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Genetic diversity and differentiation in populations of invasive Eurasian (Myriophyllum spicatum) and hybrid (Myriophyllum spicatum × Myriophyllum sibiricum) watermilfoil

Published online by Cambridge University Press:  17 April 2020

Ryan A. Thum*
Assistant Professor, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, USA
Gregory M. Chorak
Ph.D Student, Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, USA
Raymond M. Newman
Professor, Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St Paul, MN, USA
Jasmine A. Eltawely
Graduate Student, Water Resources Science, University of Minnesota, St Paul, MN, USA
Jo Latimore
Senior Academic Specialist, Michigan State University, East Lansing, MI, USA
Erick Elgin
Water Resources Educator, Michigan State University Extension, East Lansing, MI, USA
Syndell Parks
Research Technician, Grand Valley State University Robert B. Annis Water Resources Institute, Muskegon, MI, USA
Author for correspondence: Ryan A. Thum, Department of Plant Sciences and Plant Pathology, Montana State University, 313 Plant BioSciences Building, Bozeman, MT59717. (Email:


Population genetic studies of within- and among-population genetic variability are still lacking for managed submerged aquatic plant species, and such studies could provide important information for managers. For example, the extent of within-population genetic variation may influence the potential for managed populations to locally adapt to environmental conditions and control tactics. Similarly, among-population variation may influence whether specific control tactics work equally effectively in different locations. In the case of invasive Eurasian watermilfoil (Myriophyllum spicatum L.), including interspecific hybrids with native northern watermilfoil (Myriophyllum sibiricum Kom.), managers recognize that there is genetic variation for growth and herbicide response. However, it is unclear how much overall genetic variation there is, and how it is structured within and among populations. Here, we studied patterns of within- and among-lake genetic variation in 41 lakes in Michigan and 62 lakes in Minnesota using microsatellite markers. We found that within-lake genetic diversity was generally low, and among-lake genetic diversity was relatively high. However, some lakes were genetically diverse, and some genotypes were shared across multiple lakes. For genetically diverse lakes, managers should explicitly recognize the potential for genotypes to differ in control response and should account for this in monitoring and efficacy evaluation and using pretreatment herbicide screens to predict efficacy. Similarly, managers should consider differences in genetic composition among lakes as a source of variation in the growth and herbicide response of lakes with similar control tactics. Finally, laboratory or field information on control efficacy from one lake may be applied to other lakes where genotypes are shared among lakes.

Research Article
© Weed Science Society of America, 2020

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Associate Editor: Marie Jasieniuk, University of California, Davis


