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Revista
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2509-8934
Publicado por primera vez
22 Feb 2016
Periodo de publicación
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Volumen 60 (2011): Edición 1-6 (December 2011)

Detalles de la revista
Formato
Revista
eISSN
2509-8934
Publicado por primera vez
22 Feb 2016
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

38 Artículos
Acceso abierto

Stem breakage and forking in low and high elevation Pinus tecunumanii

Publicado en línea: 05 Aug 2017
Páginas: 1 - 8

Resumen

Palabras clave

  • Stem breakage
  • forking
  • low and high elevation
  • genotype*environment interaction
Acceso abierto

Heritabilities, Intertrait Genetic Correlations, G x E Interaction and Predicted Genetic Gains for Acoustic Velocity in Mid-rotation Coastal Douglas fir

Publicado en línea: 05 Aug 2017
Páginas: 8 - 18

Resumen

Abstract

Acoustic velocity (AV) data from 7,423 coastal Douglas-fir trees drawn from 347 wind-pollinated families on 14 sites, from four first-generation testing programs in the north Oregon Cascades, were analyzed. Families were measured on two or four sites at ages 23 to 41 years from seed using the Fakopp TreeSonic standingtree tool. Height (HT) and DBH data collected at ages 15 and 16 from seed, from all trees in the four programs (95,795 trees, 955 families), were used to calculate volume index (VOL = HT*DBH2) and stem taper (TAP = DBH/HT). All traits were analyzed using multivariate mixed model analyses.

Across-site individual narrow-sense heritabilities for AV2 ranged from 0.24 to 0.40 among first-generation programs, compared to 0.12 to 0.23 for HT, 0.10 to 0.16 for DBH, 0.11 to 0.20 for VOL and 0.14 to 0.17 for TAP.

Across-site type B correlations for AV2 ranged from 0.85 to 0.95, compared to 0.62 to 0.83 for HT, 0.60 to 0.74 for DBH, 0.67 to 0.78 for VOL and 0.66 to 0.79 for TAP. AV2 was negatively correlated with HT in three programs (rA = 0.17 to −0.28), and negatively correlated with DBH (−0.12 to −0.46), VOL (−0.05 to −0.44) and TAP (−0.09 to −0.40) in all four programs.

Selecting the top 10% of the families sampled based on AV2 gave predicted gains of 4.4% to 9.6% for AV2 and −9.3% to 10.6% for VOL. The adverse genetic correlations between AV2 and growth, and the losses in gain in AV2 from selection based on growth, may be overestimated by suppression of slower-growing families in these older tests.

Palabras clave

  • acoustic velocity
  • dbh
  • Douglas-fir
  • genetic correlation
  • genetic gain
  • height
  • heritability
  • taper
  • volume index
Acceso abierto

An Optimised Protocol for Fluorescent-dUTP Based SSR Genotyping and its Application to Genetic Mapping in Eucalyptus

Publicado en línea: 05 Aug 2017
Páginas: 18 - 25

Resumen

Abstract

Integration of fluorescent-dUTP in polymerase chain reaction (PCR) appears to be a sound method for fluorescence labelling of amplicons in genotyping with simple sequence repeats (SSRs) using an automated sequence analyser. However, the method has not been explored in terms of performance optimisation and cost control. In this paper, we optimised the protocol for fluorescent-dUTP based SSR genotyping in a case study with Eucalyptus. A combination of low dNTP concentration (25 μM each) in PCR reaction and a touchdown PCR programme contributed to increase dramatically the fluorescent intensity of SSR amplicons, thereby facilitating accurate and multiplexed scoring of SSR alleles. The usefulness of the optimised protocol was demonstrated in its application to genetic mapping of SSR loci onto E. urophylla and E. tereticornis linkage maps constructed previously. The protocol optimised here would provide a reliable and economical assay for sequencer-based SSR genotyping in a wide range of biological applications.

Palabras clave

  • Simple sequence repeats (SSRs)
  • genotyping
  • fluorescent-dUTP
  • genetic mapping
Acceso abierto

Two-dimensional penalized splines via Gibbs sampling to account for spatial variability in forest genetic trials with small amount of information available

Publicado en línea: 05 Aug 2017
Páginas: 25 - 35

Resumen

Abstract

Spatial environmental heterogeneity are well known characteristics of field forest genetic trials, even in small experiments (<1ha) established under seemingly uniform conditions and intensive site management. In such trials, it is commonly assumed that any simple type of experimental field design based on randomization theory, as a completely randomized design (CRD), should account for any of the minor site variability. However, most published results indicate that in these types of trials harbor a large component of the spatial variation which commonly resides in the error term. Here we applied a two-dimensional smoothed surface in an individual-tree mixed model, using tensor product of linear, quadratic and cubic B-spline bases with different and equal number of knots for rows and columns, to account for the environmental spatial variability in two relatively small (i.e., 576 m2 and 5,705 m2) forest genetic trials, with large multiple-tree contiguous plot configurations. In general, models accounting for site variability with a two-dimensional surface displayed a lower value of the deviance information criterion than the classical RCD. Linear B-spline bases may yield a reasonable description of the environmental variability, when a relatively small amount of information available. The mixed models fitting a smoothed surface resulted in a reduction in the posterior means of the error variance (σ2e), an increase in the posterior means of the additive genetic variance (σ2a) and heritability (h2HT), and an increase of 16.05% and 46.03% (for parents) or 11.86% and 44.68% (for offspring) in the accuracy of breeding values, respectively in the two experiments.

