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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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Détails du magazine
Format
Magazine
eISSN
2509-8934
Première publication
22 Feb 2016
Période de publication
1 fois par an
Langues
Anglais

Chercher

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

Détails du magazine
Format
Magazine
eISSN
2509-8934
Première publication
22 Feb 2016
Période de publication
1 fois par an
Langues
Anglais

Chercher

27 Articles
Accès libre

Identification of SNPs in candidate genes potentially involved in bud burst in European beech (Fagus sylvatica L.)

Publié en ligne: 07 Jun 2017
Pages: 1 - 20

Résumé

Abstract

European beech (Fagus sylvatica L.) is one of the most important deciduous tree species in Central Europe. Higher annual mean temperatures caused by climate change lead to earlier bud burst in spring and/or a delay of leaf senescence in autumn. Since earlier bud burst might increase the late frost risk, adaptive traits like bud burst may gain more importance in the future. Nevertheless, knowledge of the genetic background of leaf unfolding is still scarce for European beech. In the present study, we analyzed parts of ten different candidate genes for bud burst with a total length of 12,290 bp. Comparative sequencing with plant material of 12 different beech populations distributed over Germany revealed 116 SNPs (single nucleotide polymorphisms) and 20 indels. A subset of 46 SNPs was successfully used for genotyping of 100 offspring of a beech population in Germany confirming the suitability of the newly developed SNP set for population genetic studies. The provided data may be useful for further investigations of adaptation in F. sylvatica.

Mots clés

  • climate change
  • adaptation
  • SNPs
  • candidate genes
  • European beech
  • bud burst
Accès libre

How small and constrained is the genome size of angiosperm woody species

Publié en ligne: 07 Jun 2017
Pages: 20 - 32

Résumé

Abstract

Angiosperm hardwood species are generally considered to show an average smaller genome size with a narrow range of variation than their herbaceous counterparts. Various explanations pertaining to limitations of cell size exerted by wood fibers, the requirement of smaller stomata, longer generation time, large population size, etc., have been put forward to account for their small and constrained genome size. Yet studies done in the past several years show that genomically as well as evolutionarily, hardwoods are as diverse and active as their herbaceous counterparts. This is entirely supported by the presence of well developed inter and intraspecific polyploid series and natural triploidy in many genera. Polyploidy, in some instances has been shown to confer adaptability to arid and salt stress conditions and in colonization of new areas. Moreover, hardwoods also show reasonable amenability to the induced polyploidy which abruptly changes the balance between nuclear and cell size. Polyploidy has been induced in many hardwoods to restore fertility in interspecific hybrids and for the production of triploids.

Furthermore, some cases studied show that genome size variation in hardwoods can be as variable as that of herbaceous species. Genome size has been shown to vary remarkably both at homoploid level as well as by polyploidy in certain genera. In the same way, the genome size is not correlated with the habit in certain groups having both herbaceous and woody taxa. This point is further proved by the presence of secondary and insular woody habit in certain cases where either the transition to woodiness is not followed by any diminution in the genome size, or the genome size of insular woody species may be even more than that of the congeneric herbaceous species. This shows that woody habit does not by itself put any constraints on the genome size either at homoploid or at polyploidy levels. The genome size in fact, not only varies significantly in many congeneric woody species but also may not show any correlation with the habit when woody and herbaceous species are compared in some narrow taxonomic groups studied.

Mots clés

  • hardwoods
  • constrained and small genome size
  • genome size variation
  • natural and induced polyploidy
  • insular and secondary woody habit
Accès libre

Genetic variation and origin of teak (Tectona grandis L.f.) native and introduced provenances

Publié en ligne: 07 Jun 2017
Pages: 33 - 46

Résumé

Abstract

A total of 420 individuals belonged to 18 native teak (Tectona grandis L.f.) provenances from all four distributed countries and 10 introduced provenances were analyzed to for genetic variation, structure and genetic origin using SSR markers. The unbiased gene diversity for each provenance ranged from 0.4692 to 0.8523 with a mean value 0.6612, showing high variation within teak provenances and variation in India provenances was highest than in other countries’ provenances.

AMOVA analysis showed that the majority of variation existed within provenances (84.760%) and also substantial variation among countries (10.586%). As more as possible plus trees from large population should be selected or conserved in order to keep genetic variability for future improvement. Different countries populations should be preserved in the natural habitat or collected for ex site conservation with cooperation and region-wise strategies.

A Mantel test revealed significant correlation between genetic distances and geographic distances of teak provenances (R=0.7355, P<0.001). The cluster analyses by UPGMA, PCA and STRUCTURE methods gave very similar results, showing India provenances were firstly differentiated, and Laos provenances clustered with Thailand provenances, then introduced provenances and Myanmar provenances successively joined in the clusters. The introduced provenances no. 19, 20, 22, 23, 25, 27 and 28 appeared to be very closely linked to Laos provenances (especially no. 17) and Thailand provenances (especially no. 5 and 6), while provenances no. 21, 24, 26 may be originated from Myanmar provenance (especially no. 16).

Mots clés

  • Tectona grandis
  • genetic variation
  • genetic structure
  • genetic relationship
  • geographic origin
Accès libre

Investigation of gas exchange and biometric parameters in isogenic lines of poplar differing in ploidy

Publié en ligne: 07 Jun 2017
Pages: 46 - 59

Résumé

Abstract

Three poplar clones of section Populus (Brauna 11 [Populus tremula], L447 [Populus canescens] and Esch 5 [Populus tremula × Populus tremuloides]) were used to analyse the effects of ploidy levels on primary productivity and water use efficiency. The clones were established in tissue culture (2N) and lines with different ploidy levels (2N/4N and 4N) were generated via colchicine treatment. Light response curves were modelled based on gas exchange measurements carried out three times during the growing season on the 1st fully developed leaf under controlled conditions. The plants were harvested in September to analyse biometric parameters. The photosynthetic capacity was greatest in May, decreased throughout the season and increased slightly again in September. The decrease in Brauna 11 and Esch 5 varied from 20-50% compared with values in May and it was not as pronounced in L 447. Photosynthesis and intrinsic water use efficiency differed between clones, but not among the single isogenic lines within each clone. The seasons in which the experiments were conducted influenced the rankings of the 9 variants in physiological measurements, but these rankings were not uniform during the growing period. Differences in biometric parameters were detected between the clones and variants, e.g.; leaf masses were greater in all of the polyploid variants and lowest in the diploid variants. All of the L 447 lines showed the highest wood densities, which were higher in the mixoploid and lower in the tetraploid variants within each clone. A compact wood structure could prevent damage to the water-conducting system under drought stress.

Keywords

  • poplar
  • diploid
  • mixoploid
  • tetraploid
  • net photosynthesis
  • water use efficiency
  • specific leaf area
  • photosynthetic capacity
  • light response curve
  • wood density
Accès libre

Estimation of genetic parameters for height using spatial analysis in Tsuga heterophylla full-sibling family trials in British Columbia

Publié en ligne: 07 Jun 2017
Pages: 59 - 73

Résumé

Abstract

Non-spatial and spatial analyses were carried out to study the effects on genetic parameters in ten-year height growth data across two series of 10 large second-generation full-sib progeny trials of western hemlock [Tsuga heterophylla (Raf.) Sarg.] in British Columbia. To account for different and complex patterns of environmental heterogeneity, spatial single trial analyses were conducted using an individual-tree mixed model with a two-dimensional smoothing surface with tensor product of B-spline bases. The spatial single trial analysis, in all cases, showed sizeable lower Deviance Information Criterion values relative to the non-spatial analysis. Also, fitting a surface displayed a consistent reduction in the posterior mean as well as a decrease in the standard deviations of error variance, no appreciable changes in the additive variance, an increase of individual narrow-sense heritability, and accuracy of breeding values. The tensor product of cubic basis functions of B-spline based on a mixed model framework does provide a useful new alternative to model different and complex patterns of spatial variability within sites in forest genetic trials. Individual narrow-sense heritabilities estimates from the spatial single trial analyses were low (average of 0.06), but typical of this species. Estimated dominance relative to additive variances were unstable across sites (from 0.00 to 1.59). The implications of these estimations will be discussed with respect to the western hemlock genetic improvement program in British Columbia.

Mots clés

  • Tsuga heterophylla
  • non spatial and spatial single trial analysis
  • model comparison
  • spatial multi environment trial analyses
  • B spline
  • Additive and Dominance variances
  • Heritability
  • Genotype by environmental interactions
Accès libre

Near rotation-length performance of selected hybrid larch in Central Maine, U.S.A

Publié en ligne: 07 Jun 2017
Pages: 73 - 80

Résumé

Abstract

Twenty-two year measurements of a test of inter- and intraspecific larch hybrids among European (E), Japanese (J) and tamarack (T) parents growing in central Maine reveal significant hybrid vigor, especially among crosses involving J and E parents. The mean heights and diameters of all the interspecific crosses between J and E parents exceeded those of intraspecific crosses among either of the parents. The mean height after 22 years for all 17 JxE and ExJ crosses was 19.2 m (63 feet), which compares favorably with heights of loblolly pine plantations at age 25 growing in the southeastern USA, where site index ranged from 12.2 m to 24.4 m (40 and 80 feet respectively). In addition the mean height of these larch crosses was 30% greater than that of a control hybrid seed lot of German origin. Crosses between E and T parents also performed well, but exhibited relatively poor form, and seed set was very low. Seed set and viability for crosses between J and E were as good as intraspecific parental crosses. Therefore propagation of hybrid larch crosses via controlled pollination and rooted cuttings is feasible, and the potential benefits of larch plantations for Maine’s forest economy are briefly discussed.

