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Experimental Evidence For Selection Against Hybrids Between Two Interfertile Red Oak Species, Oliver Gailing, Ruhua Zhang

College of Forest Resources and Environmental Science Publications

Reproductive isolation between related oak species within one taxonomic section is incomplete. Even though pre- and post-zygotic isolation mechanisms have been described for interfertile oak species, natural hybridization is common in contact zones between related oaks. The apparent restriction of inter-specific hybrids between ecologically divergent species to intermediate environments in contact zones suggests postzygotic isolation via environmental selection against hybrids in parental environments. Overrepresentation of hybrids in seeds as compared to adult trees provides additional indirect evidence for selection against hybrids. Here, we used genetic assignment analyses in progeny obtained from a sympatric stand of Quercus rubra and Quercus ellipsoidalis, …