Genetic Architecture and Introgression in Louisiana Iris Hybrid Zones

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The studies described in this proposal integrate genetics and ecology to investigate natural gene exchange between the Louisiana Iris species, Iris fulva and I. brevicaulis. We will test for: i) the number and genomic location of genetic elements that affect growth, survivorship and reproduction in different microhabitats; ii) the relative contribution of floral and microhabitat characters on the fertility and fecundity of different genotypes in different environments; and iii) the effect of genetic elements for floral traits, male fertility and microhabitat associations on the natural transfer of genes between I. fulva and I. brevicaulis.Our proposed research also has implications for both agriculture and conservation biology. Crop improvement has historically been accomplished using the process we are studying - introgressive hybridization (i.e., the exchange of genes between hybridizing forms). This work will thus discern some of the genetic and ecological traits that affect crop improvement. Further, our studies will answer questions concerning the likelihood that genetically modified (GM) crops will accidentally exchange genes with their wild relatives. These studies also have at least two applications for determining how to manage rare species. First, environmental changes are resulting in the loss of rare species through natural hybridization with more common and prolific forms (e.g., wild canids by domestic dogs). Second, there is concern that GM species will hybridize with wild relatives, producing hybrid types capable of competitively replacing the wild species. Our studies will provide data to determine how best to prevent both of these occurrences.