Fitness dynamics within a poplar hybrid zone: I. Prezygotic and postzygotic barriers impacting a native poplar hybrid stand

摘要: Hybridization and introgression are pervasive evolutionary phenomena that provide insight into the selective forces maintain species boundaries, permit gene flow, control direction of change. Poplar trees (Populus L.) well known for their ability to form viable hybrids distinct boundaries despite this interspecific flow. We sought quantify hybridization dynamics postzygotic fitness within a hybrid stand balsam poplar balsamifera L.), eastern cottonwood (P. deltoides Marsh.), natural gain barriers maintaining stable zone. observed asymmetrical formation with P. acting as seed parent, but subsequent biased toward balsamifera. Native expressed traits intermediate parental were not universally unfit. That said, native seedlings absent from seedling population, which may indicate additional pressures controlling recruitment. It is imperative we understand zone in order impact exotic on system.