Submitted to: Plant Genetic Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2004
Publication Date: 4/1/2005
Citation: Wang, M.L., Barkley, N.L., Yu, J., Dean, R., Newman, M.L. aka Harrison Dunn, M.L., Sorrells, M., Pederson, G.A. 2005. Transfer of simple sequence repeat (ssr) markers from major cereal crops to minor grass species for germplasm characterization and evaluation. Plant Genetic Resources. 3(1):45-57.
Interpretive Summary: To classify germplasm, you need DNA markers. There are plenty of DNA markers in major crops (such as wheat, corn, rice, sorghum) but there are few markers available for minor grass species (such as finger millet, Bermuda grass). If there are no markers for these minor species, you cannot evaluate these germplasm for minor species. However, you can borrow markers from major cereal crops and then use the borrowed markers for characterization and evaluation of these minor grass species. Actually, we borrowed and found about 60% of borrowed markers which can be transferred to minor grass species. Not all borrowed markers are useful. We found only 34% of borrowed markers can be used in minor grass species. Now we have enough borrowed markers for our plant germplasm research. These markers are now being used in characterization of our collected germplasm (such as Bermuda grass and finger millet). The information from characterization and evaluation will help us preserve these minor grass species germplasm and recommend them for breeders to use for improved agricultural production and environmental sustenance.
Technical Abstract: For germplasm characterization and evaluation, a unique set of 210 SSR markers were selected from major cereal crops (wheat, rice, maize, and sorghum) and evaluated for their transferability to minor grass species (finger millet, Eleusine coracana; seashore paspalum, Paspalum vaginatum; and Bermuda grass, Cynodon Dactylon). More than half (57%) of the SSR primers screened generated reproducible cross-species or cross-genus amplicons. The transfer rate of SSR markers was correlated with the phylogenetic relationship (or genetic relatedness) of these species. Polymorphism level was not related to transfer rate and there was no significant difference in the transfer rate between genomic SSR and EST-SSR markers. In total, 412 cross-species polymorphic amplicons were identified. The level of polymorphism was significantly higher among species (67%) than within species (34%) and was also related to the degree of out-crossing for each species. Within species, the level of polymorphism detected was 57% from self-incompatible species, 39% from out-crossing species and 20% from self-pollinated species. Genomic SSRs detected a higher level of polymorphism than EST-SSRs. Transferred polymorphic SSR markers are being used for characterization and evaluation of our turf grass germplasm collection.