Palabras clave

  • genetics trials
  • spatial variability
  • tensor product of B-spline
  • error variance
  • genetic parameters
  • accuracy
Acceso abierto

Clonal Variation in Lateral and Basal Rooting of Populus Irrigated with Landfill Leachate

Publicado en línea: 05 Aug 2017
Páginas: 35 - 44

Resumen

Abstract

Successful establishment and productivity of Populus depends upon adventitious rooting from: 1) lateral roots that develop from either preformed or induced primordia and 2) basal roots that differentiate from callus at the base of the cutting in response to wounding. Information is needed for phytotechnologies about the degree to which Populus adventitious rooting is controlled by effects of individual genotypes, waste waters used as alternative fertigation sources, and their interactions. Our objective was to irrigate twelve Populus clones with well water (control) or municipal solid waste landfill leachate and to test for differences between initiation of lateral versus basal roots, as well as root growth rate and distributional trends for both root types. We evaluated number and length of lateral roots initiated from upper, middle, and lower thirds of the cutting, as well as basal callus roots. Overall, leachate irrigation affected lateral roots but not basal roots, and there was broad clonal variation between and within root types. On average, there were 129% more lateral than basal roots, which ranged from 3 to 27 (lateral) and 2 to 10 roots (basal). The percent advantage of number of roots from the middle portion of the cutting relative to other sections was 120% (upper), 193% (lower), and 24% (basal). Clones, treatments, and their interaction did not affect root growth rate, which ranged from 1.5 ± 0.6 to 3.4 ± 0.3 cm d−1, with a mean of 2.3 ± 0.2 cm d−1. These results contribute baseline information for clonal selection needed to establish Populus for phytotechnologies, energy, and fiber.

Palabras clave

  • forest genetics
  • tree improvement
  • phytotechnologies
  • hybrid poplar
  • root types
  • subsp.
Acceso abierto

Effect of genetic relatedness among parents on gain in salt tolerance in progeny of crosses of Eucalyptus occidentalis

Publicado en línea: 05 Aug 2017
Páginas: 45 - 55

Resumen

Abstract

Genetic diversity of a Eucalyptus occidentalis breeding population screened for salt and waterlogging tolerance was examined using eight microsatellite loci. Mating using an immature style ‘one stop pollination’ method between parents was carried out to produce progeny for testing under 500 mM salt waterlogging. The effect of parental genetic distance on seed production and early seedling survival was examined and inheritance of salt/or waterlogging tolerance was assessed by testing performance of progeny in comparison to parents. Diversity was moderate among the nine provenances and the families, and most of the diversity was distributed within rather than between families. Genetic relationships showed no structure in relation to provenance indicating any adaptation to saline environments has not affected genetic similarity. Breeding for salt and water tolerance may be achieved without decline in genetic diversity. There was a significant correlation between capsule production and parental genetic distance and a positive trend between increasing parental genetic distance and increasing number of germinated seeds/capsule, and seedling survival at 2 weeks and 9 months. These trends indicate expression of inbreeding depression in crosses between genetically similar parents. Heritability values, under 500 mM salt-waterlogging treatment, indicated that height had moderate heritability (h2 = 0.5). Crosses with the widest parental genetic distance produced progeny with considerable height increase above parents and this trend was evident even with moderate genetic distance indicating crossing at this level of differentiation may achieve optimum breeding gain.

Palabras clave

  • eucalypts
  • salt tolerance
  • genetic diversity
  • flat topped yate
  • microsatellite
  • inbreeding
Acceso abierto

Genetic structure and diversity of Polylepis australis (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Publicado en línea: 05 Aug 2017
Páginas: 55 - 61

Resumen

Abstract

Worldwide, large areas of forest are being transformed to other land cover types and the resulting fragmented populations may suffer from restricted gene flow leading to genetic pauperization and increased inbreeding. To assess the genetic constitution of fragmented Polylepis australis mountain forests of central Argentina, analyses of the structure and diversity of ISSR markers were carried out for 90 trees distributed throughout five river basins with differing degrees of fragmentation. Overall, average polymorphism (P) ranged between 87.2 and 94.9% (95% criterion) while marker diversity index (M) varied between 0.35 and 0.39; values which are comparable with other wind-pollinated tree species. Analysis of molecular variance (AMOVA) revealed that most genetic variation occurred within river basins (97.8%), with only a little occurring between river basins (2.2%; ΦST = 0.02). In addition, Mantel’s test indicated that P. australis does not follow the usual pattern of isolation by distance; instead the UPGMA method showed that trees from the two most degraded river basins formed a group while trees from the three better preserved basins formed another. As such, either effective pollen flow has maintained high levels of genetic diversity, or present day genetic variability is a remnant of a recently fragmented ancestral panmictic population. We conclude that, at present, genetic degradation in P. australis populations of central Argentina is not as important as ecological degradation – such as soil loss, intensive browsing by livestock or increased frequencies of wildfires, and that genetic variability is still fully available for forest restoration.

