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.
In this paper, we use six microsatellite loci to examine a spatially isolated population of Genipa americana in relation to mating system variation at the level of individual and among and within fruits, over two reproductive events. For our analysis, we sampled hierarchically among and within fruits open-pollinated seeds collected from 13 seed trees during the reproductive event in 2010 and 12 seed trees in 2011. The rate of mating among relatives (1-ts) was significantly greater than zero and different between the investigated reproductive events, indicating that some seeds are inbred. The estimate of fixation index (Fo) was significantly higher than zero for seeds from both reproductive events (2010: Fo = 0.258; 2011: Fo = 0.294), confirming that seeds present inbreeding, probably originated from mating among full-sibs. The multilocus paternity correlation within fruits (rp(w)) and among fruits (rp(a)) varied among seed trees and reproductive events. The rp(w) was significantly higher than rp(a) in both reproductive events, suggesting that it is more likely to find full-sibs within fruits (2010: 36.4%; 2011: 72.4%), than among fruits (2010: 18.9%; 2011: 12.8%). Due to the presence of inbreeding, mating among relatives and correlated mating, the within families coancestry coefficient (Θ) was higher and the variance effective size (Ne) lower than expected in open-pollinated families from panmictic populations (Θ = 0.125, Ne = 4). In practical terms for conservation programs, our results show the need to collect seeds from at least 60 seed trees to retain progeny arrays with a total effective size of 150.
ResumoA produção volumétrica tem sido prioridade nos programas de melhoramento florestal. No entanto, é necessário que a qualidade da madeira seja considerada, para que o fornecimento da matéria prima permita aumentar a eficiência e o rendimento industrial. Dessa forma, o objetivo deste trabalho foi estimar parâ-metros genéticos, correlações genéticas e ganhos com a seleção para caracteres de crescimento (diâme-tro), espessura de casca e densidade básica da madeira de Eucalyptus urophylla. Para tanto, utilizou-se discos de madeira retirados no DAP e metade da altura comercial, provenientes de árvores desbastadas em um teste de progênies de polinização aberta com 33 genótipos e duas procedências (Rio Claro-SP e Três Lagoas-MS), localizado em Selvíria-MS. Os parâmetros genéticos foram obtidos com base no procedimento REML/BLUP. O melhor desempenho para crescimento foi verificado para Rio Claro. Não foram detectadas diferenças genéticas para densidade da madeira entre as procedências. A procedência de Três Lagoas apresentou coeficiente de variação genética > 14% (diâmetro) e forte controle genético (herdabilidade > 0,6 e acurácia > 78%). Para qualidade da madeira, Rio Claro sobressaiu-se nas estimativas de herdabilidade (> 0,6 -DBM e ECD), alcançando acurácia superior a 79%. Foram encontrados resultados contrastantes para as correlações genéticas entre as duas procedências. Para a obtenção de materiais genéticos com maior densidade da madeira, a seleção para DBM é vantajosa. Palavras-chave: melhoramento florestal, qualidade da madeira, REML/BLUP. AbstractVolumetric production has been a priority in forest breeding programs. However, it is necessary to consider wood quality for the raw material supply that increases efficiency and yield. Thus, the aim of this study was to estimate genetic parameters, genitic correlations and selection gains for growth traits (diameter), bark thickness and basic density of wood in progênies of Eucalyptus urophylla. For this, we used wood discs removed at DHB and half the commercial height, from trees thinned in an open pollination progeny with 33 genotypes and two provenances (Rio Claro-SP and Três Lagoas-MS), located in Selvíria-MS. Estimates of genetic parameters were obtained using the REML/BLUP method. The best performance for growth was found in the Rio Claro provenance. Genetic differences in wood density between the provenances were not detected. The provenance of Três Lagoas showed a coefficient of genetic variation > 14% (diameter) and strong genetic control (heritability > 0.6 and accuracy > 78%). For wood quality, Rio Claro stood out in the estimates of heritability (> 0.6 -DBM and ECD), achieving a higher accuracy of 79%. Contrasting results were found for the genetic correlation between the two sources. For obtaining genetic materials with higher density wood, the selection for DBM is advantageous.
Molecular genetic studies have become an integral part of forest fragmentation analyses as they provide crucial information
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