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ARS Home » Southeast Area » Griffin, Georgia » Plant Genetic Resources Conservation Unit » Research » Publications at this Location » Publication #335503
Title: Ploidy level and genetic diversity in the Genus Paspalum, group disticha

Author
item EUDY, DOUGLAS - University Of Georgia
item BAHRI, BOCHRA - University Of Georgia
item Harrison, Melanie
item RAYMER, PAUL - University Of Georgia
item DEVOS, KATRIEN - University Of Georgia

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2017
Publication Date: 10/3/2017
Citation: Eudy, D., Bahri, B.A., Harrison, M.L., Raymer, P., Devos, K.M. 2017. Ploidy level and genetic diversity in the Genus Paspalum, group disticha. Crop Science. 57:3319-3332. https://doi.org/10.2135/cropsci2017.04.0241.
DOI: https://doi.org/10.2135/cropsci2017.04.0241

Interpretive Summary: Seashore paspalum (Paspalum vaginatum Sw.) is a grass species of increasing importance worldwide due to its salt tolerance and its ability to serve as forage, as ground cover for erosion control, and as turf for sports surfaces in vulnerable areas in the tropics and sub-tropics. Though it is a member of one of the largest grass genera, and has achieved a pan-tropical distribution along coastlines and in marshes, the details of its relationship to knotgrass (Paspalum distichum L.), ploidy level, genetic diversity, population structure, and distribution history have not been adequately resolved. We conducted DNA content measurements using flow cytometry and diversity analyses using simple sequence repeat (SSR) markers in a set of 90 Paspalum group Disticha populations. Using glume pubescence as a distinguishing characteristic, both diploids and polyploids were identified for both P. vaginatum and P. distichum. The haploid DNA content of P. vaginatum was established at ~600 Mb, similar to the monoploid DNA content previously estimated for P. distichum and P. notatum. Transferability of genomic P. vaginatum SSRs to P. distichum confirmed the close genetic relationship between the two species. Similarity in SSR allele sizes between the two species may be an indication of gene flow. Population structure analyses of the diploid Paspalum group Disticha accessions grouped the germplasm into four subpopulations. One subpopulation was comprised of four accessions that had a broad leaf texture but had mixed phenotypes for glume pubescence, while the other three subpopulations contained only members resembling P. vaginatum accessions. Our data bring into question whether P. distichum and P. vaginatum should be considered the same species.

Technical Abstract: Paspalum vaginatum Sw. is a grass species of increasing importance worldwide due to its salt tolerance and its ability to serve as forage, as ground cover for erosion control, and as turf for sports surfaces in vulnerable areas in the tropics and sub-tropics. Though it is a member of one of the largest grass genera, and has achieved a pan-tropical distribution along coastlines and in marshes, the details of its relationship to P. distichum L., ploidy level, genetic diversity, population structure, and distribution history have not been adequately resolved. We conducted DNA content measurements using flow cytometry and diversity analyses using SSR markers in a set of 90 Paspalum group Disticha accessions. Using glume pubescence as a distinguishing characteristic, both diploids and polyploids were identified for both P. vaginatum and P. distichum. The haploid DNA content of P. vaginatum was established at ~600 Mb, similar to the monoploid DNA content previously estimated for P. distichum and P. notatum. Transferability of genomic P. vaginatum SSRs to P. distichum confirmed the close genetic relationship between the two species. Similarity in SSR allele sizes between the two species may be an indication of gene flow. Population structure analyses of the diploid Paspalum group Disticha accessions grouped the germplasm into four subpopulations. One subpopulation was comprised of four accessions that had a broad leaf texture but had mixed phenotypes for glume pubescence, while the other three subpopulations contained only members resembling P. vaginatum accessions. Our data bring into question whether P. distichum and P. vaginatum should be considered the same species.