Palabras clave

  • fragmentation
  • genetic diversity
  • Argentina
  • conservation
  • ISSR
Acceso abierto

Primer Note: Development of Highly Polymorphic Nuclear Microsatellite Markers for Hinoki (Chamaecyparis obtusa)

Publicado en línea: 05 Aug 2017
Páginas: 62 - 65

Resumen

Abstract

We developed 32 microsatellite markers from an enriched genomic DNA library of hinoki (Chamaecyparis obtusa), one of the most important Japanese forestry conifer species. From a total of 1,056 cloned plasmids, 96 sequence-specific primer pairs were designed from 110 candidate clones. We selected 32 primers that showed successful amplification and marked polymorphism and evaluated their characteristics using DNA from 38 C. obtusa elite trees planted in the Forest Tree Breeding Center. The markers were highly polymorphic, with the number of alleles ranging from 8 to 32 (mean: 20.09), and expected heterozygosity ranging from 0.811 to 0.958 (mean: 0.901). Progress in breeding projects and studies of the ecological genetics of this species can be expected through the use of this enlarged marker pool.

Palabras clave

  • microsatellites
  • forest tree breeding
  • genetic resources
  • ecological genetics
Acceso abierto

Short Note: Cross-Species Amplification and Characterization of Pinus Chloroplast Microsatellite Markers in Cedrus deodara Roxb.

Publicado en línea: 05 Aug 2017
Páginas: 65 - 69

Resumen

Abstract

The study reports the transferability of chloroplast microsatellite markers developed for Pinus species to Cedrus deodara. A total of 49 primer pairs (both nuclear and chloroplast) of Pinus species were tested in C. deodara out of which 21 chloroplast primers showed positive amplification and 20 were found polymorphic. The primers were screened on 100 adult trees of two natural populations of C. deodara. Using twenty cpSSR primers, a total of 64 variants were found which combined in 70 different haplotypes. The total haplotype diversity in two populations was 0.860 and 0.876 with a mean of 0.868. These sets of markers can further be used for population genetic studies and characterization in C. deodara for which no cpSSR markers have been reported till date.

Palabras clave

  • Cross-amplification
  • cpSSRs
  • micro satellite
  • genetic diversity
Acceso abierto

Genetic variation in tree growth, stem form and mortality of Guazuma crinita in slower- and faster-growing plantations in the Peruvian Amazon

Publicado en línea: 05 Aug 2017
Páginas: 70 - 78

Resumen

Abstract

Guazuma crinita is an important timber tree with a rotation age of 6–12 years in the Peruvian Amazon. A provenance/progeny test containing 200 families from seven locations (provenances) in the Aguaytía watershed of Peru was established in three zones in the Aguaytía watershed that differ in mean annual rainfall and soil fertility. Farmers managed the replications as plantations. Replications were divided into two groups at 24 months: faster- and slower-growing plantations. The faster-growing plantations were thinned at 32 months. The objectives of this paper are to determine if genetic variation in growth traits (tree height, stem diameter) is relatively greater in the faster-growing plantations, and if there are significant differences in tree mortality and stem bifurcations among provenances and families at 24, 36 and 48 months. Variation due to provenances and families and heritability of growth traits were consistently greater in the faster-growing plantations. At 48 months, heritability of growth traits was about twice as large in the faster- than in the slower-growing plantations. There were no significant interactions between zones and either provenances or families. Tree mortality and stem bifurcations in the faster-growing plantations generally did not differ significantly among families, but did differ significantly among provenances. Based on these results and considering its rotation age, we recommend that G. crinita families/trees could be selected at 48 months in the faster-growing plantations, the plantations could be transformed into seed orchards and the seed could be used for reforestation throughout the Aguaytía watershed. Results are compared with other tropical hardwoods.

Palabras clave

  • tree improvement
  • provenance/progeny test
  • environment
  • heritability
Acceso abierto

Selection Approaches in High-Elevation Coastal Douglas-fir in The Presence of GxE Interactions

Publicado en línea: 05 Aug 2017
Páginas: 79 - 84

Resumen

Abstract

Regeneration obligations in British Columbia for high-elevation coastal sites requires a secure seed supply of quality seed in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Consequently, a seed orchard is under development to supply seed after genetic testing and selection. For this purpose, 55 coastal Douglas-fir families were field-tested for 11 years on two contrasting high-elevation sites to examine differential growth performance and tolerance to cold conditions. Although heritabilities for growth on both sites were moderate at age 11, the higher elevation colder site had substantially slower growth and over 90% of the trees exhibited some form of cold damage to foliage, branches and stems; however, variation in this damage was not significant at the family level. Combined site analysis revealed a highly significant genotype by environment (GxE) component in height that could not be removed or reduced by using site-specific error variances or spatial analysis (i.e., GxE was primarily due to rank changes of families across the two sites). This was also reflected by a drop in heritability estimates obtained from the combined site analyses. In the presence of this type of GxE, independent culling, considering height a separate trait on each site, was employed to identify parents that were at a threshold breeding value of 5% or greater in growth superiority on both sites. Average breeding values for the selected parents, based on a combined site analysis, were around 5% above the trial mean for height at age 11. The use of independent culling, for situations where accurate genetic parameters are difficult to obtain, should be considered a practical alternative to more complex and error prone methods of selection.

Palabras clave

  • independent culling
  • spatial analysis
  • breeding value
Acceso abierto

Diagnosis of interspecific hybrids between Acacia mangium and A. auriculiformis using single nucleotide polymorphism (SNP) markers

Publicado en línea: 05 Aug 2017
Páginas: 85 - 92

Resumen

Abstract

This paper describes a diagnostic system to verify interspecific hybrids between Acacia mangium and A. auriculiformis using single nucleotide polymorphism (SNP) markers. Forty-eight DNA fragments were selected based on random amplified polymorphic DNAs (RAPD) amplified across 48 individuals from each parental species, and were transformed into 44 sequence-characterized amplified region (SCAR) markers. Five SNP markers that generated species-specific alleles for each species were selected from the 28 sequenced SCARs. A multiplex single nucleotide primer extension (SNuPE) analyses of the five SNPs using 40 A. mangium, 40 A. auriculiformis and 16 Acacia hybrids showed high discrimination power. This diagnostic system, with high discriminatory ability, provides a highly reliable and fast method for identifying interspecific hybrids of A. mangium and A. auriculiformis.

