PARENT SESSION
Wednesday, August 9, 8:00-11:30 am
COS 54 - Disease ecology III: host-pathogen interactions and disease dynamics
L-5, L-6, L-7, Lobby Level, Cook Convention Center
Presiders: S Hall

Plant traits and pathogen infection from marginal and more central populations of the woodland sedge Carex blanda.

Alexander, Helen^*,1, ¹ University of Kansas, Lawrence, KS

ABSTRACT- Plant populations at the margin of their range have been postulated to consist of smaller individuals growing at lower density. Additionally marginal populations may have fewer pathogens or herbivores if marginal populations are small and isolated or if environmental conditions are less conducive to infection or infestation. Surveys conducted in 2004 and 2005 revealed that marginal populations (central KS) of the woodland sedge, Carex blanda, were unexpectedly larger than populations found in eastern KS in more continuous woodlands; these marginal populations were also more likely to lack infection/infestation by a rust and smut pathogen and a floral mite. I explored between and within site differences in plant size and biotic interactions by establishing a field experiment in 2005 in eastern KS with clonal replicates of plants from four sites, two from eastern KS and two from central KS. Although there were differences in plant size among sites, they did not correspond in ranking to the differences observed in the surveys. There were no site differences in rust infection, but there were large differences among genotypes within sites, suggesting genetically controlled disease resistance. Combining ecological surveys with field experimentation can lead to better understanding of the geographic basis to variation in biotic interactions.

Key words: host-pathogen interactions, ecological genetics, plant ecology