ALEXANDER, JASON A.*, AARON LISTON, AND STEVE POPOVICH. Department of Botany & Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, OR 97331-2902; P.O. Box 265, Shoshone, ID 83352-0265. - The conservation genetics of Astragalus oniciformis.
The genus Astragalus (Fabaceae) in North America is composed of nearly
400 species. Most Astragali in the western United States are annual
or perennial herbs and are noted as "pioneer" species that
grow in xeric habitats left vacant after the retreat of the last Ice
Age. Astragalus oniciformis Barneby is a xerophyte of the sagebrush
deserts of central Idaho. It is a narrow endemic of the upper Snake
River Plains where it inhabits stabilized, aeolian sand deposits over
Quaternary basalt flows. The demography of this species is well
known, however the genetic variation of this species has never been
documented. The objective of this study was to determine the levels
and distribution of genetic variation within and among populations of
Astragalus oniciformis. Several populations in the eastern portion of
its range are isolated from the western populations by an eight mile
long, inhospitable, basaltic lava flow. The eruption occurred 3600
years ago. The eastern populations will be analyzed to determine if
they have significantly differentiated from the western, more
contiguous populations. Inter-simple sequence repeats (ISSR) were
chose as the marker used to assess genetic variability. Eight
populations, chosen from throughout the distribution of the species,
were selected for their accessibility, density of individuals, and
large population size. Levels of genetic variation, genetic
similarity, and degree of population differentiation will be
investigated. Populations that exhibit high levels of genetic
variation and/or differentiation will be identified as a priority for
conservation.
Key words: Astragalus oniciformis, conservation genetics, ISSR, Snake River Plains