Alexandre Magno Sebbenn

Sistema de reprodução em populações de Eschweilera ovata (Cambess.) Miers

n The mating system of two populations of Eschweilera ovata was studied by allozymes analysis of progeny arrays using the mixed-mating model and correlated mating model. Deviations from mixed-mating model were evident from differences in pollen and ovule allele frequencies and allele frequency heterogeneity of pollen pools that fertilized the different trees. The multilocus outcrossing rate was high in both Camarugipe ( =0.999-0.004) and Itaparica populations ( =0.985-0.023). The high variation in individual outcrossing rate ( ranged from 0.320 to 1.000) indicated that the species is not self-incompatible. Positive differences and significantly different from zero between multilocus and single locus outcrossing rate were detected, indicating biparental inbreeding in both Camarugipe ( =0.066-0.014) and Itaparica populations ( =0.073-0.016) and possible spatial genetic structuring. Higher values of correlated mating were detected in the populations (Camarugipe, =0.577-0.088; Itaparica =0.423-0.070), showing that the families consisted mainly of half-sib and full-sib mixtures. The coancestry coefficient within families from both populations (Camarugipe, =0.211; Itaparica =0.191) was higher than the expected in half-sib families (0.125). The results were

Diversidade e estrutura genética espacial em duas populações de Myracrodruon urundeuva Fr. All. sob diferentes condições antrópicas

O objetivo deste trabalho foi estudar, por locos isoenzimaticos, a diversidade e a estrutura genetica espacial de genotipos de Myracrodruon urundeuva em duas populacoes naturais, uma no Sudoeste (Selviria-SEL) e outra no Sudeste (Paulo de Faria-PFA) do Brasil. Para isso, foram avaliados cinco sistemas isoenzimaticos, 25 e 30 individuos adultos das populacoes SEL e PFA, respectivamente. A estimativa da divergencia genetica entre populacoes foi baixa (=0,043). As heterozigosidades observada e esperada foram altas nas populacoes (0,317 e 0,511, respectivamente), e o excesso significativo de heterozigotos foi detectado na populacao PFA (= -0,252). A analise da distribuicao genetica espacial dos genotipos a partir do indice I de Moran revelou estruturacao significativa ate 5.224 m na populacao mais explorada (SEL, =0,09) e tendencia a distribuicao aleatoria na populacao menos explorada (PFA, = -0,02). A provavel causa da estruturacao na populacao SEL foi a dispersao de sementes proxima as arvores-matriz, associada ao processo de recolonizacao a partir de sementes oriundas de poucos genotipos remanescentes. As implicacoes dos resultados sao discutidas do ponto de vista da conservacao e do melhoramento genetico.

Variação genética em progênies de Myracrodruon urundeuva F.F. & M.F. Allemão em três sistemas de cultivo

Myracrodruon urundeuva is one of the tree species the wood that presents the longest durability when in contact with soil. Because of this characteristic, populations of M. urundeuva have been decimated throughout Brazil. Therefore, this work aimed at analyzing the expression of genetic variation in a natural population of M. urundeuva from the Ecological Station of the Forest Institute, located in Paulo de Faria-SP. Seeds were collected from 30 free-pollination trees in September, 1996. By using this material, three progeny trials were installed in different planting systems in Selviria - MS, following a block design with 30 treatments (progenies) and three replications. The mixed crossbreeding model for M. urundeuva was assumed. Significant differences were observed for progeny effects (progeny trials) although the progenies-environments interaction was not significant. Thus, progenies presented the same behavior in different environments; however, their best performance was in the planting involving M. urundeuva, Guazuma ulmifolia (Lam) and Anandenanthera falcata (Benth. Speg.). The progenies also presented considerable genetic variation; hence its utilization in programs for conservation and genetic improvement.

