|Reference : Spatial genetic structure in Milicia excelsa (Moraceae) indicates extensive gene dispers...|
|Scientific journals : Article|
|Life sciences : Genetics & genetic processes|
Life sciences : Agriculture & agronomy
|Spatial genetic structure in Milicia excelsa (Moraceae) indicates extensive gene dispersal in a low-density wind-pollinated tropical tree|
|Bizoux, Jean-Philippe [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]|
|Daïnou, Kasso [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]|
|Bourland, Nils [Université de Liège - ULg > > > Doct. sc. agro. & ingé. biol.]|
|Hardy, O. J. [> >]|
|Heuertz, M. [> >]|
|Mahy, Grégory [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]|
|Doucet, Jean-Louis [Université de Liège - ULg > Gembloux Agro-Bio Tech > Gembloux Agro-Bio Tech >]|
|[en] Central Africa ; Effective population density ; Gene dispersal ; Iroko ; Milicia excelsa ; Spatial genetic structure|
|[en] In this study, we analysed spatial genetic structure (SGS) patterns and estimated dispersal distances in Milicia excelsa (Welw.) C.C. Berg (Moraceae), a threatened windpollinated dioecious African tree, with typically low density ( 10 adults ⁄km2). Eight microsatellite markers were used to type 287 individuals in four Cameroonian populations characterized by different habitats and tree densities. Differentiation among populations was very low. Two populations in more open habitat did not display any correlation between genetic relatedness and spatial distance between individuals, whereas significant SGS was detected in two populations situated under continuous forest cover. SGS was weak with a maximum Sp-statistic of 0.006, a value in the lower quartile of SGS estimates for trees in the literature. Using a stepwise approach with Bayesian clustering methods, we demonstrated that SGS resulted from isolation by distance and not colonization by different gene pools. Indirect estimates of gene dispersal distances ranged from rg = 1 to 7.1 km, one order of magnitude higher than most estimates found in the literature for tropical tree species. This result can largely be explained by life-history traits of the species. Milicia excelsa exhibits a potentially wideranging wind-mediated pollen dispersal mechanism as well as very efficient seed dispersal mediated by large frugivorous bats. Estimations of gene flow suggested no major risk of inbreeding because of reduction in population density by exploitation.
Different strategy of seed collection may be required for reforestation programmes among populations with different extent of SGS.
|Researchers ; Professionals|
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