Summary
Published in Molecular Ecology 19: 132-145
As the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (Populus balsamifera, Populus deltoides) in Québec, Canada within which European exotic Populus nigra and its hybrids have been extensively planted since the 1800s. Single nucleotide polymorphisms (SNPs) that appeared fixed within each species were characterized by DNA-sequencing pools of pure individuals. Thirty-five of these diagnostic SNPs were employed in a high-throughput assay that genotyped 635 trees of different age classes, sampled from 15 sites with various degrees of anthropogenic disturbance. The degree of admixture within sampled trees was then assessed through Bayesian clustering of genotypes. Hybrids were present in seven of the populations, with 2.4% of all sampled trees showing spontaneous admixture. Sites with hybrids were significantly more disturbed than pure stands, while hybrids comprised both immature juveniles and trees of reproductive age. All three possible F1s were detected. Advanced-generation hybrids were consistently biased towards P. balsamifera regardless of whether hybridization had occurred with P. deltoides or P. nigra. Gene exchange between P. deltoides and P. nigra was not detected beyond the F1 generation; however, detection of a trihybrid demonstrates that even this apparent reproductive isolation does not necessarily result in an evolutionary dead end. Collectively, results demonstrate the natural fertility of hybrid poplars and suggest that introduced genes could potentially affect the genetic integrity of native trees, similar to that arising from introgression between natives.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forest Genetics, Forestry Research, Forests, Genetic improvement of trees
Departmental author(s):
Author(s)
THOMPSON, Stacey Lee, Manuel LAMOTHE, Patrick G. MEIRMANS, Pierre PÉRINET and Nathalie ISABEL
Year of publication :
2010
How to get the publication :
Keywords :
peuplier hybride, peuplier baumier, peuplier deltoïde, peuplier noir, Introgression, hybridization, amélioration génétique des arbres, populus balsamifera, populus deltoide, populus nigra, single nucleotide polymorphisms, balsam poplar, eastern cottonwood, black poplar, forest tree breeding