Palabras clave

  • interspecific hybrid
  • PCR
  • RAPD
  • SCAR
  • SNP
Acceso abierto

Short Note: Seven Genomic SSRs Revealed in Eucalyptus by Re-sequencing of DNA Sequences from GenBank

Publicado en línea: 05 Aug 2017
Páginas: 92 - 94

Resumen

Abstract

Seven genomic SSR markers of Eucalyptus were developed from DNA sequences of E. grandis deposited in GenBank. Their repeat motifs were revealed by resequencing with an individual tree of E. urophylla or E. tereticornis, and five out of the seven markers turned out to be heterozygous within the specific tree sequenced. The sequence identity ranged from 75.06% to 96.66%, with an average of 87.31%. These markers could be valuable in genetics studies in Eucalyptus. This report demonstrates the advantages of re-sequencing in developing SSR markers from publicly accessible databases.

Palabras clave

  • Simple sequence repeats (SSRs)
  • microsatellites
  • molecular markers
  • re-sequencing
Acceso abierto

Variations in biomass, nutrient contents and nutrient use efficiency among Chinese fir provenances

Publicado en línea: 05 Aug 2017
Páginas: 95 - 105

Resumen

Abstract

A provenance trial involving 16 Chinese fir provenances was established in southern China in 1979, and biomass, nutrient content and nutrient use efficiency were assessed at the age of 23. One-way analysis of variance revealed significant inter-provenance variation (p<0.0001) in measured variables. The mean total biomass ranged from 98.8±5.3 to 163.3±4.2 t ha−1, and the stemwood accounted for 47–65% of the total biomass, followed by roots (11–24%), stembark (7.4–13.7%), and needles and branches (< 10 %). Much of the nitrogen, phosphorus and potassium were stored in the needles, although the concentration varies among provenances. Whole-tree nutrient use efficiency varied from 115.4±2.1 to 180.2±1.02 g g−1, while efficiency in stemwood production ranged from 53.9±3.1 to 106.3±1.1 g g−1. Provenances did not display consistent variation in all measured variables, suggesting the need for multiple criteria for selection in future tree improvement program. In conclusion, the study reveals the existence of considerable variation in biomass production and nutrient use efficiency among Chinese fir provenances that can be exploited for selecting desirable genotypes for enhancing productivity of Chinese fir plantations.

Palabras clave

  • Biomass production
  • Tree improvement
  • forest nutrition
Acceso abierto

Genetic parameter estimates and parental selection in Eucalyptus longirostrata and Corymbia henryi populations tested in South Africa

Publicado en línea: 05 Aug 2017
Páginas: 105 - 113

Resumen

Abstract

The sub-tropical species, Eucalyptus longirostrata (formerly E. punctata var longirostrata) and Corymbia henryi were investigated as alternative species for growth on the Zululand coastal plain in South Africa. Provenance/progeny trials were established in 2001 at two sites, namely, Nyalazi and Kwambonambi. The seed material purchased from the Commonwealth Scientific and Industrial Research Organization in Australia in 2000 included six provenances of E. longirostrata and five provenances of C. henryi. Six-year diameter at breast height measurements were completed in 2007. Individual narrow-sense heritability coefficients for diameter growth varied from 0.30 to 0.58 for both species, with heritabilities being higher at the drier Nyalazi site. Heritabilities and breeding values were calculated prior to making selections in field. A total of 143 selections were made in the E. longirostrata trials, and 113 in the C. henryi trials during 2008. Predicted gains for the next generation range from 2.8 cm (20%) to 6.1 cm (61%) increase in diameter for E. longirostrata, and 3.4 cm (23%) to 5.4 cm (49%) increase for C. henryi, depending on site and selection scenario. Provenance differences were evident in E. longirostrata at both sites; however, there were no significant differences between the C. henryi provenances of Australian origin. The top families of both species performed better than the hybrid controls at the Nyalazi site, indicating that both E. longirostrata and C. henryi are viable alternative species for successful growth on the drier sites of the Zululand coastal plain.

Palabras clave

  • tree breeding
  • genetic parameters
  • heritability
  • genetic gains
  • BLUP
  • selection
Acceso abierto

Changes in Genetic Diversity of Whitebark Pine (Pinus albicaulis Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

Publicado en línea: 05 Aug 2017
Páginas: 113 - 123

Resumen

Abstract

We investigated the association of inbreeding and infection by the introduced disease white pine blister rust (caused by the fungus Cronartium ribicola J. C. Fisch) with genetic diversity of whitebark pine (Pinus albicaulis Engelm.) by genetically comparing cohorts of different ages in natural stands. Isozyme analysis of bud tissue was used to estimate expected and observed heterozygosity (He and Ho), and Wright’s fixation index (Fis) for three age cohorts (seedling, young, and mature), sampled from 14 sites in British Columbia, Oregon, Idaho, and Montana. Comparison of genetic diversity parameters among cohorts within a site was used to assess the extent and persistence of inbreeding with age, while comparisons of parameters among sites within a cohort were used to assess the impact of the disease on genetic diversity. Significant evidence of inbreeding (Fis >0) was found in all age cohorts. When sites were stratified by level of blister rust infection, differences in Fis and Ho among cohorts were only significant when level of infection was low. A significant negative association was found between level of blister rust infection and Ho in the mature cohort. This suggests that when differential selection due to blister rust is weak, more heterozygous individuals may be favored; however, more homozygous individuals may have higher fitness under higher blister rust levels

