Mating system parameters and genetic structure in Argentinean populations of Acacia caven (Leguminosae, Mimosoideae)

POMETTI C. L.; VILARDI J. C.; SAIDMAN B. O.

PLANT SYSTEMATICS AND EVOLUTION

SPRINGER WIEN

Año: 2011 vol. 292 p. 25 - 32

0378-2697

Acacia caven (Mol.) Mol. is native to SouthAmerica. The species is a leguminous, woody small treethat is considered to have certain potential as a managedsilvopastoral crop. Six varieties have been described for thespecies based on both morphological traits and molecularmarkers. Little information is available on its mating system.The main objectives of this work were to test thehypothesis that A. caven is an outcrosser and to estimateparameters of its mating system and population structureon the basis of isozyme markers. In the four populationsstudied, a high homozygote excess was found in theprogeny population but not in the mother plant genotypes.The estimate for the multi-locus outcrossing rate (tm) washigh (>0.957) in all populations, indicating that Acaciacaven is a predominantly outcrosser species. The results ofgenetic structure analysis within each population indicatedthat differences in allelic frequencies among families in allof the populations studied are highly significant. The differencein F estimates between progeny and mother plantssuggests some selection favouring heterozygotes betweenthe seedling and adult stages. Therefore, a strategy for exsitu conservation might emphasise sampling more populationswith a relative large number of trees per site.