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Volume 71 (2022): Issue 1 (January 2022)

Volume 70 (2021): Issue 1 (January 2021)

Volume 69 (2020): Issue 1 (January 2020)

Volume 68 (2019): Issue 1 (January 2019)

Volume 67 (2018): Issue 1 (February 2018)

Volume 66 (2017): Issue 1 (December 2017)

Volume 65 (2016): Issue 2 (December 2016)

Volume 65 (2016): Issue 1 (December 2016)

Volume 64 (2015): Issue 1-6 (December 2015)

Volume 63 (2014): Issue 1-6 (December 2014)

Volume 62 (2013): Issue 1-6 (December 2013)

Volume 61 (2012): Issue 1-6 (December 2012)

Volume 60 (2011): Issue 1-6 (December 2011)

Volume 59 (2010): Issue 1-6 (December 2010)

Volume 58 (2009): Issue 1-6 (December 2009)

Volume 57 (2008): Issue 1-6 (December 2008)

Volume 56 (2007): Issue 1-6 (December 2007)

Volume 55 (2006): Issue 1-6 (December 2006)

Volume 54 (2005): Issue 1-6 (December 2005)

Volume 53 (2004): Issue 1-6 (December 2004)

Journal Details
Format
Journal
eISSN
2509-8934
First Published
22 Feb 2016
Publication timeframe
1 time per year
Languages
English

Search

Volume 65 (2016): Issue 2 (December 2016)

Journal Details
Format
Journal
eISSN
2509-8934
First Published
22 Feb 2016
Publication timeframe
1 time per year
Languages
English

Search

10 Articles
Open Access

Hybridization of Poplars in the Central Chernozem Region of Russia

Published Online: 27 Oct 2017
Page range: 1 - 10

Abstract

Abstract

Hybridization offers huge potential in domesticating species. Poplars are important for wood production and also ornamental uses. Only two poplar parents can generate by hybridization more than 500,000 different offspring phenotypes. The article reviews some international results and presents some Russian results of poplar hybridization, emphasizing the Central Chernozem Region of the European part of Russia. During 60 years 736 crosses were realized, resulting in 54,000 hybrid seedlings. In different field trials 243 superior clones were selected. For practical operations twelve cultivars of the most productive and frost resistant poplar hybrids were selected. Three of them are now approved as varieties by the state registration authorities. In order to mitigate the risks from unforeseen disease, injury or other adverse factors in defined environments several cultivars with close economic value but with different genetic composition should be available.

Keywords

  • poplars
  • hybridization
  • field testing
  • cultivars
  • growth indices
  • Central Chernozem Region of Russia
Open Access

Effects of Ca2+ on in vitro pollen germination of three Acacia species

Published Online: 27 Oct 2017
Page range: 11 - 16

Abstract

Abstract

We investigated the effects of Ca2+ on in vitro pollen germination of Acacia auriculiformis, Acacia mangium, and Acacia crassicarpa under different concentrations of Ca2+ (50 mg.L−1, 100 mg.L−1, 150 mg.L−1, 200 mg.L−1, 250 mg.L−1, 300 mg.L−1, 350 mg.L−1 and 400 mg.L−1) in the present study. Our results revealed that Ca2+ could stimulate the pollen germination percentage and the pollen tube growth of A. auficuliformis and A. crassicarpa under a certain concentration. In vitro pollen germination of A. mangium did not require exogenous Ca2+. With high Ca2+ concentration, the pollen germination of A. auriculiformis, A. mangium, and A. crassicarpa were obviously inhibited. With the rise of Ca2+ concentration, the percentage of pollen germination, the pollen tube length, the pollen tube growth, and the number of pollen tube were increased. However, the pollen germination percentage decreased with high Ca2+ concentration.

