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Postmating barriers to hybridization between an islandís native eucalypts and an introduced congener


Larcombe, MJ and Barbour, RC and Jones, RC and Vaillancourt, RE and Potts, BM, Postmating barriers to hybridization between an island's native eucalypts and an introduced congener, Tree Genetics and Genomes, 12, (2) Article 26. ISSN 1614-2942 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 Springer Verlag

DOI: doi:10.1007/s11295-016-0979-x


We evaluate postmating barriers to hybridization between an exotic eucalypt and a group of native congeners on the island of Tasmania. We aimed to better understand the basis of reproductive isolation between the species, glean insights into the evolution of isolating mechanisms, and inform genetic risk management. Compatibility between the exotic plantation species Eucalyptus nitens (pollen parent) and 18 native Tasmanian taxa was assayed using experimental crossing for 17 taxa (13,458 flowers pollinated to produce 1058 female ◊ male cross combinations), and previous data for one species. Compatibility was assessed in terms of F1 hybrid production, as well as F1 hybrid survival and growth after 5†years. This data was combined with measurements of style length, and genetic distance from E. nitens to each maternal species, in order to determine the importance of a sequence of prezygotic and postzygotic barriers. We found that the early-acting barrier of style length (prezygotic) had the strongest isolating effect, while later-acting (postzygotic) barriers, affecting early-age growth and survival, contributed little to reproductive isolation. Style length alone explained 46†% of the variation in hybridization rate. Conversely, there was no significant relationship between genetic distance and prezygotic or postzygotic compatibility in these closely related species. This pattern is consistent with selection driving the rapid evolution of prezygotic barriers, while drift-like-processes lead to the more gradual evolution of intrinsic barriers. Although other premating and postmating barriers clearly contribute, our results highlight the important role of early-acting postmating barriers in preventing gene flow from exotic E. nitens plantations.

Item Details

Item Type:Refereed Article
Keywords:reproductive isolation, speciation, hybridization, exotic gene flow, Eucalyptus nitens, Tasmania
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Forestry sciences
Research Field:Forestry management and environment
Objective Division:Plant Production and Plant Primary Products
Objective Group:Forestry
Objective Field:Native forests
UTAS Author:Larcombe, MJ (Mr Matthew Larcombe)
UTAS Author:Barbour, RC (Dr Robert Barbour)
UTAS Author:Jones, RC (Dr Rebecca Jones)
UTAS Author:Vaillancourt, RE (Professor Rene Vaillancourt)
UTAS Author:Potts, BM (Professor Brad Potts)
ID Code:108179
Year Published:2016
Web of Science® Times Cited:3
Deposited By:Plant Science
Deposited On:2016-04-11
Last Modified:2017-11-09

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