PT Journal
AU Veron, V
   Caron, H
   Degen, B
TI Gene flow and mating system of the tropical tree Sextonia rubra
SO Silvae Genetica
JI Silvae Genet.
PY 2005
BP 275
EP 280
VL 54
IS 6
DE genetic diversity; gene flow; heterozygosity; microsatellites; mixed mating; tropical tree; twogener
AB In this paper we report a study of the mating system and gene flow of Sextonia rubra, a hermaphroditic, insect pollinated tropical tree species with a geographic distribution in the Guyana Plateau and the Amazon. Using five microsatellites we analysed 428 seeds of 27 open pollinated families at the experimental site "Paracou" in French Guiana. We observed, compared to other tropical tree species, a high level of genetic diversity. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, t(m), was 0.992 indicating nearly complete outcrossing. A significant level of biparental inbreeding and a:small proportion. of full-sibs were estimated for the 27 seed arrays. The differentiation of allelic frequencies among the pollen pools was (Phi(FT) = 0.061. We estimated mean pollen dispersal distances between 65 m and 89 m according to the dispersal models used. The joint estimation of pollen dispersal and density of reproductive trees gave an effective density estimate of 2.1-2.2 trees/ha.
ER