title: Hybrid incompatibility is acquired faster in annual than in perennial species of sunflower and tarweed.
abstract: Hybrid sterility is an important species barrier, especially in plants where hybrids can often form between divergent taxa. Here we explore how life history affects the acquisition of hybrid sterility in two groups in the sunflower family. We analyzed genetic distance and F1 pollen sterility for interspecific crosses in annual and perennial groups. We find that reproductive isolation is acquired in a steady manner and that annual species acquire hybrid sterility barriers faster than perennial species. Potential causes of the observed sterility pattern are discussed.
authors.affiliation: Department of Botany, University of British Columbia, 3529-6270 University Blvd, Vancouver, British Columbia, Canada, V6T 1Z4. gregory.owens@alumni.ubc.ca.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Owens
authors.forename: Loren H
authors.initials: LH
authors.lastname: Rieseberg
mesh_terms: D002678:Chimera / Q000235:genetics*; D019143:Evolution, Molecular; D006368:Helianthus / Q000235:genetics* / Q000254:growth & development; D060047:Reproductive Isolation; D060436:Self-Incompatibility in Flowering Plants / Q000235:genetics*; D013045:Species Specificity
keywords: Evolutionary rate; karyotypic changes; life history; plants; speciation