Palabras clave

  • whitebark pine
  • white pine blister rust
  • genetic diversity
  • isozymes
  • inbreeding
  • cohort analysis
  • heterozygosity
Acceso abierto

Genetic diversity of Anadenanthera colubrina Vell. (Brenan) var cebil, a tree species from the South American subtropical forest as revealed by cpSSR markers

Publicado en línea: 05 Aug 2017
Páginas: 123 - 132

Resumen

Abstract

Anadenanthera colubrina var cebil is a tree species native to the Upper Parana Atlantic Forest where human activities have severely impacted causing deep fragmentation. Microsatellites are not available in this species. Therefore, the first objective of this study was to generate chloroplast simple sequence repeats (cpSSR) by cross-species transfer. Understanding the evolutionary dynamics of subdivided populations is an important matter. In this way, a first approach to the characterization of the haplotypic diversity within and between populations as well as the genetic structure of native Argentinean populations were the main goals of this study.

Twenty four individuals from two populations of the Misiones province were studied and four cpSSR loci were tested. Two of them exhibited polymorphic patterns leading to the identification of 11 cpDNA haplotypes with high mean genetic diversity (GD=0.73). The minimum spanning network defined three clear groups which can be assigned to at least three subpopulations. AMOVA indicated that the total variance showed the highest percentage of variation (48%) within subpopulations with a fixation index (FST) statistically significant (FST=0.520; p<0.05). Brown’s two loci component analysis indicated that substructure population is present. Jost’s differentiation global index (Dest) was 0.049 while Dest pairwise comparison reflected a certain level of genetic structure.

The high diversity level detected in the adult trees of A. colubrina var cebil from the populations under study could be due to recent human influence. In this way, the reduction in population size caused a reduction in the number of trees leading to surviving trees showing the historical diversity of the populations analyzed.

Palabras clave

  • Upper Parana Atlantic Forest
  • Curupay
  • intraspecific genetic diversity
  • cpSSR cross-species transfer
Acceso abierto

Heritability of Yield and Secondary Traits in two populations of Para Rubber Tree (Hevea brasiliensis)

Publicado en línea: 05 Aug 2017
Páginas: 132 - 139

Resumen

Abstract

Heritability and interactions of yield and growth traits were assessed in Hevea brasiliensis using full-sib progenies and clonal populations. Using parent-offspring regression, annual mean rubber yield (ARY) and summer yield (SY) showed moderate to high heritability (ARY, h2 =34–56%; SY, h2 =36–52%). Among the yield components, girth exhibited low to moderate heritability (h2 =17–36%) while branching height showed low heritability (h2 =18%). Using forty clonal genotypes, annual mean rubber yield (H2=48%), rubber yield during peak period (H2=47%) and rubber yield during stress (or summer yield) (H2=44%) showed high estimates of heritability. Among the other yield components, except volume of latex during stress period (H2=40%), remaining yield components showed moderate estimates for heritability (H2=29–37%). Dry rubber content (DRC) based on annual mean showed very high heritability (H2=68%), followed by DRC during stress (H2=51%) and peak (H2=50%) periods. Latex flow rate based on annual mean and peak period data showed high heritability (H2=51%) followed by latex flow rate during stress period (H2=42%). Plugging indices of annual and stress period showed high heritability (H2=43%) than that of peak period (H2=25%). Regarding growth traits, girth showed high heritability (H2=50%) than girth increment (H2=32%). While bark thickness showed high heritability (H2=40%) length of tapping panel showed moderate heritability (H2=27%). Total chlorophyll content exhibited moderate heritability (H2=22%); chlorophyll pigment ratio showed low heritability (H2=5%). Based on parent-offspring analysis, annual mean rubber yield exhibited high genetic correlation with summer yield and girth. Annual mean rubber yield and summer yield were negatively correlated with branching height. Regarding phenotypic correlations among the forty clonal genotypes, annual mean rubber yield exhibited high correlation with latex volume, latex flow rate, DRC, girth and bark thickness. However, annual mean rubber yield was negatively correlated with yield depression under stress and plugging index. Rubber yield, volume and rate of flow of latex over the three periods, yield depression under stress, girth increment, annual mean plugging index and plugging index under stress showed high estimates of genetic advance. The high estimates of heritability for yield and its components coupled with their high genetic gain indicated that considerable improvement can be achieved for these traits through selection. Estimates for indirect selection efficiency were not optimal for indirect selection for yield using girth and summer yield.

