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Improving Biological Control of Brazilian Peppertree through Characterization of the Genetic Diversity in Florida

Improving Biological Control of Brazilian Peppertree through Characterization of the Genetic Diversity in Florida. W. A. Overholt, K. T. Gioeli, J. P. Cuda, C. R. Hughes and D. A. Williams. This . History of Brazilian Peppertree Introduction into Florida.

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Improving Biological Control of Brazilian Peppertree through Characterization of the Genetic Diversity in Florida

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  1. Improving Biological Control of Brazilian Peppertree through Characterization of the Genetic Diversity in Florida W. A. Overholt, K. T. Gioeli, J. P. Cuda, C. R. Hughes and D. A. Williams This

  2. History of Brazilian Peppertree Introduction into Florida • Date of first introduction uncertain, possibly as early as 1884, more likely around 1900 • Popularized as an ornamental by George Stone in Punta Gorda starting in 1926 • Recognized as a serious invasive beginning in the 1950s / 60s • Currently estimated to occupy ~ 1,000,000 acres in Florida • Distribution in north Florida appears to be limited by lack of cold tolerance

  3. Problems associated with Brazilian Peppertree in Florida • Displacement of native plant species • Poor wildlife habitat • Human/livestock health concerns

  4. Biological Control Classical Biological Control Native home Invaded area

  5. Rationale for examining BP genetic diversity • Classical biological control rests on the premise that exotic organisms often reach higher densities in invaded areas because their natural enemies are left behind in the native home. • The most promising candidate biological control agents are those which have co-evolved with the specific genotype(s) that have invaded the new area. • Thus, identifying the genetic diversity of BP in Florida, and comparing it to diversity in S. America, will help to better target foreign exploration for biological control agents.

  6. Genetic diversity of BP in South America (Barkley 1944) • Schinus terebinthifolius • S. terebinthifolius var. acutifolius (Brazil) • S. terebinthifolius var. pohlianus (Brazil, Paraguay, Argentina) • S. terebinthifolius var. raddianus (Brazil) • S. terebinthifolius var. rhoifolius (Brazil)

  7. Native Distributions of Schinus terebinthifolius taxa(NYBG 2003) -5o -32o f pohlianus acutifolius raddianus rhoifolius terebinthiolius

  8. Diversity in Florida ? • Schinus terebinthifolius • Schinus terebinthifolius var. raddianus Variation in Leaflet Morphology & Number

  9. Research Questions • Do two or more distinct varieties occur in Florida? • Is there evidence of hybridization between varieties in Florida? • Can we identify the probable native home of Florida’s genotypes? • Do new genotypes exist in Florida which do not occur in South America? • Are different genotypes adapted to various habitat types in Florida? • Are genotypes at the colonizing front different from those in areas where BP has been long established?

  10. Procedures • Collect Samples of BP Shoot Tips in South America and Florida • Perform Genetic Analyses on Samples • Use Results for Biotype Matching of Natural Enemies with BP Populations

  11. Sample collection • Statewide sampling coordinated by Bill Overholt & Ken Gioeli in Saint Lucie County • Assistance solicited from the network of Extension Agents • A minimum of 10 samples collected from each county where BP occurs in Florida • Efforts are made to distribute sample sites over representative habitat types • Terminal buds removed and placed in vials with 95% alcohol • Sites are geo-positioned and GIS Mapped • DNA (8 microsatellite loci) will be analyzed

  12. Survey in Brazil • 30 samples collected in Parana, Minas Gerais and Santa Catarina states in March 2003 • Collaborations being initiated to expand sampling to other areas (e.g., Argentina, Paraguay)

  13. Progress to date • Samples received from 25 counties • 398 individual trees Vouchered specimens Institute for Systematic Botany)

  14. Palmital (25-30) Curitiba (16-22) Balneario Camboriu (23-24) Irati (1-6) Riozinho (7-9) Survey in Brazil

  15. Preliminary analysis (125 samples):Distance between samples and relatedness

  16. Tentative conclusion • Preliminary analysis suggests that the Brazilian Peppertree population in Florida is the result of a single introduction • If this holds true after further analyses, it simplifies the search for well-adapted biological control agents

  17. Collaborators • University of Florida Department of Entomology and Nematology • University of Florida Cooperative Extension Service • University of Miami • Saint Lucie County • Florida Assn. Of Natural Resource Extension Professionals (FANREP)

  18. Brazilian Collaborators • Federal University of Parana • University of Blumeneau • University Centro Oesti, Irati • University of Vicosa

  19. Thank you!

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