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Exploring origins, invasion history and genetic diversity of Imperata cylindrica (L.) P. Beauv. (Cogongrass) in the United States using genotyping by sequencing
Author(s) -
Burrell A. Millie,
Pepper Alan E.,
Hodnett George,
Goolsby John A.,
Overholt William A.,
Racelis Alexis E.,
Diaz Rodrigo,
Klein Patricia E.
Publication year - 2015
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.13167
Subject(s) - biology , genetic diversity , imperata , evolutionary biology , lineage (genetic) , microsatellite , introgression , asexual reproduction , genetics , allele , ecology , population , gene , demography , sociology
I mperata cylindrica (Cogongrass, Speargrass) is a diploid C4 grass that is a noxious weed in 73 countries and constitutes a significant threat to global biodiversity and sustainable agriculture. We used a cost‐effective genotyping‐by‐sequencing ( GBS ) approach to identify the reproductive system, genetic diversity and geographic origins of invasions in the south‐eastern United States. In this work, we demonstrated the advantage of employing the closely related, fully sequenced crop species S orghum bicolor (L.) Moench as a proxy reference genome to identify a set of 2320 informative single nucleotide and insertion–deletion polymorphisms. Genetic analyses identified four clonal lineages of cogongrass and one clonal lineage of I mperata brasiliensis Trin. in the United States. Each lineage was highly homogeneous, and we found no evidence of hybridization among the different lineages, despite geographical overlap. We found evidence that at least three of these lineages showed clonal reproduction prior to introduction to the United States. These results indicate that cogongrass has limited evolutionary potential to adapt to novel environments and further suggest that upon arrival to its invaded range, this species did not require local adaptation through hybridization/introgression or selection of favourable alleles from a broad genetic base. Thus, cogongrass presents a clear case of broad invasive success, across a diversity of environments, in a clonal organism with limited genetic diversity.