity within NSGC barley core subset.