Mots clés

  • Hybrid larch
  • hybrid vigor
  • heterobeltiosis
  • Japanese larch
  • European larch
  • tamarack
Accès libre

Genetic parameters and prediction of breeding values in Castanopsis hystrix A.DC. for growth and form traits

Publié en ligne: 07 Jun 2017
Pages: 81 - 90

Résumé

Abstract

Castanopsis hystrix A.DC. is one of the most important and multipurpose tree species native to China. 157 open-pollinated families collected from 11 provenances in Guangdong, Guangxi, and Fujian province were used to estimate genetic parameters for height (H), diameter at breast height (DBH), ground diameter (GD), and crown width (CW) for each province and combined three provinces at ages from 3 to 9 years. The variance component was small and non-significant among provenances but was highly significant among families within provenances for H, DBH, GD, and CW. Heritability estimates were significant except for a few traits from Fujian’s provenances. Heritability ranged from 0.20 to 0.57 for H, 0.19 to 0.38 for DBH, 0.21 to 0.55 for GD, and 0.09 to 0.39 for CW. Heritability estimates for H and DBH decreased with increased age for each province and combined three provinces. Significantly high genetic correlations were observed for ageage and trait-trait correlations, indicating that genetic performance at one trait was well correlated with another trait. In total, 22 families and 60 individuals were selected for backward and forward selection based on breeding values.

Mots clés

  • Castanopsis hystrix
  • additive variance
  • individual heritability
  • genetic correlation
  • breeding values
Accès libre

Fertility Variation and its Impact on Effective Population Size in Seed Stands of Tamarindus indica and Azadirachta indica

Publié en ligne: 07 Jun 2017
Pages: 91 - 99

Résumé

Abstract

Growth and reproductive traits were assessed in seed stands of two native Indian tree species Tamarindus indica and Azadirachta indica. Positive correlation between growth (height and GBH) and reproductive traits (male and female contribution) were found in both species. Fertility was estimated from the flower and fruit production of individuals. Based on the fertility variation among individuals, parental balance, femaleness index and status number (Ns) were determined. The option of equal seed collection among individuals was also considered for estimating Ns. The percentage of fertile trees was higher in the high flowering year in both species. The best male contributing individuals also showed high female contribution (fruit production). The parental contribution in seed stands showed high deviation from expectation; 20% individuals contributed about 70% of male and female gametes in both species. Femaleness index showed that female and male contribution of individual tree was more balanced in the good flowering year, compared to the poor year. Coefficient of variation in male and female fertility was higher in the low flowering year resulting in high fertility variation among individuals and low status number. In T. indica, the female contribution was less variable compared to that of male fertility whereas in A. indica the female fertility variation was higher than that of male fertility. The relative status number (Nr = Ns/N) of the stands was lower for male and female fertility compared to the combined (male and female) fertility of individual trees.

Mots clés

  • status number
  • effective number of parents
  • sibling coefficient
  • gene diversity
  • equal seed harvest
  • Tamarindus indica
  • Azadiracta indica
Accès libre

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Publié en ligne: 07 Jun 2017
Pages: 99 - 108

Résumé

Abstract

Polyploid breeding has the potential to increase the economic secondary metabolites of Eucommia ulmoides. However, pollination with induced ploidy-mixed pollen has failed to produce polyploids (GAO, 2006). In this investigation, the morphological characterization and in vitro germination of heat-induced ploidy-mixed pollen of E. ulmoides were analysed to determine why there is no polyploid production. Heat-treated pollen grains were easily distinguished as large and small according to their length. The large pollen grains were significantly longer than both untreated and heat-treated small samples, suggesting that they were probably 2n pollen. Rather than the three germinal pores in small pollen, the large grains typically had four pores and, in some cases, shallow furrows, which might affect their germination. Although the maximal germination rates of the treated small and large pollen were not significantly different, the large pollen germinated tardily during the early stages of incubation. The small pollen maintained its growth during the incubation, but the tube growth of large pollen almost stopped after 24 h incubation. Both vegetative and generative nuclei in the large pollen moved into tubes later than in small pollen and the frequency of mitosis in generative nuclei of large pollen was low. Therefore, the tardy germination, poor tube growth, and weak activity of both vegetative and generative nuclei probably caused the poor competition of large pollen in certation. Finally, techniques to increase the competition of highploidy pollen and the prospect of 2n female gamete induction in the polyploid breeding program of E. ulmoides are discussed.

Mots clés

  • Eucommia ulmoides Oliver
  • heat-treated pollen
  • polyploid breeding
  • poor competition
  • tardy germination
Accès libre

Individual, fruit, and annual variation in correlated mating in a Genipa americana population

Publié en ligne: 07 Jun 2017
Pages: 108 - 116

Résumé

Abstract

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.

Mots clés

  • Inbreeding
  • Mating system
  • Microsatellite markers
  • Tropical tree species.
Accès libre

Five Years Performance of New Introduced Salt Tolerant Hybrid Poplar clones (Mofid and P. × albaeuphratica) In Iran (West Azar-Bayjan)

Publié en ligne: 07 Jun 2017
Pages: 117 - 120

Résumé

Mots clés

  • Hybrid poplar
  • Inter specific hybrid
  • Populus euphratica Oliv. × P. alba L.
  • Populus alba L. × P. euphratica Oliv
Accès libre

Differentiation of six Eucalyptus trees grown in Mexico by ITS and six chloroplast barcoding markers

Publié en ligne: 07 Jun 2017
Pages: 121 - 130

Résumé

Abstract

Different species of the genus Eucalyptus, originally native to Australia, are being cultivated in different parts of the world due to their fast growth and beneficial wood properties. In Mexico, probably up to 25 different Eucalyptus species (many of them with unknown species declaration) were introduced early in the 20th century. Many Eucalyptus species are cross compatible and information about provenances of the single eucalypt species is rare. In this study, an experimental plantation established in 1984 and located in Northeast of Mexico was chosen as example to re-assign the species name of six randomly selected Eucalyptus trees growing in this plantation. First, a phylogenetic tree was constructed from complete chloroplast sequences of 31 Eucalyptus species available in the NCBI database. The phylogenetic tree includes three of the nine Eucalyptus species known to be introduced to Mexico, namely E. camaldulensis, E. saligna and E. grandis, which belong to a clade named “Symphyomyrts”. By employing combined BLASTN and UPGMA analyses of six chloroplast (cp) regions, three of the six unknown eucalypt samples (Euc4, 5, 6) cluster together with E. microtheca and E. cladocalyx, whereas the other three (Euc1, 2, 3) were more similar to a group containing E. camaldulensis, E. grandis and E. saligna. UPGMA analysis of the ITS region overall shows the same rough clustering, but provide more detailed information for two samples being most likely assigned to E. camaldulensis.

Mots clés

  • matK
  • rbcL
  • intergenic linker
  • psbA_matK
  • psbK_psbI
  • trnG_psbK
  • matK_trnK
  • chloroplast
  • Internal transcribed spacer
Accès libre

Provenance by site interaction and stability analysis of European beech (Fagus sylvatica L.) provenances grown in common garden experiments

Publié en ligne: 07 Jun 2017
Pages: 133 - 147

Résumé

Abstract

Fifteen provenances of European beech (Fagus sylvatica L.) were evaluated for stability and adaptability by height growth at four test sites in Bosnia and Herzegovina (1), Croatia (1) and Serbia (2). Provenance trials were established in spring 2007 by planting 2- and 3-yearold seedlings and arranged in a randomized complete block design. The data from seven 6- year-old and eight 5-year-old provenances were obtained in 2009 and analyzed separately. Finlay and Wilkinson’s regression analysis and Additive main effects and multiplicative interaction model (AMMI model) were used to assess provenance by site interaction (P × S) and to identify beech provenances that have high and stable performance in different environments, at the juvenile stage of development. Analysis of variance showed that effects of provenance, site, and P×S interaction are highly significant (p<0.001) in both age groups. Linear regression model evidenced that most of the provenances had regression coefficients not significantly different from unity (b=1.0), except for provenances Sjeverni Dilj Caglinski (HR24) and Vranica-Bistrica (BA59). The partitioning of the total sum of squares (SS) exhibited that the site effect was the predominant source of variation in both age groups of provenances (50.7% and 38.5%, respectively). Additionally, regression analysis explained 15.8% and 33.2% of provenance by site interaction terms, in provenances age six and five years, respectively, while the AMMI analysis accounted for 62.2% and 78.7% in P×S interaction. The results of AMMI showed that the first principal component (PC1) was statistically significant in both age groups. Adaptability and stability of provenances to the test sites were estimated with AMMI1 and AMMI2 biplots. Provenance Sjeverni Dilj Caglinski (HR24) showed constant performance over tested sites, characterizing with aboveaverage height growth at low yielding environments. Provenances HR25 and BA61 showed the opposite type of adaptation, being adapted to high yielding sites. Provenance Valkonya (HU42) was characterized by IPCA1 score close to zero and above average mean height growth, suggesting general adaptation to the tested environments. The implication of P×S was discussed in light of impact of climate change on beech and selection of most suitable provenances for future reforestation programs.