Keywords

  • Acacia
  • calcium
  • pollen germination percentage
  • pollen tube
Open Access

Detecting differential viability selection between environments by analysis of compositional differentiation at different levels of genetic integration

Published Online: 27 Oct 2017
Page range: 17 - 29

Abstract

Abstract

Viability selection can be detected directly in an environment when the genotypes of the individuals at one ontogenetic stage (e.g. seeds) and the genotypes of the survivors at a later stage are both known, but genotypes at the earlier stage often cannot be determined. In this case, differential viability selection between environments can be detected as differences in the distributions of genetic types among survivors growing in different environments, provided that the survivors stem from random samples of seeds from the same base population (e.g. seed lot). Since common FST-outlier methods for detecting selected gene loci use only allele frequencies, selection that affects the higher hierarchical levels of genetic integration (single- or multi-locus genotypes) without changing allele frequencies is not noticed. A new method for detecting differential viability selection at any level of genetic integration enables discovery of elementary mechanisms of selection that older methods miss. It is based on two measures of compositional differentiation between environments. δSD measures qualita-tive differences between distributions of genetic types at any given integration level without regarding differences in their constituent alleles, while ΔSD measures quantitative differences between the same distributions by additionally considering the genic differences. The difference between these measures expresses the degree to which the patterns of gene association in the genotypes differ between environments. The P-values of all measures are estimated by permutation analysis under the assumption that survivors were randomly assigned to environments. Significance indicates the occurrence of differential viability selection at the loci. As a case study, a field study of viability in juvenile beech (Fagus sylvatica L.) for twelve enzyme loci is reanalyzed. It turns out that the significant differential selection for genotypes detected at three loci can be attributed to three combinations of selective effects: on alleles only (SKDH-A), mostly alleles but also association patterns (LAP-A); interaction of effects on alleles and association patterns that are non-significant when viewed separately (AAT-B).

Keywords

  • Compositional differentiation
  • gene association
  • genetic distance
  • genetic integration
  • genetic variation
  • viability selection
  • European beech (Fagus sylvatica L.)
Open Access

Clonal selection of Eucalyptus grandis x Eucalyptus globulus for productivity, adaptability, and stability, using SNP markers

Published Online: 27 Oct 2017
Page range: 30 - 38

Abstract

Abstract

In Uruguay, reforestations with Eucalyptus sp. is of fundamental importance to supply paper, pulp, and wood production. This study investigates genetic, productivity, stability, and adaptability parameters in the selection of Eucalypts grandis x Eucalyptus globulus full-sib hybrid clones. The study was conducted in a clonal test, repeated in two different soils types, in Rio Negro State, Uruguay. The population was characterized phenotypically for diameter at breast height (dbh) and genotyped for SNP markers (EuCHIP60K chip). Mean dbh was similar between sites and the genotype–environment interaction was simple. We found high genotype correlation in clone performance between environments (0.708), indicating the possibility of selecting the same clones for both study locations. Mean heritability between clones (0.724), coefficient of individual genetic variation (10.9 %), and relative variation (0.916), suggest the possibility of gains (estimated at 3.1 % for both sites together) by selecting clones with higher growth rates. A total of 15,196 SNPs were used to confirm parentage and test a genomic selection model for dbh. The predictive capacity was negative (-0.15) given the small population size (78 individuals). The most adaptable material among the tested study sites presented higher values for SNP heterozygosity. Thus, using molecular markers to identify clones responsive to environmental changes can act as a powerful tool in Eucalyptus breeding programs. The hybrid population showed greater adaptability than E. globulus for this region.

Keywords

  • Eucalyptus hybrid
  • forest breeding
  • gene markers
  • population genetics
  • quantitative genetics
Open Access

Comparison of fine-scale spatial genetic structure of two sympatric Rhododendron shrub species in forest habitat having different seed weights: A case study

Published Online: 27 Oct 2017
Page range: 39 - 45

Abstract

Abstract

Restricted seed dispersal is one of the most prevalent determinants of spatial genetic structure (SGS) at a fine spatial scale within a plant population. Rhododendron kaempferi and R. semibarbatum are common and coexistent Ericaceous species in the shrub layer of secondary deciduous broad-leaved forests in the northern Kanto District, central Japan. The two species have entomophilous flowers and are thought to have similar pollination styles. However, R. kaempferi produces threefold heavier seeds than R. semibarbatum. Therefore, we tested the hypothesis that the intensity of SGS was stronger in R. kaempferi than in R. semibarbatum in a forest stand. We comparatively examined the SGS for 73 individuals of R. kaempferi and 36 individuals of R. semibarbatum by using highly variable nuclear microsatellite loci. The analysis revealed significant SGS in both species at the shortest distance (<3 m); a measure to quantify SGS showed a counterintuitive result: R. semibarbatum exhibited stronger SGS than R. kaempferi. This result might be explained by the ecological consequences of R. semibarbatum producing lighter seeds, which might have greater dispersal efficacy, but its safe sites could be more restricted than those of R. kaempferi; in contrast, R. kaempferi producing heavier seeds might have more limited seed dispersal, but its safe sites for seedling establishment could be more prevalent than those for R. semibarbatum. The different strategies for the trade-off between seed weight and site selection of the two Rhododendron species might be reflected in the difference in the intensity of SGS in this study plot.

