Submitted to: Crop and Pasture Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2011
Publication Date: December 16, 2011
Repository URL: http://handle.nal.usda.gov/10113/56821
Citation: Jakubowski, A., Casler, M.D., Johnson, R.C., Hu, J., Jackson, R. 2011. Genetic diversity and population structure of Eurasian populations of reed canarygrass: cytotypes, cultivars, and interspecific hybrids. Crop and Pasture Science. 62:982-991. Interpretive Summary: Reed canarygrass is an important pasture grass in the northern USA and has also been proposed for development as a perennial biofuel crop. The choice of breeding materials to be used for new variety development depends on their origin and genetic profile. We conducted a genetic analysis of reed canarygrass plants collected throughout Europe and Asia in an effort to describe and document the various genetic lineages through Europe and Asia. We found evidence for seven distinct lineages plus some evidence for hybridization or mixture of lineages in some locations. Our results indicate that humans have been responsible for moving this species throughout Eurasia and plant breeders have incorporated much of this variability into modern varieties of this species. Our results provide the basis for selecting plants of diverse origin for use by forage breeders in developing new varieties for both forage and bioenergy end uses.
Technical Abstract: The Phalaris arundinacea “species complex” is made up of three cytotypes ranging from 2x to 6x, with the 4x cytotype (P. arundinacea L.) most common. The species is an important forage crop and is a potential biofuel feedstock due to its wide environmental tolerance and ability to be successful on marginal lands. Active breeding programs have existed since the early 20th century, but little is known about the genetics of the species. We evaluated the population structure of 84 wild accessions collected throughout Eurasia and 24 cultivars, and the relationship between 4x and 6x cytotypes. Seven subpopulations are present in Europe with a high level of admixture between subpopulations. These results suggest that reed canarygrass germplasm has moved throughout Eurasia, either by natural dispersal or by humans moving germplasm for use in agriculture. Cultivars have incorporated much of this diversity, although modern low-alkaloid cultivars appear to come from a relatively small gene pool. We also find some evidence that the 6x cytotype is made up of three sub-genomes that is a combination of genomes present in 4x P. arundinacea and P. aquatica, although the 6x cytotype does not appear to be a direct hybrid between the species.