Mots clés

  • European beech
  • provenance trial
  • provenance × site interaction
  • linear regression model
  • AMMI analysis
  • biplot.
Accès libre

Expression of three phenylpropanoid pathway genes in Scots pine (Pinus sylvestris L.) in open-pollinated families with differing relative wood densities during early and late wood formation

Publié en ligne: 07 Jun 2017
Pages: 148 - 159

Résumé

Abstract

Wood volume and quality are the most important aspects of commercial forestry production, and studies of wood formation are important in order to increase the value and efficiency of forestry production. The phenylpropanoid pathway produces various compounds with diverse functions both for plant defence against biotic and abiotic stress as well as structural development. One of the main roles is monolignol production for lignin biosynthesis, which is a crucial aspect of wood formation. For this study three candidate genes involved in lignin biosynthesis were selected: phenylalanine ammonialyase (PAL1), cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR). Candidate gene expression was analysed in selected individuals with high and low wood density from open-pollinated Scots pine families during early wood (EW) and late wood (LW) formation and correlation between expression of these genes, total lignin content, and wood density was determined. Wood density values for analysed trees were similar within tree families but differed significantly between families with high and low wood density (p=1,06E-20). Wood density was slightly negatively correlated with lignin content (r=-0.36, p=0.038), but only in individuals in the high density wood group. In trees with low wood density, expression of the CAD gene was significantly lower in late wood formation compared to early wood (p=0.00179). In trees with high wood density, expression of the PAL1 gene was five times higher during early wood formation compared to late wood formation. A positive correlation was detected between PAL1 and CCR gene expression during early wood formation (r=0.804) and late wood formation (r=0.466).

Mots clés

  • CAD
  • CCR
  • PAL1
  • Scots pine
  • Pinus sylvestris
  • wood density
  • early wood
  • late wood
Accès libre

Genetic and phenotypic correlations among volume, wood specific gravity and foliar traits in white spruce (Picea glauca (Moench) Voss)

Publié en ligne: 07 Jun 2017
Pages: 159 - 170

Résumé

Abstract

White spruce is highly valued by the forest products industry in North America. Through tree improvement efforts, selected genotypes can exceed wild sources by 30% in volume. Negative correlations between growth and wood specific gravity have been established, but differences in leaf morphology between high and low performing genotypes are less well understood. We sampled five trees from each of 30 families at each of two locations in a 25-year old progeny test in Minnesota. One wood core was collected from each tree to sample wood specific gravity (WSG), along with a branch collected from the upper crown to examine foliar traits. We confirmed negative correlations between stem volume and WSG, but several families combined high wood volume with only small reductions in WSG. Leaf area ratio and specific leaf area were positively, genetically correlated with volume growth but not correlated with WSG. Increased growth rates of selected genotypes may be attributed, in part, to shifts in allocation to leaves and in leaf morphology that may optimize light interception.

Mots clés

  • white spruce
  • genetic correlations
  • wood specific gravity
  • specific leaf area
  • genotype by environment interaction
  • foliar nitrogen
Accès libre

Use of genetic markers to build a new generation of Eucalyptus pilularis breeding population

Publié en ligne: 07 Jun 2017
Pages: 170 - 181

Résumé

Abstract

Tree improvement generally proceeds by incremental gains obtained from recurrent selection in large diverse populations but is slow due to long generation times and delay till trees reach assessment age. This places a premium upon extracting data from historic introductions used to found landraces when reinstating modern breeding programs. The value of such resources, however, may be degraded due to a lack of records on germplasm origins, pedigrees and early performance, but DNA technology may help recoup some of this value. Eucalyptus pilularis (subgenus Eucalyptus) is regarded as a premier hardwood plantation species for saw log and poles in Australia, but has not been used extensively despite early introductions and testing in many countries overseas. Here we use DNA fingerprinting to assess genetic diversity and inbreeding in historic introductions of E. pilularis to evaluate this resource in advance of a reinvigorated breeding effort for this species in Brazil. As expected, based on the available documentation for the introductions, genetic diversity relative to Australian reference populations does not appear to be compromised, and there was unlikely to be excessive inbreeding. Also, favorable, was the likelihood that further selections should not unduly increase the relationship in the next generation. Interestingly, we note the importance of testing widely adapted sources of germplasm when making introductions, as provenances which performed poorly in tests on productive sites in Australia, may have value when matched with lower fertility sites overseas.

Mots clés

  • Blackbutt
  • genetic diversity
  • relatedness
  • growth
  • pedigree information
Accès libre

Tracing the origin and species identity of Quercus robur and Quercus petraea in Europe: a review

Publié en ligne: 07 Jun 2017
Pages: 182 - 193

Résumé

Abstract

Traceability of forest material has received recently increasing interest and European regulations already apply on forest reproductive material and timber. DNA fingerprinting methods allow identification of species and control of geographic origin, providing that genetic reference data is available. In this review, we focus on the two economically important European oak species, Quercus robur and Q. petraea. We describe the available molecular markers and data, and discuss their applicability for traceability systems of forest reproductive material at a European scale. We also provide insights on the use of DNA fingerprinting on timber material.

Mots clés

  • Quercus
  • oak
  • molecular markers
  • traceability
  • Europe
  • forest reproductive material
  • timber
Accès libre

PCR-RFLP analysis of cpDNA in Gigantochloa scortechinii (Poaceae: Bambuseae) in Peninsular Malaysia and implications for the use of cpDNA markers in systematic studies

Publié en ligne: 07 Jun 2017
Pages: 194 - 200

Résumé

Abstract

Gigantochloa is a paleotropical woody bamboo genus that has been widely cultivated in SE Asia because of its usefulness. Recent studies have shown that species of this genus enter into an introgression complex with other genera of the same subtribe Bambusinae. Within G. scortechinii, a common species indigenous to Malay Peninsula and common in Peninsular Malaysia, two distinct chloroplast DNA (cpDNA) lineages, the Gombak- and Langat-type, were recovered. We report the development of a PCR-based restriction fragment length polymorphism (RFLP) marker for depicting the genetic differentiation in G. scortechinii based on cpDNA. We determined a cpDNA region and its corresponding restriction enzyme which can produce different RFLP profiles for the two cpDNA lineages. Our design was verified with empirical studies. The Gombak-type was the dominant cpDNA genotype for G. scortechinii in Peninsular Malaysia. Implications for the continued use of cpDNA markers in systematic studies are discussed.

Mots clés

  • chloroplast capture
  • cpDNA differentiation
  • Gigantochloa
  • population genetics
  • restriction digestion
Accès libre

Genetic diversity and spatial genetic structure in populations of Orbignya phalerata Mart. under different exploitation intensities in the Brazilian savanna

Publié en ligne: 07 Jun 2017
Pages: 201 - 211

Résumé

Abstract

Genetic studies in tropical tree species have found signs of decreased genetic diversity and increased levels of inbreeding and spatial genetic structure (SGS) in fragmented and exploited populations. The aim of this paper was to investigate genetic diversity, structure, and intrapopulation SGS using eight microsatellite loci for three Orbignya phalerata populations that have undergone different intensities of seed harvesting. From each population, we georeferenced and sampled 30 seedlings, 30 juveniles, and 30 adult trees. The total number of alleles over all loci (k), and observed (Ho) and expected heterozygosity (He) presented lower values for the population experiencing more intense fruit harvesting than less heavily exploited populations, suggesting that fruit harvesting may decrease genetic diversity. Null alleles were detected in practically all loci among seedlings, juveniles, and adults in all populations, indicating that the estimates of Ho, He, and fixation index (F) are biased. When corrected for null alleles (FNull), the fixation index decreased for all samples, resulting in significantly higher than zero results for seedlings of all populations, but not for juveniles and adults of all populations. The comparison of FNull values between cohorts in the most heavily exploited population (ESP) suggests that inbred individuals are eliminated between seedling and adult stages. Significant SGS was detected up to 60 m in all populations, which indicates short distance seed dispersal. Genetic differentiation (G’ST) between pairwise populations was related to spatial distance between populations, with the greatest difference between more distant populations.

Mots clés

  • babassu
  • Orbignya phalerata
  • forest management
  • exploitation
  • genetic diversity
Accès libre

Development of PCR based markers in Terpene synthase genes for marker assisted selection of high resin yielders in Pinus roxburghii Sarg

Publié en ligne: 07 Jun 2017
Pages: 211 - 220

Résumé

Abstract

Pine oleoresin is a complex mixture of volatile and nonvolatile terpenes and is exploited for commercial production in India. Pines have long reproductive cycle vegetative phase extending upto many years. Therefore, there is an urgent need to identify high resin pine yielders at an early stage. Due to the strong influence of genetic factors on resin yield in pine species, marker assisted selection may serve as a potential tool for early identification of the genotype of interest. This study was planned to identify high resin pine yielders at early stage to avoid exploitation of natural germplasm of chir pine. Protein sequences of different terpene synthases were downloaded from the NCBI database and were multiply aligned to identify conserved and variable regions across the sequences. Primers were designed based on the related coding sequences to target these regions using Primer 3 software to amplify and isolate related genomic loci in chir pine genotypes. These primers were characterized for specificity using Primer Blast and the presence of hairpin loop formation using OligoCalc software. DNA was extracted from different resin yielding pine genotypes and primers were run on them for molecular studies. With the help of bioinformatics tools, we were able to associate some markers with resin yield. This study holds a key promise for the conservation of pine germplasm in natural habitat.

Mots clés

  • Pinus roxburghii Sarg
  • Terpene synthase
  • PCR-marker
  • Bioinformatics
  • association analysis
Accès libre

Association mapping for identification of ISSR and AFLP markers linked with resin yield in Himalayan Chir Pine (Pinus roxburghii Sarg

Publié en ligne: 07 Jun 2017
Pages: 220 - 239

Résumé

Abstract

In Pinus roxburghii, marker-trait associations were studied for resin yield using a set of 238 DNA based markers derived from 9 ISSR and 5 AFLP primer pairs. A total of 240 genotypes of P. roxburghii from a natural population in Chakrata division (Tiunee range), Uttarakhand (India) were evaluated for resin yield. Based on stable resin production in consecutive years, 53 genotypes that were best representatives of the variation in resin yield (0.25 to 8.0 kg/tree/year) were used for genotyping and association analysis. For carrying out the association studies, two approaches were used. First, using simple linear regression, resin yield was regressed on all 238 available polymorphic markers (148 ISSR markers and 90 AFLP markers) and second, evidence for association was examined applying population structure information using STRUCTURE and STRAT to avoid any spurious associations between a candidate marker and phenotype. In regression analysis, 16 ISSR and 12 AFLP markers showed significant association with resin yield. In the second approach, 18 ISSR and 18 AFLP loci were found to be associated with resin yield in the absence of population structure out of which 2 ISSR and 3 AFLP loci were common with those associated in regression analysis. After accounting for population structure, 38 ISSR, and 3 AFLP loci revealed association out of which one ISSR and one AFLP locus was found to be common with both simple linear regression and test of association in the absence of population stratification. There was no obvious correlation between population structure and resin yield.