Keywords

  • nuclear microsatellite
  • Rhododendron kaempferi
  • Rhododendron semibarbatum
  • seed dispersal
Open Access

Gene dispersal via seeds and pollen and their effects on genetic structure in the facultative-apomictic Neotropical tree Aspidosperma polyneuron

Published Online: 27 Oct 2017
Page range: 46 - 57

Abstract

Abstract

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.

Keywords

  • Apomictic
  • conservation genetics
  • gene flow
  • propagule dispersal
  • tropical rainforest
Open Access

Growth Performance and Heritability Estimation of Acacia crassicarpa in a Progeny Trial in eastern Thailand

Published Online: 27 Oct 2017
Page range: 58 - 64

Abstract

Abstract

Growth performance and heritability were studied in a progeny trial of Acacia crassicarpa in Chacheongsao province, eastern Thailand in order to provide information on suitable families for seed improvement and production. A randomized complete block design (originally 8 blocks, 80 family plots/block, 4 trees/plot) of the best 80 half-sib families selected from 7 provenances was thinned at ages 2.5, 4 and 5 years based on growth and tree form and so that there was one tree/plot remained at the stage of present study. All remaining trees were measured for diameter at breast height (DBH), tree height (H), individual volume (VOL) and stem form (straightness and forked height) at ages 12, 12.5, 13 and 13.5 years, respectively. Narrow sense heritability (h2) based on family was estimated for each characteristic. Analysis of variance showed that there were highly significant differences among families at the four ages for DBH, H and VOL. Stem straightness and forked height were not significantly different among families. The heritability of DBH was increased as trees were mature (h2 = 0.236, 0.285, 0.288, and 0.291) but those of H and VOL were a little decreased. The heritability of stem straightness was very low (0.013) and that of forked height was also low (0.138). The results implied that the tree breeding of A. crassicarpa could improve DBH, H and VOL considerably. Further selection testing is required to increase the heritability of stem form. The measured data would be useful for tree improvement and seed orchard establishment of Acacia crassicarpa.

Keywords

  • Growth performance
  • Heritability
  • Progeny trail
  • Selection gain
  • Acacia crassicarpa
Open Access

Genetic and adaptive trait variation in seedlings of European beech provenances from Northern Germany

Published Online: 27 Oct 2017
Page range: 65 - 73

Abstract

Abstract

European beech (Fagus sylvatica L.) will most likely be threatened by climate change. Therefore, more knowledge of its adaptation potential to changing environmental conditions is required. Several studies showed differences in adaptive traits for beech populations from across Europe, but there is also growing evidence for microevolutionary processes occurring within short geographic distances in this species, or even a lack of local adaptation. Hence, a more regional perspective for adaptation research in beech might be appropriate. Here, we investigated the performance (height, height increment and mortality) and genetic structure based on microsatellite markers of 2400 beech seedlings from provenances growing along a temperature and precipitation gradient in Northern Germany in a common garden experiment. Differences for all traits were found among provenances. Provenances from lower precipitation areas did not perform better than provenances from higher precipitation areas at the common garden site, which was located near the lower precipitation limit of beech. Further, neighboring provenances growing on either sandy or loamy soils showed more different adaptive trait variation than distant provenances. We detected minor genetic structure among provenances and a high genetic diversity within them. Thus, small-scale adaptive trait variation in beech can occur, despite low but significant genetic population structure among provenances.

