PARENT SESSION
Poster Session 36: Genetics / Population Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Hierarchical patterns of paternity within crowns of Albizia julibrissin (Fabaceae).
Pardini, Eleanor*,1, Hamrick, James1, 1 University of Georgia, Athens, GA
ABSTRACT- Patterns of paternity were assessed within six tree crowns of Albizia julibrissin (Mimosa; Fabaceae) in Athens, GA. Within tree crowns, flowers are clustered in dense inflorescences, which are grouped at the ends of branches. Flowers within a single inflorescence flower synchronously and last about one day while inflorescences within the same cluster flower variably over several weeks. The floral architecture and phenology within tree crowns offer the potential for flowers within inflorescences to have a higher than random chance of being pollinated by the same pollen donors. To test this, we used a hierarchical sampling scheme to sample all fruits from three inflorescences from four clusters from the crowns of six trees. We assayed 14 polymorphic allozyme loci to determine the multilocus genotype of the pollen donor to each singly-sired fruit. We identified pollen donors for 205 fruits from 67 inflorescences from the six trees. Genetic diversity was high in all tree crowns (mean He = 0.303). A very low proportion of diversity was partitioned among trees crowns (GST = 0.047). Analysis of molecular variance revealed a high proportion of genetic diversity (92.0%) was partitioned within inflorescences in tree crowns. Analysis of paternal genotypic diversity indicated tree crowns received pollen from many unique pollen donors. Simulation analyses revealed a trend for fruits within the same inflorescence to have a higher than random chance of sharing a common pollen donor. Overall these results indicate that Albizia julibrissin individuals draw pollen from many pollen donors but that consecutive mating events within individuals are not random. The biological importance of non-random mating within tree crowns is discussed.
Key words: Albizia, julibrissin, correlated, paternity