Mots clés

  • regression
  • population structure
  • structured association test
  • ISSR
  • AFLP
  • Pinus roxburghii
Accès libre

Inducing genetic variation in growth related characteristics of poplar germplasm, by producing inter-specific hybrids between P. alba and P. euphratica

Publié en ligne: 07 Jun 2017
Pages: 239 - 248

Résumé

Abstract

Crosses were made between two Populus species to create two hybrid groups, P. alba ♀ * P. euphratica ♂ and P. euphratica ♀ * P. alba ♂. Aseptic immature hybrid seeds were first grown on MS medium. Hybrid seedlings were then acclimatized and grown in greenhouse conditions and transplanted to an experimental field. Growth related characteristics were recorded on 307 three years-old seedlings of new inter-specific hybrids of six half-sib families, in order to assess possible potentials of the two hybrid groups. Double nested analysis of variance revealed significant differences between the hybrid groups and siblings based on majority of the studied characters. The hybrid groups formed two distinct groups for some of the studied characteristics which implied maternal effects of inheritance on the traits. The first hybrid group had more but shorter and closer branches than the second group. Adaxial stomata number for the two hybrid groups varied between 4.7 to 123. Whereas, there were no such strong differences between vegetative characteristics of the two groups. The second hybrid group had a very condense layer of white fuzz on its abaxial leaf surface, inherited from its female parents. This may lead to suggest some kinds of photosynthesis and respiration functions such as leaf sub-stomatal chambers’ functions for the mentioned fuzzy trichomes of the second hybrid group and their female parental species, P. alba. In essence, 307 new divergent poplar hybrid genotypes were produced by which ecological zone of poplar species could be extended in the country as well as high yielding genotypes would be promising.

Mots clés

  • Populus euphratica
  • Populus alba
  • Nested ANOVA
  • Inter specific hybrids
  • Adaxial stomata
  • Morphologic traits
Accès libre

Mating system variation among populations, individuals and within and among fruits in Bertholletia excelsa

Publié en ligne: 07 Jun 2017
Pages: 248 - 259

Résumé

Abstract

The aim of this study was to investigate variation in mating system among three Brazilian Amazon populations of the tree Bertholletia excelsa with different levels of anthropogenic interventions. We collected open-pollinated seeds from one natural population, remnant trees dispersed in a pasture, and trees from a plantation. Outcrossing rate not varied among the populations and indicates that all seeds were originated from outcrossing (tm=1.0). Mating among relatives was significant higher in the plantation than forest and pasture populations, probably due the fact that many trees are related in the plantation. Correlated mating was significantly higher in pasture (rp=0.47) and plantation (rp=0.51) than in the natural population (rp=0.22), suggesting that trees in natural population are pollinated by a higher number of pollen donors. The paternity correlation was significantly higher within (rp(w)=0.41) than among fruits (rp(a)=0.18), showing a higher probability to find full-sibs within than among fruits. The fixation index was generally lower in seed trees than in their seedlings, suggesting selection for heterozygous individuals from seedling to adult stages. Progeny arrays collected from the natural population had a lower proportion of pairwise full-sibs than in pasture and plantation and higher variance effective size (2.75) than trees in pasture (2.15) and plantations (2.22). Results highlight that seed collections for conservation, breeding and reforestation programs preferentially should be carried out in natural populations due low proportion highest variance effective size within progeny.

Keywords

  • Brazil nut tree
  • Brazilian Amazon
  • conservation genetics
  • Lecythidaceae
  • microsatellite markers
  • population genetics
  • tropical tree species
Accès libre

PCR-based detection of single sequence variants from a natural collection of the non-model tree species European Aspen Populus tremula (L.)

Publié en ligne: 07 Jun 2017
Pages: 259 - 269

Résumé

Abstract

In the present study we present and discuss the identification of species-specific SNPs to rule out any experimental influence of species-specific primer design (Populus tremula vs. the closely related model-species Populus trichocarpa) on the detectability of SNPs. Applying a species-optimized method, partial sequences of 14 genes involved in xylem cell development, xylogenesis, pectin formation, and drought stress reaction were analyzed at the genomic level. About 3 Mb of sequence information were generated by Sanger sequencing technology and 258 sequence variants were identified. 15 out of these represent insertions /deletions located exclusively in non-coding regions and the remaining 243 are SNPs found in coding and non-coding regions of candidate genes.

The introduction of a species-specific SNP detection pipeline will help to detect nucleotide variants in P. tremula and to conduct association mapping in natural P. tremula populations.

Mots clés

  • drought stress tolerance
  • natural population
  • Populus tremula
  • SNP
  • xylem cell formation
Accès libre

Forest decline has not reduced genetic diversity of naturally regenerated Norway spruce from the Beskids, Poland

Publié en ligne: 07 Jun 2017
Pages: 270 - 278

Résumé

Abstract

Norway spruce forests decline in the Beskids raises concerns about reduction of genetic variation in a next generation of forest. We aim to determine whether the genetic diversity in declining spruce stands was successfully transmitted to its self-seeded progeny. Using three nuclear microsatellite markers, we carried out the genetic assessment of naturally regenerated progeny and compered them with their maternal stands at an initial stage of decline. We investigated three spruce stands from the Śląski and Żywiecki Beskid and one primeval forest from the Tatras, as a reference. We noticed a high level of gene diversity, allelic richness and an effective number of alleles in progeny of all stands, without differences between declining stands from the Beskids and the primeval forest. The gene diversity was similar in maternal trees and their offspring. Higher gene diversity and generally higher number of alleles were noticed in young generation of stands. Genetic identity between generations was high in analyzed seed stands and the highest in the primeval forest. The results we presented indicate no significant effect of drastic reduction in the population size due to the forest decline on the level of genetic variation in self-seeded progeny of Norway spruce from the Beskids.

Mots clés

  • forest decline
  • genetic diversity
  • Norway spruce
  • Beskids
  • natural regeneration
  • primeval forest
Accès libre

Logging decreases the pollen dispersal distance in a low-density population of the tree Bagassa guianensis in the Brazilian Amazon

Publié en ligne: 07 Jun 2017
Pages: 279 - 290

Résumé

Abstract

This study investigates the distance and patterns of pollen dispersal before and after logging in a low-density population of the dioecious, insect pollinated tree species, Bagassa guianensis, in the Brazilian Amazon. All adult trees found before and after logging in a 500 ha plot were mapped and genotyped for six microsatellite loci. Seeds collected before and after logging were also sampled and genotyped. We used a categorical paternity analysis to determine seed paternity. Our results showed similar levels of pollen flow before (23%) and after logging (26%), but an increase in the mean effective pollination neighbourhood area, and a decrease in the rate of mating among relatives after logging, resulting in open pollinated seeds with lower levels of inbreeding (0.126) than before logging (0.222). We also detected changes in the mating pattern between before and after logging, a decrease in the median pollen dispersal distance and effective number of pollen donors after logging. Our results support the idea that reproductive trees should be maintained in the plot and around logged areas, using lowest levels of logging intensity to maintain pollen flow and decrease the relatedness of subsequent generations.

Keywords

  • Dioecious species
  • paternity analysis
  • pollen dispersal
  • tatajuba
  • tropical tree species
Accès libre

Genetic Parameters of Interspecific Hybrids of Eucalyptus grandis and E. urophylla Seedlings and Cuttings

Publié en ligne: 07 Jun 2017
Pages: 291 - 308

Résumé

Abstract

The current E. grandis × E. urophylla hybrid breeding strategy of South Africa’s Forestry Industry is to maintain large breeding populations of both parental species in which parents are selected based on their general combining ability (GCA) estimates or predicted individual tree breeding values and are used for interspecific hybrid crosses. The hybrid material is first screened in seedling progeny trials after which superior individuals are selected and tested as clones. Although this strategy has delivered superior clones for commercial production in South Africa, it is a time consuming strategy to follow and more cost effective strategies are being investigated. In order to review the current hybrid breeding strategy, information on the genetic control of the traits of interest is needed for E. grandis × E. urophylla seedling and clonal populations. The main objectives of this study were therefore to firstly estimate genetic parameters for E. grandis × E. urophylla hybrid seedling and clonal populations; secondly to investigate the correlation between E. grandis and E. urophylla parental (GCA) or individual breeding values and their general hybridising ability (GHA); and lastly to determine the correlation between E. grandis × E. urophylla hybrid seedling ortets and their ramets.

Results of our study indicated that non-additive genetic variation explained the majority of the total genetic variation in E. grandis × E. urophylla seedling and clonal populations. Due to the pre-eminence of non-additive variance, the pure-hybrid correlations were weak, especially for clonal populations. It would therefore seem that GCA or predicted individual breeding values are not good predictors of GHA for growth performance in the observed populations. Our study also indicated a weak coefficient of correlation between the growth performance of seedling ortets and their ramets. These results suggest that: firstly a hybrid breeding strategy to capture non-additive genetic variation should be adopted; and secondly that the first phase of screening E. grandis × E. urophylla hybrid material as seedlings should be revisited.