Palabras clave

  • full-sibs
  • clonal population
  • latex yield
  • dry rubber content
  • girth
  • branching height
  • genotypic coefficient of variation
  • phenotypic coefficient of variation
  • parent-offspring regression
  • heritability
  • genetic correlation
  • phenotypic correlation
  • genetic gain
Acceso abierto

A combination of fruit and leaf morphology enables taxonomic classification of the complex Q. robur L. – Q. x rosacea Bechst. – Q. petraea (Matt.) Liebl. in autochthonous stands in Flanders

Publicado en línea: 05 Aug 2017
Páginas: 139 - 148

Resumen

Abstract

Hybrids between Quercus robur and Q. petraea have been a sought topic of many studies in Europe during the last decades. Here, leaf and fruit morphology were studied in five oak stands where both species occur naturally intermixed. The stands are relicts of old, possibly medieval coppice wood. Twenty two leaf characters and nine fruit characters were assessed on three leaves and three fruits per tree and for thirty trees per stand. A principal component analysis (PCA) resulted in a bimodal distribution with restricted overlap along the first component when both leaf and fruit data were processed together. For leaf and fruit data separately, the analysis produced only continuous clusters of trees. Two types of putative hybrids can be defined that either show a petiole length of the leaf (PL) according to Q. robur and a petiole length of the fruit (FP1) according to Q. petraea, or vice versa. These hybrids cluster within both groups of the PCA analysis, but not all are situated close to or in the intermediate area between the groups. A lowered mean relative number of developed acorns in the hybrid groups in comparison to their putative maternal parent, based on the assumption of matroclinal inheritance of PL, is observed. This might indicate a reduced ability for successful fertilisation in the hybrids. These results suggest the presence of putative hybrids and introgressed forms within the morphological distinct Q. robur and Q. petraea groups and argument for a taxonomically defined Q. x rosacea based on PL and FP1 limits.

Palabras clave

  • hybridisation
  • leaf and fruit morphology
  • number of undeveloped acorns
  • taxonomy
Acceso abierto

Competition Effects in a Young Sitka Spruce (Picea sitchensis, Bong. Carr) Clonal Trial

Publicado en línea: 05 Aug 2017
Páginas: 149 - 155

Resumen

Abstract

In the analysis of forestry experiments, there may be a need to adjust for competition between plots before predicting deployment performance in the field but there have been few attempts to investigate this. Our analysis looked at diameter data from a 19-year old Sitka spruce clonal trial growing in Scotland. Using a sequence of nested models, a likelihood ratio test indicated that fitting competition at both the genetic and residual level provided a significantly better fit than models which either ignored competition or fitted it at just the genetic or just the residual level. A strong negative genetic correlation of −0.93±0.05 was found between the direct genetic effects and competition effects. This was not significantly different from −1, indicating that competition is almost exactly proportional to the direct genetic effect and that a tree will exert a competitive effect which is closely related to its own genetic merit for size. At the residual level, the correlation between direct and competition effect was estimated as −0.17±0.03. We conclude that competition exists at both the genetic and environmental levels and including it in genetic evaluation systems gives a better prediction of future performance. Results also demonstrate that it is possible to obtain useful information about competition effects from a single-tree plot experiment.

Palabras clave

  • genetic variance
  • genetic prediction
  • single-plot design
  • local spatial trends
Acceso abierto

Induction of 2n pollen by colchicine in Populus × popularis and its triploids breeding

Publicado en línea: 05 Aug 2017
Páginas: 155 - 160

Resumen

Abstract

Induction of 2n pollen is a required technique for cultivating polyploid via sexual polyploidy. Orthogonal design or Taguchi Design was applied to select the best treatment process of 2n pollen induction in Populus × popularis from different levels of the meiosis stage of male flower buds, colchicine concentration, times of injection, and interval between injections. Flow cytometry and chromosome counting were used to identify the triploids from the offspring of P. × euramericana. (Dode) Guinier pollinated with induced pollen of P. × popularis. The results showed that high 2n pollen rate can be achieved by selecting the flower buds during diakinesis stage in meiosis, and then injecting 0.6% colchicine 4 times with 2 hours interval. The 2n pollen rate reached 62.10% by this process, and two triploids were obtained, which indicates that it is possible for cultivating triploids via 2n pollen induction by colchicine treatment in poplar. Results and protocol related to 2n pollen induction, polyploid identification and effect of 2n pollen in this study might be applicable in polyploidy breeding in section Aigeiros and Tacamahaca of poplar.

Palabras clave

  • 2n pollen
  • poplar
  • polyploid breeding
  • colchicine
  • Orthogonal design
Acceso abierto

Short note: Development of Six EST-SSR Markers in Larch

Publicado en línea: 05 Aug 2017
Páginas: 161 - 163

Resumen

Abstract

Six simple sequence repeats (SSR) markers were developed from expressed sequence tags (ESTs) in the genus Larix. Based on evaluation with 49 L. kaempferi genotypes, the number of alleles per locus ranged from two to four, and the expected (He) and observed (Ho) heterozygosity values were 0.225−0.694 and 0.201−0.656, respectively. The inbreeding coffcient (FIS) for all loci were less than zero except that LAReSSR85 was 0.4383. All the six EST-SSR markers were transferable to L. gmelini, L. olgensis var Koreana, L. principisrupprechtii and L. olgensis. BlastX analysis showed that five of the EST-SSRs were homologous to known genes. The six EST-SSR markers developed here can be valuable for biological applications in Larix.