Mating system of a population of Myracrodruon urundeuva F.F. & M.F. Allemão using the fAFLP molecular marker

The mating system and genetic diversity were studied in a natural population of Myracrodruon urundeuva originating from 30 open-pollinated trees at the Paulo de Faria Ecological Station, SP, Brazil. The progenies were planted on the Teaching and Research Farm of the Ilha Solteira Engineering School, UNESP. Using the fAFLP molecular marker, eleven loci were selected to study the mating system. The mating system was analyzed using the multilocus mixed-mating model. The estimates of genetic divergence between pollen and ovule allele frequencies were significant for eight loci, suggesting nonrandom outcrossing. The estimates of the multilocus outcrossing rate revealed that M. urundeuva possesses a mating system with a predominance of outcrossing events (q = 0.940 ± 0.086). The estimates of coancestry among plants within progenies (q = 0.185) was higher than that expected for half-sib progenies (0.125) and the indirect estimate of the correlation of outcrossed paternity within progeny arrays (rp) was 0.403, suggesting that progenies have a high proportion of full-sibs. Result analysis suggests the need for the application of biometric models that take into account deviations from random outcrossing in the estimations of genetic parameters for quantitative traits and the need for retaining large sample sizes in order to preserve genetic variability.

Paternity analysis reveals significant isolation and near neighbor pollen dispersal in small Cariniana legalis Mart. Kuntze populations in the Brazilian Atlantic Forest

Abstract Throughout the world, large trees are increasingly rare. Cariniana legalis is the tallest tree species of the Brazilian Atlantic Forest, reaching up to 60 m in height. Due to extensive deforestation of the Atlantic Forest, remnant C. legalis populations are small and spatially isolated, requiring the development of strategies for their conservation. For in situ and ex situ genetic conservation to be effective, it is important to understand the levels and patterns of spatial genetic structure (SGS), and gene flow. We investigated SGS and pollen flow in three small, physically isolated C. legalis stands using microsatellite loci. We measured, mapped, and sampled all C. legalis trees in the three stands: 65 trees from Ibicatu population, 22 trees from MGI, and 4 trees from MGII. We also collected and genotyped 600 seeds from Ibicatu, 250 seeds from MGI, and 200 seeds from MGII. Significant SGS was detected in Ibicatu up to 150 m, but substantial levels of external pollen flow were also detected in Ibicatu (8%), although not in MGI (0.4%) or MGII (0%). Selfing was highest in MGII (18%), the smallest group of trees, compared to MGI (6.4%) and Ibicatu (6%). In MGI and MGII, there was a strong pattern of mating among near‐neighbors. Seed collection strategies for breeding, in situ and ex situ conservation and ecological restoration, must ensure collection from seed trees located at distances greater than 350 m and from several forest fragments.

Mendelian inheritance, linkage and linkage disequilibrium in microsatellite loci of Copaifera langsdorffii Desf.

Copaifera langsdorffii is a Neotropical tree with wide distribution in the Brazilian Atlantic rain forest and savanna. Although eight microsatellite loci (SSR) were developed in 2000 and have been widely used since then, there is yet no information about their inheritance, linkage and linkage disequilibrium (LD). Through the analysis of 28 open-pollinated (OP) progenies, the SSR loci revealed Mendelian inheritance and independent assortment. Using these progenies, young and adult trees LD was mainly detected in OP progenies. Our results show clear evidence that the eight SSR loci can be used without restriction in genetic diversity, mating system and parentage analysis.

Long‐distance dispersal in a fire‐ and livestock‐protected savanna

Savannas are highly diverse and dynamic environments that can shift to forest formations due to protection policies. Long-distance dispersal may shape the genetic structure of these new closed forest formations. We analyzed eight microsatellite loci using a single-time approach to understand contemporary pollen and effective seed dispersal of the tropical tree, Copaifera langsdorffii Desf. (Fabaceae), occurring in a Brazilian fire- and livestock-protected savanna. We sampled all adult trees found within a 10.24 ha permanent plot, young trees within a subplot of 1.44 ha and open-pollinated seeds. We detected a very high level of genetic diversity among the three generations in the studied plot. Parentage analysis revealed high pollen immigration rate (0.64) and a mean contemporary pollen dispersal distance of 74 m. In addition, half-sib production was 1.8 times higher than full-sibs in significant higher distances, indicating foraging activity preference for different trees at long distances. There was a significant and negative correlation between diameter at breast height (DBH) of the pollen donor with the number of seeds (r = −0.640, P-value = 0.032), suggesting that pollen donor trees with a higher DBH produce less seeds. The mean distance of realized seed dispersal (recruitment kernel) was 135 m due to the large home range dispersers (birds and mammals) in the area. The small magnitude of spatial genetic structure found in young trees may be a consequence of overlapping seed shadows and increased tree density. Our results show the positive side of closed canopy expansion, where animal activities regarding pollination and seed dispersal are extremely high.