Mots clés

  • Eucalyptus grandis x E. urophylla
  • genetic parameters
  • seedlings and cuttings
  • pearson correlations
27 Articles
Accès libre

Identification of SNPs in candidate genes potentially involved in bud burst in European beech (Fagus sylvatica L.)

Publié en ligne: 07 Jun 2017
Pages: 1 - 20

Résumé

Abstract

European beech (Fagus sylvatica L.) is one of the most important deciduous tree species in Central Europe. Higher annual mean temperatures caused by climate change lead to earlier bud burst in spring and/or a delay of leaf senescence in autumn. Since earlier bud burst might increase the late frost risk, adaptive traits like bud burst may gain more importance in the future. Nevertheless, knowledge of the genetic background of leaf unfolding is still scarce for European beech. In the present study, we analyzed parts of ten different candidate genes for bud burst with a total length of 12,290 bp. Comparative sequencing with plant material of 12 different beech populations distributed over Germany revealed 116 SNPs (single nucleotide polymorphisms) and 20 indels. A subset of 46 SNPs was successfully used for genotyping of 100 offspring of a beech population in Germany confirming the suitability of the newly developed SNP set for population genetic studies. The provided data may be useful for further investigations of adaptation in F. sylvatica.

Mots clés

  • climate change
  • adaptation
  • SNPs
  • candidate genes
  • European beech
  • bud burst
Accès libre

How small and constrained is the genome size of angiosperm woody species

Publié en ligne: 07 Jun 2017
Pages: 20 - 32

Résumé

Abstract

Angiosperm hardwood species are generally considered to show an average smaller genome size with a narrow range of variation than their herbaceous counterparts. Various explanations pertaining to limitations of cell size exerted by wood fibers, the requirement of smaller stomata, longer generation time, large population size, etc., have been put forward to account for their small and constrained genome size. Yet studies done in the past several years show that genomically as well as evolutionarily, hardwoods are as diverse and active as their herbaceous counterparts. This is entirely supported by the presence of well developed inter and intraspecific polyploid series and natural triploidy in many genera. Polyploidy, in some instances has been shown to confer adaptability to arid and salt stress conditions and in colonization of new areas. Moreover, hardwoods also show reasonable amenability to the induced polyploidy which abruptly changes the balance between nuclear and cell size. Polyploidy has been induced in many hardwoods to restore fertility in interspecific hybrids and for the production of triploids.

Furthermore, some cases studied show that genome size variation in hardwoods can be as variable as that of herbaceous species. Genome size has been shown to vary remarkably both at homoploid level as well as by polyploidy in certain genera. In the same way, the genome size is not correlated with the habit in certain groups having both herbaceous and woody taxa. This point is further proved by the presence of secondary and insular woody habit in certain cases where either the transition to woodiness is not followed by any diminution in the genome size, or the genome size of insular woody species may be even more than that of the congeneric herbaceous species. This shows that woody habit does not by itself put any constraints on the genome size either at homoploid or at polyploidy levels. The genome size in fact, not only varies significantly in many congeneric woody species but also may not show any correlation with the habit when woody and herbaceous species are compared in some narrow taxonomic groups studied.

Mots clés

  • hardwoods
  • constrained and small genome size
  • genome size variation
  • natural and induced polyploidy
  • insular and secondary woody habit
Accès libre

Genetic variation and origin of teak (Tectona grandis L.f.) native and introduced provenances

Publié en ligne: 07 Jun 2017
Pages: 33 - 46

Résumé

Abstract

A total of 420 individuals belonged to 18 native teak (Tectona grandis L.f.) provenances from all four distributed countries and 10 introduced provenances were analyzed to for genetic variation, structure and genetic origin using SSR markers. The unbiased gene diversity for each provenance ranged from 0.4692 to 0.8523 with a mean value 0.6612, showing high variation within teak provenances and variation in India provenances was highest than in other countries’ provenances.

AMOVA analysis showed that the majority of variation existed within provenances (84.760%) and also substantial variation among countries (10.586%). As more as possible plus trees from large population should be selected or conserved in order to keep genetic variability for future improvement. Different countries populations should be preserved in the natural habitat or collected for ex site conservation with cooperation and region-wise strategies.

A Mantel test revealed significant correlation between genetic distances and geographic distances of teak provenances (R=0.7355, P<0.001). The cluster analyses by UPGMA, PCA and STRUCTURE methods gave very similar results, showing India provenances were firstly differentiated, and Laos provenances clustered with Thailand provenances, then introduced provenances and Myanmar provenances successively joined in the clusters. The introduced provenances no. 19, 20, 22, 23, 25, 27 and 28 appeared to be very closely linked to Laos provenances (especially no. 17) and Thailand provenances (especially no. 5 and 6), while provenances no. 21, 24, 26 may be originated from Myanmar provenance (especially no. 16).

Mots clés

  • Tectona grandis
  • genetic variation
  • genetic structure
  • genetic relationship
  • geographic origin
Accès libre

Investigation of gas exchange and biometric parameters in isogenic lines of poplar differing in ploidy

Publié en ligne: 07 Jun 2017
Pages: 46 - 59

Résumé

Abstract

Three poplar clones of section Populus (Brauna 11 [Populus tremula], L447 [Populus canescens] and Esch 5 [Populus tremula × Populus tremuloides]) were used to analyse the effects of ploidy levels on primary productivity and water use efficiency. The clones were established in tissue culture (2N) and lines with different ploidy levels (2N/4N and 4N) were generated via colchicine treatment. Light response curves were modelled based on gas exchange measurements carried out three times during the growing season on the 1st fully developed leaf under controlled conditions. The plants were harvested in September to analyse biometric parameters. The photosynthetic capacity was greatest in May, decreased throughout the season and increased slightly again in September. The decrease in Brauna 11 and Esch 5 varied from 20-50% compared with values in May and it was not as pronounced in L 447. Photosynthesis and intrinsic water use efficiency differed between clones, but not among the single isogenic lines within each clone. The seasons in which the experiments were conducted influenced the rankings of the 9 variants in physiological measurements, but these rankings were not uniform during the growing period. Differences in biometric parameters were detected between the clones and variants, e.g.; leaf masses were greater in all of the polyploid variants and lowest in the diploid variants. All of the L 447 lines showed the highest wood densities, which were higher in the mixoploid and lower in the tetraploid variants within each clone. A compact wood structure could prevent damage to the water-conducting system under drought stress.

Keywords

  • poplar
  • diploid
  • mixoploid
  • tetraploid
  • net photosynthesis
  • water use efficiency
  • specific leaf area
  • photosynthetic capacity
  • light response curve
  • wood density
Accès libre

Estimation of genetic parameters for height using spatial analysis in Tsuga heterophylla full-sibling family trials in British Columbia

Publié en ligne: 07 Jun 2017
Pages: 59 - 73

Résumé

Abstract

Non-spatial and spatial analyses were carried out to study the effects on genetic parameters in ten-year height growth data across two series of 10 large second-generation full-sib progeny trials of western hemlock [Tsuga heterophylla (Raf.) Sarg.] in British Columbia. To account for different and complex patterns of environmental heterogeneity, spatial single trial analyses were conducted using an individual-tree mixed model with a two-dimensional smoothing surface with tensor product of B-spline bases. The spatial single trial analysis, in all cases, showed sizeable lower Deviance Information Criterion values relative to the non-spatial analysis. Also, fitting a surface displayed a consistent reduction in the posterior mean as well as a decrease in the standard deviations of error variance, no appreciable changes in the additive variance, an increase of individual narrow-sense heritability, and accuracy of breeding values. The tensor product of cubic basis functions of B-spline based on a mixed model framework does provide a useful new alternative to model different and complex patterns of spatial variability within sites in forest genetic trials. Individual narrow-sense heritabilities estimates from the spatial single trial analyses were low (average of 0.06), but typical of this species. Estimated dominance relative to additive variances were unstable across sites (from 0.00 to 1.59). The implications of these estimations will be discussed with respect to the western hemlock genetic improvement program in British Columbia.

Mots clés

  • Tsuga heterophylla
  • non spatial and spatial single trial analysis
  • model comparison
  • spatial multi environment trial analyses
  • B spline
  • Additive and Dominance variances
  • Heritability
  • Genotype by environmental interactions
Accès libre

Near rotation-length performance of selected hybrid larch in Central Maine, U.S.A

Publié en ligne: 07 Jun 2017
Pages: 73 - 80

Résumé

Abstract

Twenty-two year measurements of a test of inter- and intraspecific larch hybrids among European (E), Japanese (J) and tamarack (T) parents growing in central Maine reveal significant hybrid vigor, especially among crosses involving J and E parents. The mean heights and diameters of all the interspecific crosses between J and E parents exceeded those of intraspecific crosses among either of the parents. The mean height after 22 years for all 17 JxE and ExJ crosses was 19.2 m (63 feet), which compares favorably with heights of loblolly pine plantations at age 25 growing in the southeastern USA, where site index ranged from 12.2 m to 24.4 m (40 and 80 feet respectively). In addition the mean height of these larch crosses was 30% greater than that of a control hybrid seed lot of German origin. Crosses between E and T parents also performed well, but exhibited relatively poor form, and seed set was very low. Seed set and viability for crosses between J and E were as good as intraspecific parental crosses. Therefore propagation of hybrid larch crosses via controlled pollination and rooted cuttings is feasible, and the potential benefits of larch plantations for Maine’s forest economy are briefly discussed.

