ARS | Publication request: GENETIC RELATIONSHIPS AND POPULATION STRUCTURE OF THE ENDANGERED STEAMBOAT BUCKWHEAT, ERIOGONUM OVALIFOLIUM VAR. WILLIAMSIAE (POLYGONACEAE)

Submitted to: American Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2000
Publication Date: N/A

Interpretive Summary: Steamboat buckwheat (Eriogonum ovalifolium var.williamsiae) is a small shrub that is found only at a single location in Washoe County, Nevada. Part of the population occurs on land that is currently being developed for geothermal power. Before endorsing further development that might negatively impact or destroy parts of this apparently unique population, it t is important to obtain information on the genetic constitution of this population, and to determine whether it is sufficiently similar to other populations of this species so as to justify withdrawing its rare status. In addition, we seek to learn whether certain parts of the lone population are more genetically unique than others. For example, do some sites within the Steamboat Hills location harbor genetic information that is not present in other parts of the population, or are all the sites within Steamboat Hills representative of the genetic diversity of this plant? Our results suggest that though Steamboat buckwheat is morphologically distinct from other populations of this species, genetically it is very similar to those other populations, so similar, in fact, as to suggest that its rare status should be considered for withdrawal. We also discovered that the Steamboat Hills population, while genetically quite variable for a rare taxa, is not subdivided into subpopulations of genetic distinctness. Thus, also variable the population is quite uniform through the Steamboat Hills.

Technical Abstract: Eriogonum ovalifolium var. williamsiae (steamboat buckwheat) is a narrow endemic subshrub, known from a single locality in Washoe County, Nevada. We examined genetic structure of the only known population by analyzing patterns of allozyme variation. Our results suggest that Steamboat Buckwheat has high genetic variability, with levels of variation similar to that typical of a widespread species rather than a narrow endemic. Genotype frequencies suggest that mating is random. We detected no genetic subdivision of the population. Several clones spanning up to 67 cm were found, but we do not know if such clones are common. We also used allozymes to assess the genetic similarity of var. williamsiae to five other varieties of E. ovalifolium. All six varieties are very closely related; var. williamsiae is most similar genetically to the widespread var. ovalifolium. Although var. williamsiae and var. ovalifolium are morphologically distinct, their genetic similarity warrants further study to determine if they should be treated as separate taxa. Information gathered from this study, in concert with ongoing work on the breeding system of steamboat buckwheat, should be helpful in forming successful management strategies for this plant.