eMonocot Cyperaceae

an authoritative resource for Cyperaceae data worldwide, integrating global and regional perspectives

Clonal structure and hybrid susceptibility to a smut pathogen in microscale hybrid zones of northern wetland Carex (Cyperaceae)

Publication Type:Journal Article
Year of Publication:2002
Authors:McIntire, E. J. B., Waterway M. J.
Journal:American Journal of Botany
Volume:89
Pagination:642-654
Keywords:allozyme variation, allozymes, anthracoidea limosa, carex limosa, carex rariflora, clonal growth, disease, environmental heterogeneity, evolution, genetic diversity, herbivory, hybridization, patterned fens, plant, population-dynamics, spatial autocorrelation, vegetation, water chemistry
Abstract:

Interspecific hybrid taxa, especially those with the potential for clonal spread, may play important roles in community dynanines and plant-pathogen interactions. This study combines the mapping of clonal structure for two rhizomatous sedges (Carex limosa, C. rariflora) and their nearly sterile interspecific hybrid with an investigation of the relationship between these taxa and a nonsystemic floral smut pathogen (Anthroacoidea limosa) in six subarctic fens in Nouveau-Quebec, Canada. We used allozyme polymorphisms in 14 of 18 putative loci to confirm hybrid identification and to distinguish among genotypes for mapping. The incidence of A. limosa was 5-20 times greater on hybrids than on parental taxa across all sites at two spatical scales (intensive = extent 10.5 m. extensive extent = entire fens). Spatial autocorrelation was detected in smut incidence; however, kits statistical removal did not alter the strong association between hybrids and smut infection. Smut incidence on both C. limosa and hybrids was greater when they were growing in areas of high hybrid density. Our study provides evidence that disease can help maintain boundaries between species. We suggest explanations for hybrid susceptibility and provide evidence for a model in which hybrids act as a source for reinfection for all three taxa during subsequent years.

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