Mots clés

  • Hybrid larch
  • hybrid vigor
  • heterobeltiosis
  • Japanese larch
  • European larch
  • tamarack
Accès libre

Genetic parameters and prediction of breeding values in Castanopsis hystrix A.DC. for growth and form traits

Publié en ligne: 07 Jun 2017
Pages: 81 - 90

Résumé

Abstract

Castanopsis hystrix A.DC. is one of the most important and multipurpose tree species native to China. 157 open-pollinated families collected from 11 provenances in Guangdong, Guangxi, and Fujian province were used to estimate genetic parameters for height (H), diameter at breast height (DBH), ground diameter (GD), and crown width (CW) for each province and combined three provinces at ages from 3 to 9 years. The variance component was small and non-significant among provenances but was highly significant among families within provenances for H, DBH, GD, and CW. Heritability estimates were significant except for a few traits from Fujian’s provenances. Heritability ranged from 0.20 to 0.57 for H, 0.19 to 0.38 for DBH, 0.21 to 0.55 for GD, and 0.09 to 0.39 for CW. Heritability estimates for H and DBH decreased with increased age for each province and combined three provinces. Significantly high genetic correlations were observed for ageage and trait-trait correlations, indicating that genetic performance at one trait was well correlated with another trait. In total, 22 families and 60 individuals were selected for backward and forward selection based on breeding values.

Mots clés

  • Castanopsis hystrix
  • additive variance
  • individual heritability
  • genetic correlation
  • breeding values
Accès libre

Fertility Variation and its Impact on Effective Population Size in Seed Stands of Tamarindus indica and Azadirachta indica

Publié en ligne: 07 Jun 2017
Pages: 91 - 99

Résumé

Abstract

Growth and reproductive traits were assessed in seed stands of two native Indian tree species Tamarindus indica and Azadirachta indica. Positive correlation between growth (height and GBH) and reproductive traits (male and female contribution) were found in both species. Fertility was estimated from the flower and fruit production of individuals. Based on the fertility variation among individuals, parental balance, femaleness index and status number (Ns) were determined. The option of equal seed collection among individuals was also considered for estimating Ns. The percentage of fertile trees was higher in the high flowering year in both species. The best male contributing individuals also showed high female contribution (fruit production). The parental contribution in seed stands showed high deviation from expectation; 20% individuals contributed about 70% of male and female gametes in both species. Femaleness index showed that female and male contribution of individual tree was more balanced in the good flowering year, compared to the poor year. Coefficient of variation in male and female fertility was higher in the low flowering year resulting in high fertility variation among individuals and low status number. In T. indica, the female contribution was less variable compared to that of male fertility whereas in A. indica the female fertility variation was higher than that of male fertility. The relative status number (Nr = Ns/N) of the stands was lower for male and female fertility compared to the combined (male and female) fertility of individual trees.

Mots clés

  • status number
  • effective number of parents
  • sibling coefficient
  • gene diversity
  • equal seed harvest
  • Tamarindus indica
  • Azadiracta indica
Accès libre

Morphological characterization and in vitro germination of heat-treated pollen in Eucommia ulmoides

Publié en ligne: 07 Jun 2017
Pages: 99 - 108

Résumé

Abstract

Polyploid breeding has the potential to increase the economic secondary metabolites of Eucommia ulmoides. However, pollination with induced ploidy-mixed pollen has failed to produce polyploids (GAO, 2006). In this investigation, the morphological characterization and in vitro germination of heat-induced ploidy-mixed pollen of E. ulmoides were analysed to determine why there is no polyploid production. Heat-treated pollen grains were easily distinguished as large and small according to their length. The large pollen grains were significantly longer than both untreated and heat-treated small samples, suggesting that they were probably 2n pollen. Rather than the three germinal pores in small pollen, the large grains typically had four pores and, in some cases, shallow furrows, which might affect their germination. Although the maximal germination rates of the treated small and large pollen were not significantly different, the large pollen germinated tardily during the early stages of incubation. The small pollen maintained its growth during the incubation, but the tube growth of large pollen almost stopped after 24 h incubation. Both vegetative and generative nuclei in the large pollen moved into tubes later than in small pollen and the frequency of mitosis in generative nuclei of large pollen was low. Therefore, the tardy germination, poor tube growth, and weak activity of both vegetative and generative nuclei probably caused the poor competition of large pollen in certation. Finally, techniques to increase the competition of highploidy pollen and the prospect of 2n female gamete induction in the polyploid breeding program of E. ulmoides are discussed.

Mots clés

  • Eucommia ulmoides Oliver
  • heat-treated pollen
  • polyploid breeding
  • poor competition
  • tardy germination
Accès libre

Individual, fruit, and annual variation in correlated mating in a Genipa americana population

Publié en ligne: 07 Jun 2017
Pages: 108 - 116

Résumé

Abstract

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.

Mots clés

  • Inbreeding
  • Mating system
  • Microsatellite markers
  • Tropical tree species.
Accès libre

Five Years Performance of New Introduced Salt Tolerant Hybrid Poplar clones (Mofid and P. × albaeuphratica) In Iran (West Azar-Bayjan)

Publié en ligne: 07 Jun 2017
Pages: 117 - 120

Résumé

Mots clés

  • Hybrid poplar
  • Inter specific hybrid
  • Populus euphratica Oliv. × P. alba L.
  • Populus alba L. × P. euphratica Oliv
Accès libre

Differentiation of six Eucalyptus trees grown in Mexico by ITS and six chloroplast barcoding markers

Publié en ligne: 07 Jun 2017
Pages: 121 - 130

Résumé

Abstract

Different species of the genus Eucalyptus, originally native to Australia, are being cultivated in different parts of the world due to their fast growth and beneficial wood properties. In Mexico, probably up to 25 different Eucalyptus species (many of them with unknown species declaration) were introduced early in the 20th century. Many Eucalyptus species are cross compatible and information about provenances of the single eucalypt species is rare. In this study, an experimental plantation established in 1984 and located in Northeast of Mexico was chosen as example to re-assign the species name of six randomly selected Eucalyptus trees growing in this plantation. First, a phylogenetic tree was constructed from complete chloroplast sequences of 31 Eucalyptus species available in the NCBI database. The phylogenetic tree includes three of the nine Eucalyptus species known to be introduced to Mexico, namely E. camaldulensis, E. saligna and E. grandis, which belong to a clade named “Symphyomyrts”. By employing combined BLASTN and UPGMA analyses of six chloroplast (cp) regions, three of the six unknown eucalypt samples (Euc4, 5, 6) cluster together with E. microtheca and E. cladocalyx, whereas the other three (Euc1, 2, 3) were more similar to a group containing E. camaldulensis, E. grandis and E. saligna. UPGMA analysis of the ITS region overall shows the same rough clustering, but provide more detailed information for two samples being most likely assigned to E. camaldulensis.

Mots clés

  • matK
  • rbcL
  • intergenic linker
  • psbA_matK
  • psbK_psbI
  • trnG_psbK
  • matK_trnK
  • chloroplast
  • Internal transcribed spacer
Accès libre

Provenance by site interaction and stability analysis of European beech (Fagus sylvatica L.) provenances grown in common garden experiments

Publié en ligne: 07 Jun 2017
Pages: 133 - 147

Résumé

Abstract

Fifteen provenances of European beech (Fagus sylvatica L.) were evaluated for stability and adaptability by height growth at four test sites in Bosnia and Herzegovina (1), Croatia (1) and Serbia (2). Provenance trials were established in spring 2007 by planting 2- and 3-yearold seedlings and arranged in a randomized complete block design. The data from seven 6- year-old and eight 5-year-old provenances were obtained in 2009 and analyzed separately. Finlay and Wilkinson’s regression analysis and Additive main effects and multiplicative interaction model (AMMI model) were used to assess provenance by site interaction (P × S) and to identify beech provenances that have high and stable performance in different environments, at the juvenile stage of development. Analysis of variance showed that effects of provenance, site, and P×S interaction are highly significant (p<0.001) in both age groups. Linear regression model evidenced that most of the provenances had regression coefficients not significantly different from unity (b=1.0), except for provenances Sjeverni Dilj Caglinski (HR24) and Vranica-Bistrica (BA59). The partitioning of the total sum of squares (SS) exhibited that the site effect was the predominant source of variation in both age groups of provenances (50.7% and 38.5%, respectively). Additionally, regression analysis explained 15.8% and 33.2% of provenance by site interaction terms, in provenances age six and five years, respectively, while the AMMI analysis accounted for 62.2% and 78.7% in P×S interaction. The results of AMMI showed that the first principal component (PC1) was statistically significant in both age groups. Adaptability and stability of provenances to the test sites were estimated with AMMI1 and AMMI2 biplots. Provenance Sjeverni Dilj Caglinski (HR24) showed constant performance over tested sites, characterizing with aboveaverage height growth at low yielding environments. Provenances HR25 and BA61 showed the opposite type of adaptation, being adapted to high yielding sites. Provenance Valkonya (HU42) was characterized by IPCA1 score close to zero and above average mean height growth, suggesting general adaptation to the tested environments. The implication of P×S was discussed in light of impact of climate change on beech and selection of most suitable provenances for future reforestation programs.

Mots clés

  • European beech
  • provenance trial
  • provenance × site interaction
  • linear regression model
  • AMMI analysis
  • biplot.
Accès libre

Expression of three phenylpropanoid pathway genes in Scots pine (Pinus sylvestris L.) in open-pollinated families with differing relative wood densities during early and late wood formation

Publié en ligne: 07 Jun 2017
Pages: 148 - 159

Résumé

Abstract

Wood volume and quality are the most important aspects of commercial forestry production, and studies of wood formation are important in order to increase the value and efficiency of forestry production. The phenylpropanoid pathway produces various compounds with diverse functions both for plant defence against biotic and abiotic stress as well as structural development. One of the main roles is monolignol production for lignin biosynthesis, which is a crucial aspect of wood formation. For this study three candidate genes involved in lignin biosynthesis were selected: phenylalanine ammonialyase (PAL1), cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR). Candidate gene expression was analysed in selected individuals with high and low wood density from open-pollinated Scots pine families during early wood (EW) and late wood (LW) formation and correlation between expression of these genes, total lignin content, and wood density was determined. Wood density values for analysed trees were similar within tree families but differed significantly between families with high and low wood density (p=1,06E-20). Wood density was slightly negatively correlated with lignin content (r=-0.36, p=0.038), but only in individuals in the high density wood group. In trees with low wood density, expression of the CAD gene was significantly lower in late wood formation compared to early wood (p=0.00179). In trees with high wood density, expression of the PAL1 gene was five times higher during early wood formation compared to late wood formation. A positive correlation was detected between PAL1 and CCR gene expression during early wood formation (r=0.804) and late wood formation (r=0.466).