Palabras clave

  • Expressed sequence tag (EST)
  • Simple sequence repeats (SSRs)
  • cross-species transferability
Acceso abierto

Juvenile growth of provenances and open pollinated families of four Russian larch species (Larix Mill.) in Swedish field tests

Publicado en línea: 05 Aug 2017
Páginas: 165 - 177

Resumen

Abstract

Four Russian larch species; (Larix sukaczewii Dyl., L. sibirica Ledeb., L. gmelinii Rupr. and L. cajanderi Mayr.) were tested in combined provenance-progeny tests on three sites in Sweden. 29 provenances, two seed orchards and four seed stands-material were assessed for juvenile height growth and survival after five growing seasons in the field. Genetic parameters were also determined on the family level. The results show that provenances of L. sukaczewii originating from western Russia have the highest survival. Compared to the closely related L. sibirica, L. sukaczewii show better adaptation, a pattern that has also been observed in Finland and Iceland. Provenances of L. gmelinii from the Russian Far East demonstrate best juvenile height growth on all three sites. L. cajanderi from northern interior Siberia failed on all three sites. Both climatic and geographical variables showed strong correlation with survival and height. At this early evaluation it seems like provenances of L. sukaczewii can be transferred northward with satisfactory survival whereas southern transfer or transfer from strongly continental areas in Russia to the semi maritime climate in Sweden results in poor growth. CVA values suggested relatively high genetic variation in height for L. sukaczewii and L. sibirica. The heritabilities for height growth and survival were at this early evaluation generally low (h2 < 0.10) and often non-significant.

Palabras clave

  • provenance trials
  • half-sib families
  • heritability
  • height growth
  • genetic variation
  • climatic change
Acceso abierto

Early Realized Gains for Two-cycle Selection for Black Spruce and Their Implications for Testing Effort Allocation

Publicado en línea: 05 Aug 2017
Páginas: 178 - 186

Resumen

Abstract

Deployment of improved black spruce (Picea mariana (Mill.) B.S.P.) seedlots in New Brunswick (NB) is a standard silvicultural practice. Most plantations have been established using elite-stand seedlots in the 1980s, first-generation seedling seed orchard seedlots in the 1990s and thereafter second-generation clonal seed orchard seedlots. A large-plot realized gain test was established at six sites in NB to provide estimates of actual gains from planting these improved seedlots. The test compared four improved seedlots, representing seedlots collecting from an elite stand, a first-generation seed orchard, two second-generation orchards and a mix of eight elite full-sib families identified in second-generation testing populations, with one unimproved checklot. This paper presents height measurements taken on trees at age 5. Results indicate that realized genetic gains from two-cycle selection and breeding are reasonably high and, in general, the more improved the seedlot, the higher the gain. Planting the elite-stand or the first-generation orchard seedlot would produce a gain of about 10% (relative to the checklot) in 5-yr height and an additional 5.8% gain could be obtained from planting the second-generation orchard seedlot. Even higher gain could be obtained via the deployment of the elite full-sib families, which was estimated to be about 8.6% more than the deployment of the second-generation orchard seedlot. While the realized gain varied with site, the ranking of gain achieved for the different seedlots was similar between sites. The above information was further used to optimize testing efforts for realized gain tests. To detect a typical gain of 5 to 10% at a significance level of 0.05 with a predetermined power of 0.80, each test should include 5 to 10 blocks per site (the number of sites is fixed at 4) or 4 to 6 sites (the number of blocks per site is fixed at 6) paired with planting 36 to 49 trees per plot. These approximate numbers of sites and blocks per site should be modified, depending on the interactions of seedlot with site and with block within site.

Palabras clave

  • tree improvement
  • realized gain test
  • power analysis
  • seedlot deployment
Acceso abierto

Comparison of French and German sessile oak (Quercus petraea (Matt.) Liebl.) provenances

Publicado en línea: 05 Aug 2017
Páginas: 186 - 196

Resumen

Abstract

Provenances originating from French and German sessile oak seed sources were analysed 23 years after planting at nine different locations in Northwest Germany. In general, German provenances are better adapted to the prevailing conditions of the test sites showing a better survival. Differences between the provenances in measured growth characters (“DBH”, “height”) were less pronounced than in observed quality parameters (“form”, “crown”). Five of the German provenances showed a better stem form; only three French provenances exceeded the overall mean. Variation in phenotypic stability between provenances could be observed as well as rank changes of provenances measured at different ages. Observed variation in stability was mainly attributable to single provenances, however, no pattern of variation could be detected. Besides the German seed sources “Bundesgebiet”, “Spessart” and “Göhrde” some French provenances (“Reno Valdieu”, “Bertranges”, “Darney” and “Der”) can be recommended as substitute in low crop years.

Palabras clave

  • provenance
  • test
  • adaptation
  • stability
Acceso abierto

Genetic Variation and Tree Improvement of Konishii fir (Cunninghamia lanceolata (Lamb.) Hook. var. konishii) in Taiwan

Publicado en línea: 05 Aug 2017
Páginas: 196 - 205

Resumen

Abstract

We analyzed a 21-year old progeny test of Konishii fir (Cunninghamia lanceolata (Lamb.) Hook. var. konishii) involving 75 families. Tree height and diameter at breast height (DBH) were periodically recorded. At age 21, average height, DBH, and volume were 15.2 m, 20.2 cm, and 278 dm3, respectively. At this age, family accounted for 9, 12, and 11% of the total variance in height, DBH and volume, respectively. Also at age 21, individual tree heritability was 0.35, 0.49, and 0.45 for height, DBH and volume, respectively, and family heritability was 0.53, 0.69, and 0.66 for the three respective characteristics. The age trend for all genetic parameters was more stable for DBH than for height and volume. Family (backward) selection for DBH at age 21 resulted in a 9.6% gain and indirectly 5.1 and 21.0% gains for height and volume, respectively, compared to 5.2 and 20.1% gains for height and volume, respectively, when selection for these characteristics is done directly. DBH is an effective proxy trait for selection in growth. DBH is also less susceptible than height to typhoon damage, which frequently afflicts tree plantations in Taiwan. Therefore, DBH should be considered as the primary trait for selection for Konishii fir in Taiwan. Konishii fir is a genetically variable species despite its limited geographic range, and is fast growing which makes it a viable candidate species for tree improvement.