Keywords

  • Mortality
  • adaptive traits
  • climate change
  • genetic diversity
Open Access

Whole-genome draft assembly of Populus tremula x P. alba clone INRA 717-1B4

Published Online: 27 Oct 2017
Page range: 74 - 79

Abstract

Abstract

Populus trichocarpa and P. deltoides are the only Populus species known to date to have a publicly available nuclear genome sequence that has been assembled to chromosomes and annotated (https://phytozome.jgi.doe.gov/). Here we focus on the clone INRA 717-1B4, a female P. tremula x P. alba (P. x canescens) interspecific hybrid that is universally used by scientists worldwide as a tree model in transgenic experiments. The already available INRA 717-1B4 nuclear genomic resource (v1.1 of sPta717 at http://aspendb.uga.edu/index.php/databases/spta-717-genome) presents only INRA 717-1B4 genomic regions with high similarity to the P. trichocarpa genomic reference sequences. We assembled draft genomic scaffolds by a combination of de novo assembly with reference-based assembly using 30x resequencing NGS data (Illumina MiSeq® and Ion Torrent Ion PGM™) of INRA 717-1B4. In total, 419,969 scaffolds of length larger than 500 bp were generated. The mean length of the scaffolds is 2,166 bp and the size of the largest scaffold 84,573 bp. The N50 contig length is 3,850 bp when considering contigs larger than 1,000 bp. Probably due to the high level of heterozygosity of this interspecific hybrid, the accumulated scaffold length is with 0.9 GB about twice the expected size of the haploid nuclear genome. DNA sequences of the genomic scaffolds of INRA 717-1B4 are publicly available for Blast analyses and download via the new INRA web portal at https://urgi.versailles.inra.fr/Species/Forest-trees/Populus/Clone-INRA-717-1B4/. This new genomic sequence resource will complement the already available INRA 717-1B4 resources and will facilitate the future optimization of genetic transformation experiments to discover gene function.

Keywords

  • INRA 717-1B4
  • P. x canescens
  • poplars
  • next generation sequencing
  • genome assembly
  • scaffolds
  • model tree
Open Access

Genetic effects on heartwood color variation in Cryptomeria japonica

Published Online: 27 Oct 2017
Page range: 80 - 87

Abstract

Abstract

To obtain fundamental and useful information regarding heartwood color traits in Japanese cedar, the validity of using L* index for expressing heartwood color and genetic and environmental influences on heartwood color were analyzed using 118 clones with 303 individuals aged approximately 30 years. As for three clones with typical reddish and blackish heartwood, relationships between heartwood color and moisture/potassium content, which were pointed out as ones of the causative agents of blackish heartwood, and the color change after approximately 20 years of conservation were investigated.

Based on the continuity, width range, and standard deviation of each index of L*a*b* data, L* was found out to be an appropriate index to express heartwood color in this species. L* values significantly differed between clones. A moderately high repeatability of clones was detected in L* value. Spatial autocorrelation analysis also showed a stronger effect genetically than environmentally. Moisture and potassium contents significantly differed between two groups of reddish and blackish heartwood. Therefore, the absorption and accumulation of water and potassium into trunk may be genetically regulated. As for the L* value of heartwood color after approximately 20 years of conservation, the difference between two groups was still significant, but the lightness in blackish heartwood increased such that the difference was greatly reduced.

Keywords

  • Japanese cedar
  • heartwood color
  • L*a*b* color sytem
  • spatial autocorrelation
  • potassium
10 Articles
Open Access

Hybridization of Poplars in the Central Chernozem Region of Russia

Published Online: 27 Oct 2017
Page range: 1 - 10

Abstract

Abstract

Hybridization offers huge potential in domesticating species. Poplars are important for wood production and also ornamental uses. Only two poplar parents can generate by hybridization more than 500,000 different offspring phenotypes. The article reviews some international results and presents some Russian results of poplar hybridization, emphasizing the Central Chernozem Region of the European part of Russia. During 60 years 736 crosses were realized, resulting in 54,000 hybrid seedlings. In different field trials 243 superior clones were selected. For practical operations twelve cultivars of the most productive and frost resistant poplar hybrids were selected. Three of them are now approved as varieties by the state registration authorities. In order to mitigate the risks from unforeseen disease, injury or other adverse factors in defined environments several cultivars with close economic value but with different genetic composition should be available.

