This study examines the levels of gene flow, the distance and the patterns of pollen and seed dispersal, the intra-population spatial genetic structure (SGS) and the effective population size of a spatially isolated Myracrodruon urundeuva population using five microsatellite loci. The study was carried out in the Paulo de Faria Ecological Station, São Paulo State, Brazil and included the sampling and mapping of 467 adult-trees and 149 juveniles. Open-pollinated seeds (514) from 29 seed-trees were also sampled and genotyped. Significant SGS was detected in both adult (S p = 0.0269) and juveniles trees (S p = 0.0246), indicating short-distance seed dispersal. Using maternity analysis, all juveniles had the mother-tree assigned within the stand. A father-tree within the stand was also assigned for 97.3% of the juveniles and 98.4% of offspring. The average pollen dispersal distance measured in juvenilesd ¼ 138 AE 169 m; mean AE SD and offspringd ¼ 252 AE 204 m were higher than the average seed dispersal distance measured in juvenileŝ d ¼ 124 AE 150 m . About 70% of the pollen from juveniles and 51% from offspring traveled less than 200 m and, 72% of the seeds traveled less than 50 m. The effective population size of the studied sample indicates that the 467 adult-trees and 145 juveniles correspond respectively to 335 and 63 individuals that are neither inbred nor relatives.The results are discussed in relation to their impact on seed collection practices and genetic conservation.

Pollen flow and dispersal patterns were investigated in a small, isolated forest fragment of the Neotropical insect pollinated tree Copaifera langsdorffii, using paternity analysis and eight microsatellite loci. We also investigated the coancestry and effective population size of progeny arrays for conservation and environmental restoration purposes. Open-pollinated seeds were collected from 15 seed trees within the forest fragment, in which all adult trees were mapped, measured and genotyped. Twenty seeds were also collected from the nearest neighbor tree located 1.2 km from the forest fragment. Our results show that levels of genetic diversity were significantly higher in adults than offspring and significant levels of inbreeding were detected in offspring (F = 0.226). From paternity analysis, we observed low levels of selfing (s = 8%) and pollen immigration (m = 8%) in the fragment, but very high levels were detected for the isolated tree (s = 20%; m = 75%), indicating that the population and the tree are not reproductively isolated and are connected by patterns of long distance pollen dispersal (maximum detected 1,420 m). Within the forest fragment, the pattern of pollen dispersal was a near neighbor pattern with 49% of the pollen being dispersed within 50 m. The effective population size of the progeny array was low, indicating the need to collect seeds from a large number of seed trees (at least 76) for conservation purposes. The results show that the spatial isolation of the population and isolated tree due to forest fragmentation has not disrupted genetic connectivity; however, spatial isolation does seem to increase selfing and correlated mating.

Facultative apomictic trees can produce offspring with a genotype identical to the mother due to asexual propagation through the embryo derived from cells in the maternal ovule tissues. These trees can also produce offspring with a genotype different from the mother due to genetic recombination. For many trees, these reproductive processes remain largely unexplored. Herein, we use microsatellite markers to identify apomictic and sexual reproduction in samples of adult and juvenile trees of the tropical, insect pollinated and wind seed dispersed Aspidosperma polyneuron, within a conservation area in Brazil. We also investigate seed and pollen flow and dispersal patterns and compare the genetic diversity, inbreeding, and intrapopulation spatial genetic structure (SGS) between adults and juveniles in two plots. Our results show that the species present both apomictic and sexual reproduction. Sexual reproduction occurred mainly by outcrossing, but we did detect instances of self-fertilization and mating among relatives, which explains the inbreeding observed in juveniles. Seed dispersal distance was shorter than pollen dispersal distance in one of the plots, suggesting that insect vectors are more efficient in gene dispersal than wind for seed dispersal in a high density tropical forest. The patterns of pollen and seed dispersal showed isolation by distance, explaining the SGS detected for adults and juveniles. Our results show that both seed and pollen flow increase the allelic diversity in the population. The regeneration of apomictic individuals may guarantee the continuation of genotypes adapted specifically to the study site, while sexual reproduction results in new genotypes.