Genetic structure and diversity in wild and breeding populations of Eucalyptus urophylla

Abstract Eucalyptus urophylla S.T. Blake is a species of great commercial importance, especially in tropical regions, and it is the main eucalypts species cultivated in Brazil. This study evaluated the genetic diversity among and within seven populations of E. urophylla and estimated the genetic distance between individuals to draw inferences about the genetic structure between and within the sampled populations. For that, 19 microsatellite markers were genotyped in 254 individuals originating from four wild populations, introduced in Brazil, two breeding populations, and one population consisting of commercial clones. The wild populations of E. urophylla introduced in Brazil have high genetic similarity and the few generations of breeding have already generated significant differences in population structure between improved and wild populations. As expected, breeding populations are closer to commercial clones than wild populations. However, compared to wild populations, breeding populations exhibit greater genetic diversity as they originated from a mixture of provenances. The population formed by clones was the only one that showed a negative Wright fixation index, that is, heterozygosity was higher than expected for a population in Hardy-Weinberg equilibrium.