Keywords

  • poplars
  • hybridization
  • field testing
  • cultivars
  • growth indices
  • Central Chernozem Region of Russia
Open Access

Effects of Ca2+ on in vitro pollen germination of three Acacia species

Published Online: 27 Oct 2017
Page range: 11 - 16

Abstract

Abstract

We investigated the effects of Ca2+ on in vitro pollen germination of Acacia auriculiformis, Acacia mangium, and Acacia crassicarpa under different concentrations of Ca2+ (50 mg.L−1, 100 mg.L−1, 150 mg.L−1, 200 mg.L−1, 250 mg.L−1, 300 mg.L−1, 350 mg.L−1 and 400 mg.L−1) in the present study. Our results revealed that Ca2+ could stimulate the pollen germination percentage and the pollen tube growth of A. auficuliformis and A. crassicarpa under a certain concentration. In vitro pollen germination of A. mangium did not require exogenous Ca2+. With high Ca2+ concentration, the pollen germination of A. auriculiformis, A. mangium, and A. crassicarpa were obviously inhibited. With the rise of Ca2+ concentration, the percentage of pollen germination, the pollen tube length, the pollen tube growth, and the number of pollen tube were increased. However, the pollen germination percentage decreased with high Ca2+ concentration.

Keywords

  • Acacia
  • calcium
  • pollen germination percentage
  • pollen tube
Open Access

Detecting differential viability selection between environments by analysis of compositional differentiation at different levels of genetic integration

Published Online: 27 Oct 2017
Page range: 17 - 29

Abstract

Abstract

Viability selection can be detected directly in an environment when the genotypes of the individuals at one ontogenetic stage (e.g. seeds) and the genotypes of the survivors at a later stage are both known, but genotypes at the earlier stage often cannot be determined. In this case, differential viability selection between environments can be detected as differences in the distributions of genetic types among survivors growing in different environments, provided that the survivors stem from random samples of seeds from the same base population (e.g. seed lot). Since common FST-outlier methods for detecting selected gene loci use only allele frequencies, selection that affects the higher hierarchical levels of genetic integration (single- or multi-locus genotypes) without changing allele frequencies is not noticed. A new method for detecting differential viability selection at any level of genetic integration enables discovery of elementary mechanisms of selection that older methods miss. It is based on two measures of compositional differentiation between environments. δSD measures qualita-tive differences between distributions of genetic types at any given integration level without regarding differences in their constituent alleles, while ΔSD measures quantitative differences between the same distributions by additionally considering the genic differences. The difference between these measures expresses the degree to which the patterns of gene association in the genotypes differ between environments. The P-values of all measures are estimated by permutation analysis under the assumption that survivors were randomly assigned to environments. Significance indicates the occurrence of differential viability selection at the loci. As a case study, a field study of viability in juvenile beech (Fagus sylvatica L.) for twelve enzyme loci is reanalyzed. It turns out that the significant differential selection for genotypes detected at three loci can be attributed to three combinations of selective effects: on alleles only (SKDH-A), mostly alleles but also association patterns (LAP-A); interaction of effects on alleles and association patterns that are non-significant when viewed separately (AAT-B).

Keywords

  • Compositional differentiation
  • gene association
  • genetic distance
  • genetic integration
  • genetic variation
  • viability selection
  • European beech (Fagus sylvatica L.)
Open Access

Clonal selection of Eucalyptus grandis x Eucalyptus globulus for productivity, adaptability, and stability, using SNP markers

Published Online: 27 Oct 2017
Page range: 30 - 38

Abstract

Abstract

In Uruguay, reforestations with Eucalyptus sp. is of fundamental importance to supply paper, pulp, and wood production. This study investigates genetic, productivity, stability, and adaptability parameters in the selection of Eucalypts grandis x Eucalyptus globulus full-sib hybrid clones. The study was conducted in a clonal test, repeated in two different soils types, in Rio Negro State, Uruguay. The population was characterized phenotypically for diameter at breast height (dbh) and genotyped for SNP markers (EuCHIP60K chip). Mean dbh was similar between sites and the genotype–environment interaction was simple. We found high genotype correlation in clone performance between environments (0.708), indicating the possibility of selecting the same clones for both study locations. Mean heritability between clones (0.724), coefficient of individual genetic variation (10.9 %), and relative variation (0.916), suggest the possibility of gains (estimated at 3.1 % for both sites together) by selecting clones with higher growth rates. A total of 15,196 SNPs were used to confirm parentage and test a genomic selection model for dbh. The predictive capacity was negative (-0.15) given the small population size (78 individuals). The most adaptable material among the tested study sites presented higher values for SNP heterozygosity. Thus, using molecular markers to identify clones responsive to environmental changes can act as a powerful tool in Eucalyptus breeding programs. The hybrid population showed greater adaptability than E. globulus for this region.