Aiken, SG, Newroth, PR, Wile, I (1979) The biology of Canadian weeds 34. Myriophyllum spicatum L. Can J Plant Sci 59:20121510.4141/cjps79-028CrossRefGoogle Scholar
Barrett, SCH, Eckert, DG, Husband, B (1993) Evolutionary processes in aquatic plant populations. Aquat Bot 44:10514510.1016/0304-3770(93)90068-8CrossRefGoogle Scholar
Bednarz, RH, Wandell, P, Steen, P, Dimond, W, Latimore, J (2015) Cooperative Lakes Monitoring Program Manual. Lansing: Michigan Department of Environmental Quality Report Number MI/DEQ/WRD-15/004Google Scholar
Benoit, LK, Les, DH (2013) Rapid identification and molecular characterization of phytoene desaturase mutations in fluridone-resistant hydrilla (Hydrilla verticillata). Weed Sci 61:324010.1614/WS-D-12-00018.1CrossRefGoogle Scholar
Berger, ST, Netherland, MD, Macdonald, GE (2012) Evaluating fluridone sensitivity of multiple hybrid and Eurasian watermilfoil accessions under mesocosm conditions. J Aquat Plant Manag 50:135146Google Scholar
Berger, ST, Netherland, MD, MacDonald, GE (2015) Laboratory documentation of multiple-herbicide tolerance to fluridone, norflurazon, and topramazone in a hybrid watermilfoil (Myriophyllum spicatum × M. sibiricum) population. Weed Sci 63:23524110.1614/WS-D-14-00085.1CrossRefGoogle Scholar
Bultemeier, BW, Netherland, MD, Ferrell, JA, Haller, WT (2009) Differential herbicide response among three phenotypes of Cabomba caroliniana. Invasive Plant Sci Manag 2:352359CrossRefGoogle Scholar
Clark, LV, Jasieniuk, M (2011) Polysat: an R package for polyploid microsatellite analysis. Mol Ecol Resour 11:56256610.1111/j.1755-0998.2011.02985.xCrossRefGoogle Scholar
Grafé, SF, Boutin, C, Pick, FR (2015) A PCR-RFLP method to detect hybridization between the invasive Eurasian watermilfoil (Myriophyllum spicatum) and the native northern watermilfoil (Myriophyllum sibiricum), and its application in Ontario lakes. Botany 93:117121CrossRefGoogle Scholar
Hartleb, CF, Madsen, JD, Boylen, CW (1993) Environmental factors affecting seed germination in Myriophyllum spicatum L. Aquat Bot 45:152510.1016/0304-3770(93)90049-3CrossRefGoogle Scholar
Hutchinson, GE (1975) A Treatise on Limnology. Volume 3, Limnological Botany. New York: Wiley. 660 pGoogle Scholar
Kimura, M, Crow, J (1964) The number of alleles that can be maintained in a finite population. Genetics 49:725738Google Scholar
LaRue, EA, Zuellig, MP, Netherland, MD, Heilman, MA, Thum, RA (2013) Hybrid watermilfoil lineages are more invasive and less sensitive to a commonly used herbicide than their exotic parent (Eurasian watermilfoil). Evol Appl 6:46247110.1111/eva.12027CrossRefGoogle Scholar
Michel, AR, Arias, RS, Scheffler, BE, Duke, SO, Netherland, MD, Dayan, FE (2004) Somatic mutation-mediated evolution of herbicide resistance in the nonindigenous invasive plant hydrilla (Hydrilla verticillata). Mol Ecol 13:3229323710.1111/j.1365-294X.2004.02280.xCrossRefGoogle Scholar
Moody, ML, Palomino, PS, Weyl, PS, Coetzee, JA, Newman, RM, Liu, X, Xu, X, Harms, N, Thum, RA (2016) Unraveling the biogeographic history of the Eurasian watermilfoil invasion in North America. Am J Bot 103:70971810.3732/ajb.1500476CrossRefGoogle Scholar
Nei, M (1987) Molecular Evolutionary Genetics. New York: Columbia University Press. 512 p10.7312/nei-92038CrossRefGoogle Scholar
Netherland, MD, Willey, L (2017) Mesocosm evaluations of three herbicides on Eurasian watermilfoil (Myriophyllum spicatum) and hybrid watermilfoil (Myriophyllum spicatum x Myriophyllum sibiricum): developing a predictive assay. J Aquat Plant Manag 55: 3942Google Scholar
Parks, S, McNair, JN, Hausler, P, Tyning, P, Thum, RA (2016) Divergent responses of cryptic invasive watermilfoils to treatment with auxinic herbicides in a large Michigan Lake. Lake Reserv Manag 32:36637210.1080/10402381.2016.1212955CrossRefGoogle Scholar
Pashnick, J, Thum, RA (2020) Comparison of molecular markers to distinguish genotypes of Eurasian watermilfoil, northern watermilfoil, and their hybrids. J Aquat Plant Manag 58:6166Google Scholar
Patten, BC (1955) Germination of the seed of Myriophyllum spicatum L. J Torrey Bot Soc 82:5056CrossRefGoogle Scholar
Peakall, R, Smouse, PE (2006) GenAlEx: genetic analysis in Excel. Population genetic software for teaching and research. Mol Ecol Notes 6:28829510.1111/j.1471-8286.2005.01155.xCrossRefGoogle Scholar
Philbrick, CT, Les, DH (1996) Evolution of aquatic angiosperm reproductive systems: what is the balance between sexual and asexual reproduction in aquatic angiosperms? BioScience 46:813826CrossRefGoogle Scholar
Santamaría, L (2002) Why are most aquatic plants widely distributed? Dispersal, clonal growth and small-scale heterogeneity in a stressful environment. Acta Oecol 23:13715410.1016/S1146-609X(02)01146-3CrossRefGoogle Scholar
Sculthorpe, CD (1967) The Biology of Aquatic VascuIar Plants. New York: St Martin’s. 610 pGoogle Scholar
Taylor, LA, McNair, JN, Guastello, P, Pashnick, J, Thum, RA (2017) Heritable variation for vegetative growth rate in ten distinct genotypes of hybrid watermilfoil. J Aquat Plant Manag 55:5157Google Scholar
Thum, RA, McNair, JN (2018) Inter- and intraspecific hybridization affects vegetative growth and invasiveness in Eurasian watermilfoil. J Aquat Plant Manag 56:2430Google Scholar
Thum, RA, Wcisel, DJ, Zuellig, MP, Heilman, M, Hausler, P, Tyning, P, Huberty, L, Netherland, MD (2012) Field documentation of decreased herbicide response by a hybrid watermilfoil population. J Aquat Plant Manag 50:141146Google Scholar
Wu, Z-G, Yu, D, Xu, X-W (2013) Development of microsatellite markers in the hexaploid aquatic macrophyte, Myriophyllum spicatum (Haloragaceae). Appl Plant Sci 1(2):120023010.3732/apps.1200230CrossRefGoogle Scholar
Xiao, C, Wang, X, Xia, J, Liu, G (2010) The effect of temperature, water level, and burial depth on seed germination in Myriophyllum spicatum and Potamogeton malaianus. Aquat Bot 92:2832CrossRefGoogle Scholar
Zuellig, MP, Thum, RA (2012) Multiple introductions of invasive Eurasian watermilfoil and recurrent hybridization with native northern watermilfoil in North America. J Aquat Plant Manag 50:119Google Scholar