Mots clés

  • CAD
  • CCR
  • PAL1
  • Scots pine
  • Pinus sylvestris
  • wood density
  • early wood
  • late wood
Accès libre

Genetic and phenotypic correlations among volume, wood specific gravity and foliar traits in white spruce (Picea glauca (Moench) Voss)

Publié en ligne: 07 Jun 2017
Pages: 159 - 170

Résumé

Abstract

White spruce is highly valued by the forest products industry in North America. Through tree improvement efforts, selected genotypes can exceed wild sources by 30% in volume. Negative correlations between growth and wood specific gravity have been established, but differences in leaf morphology between high and low performing genotypes are less well understood. We sampled five trees from each of 30 families at each of two locations in a 25-year old progeny test in Minnesota. One wood core was collected from each tree to sample wood specific gravity (WSG), along with a branch collected from the upper crown to examine foliar traits. We confirmed negative correlations between stem volume and WSG, but several families combined high wood volume with only small reductions in WSG. Leaf area ratio and specific leaf area were positively, genetically correlated with volume growth but not correlated with WSG. Increased growth rates of selected genotypes may be attributed, in part, to shifts in allocation to leaves and in leaf morphology that may optimize light interception.

Mots clés

  • white spruce
  • genetic correlations
  • wood specific gravity
  • specific leaf area
  • genotype by environment interaction
  • foliar nitrogen
Accès libre

Use of genetic markers to build a new generation of Eucalyptus pilularis breeding population

Publié en ligne: 07 Jun 2017
Pages: 170 - 181

Résumé

Abstract

Tree improvement generally proceeds by incremental gains obtained from recurrent selection in large diverse populations but is slow due to long generation times and delay till trees reach assessment age. This places a premium upon extracting data from historic introductions used to found landraces when reinstating modern breeding programs. The value of such resources, however, may be degraded due to a lack of records on germplasm origins, pedigrees and early performance, but DNA technology may help recoup some of this value. Eucalyptus pilularis (subgenus Eucalyptus) is regarded as a premier hardwood plantation species for saw log and poles in Australia, but has not been used extensively despite early introductions and testing in many countries overseas. Here we use DNA fingerprinting to assess genetic diversity and inbreeding in historic introductions of E. pilularis to evaluate this resource in advance of a reinvigorated breeding effort for this species in Brazil. As expected, based on the available documentation for the introductions, genetic diversity relative to Australian reference populations does not appear to be compromised, and there was unlikely to be excessive inbreeding. Also, favorable, was the likelihood that further selections should not unduly increase the relationship in the next generation. Interestingly, we note the importance of testing widely adapted sources of germplasm when making introductions, as provenances which performed poorly in tests on productive sites in Australia, may have value when matched with lower fertility sites overseas.

Mots clés

  • Blackbutt
  • genetic diversity
  • relatedness
  • growth
  • pedigree information
Accès libre

Tracing the origin and species identity of Quercus robur and Quercus petraea in Europe: a review

Publié en ligne: 07 Jun 2017
Pages: 182 - 193

Résumé

Abstract

Traceability of forest material has received recently increasing interest and European regulations already apply on forest reproductive material and timber. DNA fingerprinting methods allow identification of species and control of geographic origin, providing that genetic reference data is available. In this review, we focus on the two economically important European oak species, Quercus robur and Q. petraea. We describe the available molecular markers and data, and discuss their applicability for traceability systems of forest reproductive material at a European scale. We also provide insights on the use of DNA fingerprinting on timber material.

Mots clés

  • Quercus
  • oak
  • molecular markers
  • traceability
  • Europe
  • forest reproductive material
  • timber
Accès libre

PCR-RFLP analysis of cpDNA in Gigantochloa scortechinii (Poaceae: Bambuseae) in Peninsular Malaysia and implications for the use of cpDNA markers in systematic studies

Publié en ligne: 07 Jun 2017
Pages: 194 - 200

Résumé

Abstract

Gigantochloa is a paleotropical woody bamboo genus that has been widely cultivated in SE Asia because of its usefulness. Recent studies have shown that species of this genus enter into an introgression complex with other genera of the same subtribe Bambusinae. Within G. scortechinii, a common species indigenous to Malay Peninsula and common in Peninsular Malaysia, two distinct chloroplast DNA (cpDNA) lineages, the Gombak- and Langat-type, were recovered. We report the development of a PCR-based restriction fragment length polymorphism (RFLP) marker for depicting the genetic differentiation in G. scortechinii based on cpDNA. We determined a cpDNA region and its corresponding restriction enzyme which can produce different RFLP profiles for the two cpDNA lineages. Our design was verified with empirical studies. The Gombak-type was the dominant cpDNA genotype for G. scortechinii in Peninsular Malaysia. Implications for the continued use of cpDNA markers in systematic studies are discussed.

Mots clés

  • chloroplast capture
  • cpDNA differentiation
  • Gigantochloa
  • population genetics
  • restriction digestion
Accès libre

Genetic diversity and spatial genetic structure in populations of Orbignya phalerata Mart. under different exploitation intensities in the Brazilian savanna

Publié en ligne: 07 Jun 2017
Pages: 201 - 211

Résumé

Abstract

Genetic studies in tropical tree species have found signs of decreased genetic diversity and increased levels of inbreeding and spatial genetic structure (SGS) in fragmented and exploited populations. The aim of this paper was to investigate genetic diversity, structure, and intrapopulation SGS using eight microsatellite loci for three Orbignya phalerata populations that have undergone different intensities of seed harvesting. From each population, we georeferenced and sampled 30 seedlings, 30 juveniles, and 30 adult trees. The total number of alleles over all loci (k), and observed (Ho) and expected heterozygosity (He) presented lower values for the population experiencing more intense fruit harvesting than less heavily exploited populations, suggesting that fruit harvesting may decrease genetic diversity. Null alleles were detected in practically all loci among seedlings, juveniles, and adults in all populations, indicating that the estimates of Ho, He, and fixation index (F) are biased. When corrected for null alleles (FNull), the fixation index decreased for all samples, resulting in significantly higher than zero results for seedlings of all populations, but not for juveniles and adults of all populations. The comparison of FNull values between cohorts in the most heavily exploited population (ESP) suggests that inbred individuals are eliminated between seedling and adult stages. Significant SGS was detected up to 60 m in all populations, which indicates short distance seed dispersal. Genetic differentiation (G’ST) between pairwise populations was related to spatial distance between populations, with the greatest difference between more distant populations.

Mots clés

  • babassu
  • Orbignya phalerata
  • forest management
  • exploitation
  • genetic diversity
Accès libre

Development of PCR based markers in Terpene synthase genes for marker assisted selection of high resin yielders in Pinus roxburghii Sarg

Publié en ligne: 07 Jun 2017
Pages: 211 - 220

Résumé

Abstract

Pine oleoresin is a complex mixture of volatile and nonvolatile terpenes and is exploited for commercial production in India. Pines have long reproductive cycle vegetative phase extending upto many years. Therefore, there is an urgent need to identify high resin pine yielders at an early stage. Due to the strong influence of genetic factors on resin yield in pine species, marker assisted selection may serve as a potential tool for early identification of the genotype of interest. This study was planned to identify high resin pine yielders at early stage to avoid exploitation of natural germplasm of chir pine. Protein sequences of different terpene synthases were downloaded from the NCBI database and were multiply aligned to identify conserved and variable regions across the sequences. Primers were designed based on the related coding sequences to target these regions using Primer 3 software to amplify and isolate related genomic loci in chir pine genotypes. These primers were characterized for specificity using Primer Blast and the presence of hairpin loop formation using OligoCalc software. DNA was extracted from different resin yielding pine genotypes and primers were run on them for molecular studies. With the help of bioinformatics tools, we were able to associate some markers with resin yield. This study holds a key promise for the conservation of pine germplasm in natural habitat.

Mots clés

  • Pinus roxburghii Sarg
  • Terpene synthase
  • PCR-marker
  • Bioinformatics
  • association analysis
Accès libre

Association mapping for identification of ISSR and AFLP markers linked with resin yield in Himalayan Chir Pine (Pinus roxburghii Sarg

Publié en ligne: 07 Jun 2017
Pages: 220 - 239

Résumé

Abstract

In Pinus roxburghii, marker-trait associations were studied for resin yield using a set of 238 DNA based markers derived from 9 ISSR and 5 AFLP primer pairs. A total of 240 genotypes of P. roxburghii from a natural population in Chakrata division (Tiunee range), Uttarakhand (India) were evaluated for resin yield. Based on stable resin production in consecutive years, 53 genotypes that were best representatives of the variation in resin yield (0.25 to 8.0 kg/tree/year) were used for genotyping and association analysis. For carrying out the association studies, two approaches were used. First, using simple linear regression, resin yield was regressed on all 238 available polymorphic markers (148 ISSR markers and 90 AFLP markers) and second, evidence for association was examined applying population structure information using STRUCTURE and STRAT to avoid any spurious associations between a candidate marker and phenotype. In regression analysis, 16 ISSR and 12 AFLP markers showed significant association with resin yield. In the second approach, 18 ISSR and 18 AFLP loci were found to be associated with resin yield in the absence of population structure out of which 2 ISSR and 3 AFLP loci were common with those associated in regression analysis. After accounting for population structure, 38 ISSR, and 3 AFLP loci revealed association out of which one ISSR and one AFLP locus was found to be common with both simple linear regression and test of association in the absence of population stratification. There was no obvious correlation between population structure and resin yield.