Keywords

  • Eucalyptus hybrid
  • forest breeding
  • gene markers
  • population genetics
  • quantitative genetics
Open Access

Comparison of fine-scale spatial genetic structure of two sympatric Rhododendron shrub species in forest habitat having different seed weights: A case study

Published Online: 27 Oct 2017
Page range: 39 - 45

Abstract

Abstract

Restricted seed dispersal is one of the most prevalent determinants of spatial genetic structure (SGS) at a fine spatial scale within a plant population. Rhododendron kaempferi and R. semibarbatum are common and coexistent Ericaceous species in the shrub layer of secondary deciduous broad-leaved forests in the northern Kanto District, central Japan. The two species have entomophilous flowers and are thought to have similar pollination styles. However, R. kaempferi produces threefold heavier seeds than R. semibarbatum. Therefore, we tested the hypothesis that the intensity of SGS was stronger in R. kaempferi than in R. semibarbatum in a forest stand. We comparatively examined the SGS for 73 individuals of R. kaempferi and 36 individuals of R. semibarbatum by using highly variable nuclear microsatellite loci. The analysis revealed significant SGS in both species at the shortest distance (<3 m); a measure to quantify SGS showed a counterintuitive result: R. semibarbatum exhibited stronger SGS than R. kaempferi. This result might be explained by the ecological consequences of R. semibarbatum producing lighter seeds, which might have greater dispersal efficacy, but its safe sites could be more restricted than those of R. kaempferi; in contrast, R. kaempferi producing heavier seeds might have more limited seed dispersal, but its safe sites for seedling establishment could be more prevalent than those for R. semibarbatum. The different strategies for the trade-off between seed weight and site selection of the two Rhododendron species might be reflected in the difference in the intensity of SGS in this study plot.

Keywords

  • nuclear microsatellite
  • Rhododendron kaempferi
  • Rhododendron semibarbatum
  • seed dispersal
Open Access

Gene dispersal via seeds and pollen and their effects on genetic structure in the facultative-apomictic Neotropical tree Aspidosperma polyneuron

Published Online: 27 Oct 2017
Page range: 46 - 57

Abstract

Abstract

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.

Keywords

  • Apomictic
  • conservation genetics
  • gene flow
  • propagule dispersal
  • tropical rainforest
Open Access

Growth Performance and Heritability Estimation of Acacia crassicarpa in a Progeny Trial in eastern Thailand

Published Online: 27 Oct 2017
Page range: 58 - 64

Abstract

Abstract

Growth performance and heritability were studied in a progeny trial of Acacia crassicarpa in Chacheongsao province, eastern Thailand in order to provide information on suitable families for seed improvement and production. A randomized complete block design (originally 8 blocks, 80 family plots/block, 4 trees/plot) of the best 80 half-sib families selected from 7 provenances was thinned at ages 2.5, 4 and 5 years based on growth and tree form and so that there was one tree/plot remained at the stage of present study. All remaining trees were measured for diameter at breast height (DBH), tree height (H), individual volume (VOL) and stem form (straightness and forked height) at ages 12, 12.5, 13 and 13.5 years, respectively. Narrow sense heritability (h2) based on family was estimated for each characteristic. Analysis of variance showed that there were highly significant differences among families at the four ages for DBH, H and VOL. Stem straightness and forked height were not significantly different among families. The heritability of DBH was increased as trees were mature (h2 = 0.236, 0.285, 0.288, and 0.291) but those of H and VOL were a little decreased. The heritability of stem straightness was very low (0.013) and that of forked height was also low (0.138). The results implied that the tree breeding of A. crassicarpa could improve DBH, H and VOL considerably. Further selection testing is required to increase the heritability of stem form. The measured data would be useful for tree improvement and seed orchard establishment of Acacia crassicarpa.

