Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/21/2005
Publication Date: 1/1/2006
Citation: Wieners, R.R., Fei, S., Johnson, R.C. 2006. Characterization of a usda kentucky bluegrass (poa pratensis l.) core collection for reproductive mode and dna content by flow cytometry. Genetic Resources and Crop Evolution. doi:10.1007/s10722-005-7766-0. Interpretive Summary: Using cell flow cytometry, we have characterized a Kentucky bluegrass core collection for reproductive mode and DNA content in a short time and at minimal expense. The sensitivity of flow cytometry in analyzing bulk tissue samples with varied sample size showed that a 10 plant sample is the best population size to find aberrant plants in a bulk sample. The information provided in this paper is valuable for utilization of this core collection for breeding purposes and the techniques described could be used to characterize reproductive mode and DNA content in larger numbers of accessions of Poa pratensis collections.
Technical Abstract: Kentucky bluegrass (Poa pratensis L.) is an important turf and forage grass species with a facultative apomictic breeding behavior. In this study, mature seed and leaf tissue from 38 accessions of a USDA core collection of Kentucky bluegrass were analyzed with flow cytometry to characterize the reproductive mode and DNA content for each accession. Major reproductive pathways for each accession were determined based upon the presence and the position of the peaks observed and the known methods of reproduction for Kentucky bluegrass. While the majority of the accessions exhibited facultative apomictic reproductive behavior with a combination of reduced, zygotic and unreduced, parthenogenic embryo production, obligate sexual or obligate apomictic accessions were also found to be present in this core collection. In addition, reduced, parthenogenic and unreduced zygotic embryos were also detected in several accessions. Flow cytometry analysis of somatic tissue revealed a large range of DNA variation within this core collection. We also examined the sensitivity of flow cytometry in analyzing bulked samples containing a large number of plants with varied DNA content and determined that flow cytometry can effectively detect a plant having a different DNA content within a 15-plant bulk sample. Overall the combination of mature seed and somatic tissue analysis generated important information for the Kentucky bluegrass core collection and can be an effective and affordable tool to characterize even greater numbers of Kentucky bluegrass accessions.