Recent Topics Posters
Dobson, Mary C. , Martin, Noland H. .
Patterns of Fungal Infection and Herbivore Attack in Louisiana Iris
Identifying patterns of resistance to fungal infection and herbivore attack is pertinent to understanding the role that hybridization plays in the formation of species. While the hybridization of plants is common in nature, there are conflicting hypotheses to explain whether this phenomenon is beneficial or maladaptive in maintaining the genetic integrity of the parental species. Two of these hypotheses are the Hybrid Vigor Hypothesis and the Hybrid Susceptibility Hypothesis. The Hybrid Vigor Hypothesis suggests that introgression of parental genomes may produce more resistant hybrids, which may eventually lead to novel species. The Hybrid Susceptibility Hypothesis, on the other hand, suggests that an increase in susceptibility among hybrids maintains parental lineages. These alternative hypotheses were tested in two species of Louisiana iris, Iris fulva and I. brevicaulis, F1 and reciprocal backcross hybrids. In experimental populations planted out into nature in 2008, data were collected regarding the presence or absence of both fungal infection and herbivore attack. Data were then analyzed to determine the patterns of infection/attack with respect to crosstype. Significant results were found to support the Hybrid Susceptibility Hypothesis in the case of fungal infection, and hybrid intermediacy was found with respect to herbivore attack. In 2009, photosynthesis data were recorded as an asexual fitness component, which also showed significant differences among crosstypes. These data, however, support the Hybrid Vigor Hypothesis. The conflicting results highlight the complexity of ecological factors that allow the formation or prevention of natural hybrid zones.
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1 - Texas State University-San Marcos, Biology, 401 N. Fredericksburg #501, San Marcos, TX, 78666, USA
2 - Texas State University-San Marcos, Biology, 601 University Drive, San Marcos, TX, 78666, USA
Presentation Type: Recent Topics Poster
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM