The mating system of Caesalpinia echinata Lam. implanted in arboretum was studied by allozymes analysis of progeny arrays using the mixed-mating model and correlated-mating model. Deviations from mixed-mating model were observed from heterogeneity of pollen pools allele frequencies that fertilized different trees. The multilocus outcrossing rate was high (t m = 0.969), indicating that the species is predominantly allogamous. The high variation observed in the individual outcrossing rate (tranged from 0.77 to 1.00) shows that the species is not auto-incompatible. It was detected significant positive difference between multilocus and single locus outcrossing rate suggesting that biparental inbreeding has occurred (t m - t s = 0.078). High value of paternity correlation was detected (r p = 0.822), demonstrating that families are composed by full sibs, mainly. The coefficient of coancestry within families (thetaxy = 0.269) was higher than expected in half-sibs families (0.125). The results are discussed in the viewpoint of the sampling to genetic conservation and environmental recovering.
biparental inbreeding; brazilwood; coancestry; effective variance size; outcrossing rate