Mots clés

  • regression
  • population structure
  • structured association test
  • ISSR
  • AFLP
  • Pinus roxburghii
Accès libre

Inducing genetic variation in growth related characteristics of poplar germplasm, by producing inter-specific hybrids between P. alba and P. euphratica

Publié en ligne: 07 Jun 2017
Pages: 239 - 248

Résumé

Abstract

Crosses were made between two Populus species to create two hybrid groups, P. alba ♀ * P. euphratica ♂ and P. euphratica ♀ * P. alba ♂. Aseptic immature hybrid seeds were first grown on MS medium. Hybrid seedlings were then acclimatized and grown in greenhouse conditions and transplanted to an experimental field. Growth related characteristics were recorded on 307 three years-old seedlings of new inter-specific hybrids of six half-sib families, in order to assess possible potentials of the two hybrid groups. Double nested analysis of variance revealed significant differences between the hybrid groups and siblings based on majority of the studied characters. The hybrid groups formed two distinct groups for some of the studied characteristics which implied maternal effects of inheritance on the traits. The first hybrid group had more but shorter and closer branches than the second group. Adaxial stomata number for the two hybrid groups varied between 4.7 to 123. Whereas, there were no such strong differences between vegetative characteristics of the two groups. The second hybrid group had a very condense layer of white fuzz on its abaxial leaf surface, inherited from its female parents. This may lead to suggest some kinds of photosynthesis and respiration functions such as leaf sub-stomatal chambers’ functions for the mentioned fuzzy trichomes of the second hybrid group and their female parental species, P. alba. In essence, 307 new divergent poplar hybrid genotypes were produced by which ecological zone of poplar species could be extended in the country as well as high yielding genotypes would be promising.

Mots clés

  • Populus euphratica
  • Populus alba
  • Nested ANOVA
  • Inter specific hybrids
  • Adaxial stomata
  • Morphologic traits
Accès libre

Mating system variation among populations, individuals and within and among fruits in Bertholletia excelsa

Publié en ligne: 07 Jun 2017
Pages: 248 - 259

Résumé

Abstract

The aim of this study was to investigate variation in mating system among three Brazilian Amazon populations of the tree Bertholletia excelsa with different levels of anthropogenic interventions. We collected open-pollinated seeds from one natural population, remnant trees dispersed in a pasture, and trees from a plantation. Outcrossing rate not varied among the populations and indicates that all seeds were originated from outcrossing (tm=1.0). Mating among relatives was significant higher in the plantation than forest and pasture populations, probably due the fact that many trees are related in the plantation. Correlated mating was significantly higher in pasture (rp=0.47) and plantation (rp=0.51) than in the natural population (rp=0.22), suggesting that trees in natural population are pollinated by a higher number of pollen donors. The paternity correlation was significantly higher within (rp(w)=0.41) than among fruits (rp(a)=0.18), showing a higher probability to find full-sibs within than among fruits. The fixation index was generally lower in seed trees than in their seedlings, suggesting selection for heterozygous individuals from seedling to adult stages. Progeny arrays collected from the natural population had a lower proportion of pairwise full-sibs than in pasture and plantation and higher variance effective size (2.75) than trees in pasture (2.15) and plantations (2.22). Results highlight that seed collections for conservation, breeding and reforestation programs preferentially should be carried out in natural populations due low proportion highest variance effective size within progeny.

Keywords

  • Brazil nut tree
  • Brazilian Amazon
  • conservation genetics
  • Lecythidaceae
  • microsatellite markers
  • population genetics
  • tropical tree species
Accès libre

PCR-based detection of single sequence variants from a natural collection of the non-model tree species European Aspen Populus tremula (L.)

Publié en ligne: 07 Jun 2017
Pages: 259 - 269

Résumé

Abstract

In the present study we present and discuss the identification of species-specific SNPs to rule out any experimental influence of species-specific primer design (Populus tremula vs. the closely related model-species Populus trichocarpa) on the detectability of SNPs. Applying a species-optimized method, partial sequences of 14 genes involved in xylem cell development, xylogenesis, pectin formation, and drought stress reaction were analyzed at the genomic level. About 3 Mb of sequence information were generated by Sanger sequencing technology and 258 sequence variants were identified. 15 out of these represent insertions /deletions located exclusively in non-coding regions and the remaining 243 are SNPs found in coding and non-coding regions of candidate genes.

The introduction of a species-specific SNP detection pipeline will help to detect nucleotide variants in P. tremula and to conduct association mapping in natural P. tremula populations.

Mots clés

  • drought stress tolerance
  • natural population
  • Populus tremula
  • SNP
  • xylem cell formation
Accès libre

Forest decline has not reduced genetic diversity of naturally regenerated Norway spruce from the Beskids, Poland

Publié en ligne: 07 Jun 2017
Pages: 270 - 278

Résumé

Abstract

Norway spruce forests decline in the Beskids raises concerns about reduction of genetic variation in a next generation of forest. We aim to determine whether the genetic diversity in declining spruce stands was successfully transmitted to its self-seeded progeny. Using three nuclear microsatellite markers, we carried out the genetic assessment of naturally regenerated progeny and compered them with their maternal stands at an initial stage of decline. We investigated three spruce stands from the Śląski and Żywiecki Beskid and one primeval forest from the Tatras, as a reference. We noticed a high level of gene diversity, allelic richness and an effective number of alleles in progeny of all stands, without differences between declining stands from the Beskids and the primeval forest. The gene diversity was similar in maternal trees and their offspring. Higher gene diversity and generally higher number of alleles were noticed in young generation of stands. Genetic identity between generations was high in analyzed seed stands and the highest in the primeval forest. The results we presented indicate no significant effect of drastic reduction in the population size due to the forest decline on the level of genetic variation in self-seeded progeny of Norway spruce from the Beskids.

Mots clés

  • forest decline
  • genetic diversity
  • Norway spruce
  • Beskids
  • natural regeneration
  • primeval forest
Accès libre

Logging decreases the pollen dispersal distance in a low-density population of the tree Bagassa guianensis in the Brazilian Amazon

Publié en ligne: 07 Jun 2017
Pages: 279 - 290

Résumé

Abstract

This study investigates the distance and patterns of pollen dispersal before and after logging in a low-density population of the dioecious, insect pollinated tree species, Bagassa guianensis, in the Brazilian Amazon. All adult trees found before and after logging in a 500 ha plot were mapped and genotyped for six microsatellite loci. Seeds collected before and after logging were also sampled and genotyped. We used a categorical paternity analysis to determine seed paternity. Our results showed similar levels of pollen flow before (23%) and after logging (26%), but an increase in the mean effective pollination neighbourhood area, and a decrease in the rate of mating among relatives after logging, resulting in open pollinated seeds with lower levels of inbreeding (0.126) than before logging (0.222). We also detected changes in the mating pattern between before and after logging, a decrease in the median pollen dispersal distance and effective number of pollen donors after logging. Our results support the idea that reproductive trees should be maintained in the plot and around logged areas, using lowest levels of logging intensity to maintain pollen flow and decrease the relatedness of subsequent generations.

Keywords

  • Dioecious species
  • paternity analysis
  • pollen dispersal
  • tatajuba
  • tropical tree species
Accès libre

Genetic Parameters of Interspecific Hybrids of Eucalyptus grandis and E. urophylla Seedlings and Cuttings

Publié en ligne: 07 Jun 2017
Pages: 291 - 308

Résumé

Abstract

The current E. grandis × E. urophylla hybrid breeding strategy of South Africa’s Forestry Industry is to maintain large breeding populations of both parental species in which parents are selected based on their general combining ability (GCA) estimates or predicted individual tree breeding values and are used for interspecific hybrid crosses. The hybrid material is first screened in seedling progeny trials after which superior individuals are selected and tested as clones. Although this strategy has delivered superior clones for commercial production in South Africa, it is a time consuming strategy to follow and more cost effective strategies are being investigated. In order to review the current hybrid breeding strategy, information on the genetic control of the traits of interest is needed for E. grandis × E. urophylla seedling and clonal populations. The main objectives of this study were therefore to firstly estimate genetic parameters for E. grandis × E. urophylla hybrid seedling and clonal populations; secondly to investigate the correlation between E. grandis and E. urophylla parental (GCA) or individual breeding values and their general hybridising ability (GHA); and lastly to determine the correlation between E. grandis × E. urophylla hybrid seedling ortets and their ramets.

Results of our study indicated that non-additive genetic variation explained the majority of the total genetic variation in E. grandis × E. urophylla seedling and clonal populations. Due to the pre-eminence of non-additive variance, the pure-hybrid correlations were weak, especially for clonal populations. It would therefore seem that GCA or predicted individual breeding values are not good predictors of GHA for growth performance in the observed populations. Our study also indicated a weak coefficient of correlation between the growth performance of seedling ortets and their ramets. These results suggest that: firstly a hybrid breeding strategy to capture non-additive genetic variation should be adopted; and secondly that the first phase of screening E. grandis × E. urophylla hybrid material as seedlings should be revisited.

Mots clés

  • Eucalyptus grandis x E. urophylla
  • genetic parameters
  • seedlings and cuttings
  • pearson correlations

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