SMITH, JAMES F.* AND TERRY A. BATEMAN. Department of Biology, Boise State University, Boise, ID, 83725. - Genetic differentiation of rare and common varieties of Eriogonum shockleyi (Polygonaceae) in Idaho using ISSR variability.
Idaho populations of Eriogonum shockleyi are taxonomically
divided into two varieties. These are E. shockleyi var.
packardae, which is endemic to Idaho, and the typical variety
is widespread in the western United States. Recent morphological
investigations of E. shockleyi in Idaho have identified
potentially reliable morphological characters for field identification
of the subspecific taxa. This paper investigates the genetic basis
for the separation of the two varieties of E. shockleyi using
ISSR markers. Although there were some morphological differences
found between the populations that correlated with the two varieties,
there were no molecular markers identified in this study to
distinguish between them. Morphological measurements obtained in the
field indicate that although a population may have an overall average
morphology that defines the variety, some individuals in nearly all
populations have putative diagnostic characters that define the other
variety. The morphological characters used to distinguish the two
varieties are most likely the result of environmental variability and
could result from differences in precipitation and soil water
retention. Alternatively, high levels of outcrossing through pollen
flow could be obscuring selection for morphological characters at
particular sites.
Key words: Eriogonum shockleyi, ISSR, Polygonaceae, varieties