Keywords

  • Growth performance
  • Heritability
  • Progeny trail
  • Selection gain
  • Acacia crassicarpa
Open Access

Genetic and adaptive trait variation in seedlings of European beech provenances from Northern Germany

Published Online: 27 Oct 2017
Page range: 65 - 73

Abstract

Abstract

European beech (Fagus sylvatica L.) will most likely be threatened by climate change. Therefore, more knowledge of its adaptation potential to changing environmental conditions is required. Several studies showed differences in adaptive traits for beech populations from across Europe, but there is also growing evidence for microevolutionary processes occurring within short geographic distances in this species, or even a lack of local adaptation. Hence, a more regional perspective for adaptation research in beech might be appropriate. Here, we investigated the performance (height, height increment and mortality) and genetic structure based on microsatellite markers of 2400 beech seedlings from provenances growing along a temperature and precipitation gradient in Northern Germany in a common garden experiment. Differences for all traits were found among provenances. Provenances from lower precipitation areas did not perform better than provenances from higher precipitation areas at the common garden site, which was located near the lower precipitation limit of beech. Further, neighboring provenances growing on either sandy or loamy soils showed more different adaptive trait variation than distant provenances. We detected minor genetic structure among provenances and a high genetic diversity within them. Thus, small-scale adaptive trait variation in beech can occur, despite low but significant genetic population structure among provenances.

Keywords

  • Mortality
  • adaptive traits
  • climate change
  • genetic diversity
Open Access

Whole-genome draft assembly of Populus tremula x P. alba clone INRA 717-1B4

Published Online: 27 Oct 2017
Page range: 74 - 79

Abstract

Abstract

Populus trichocarpa and P. deltoides are the only Populus species known to date to have a publicly available nuclear genome sequence that has been assembled to chromosomes and annotated (https://phytozome.jgi.doe.gov/). Here we focus on the clone INRA 717-1B4, a female P. tremula x P. alba (P. x canescens) interspecific hybrid that is universally used by scientists worldwide as a tree model in transgenic experiments. The already available INRA 717-1B4 nuclear genomic resource (v1.1 of sPta717 at http://aspendb.uga.edu/index.php/databases/spta-717-genome) presents only INRA 717-1B4 genomic regions with high similarity to the P. trichocarpa genomic reference sequences. We assembled draft genomic scaffolds by a combination of de novo assembly with reference-based assembly using 30x resequencing NGS data (Illumina MiSeq® and Ion Torrent Ion PGM™) of INRA 717-1B4. In total, 419,969 scaffolds of length larger than 500 bp were generated. The mean length of the scaffolds is 2,166 bp and the size of the largest scaffold 84,573 bp. The N50 contig length is 3,850 bp when considering contigs larger than 1,000 bp. Probably due to the high level of heterozygosity of this interspecific hybrid, the accumulated scaffold length is with 0.9 GB about twice the expected size of the haploid nuclear genome. DNA sequences of the genomic scaffolds of INRA 717-1B4 are publicly available for Blast analyses and download via the new INRA web portal at https://urgi.versailles.inra.fr/Species/Forest-trees/Populus/Clone-INRA-717-1B4/. This new genomic sequence resource will complement the already available INRA 717-1B4 resources and will facilitate the future optimization of genetic transformation experiments to discover gene function.

Keywords

  • INRA 717-1B4
  • P. x canescens
  • poplars
  • next generation sequencing
  • genome assembly
  • scaffolds
  • model tree
Open Access

Genetic effects on heartwood color variation in Cryptomeria japonica

Published Online: 27 Oct 2017
Page range: 80 - 87

Abstract

Abstract

To obtain fundamental and useful information regarding heartwood color traits in Japanese cedar, the validity of using L* index for expressing heartwood color and genetic and environmental influences on heartwood color were analyzed using 118 clones with 303 individuals aged approximately 30 years. As for three clones with typical reddish and blackish heartwood, relationships between heartwood color and moisture/potassium content, which were pointed out as ones of the causative agents of blackish heartwood, and the color change after approximately 20 years of conservation were investigated.

Based on the continuity, width range, and standard deviation of each index of L*a*b* data, L* was found out to be an appropriate index to express heartwood color in this species. L* values significantly differed between clones. A moderately high repeatability of clones was detected in L* value. Spatial autocorrelation analysis also showed a stronger effect genetically than environmentally. Moisture and potassium contents significantly differed between two groups of reddish and blackish heartwood. Therefore, the absorption and accumulation of water and potassium into trunk may be genetically regulated. As for the L* value of heartwood color after approximately 20 years of conservation, the difference between two groups was still significant, but the lightness in blackish heartwood increased such that the difference was greatly reduced.

Keywords

  • Japanese cedar
  • heartwood color
  • L*a*b* color sytem
  • spatial autocorrelation
  • potassium

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