TAMANHO AMOSTRAL PARA CONSERVAÇÃO EX SITU DE ESPÉCIES ARBÓREAS COM SISTEMA MISTO DE REPRODUÇÃO

Abstract

The aim of this study was to determine the number of trees per family and the number of · families necessary for ex situ conservat1on of a simple population of tree species with mixed matmg system. The numbers of families per population were estimated by the relation between effective population size ( N.) target of conservation and the variance effeétive population size ( N ) of a family. The f; was estimated from avefage of coefficient of Ô ancestry within open-pollinated families, calculated f r om parameters of mating system by genetic marker data in coniferous and evergreen trees species, assuming moderate leveis of mbreeding (0.1) and coancestry (0.125) in population target of seeds collect. The results showed that there was no sampling advantages in conserving more than 20 plants per family, even in populations with moderates leveis of inbreeding (0.1) and coancestry (0.125). There was no difference in sample s1ze found for evergreen and coniferous species. However, there are great differences among species in the number of families for conservat1on. The family number necessary to retain the effective population size at 50 ranged in evergreen and coniferous from 16.5 to 34.8 and 16.7 to 31.6, with average at 23.7 and 21.3, respectively. Thus, the conservation of 20 trees per family and 35 families per population is enough to ex situ conservation, in short time view, f rom species with mixed mating system, but high outcrossing rate (t > 0.8).