DOT Project Number:  90-00-LRTF-820

Fiscal Year:  1998

Award:  $15,120.00

Principal Investigator:  Dr. Daryl Smith, Department of Biology, University of Northern Iowa, daryl.smith@uni.edu; Greg Houseal, Native Roadside Vegetation Center, University of Northern Iowa

Summary Report:

REGIONAL VARIATIONS IN NATIVE TALLGRASS PRAIRIE SPECIES

The Iowa Ecotype Project collects, propagates, and commercially releases Iowa-origin seed of tallgrass prairie species for the purpose of reconstructing prairie plantings on roadsides and other areas. Three garden plots corresponding to three project zones have been established on the University of Northern Iowa campus consisting of several hundred accessions of over 25 plant species. Floral development, height, and other characteristics were recorded for accessions of Oxeye false sunflower (Heliopsis helianthoides), Horsemint (Monarda fistulosa), Rough blazingstar (Liatris aspera) and Prairie blazingstar (Liatris pycnostachya). In addition, 60 accessions of big bluestem (Andropogon gerardii) were analyzed with isoelectric focusing of esterase and phosphohexose isomerase.

Though not true common gardens, and thus not amenable to statistical scrutiny, observations of accessions in the Iowa Ecotype Plots on the UNI campus provide evidence suggestive of both local and regional variation in prairie plant populations. Local variation in growth form is indicated by accessions of short-statured plants, possibly an adaptation to a dry or drought-prone soil type. Quantitative observations indicate a lag of 10 days to two weeks in floral development from north to south in some species. Regional or latitudinal variation is evident in the delayed flowering from northern- to southern-origin accessions of prairie blazingstar and big bluestem and oxeye sunflower. Pale purple coneflower exhibited no obvious differences in flowering across zones. A greater percentage of the flowering scape of rough blazingstar was still in bloom in southern Iowa plants vs central or northern Iowa plants, though there was a great amount of variation within each zone. This garden had experienced high mortality/predation after out-planting, and recruitment of new individuals from seed may be confounding the interpretation.

Isoelectric focusing of seed proteins is limited in it’s ability to detect genetic variation, and it is difficult to draw conclusions about the relatedness of the populations analyzed, however, isoelectric focusing of esterase and phosphohexose-isomerase in seed proteins of accessions of big bluestem provides indirect evidence of genetic variation in sub-populations of this species in Iowa.