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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT & EVALUATION OF BIOLOGICAL CONTROL AGENTS FOR INVASIVE SPECIES THREATENING THE EVERGLADES & OTHER NATURAL AND MANANGED SYSTEMS

Location: Invasive Plant Research Laboratory

Title: Hybrid vigor for the invasive exotic Brazilian peppertree (Schinus terebinthifolius Raddi., Anacardiaceae) in Florida

Authors
item Geiger, John
item Pratt, Paul
item Wheeler, Gregory
item Williams, Dean -

Submitted to: International Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2011
Publication Date: June 15, 2011
Citation: Geiger, J.H., Pratt, P.D., Wheeler, G.S. 2011. Hybrid vigor for the invasive exotic Brazilian peppertree (Schinus terebinthifolius Raddi., Anacardiaceae) in Florida. International Journal of Plant Science. 172(5):655-663.

Interpretive Summary: How can successful invaders overcome reduced genetic variation via small founder population sizes to persist, thrive, and successfully adapt to a new set of environmental conditions? An expanding body of literature posits hybridization, both inter- and intraspecific, as a driver of the evolution of invasiveness via genetic processes. We studied Brazilian peppertree (Schinus terebinthifolius), a tree species native to South America that is a successful invader throughout Florida. The tree was introduced separately to the east and west coasts of Florida over 100 years ago from genetically distinct source populations. We conducted a common garden experiment to compare the early life stage performance of hybrids versus their progenitors. We hypothesized that hybrids would outperform their progenitors due to the positive genetic effects of intraspecific hybridization (i.e. hybrid vigor). Hybrid seeds germinated at higher rates than eastern haplotype seeds. Over the eight month experiment, a greater proportion of hybrid seedlings survived than western haplotype seedlings and hybrids attained greater biomass than the western types. The cumulative hybrid advantage of both seed germination and seedling survival lead to the establishment of nearly 45% more hybrid seedlings versus either progenitor. Documenting fitness advantages for hybrids over their progenitors is a requisite finding to consider hybridization as a factor in the success of invasive species.

Technical Abstract: How can successful invaders overcome reduced genetic variation via small founder population sizes to persist, thrive, and successfully adapt to a new set of environmental conditions? An expanding body of literature posits hybridization, both inter- and intraspecific, as a driver of the evolution of invasiveness via genetic processes. We studied Brazilian peppertree (Schinus terebinthifolius), a tree species native to South America that is a successful invader throughout Florida. The tree was introduced separately to the east and west coasts of Florida over 100 years ago from genetically distinct source populations. We conducted a common garden experiment to compare the early life stage performance of hybrids versus their progenitors. We hypothesized that hybrids would outperform their progenitors due to the positive genetic effects of intraspecific hybridization (i.e. hybrid vigor). Hybrid seeds germinated at higher rates than eastern haplotype seeds. Over the eight month experiment, a greater proportion of hybrid seedlings survived than western haplotype seedlings and hybrids attained greater biomass than the western types. The cumulative hybrid advantage of both seed germination and seedling survival lead to the establishment of nearly 45% more hybrid seedlings versus either progenitor. Documenting fitness advantages for hybrids over their progenitors is a requisite finding to consider hybridization as a factor in the success of invasive species.

Last Modified: 7/23/2014
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