Microsatellite Markers for Cariniana legalis (Lecythidaceae) and Their Transferability to C. estrellensis

Premise of the study: Microsatellite primers were developed in the neotropical tree species Cariniana legalis (Lecythidaceae) to investigate its genetic diversity, mating system, and gene flow. Methods and Results: We identified 96 clones containing 82 repeat motifs from a genomic library enriched for (CT)8 and (GT)8 motifs. Primer pairs were developed for 13 microsatellite loci and validated in 51 C. legalis specimens and 26 C. estrellensis specimens. Eleven loci were polymorphic, revealing a maximum of two to 15 alleles per locus in C. legalis and three to 12 in C. estrellensis. For C. legalis, the observed (Ho) and expected (He) heterozygosities ranged from 0 to 0.99 and from 0.07 to 0.90, respectively. For C. estrellensis, Hoand Heranged from 0 to 0.96 and from 0.14 to 0.91, respectively. Conclusions: The primers identified polymorphic loci that are suitable to study genetic diversity and structure, mating system, and gene flow in C. legalis and the related species C. estrellensis.

Mating system and genetic diversity of progenies before and after logging: a case study of Bagassa guianensis (Moraceae), a low-density dioecious tree of the Amazonian forest

The logging of large trees in tropical forests causes a decrease in the density of reproductive individuals, which likely affects the pattern of pollen dispersal and the mating system of the remaining trees in the population. Here, we investigate the impact of logging on mating system and genetic diversity of the low-density, thrip-pollinated, dioecious tree Bagassa guianensis within a 500-ha plot at Tapajós National Forest, Pará State, Brazil. Mating system parameters of the logged population were estimated using mixed-mating model. Six microsatellite loci were used to genotype 232 seeds from ten remnant female trees over three seasons (2006, 2007, and 2008). The data were compared with the mating system of the unlogged population of B. guianensis (18 female trees, 488 seeds) in the same plot. The overall number of alleles found in the open-pollinated progenies decreased after logging (K = 71 before logging and K = 57 after logging, considering the three after logging seasons pooled), as well as the average number of alleles per locus (A = 11.8 and 9.5, respectively). Similarly, the number of private alleles, which is defined in the context of this study as the number of alleles observed in the population exclusively before or after logging, also decreased after logging (15 and 1, respectively). However, the average number of alleles per locus and the observed and expected heterozygosities were not significantly higher before logging than after logging. Logging also did not affect the inbreeding of progenies in the population. Somewhat unexpectedly, the effective number of pollen donors was consistently higher after (Nep = 14.5 in 2006, 8.1 in 2007, and 6.3 in 2008) than before logging (Nep = 3.4), suggesting that the loss of alleles in the population was compensated by the higher heterogeneity in the pollen pool after the removal of the largest trees by logging. Potential causes explaining the patterns found here include the maintenance of large patches of forest around the logged plot and the species’ ability to perform long-distance pollination by airborne thrips. Maintenance of landscape integrity as logged and unlogged forests around the exploited areas is recommended to enhance pollen migration and to avoid long-term losses in genetic diversity.

Estimative of genetic parameters in progeny test of Pinus caribaea Morelet var. hondurensis Barret & Golfari by quantitative traits and microsatellite markers

The aims of this work were to estimate the coefficient of relatedness within families and the genetic parameters for growth related traits in a progeny test from an open-pollinated variety of Pinus caribaea Morelet hondurensis Barret & Golfari, established in Mato Grosso do Sul State, Brazil. The experimental design was the triple 10 x 10 lattice, with 96 families, three replicates, and ten plants per plot. Fourteen years after planting, the trial was measured for the following traits: total height, diameter at breast height (DBH), and true volume. The estimation of coefficients of relatedness within family from microsatellite loci indicated that families are true half-sibs ( ). Thus, the additive genetic variance ( ) can be estimated assuming that the genetic variance among progenies ( ) accounts for ¼ of additive genetic variance ( ). The estimative of heritability coefficients at individual level ( ) was relatively high (0.28 for DBH and 0.44 for height). The heritability coefficient considering the average families ( ) was also high, ranging among the traits from 0.50 to 0.58. These results suggest that the population can be improved by both massal and among families selection. Additionally, the estimated genetic gains with sequential selection among and within families were high (ranging from 8.92% for height to 37.56% for volume), demonstrating that this method of selection can generate high genetic improvement.