Apomixis, hybridization, and taxonomic complexity in eastern north AmericanAmelanchier (Rosaceae)

Springer Science and Business Media LLC - Tập 31 - Trang 345-354 - 1996
Christopher S. Campbell1, Wesley A. Wright1
1Department of Plant Biology and Pathology, University of Maine, Orono, U.S.A.

Tóm tắt

Apomixis and hybridization together contribute to taxonomic complexity inAmelanchier. Hybridization combines genetically divergent genomes and spawns new forms that apomixis perpetuates. Apomixis is aposporous, facultative, and pseudogamous in the genus, and apomicts are generally polyploid, pollen fertile, and pollinated by generalists. That gene flow actually occurs is empirically evident. As apomixis is genetically dominant over sexuality, hybrids involving at least one apomictic parent are apomictic. Clonal reproduction may thus perpetuate F1 individuals and generate agamospecies. Alternatively hybrids may interbreed and backcross to create hybrid swarms or cross with species other than the parents. In eastern North America, the abundance of published names and general taxonomic confusion in the genus doubtless result at least in part from this interplay of apomixis and hybridization. The roles of apomixis and hybridization in diversification withinAmelanchier are examined in light of new data about breeding system of an apomictic, hybrid microspecies, informally namedA. “erecta” and its formation of a hybrid swarm with anotherAmelanchier apomict,A. laevis.

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Springer Science and Business Media LLC

Tập 31

345-354

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