Palabras clave

  • Konishii fir
  • genetic variation
  • tree improvement
  • Taiwan
Acceso abierto

The effectiveness of phenotypic selection in natural populations: a case study from the Peruvian Amazon

Publicado en línea: 05 Aug 2017
Páginas: 205 - 209

Resumen

Abstract

Phenotypic selection is commonly used in agroforestry, both in genetic improvement and as a component of “good practice” in seed collection. In the first case, the aim is to secure genetic gain. In the second case, selection is used to ensure that seed supplies meet given minimum quality standards, or that poor quality sources are avoided. Here we examine the effectiveness of phenotypic selection in natural forest stands of the Amazonian timber and multipurpose tree Calycophyllum spruceanum Benth.. We ask (a) whether mothertrees with high estimated annual height and diameter increments had faster growing progeny than mothertrees with low values; (b) whether forked mother-trees tended to have higher proportions of forked progeny than unforked trees; (c) whether spatially isolated mother-trees tend to produce slower growing progeny than mother-trees growing together with conspecifics. In each case, we found no evidence of differences between the respective groups. We offer explanations for these findings and discuss their implications for tree improvement and seed collection.

Palabras clave

  • progeny-test
  • tree domestication
  • tree improvement
  • seed collection
  • tropical rainforest
Acceso abierto

Genetic Variation in Needle Epicuticular Wax Characteristics in Pinus Pinceana Seedlings

Publicado en línea: 05 Aug 2017
Páginas: 210 - 215

Resumen

Abstract

Seedlings from each of 12 Pinus pinceana populations from throughout the species’ range in Mexico were evaluated in a common-garden test to (1) determine the level of genetic variation and genetic structure of epicuticular needle wax quantity, (2) examine differences in wax chemical composition, and (3) seek evidence for an adaptive response in wax composition and quantity across environmental and geographic gradients. Regions and populations within regions showed high variation (38.2% and 10.5%, respectively, of the total variation) in wax quantity. Epicuticular wax recovered from primary needles of P. pinceana comprised eight classes. Secondary alcohols (71.7%) were the major homologs identified by gas chromatography. Seedlings from the northern region were separated based on wax composition from seedlings from the central and southern regions by canonical discriminant analysis. A strong differentiation among regions (QSTR=0.571) and populations within regions (QSTP(R)=0.384) was observed for wax quantity. Data on wax quantity and chemical composition indicate that physicochemical characteristics of epicuticular wax may show adaptation of P. pinceana to local environments.

Palabras clave

  • environmental adaptation
  • epicuticular wax characteristics
  • genetic variation
  • physicochemical characteristics
  • selection
Acceso abierto

Microsatellite-based Genotyping of the Commercial Eucalyptus Clones Cultivated in China

Publicado en línea: 05 Aug 2017
Páginas: 216 - 223

Resumen

Abstract

A proper identification of clones is necessary in clonal forestry and will help to protect the legitimate interests of breeders, growers and industry. Twenty-four of the Eucalyptus clones most widely cultivated in China were analyzed using a set of 24 microsatellite markers to develop their DNA-based fingerprints and exploit the genetic variations. A total of 286 alleles were detected, averaging at 11.9 alleles per marker locus. All the microsatellites were polymorphic among the clones investigated. The observed heterozygosity (Ho) varied with locus between 0.500 and 1.000 with a mean of 0.885. The 24 clones could be uniquely fingerprinted based on their multilocus genotypes at a minimum of three loci (Embra169, Embra72 and Embra2). The dendrogram constructed from the genotypic similarity coefficients separated the 24 clones into three groups, matching essentially the historically known or speculated clonal origins. Clones T13, Guanglin-5 and Guanglin-9 turned out to be full siblings of cross DH32 while the DH201-2 sampled here appeared to be mislabelled.

Palabras clave

  • Microsatellite
  • clone
  • genotyping
  • genetic variation
Acceso abierto

Density and wood biomass development in whole-tree analyses of Scots pine, and aspects on heritability estimates

Publicado en línea: 05 Aug 2017
Páginas: 224 - 232

Resumen

Abstract

Twelve trees in a 36 year old full-sib progeny plantation, testing a part of the Scots pine breeding population, were analysed for wood density and the width of the earlywood and latewood sections in each annual ring. Wood samples (stem discs) were taken with 1 m intervals along the stem and the analyses covered thus the whole stem. Based on these data, the biomass of the earlywood and latewood of each annual ring in each 1 meter stem section was estimated. Latewood density increased from pith to bark while it decreased from stem base to top. Earlywood density was of similar size both radially and vertically. The biomass in each annual ring increased until around ring number 10 from pith for both wood types. For earlywood it then decreased while it remained quite constant for latewood. Latewood biomass decreased more rapidly towards the top of the tree than earlywood biomass. Heritabilities for earlywood and latewood in each annual ring at breast height (estimated in the same material in a previous study) were related to the corresponding biomasses to indirectly estimate overall heritability for wood density valid for the whole stem. The analyses indicate that the decrease in heritability for latewood density and increase for earlywood density, from the pith to bark, is compensated by the increase in latewood biomass in relation to earlywood biomass. Thus, the heritability of the latewood density and earlywood density seems to have the same influence on the overall heritability for density in the whole stem.

Palabras clave

  • wood density
  • biomass
  • stem
  • earlywood
  • latewood
  • heritability
  • selection
  • genetic improvement
Acceso abierto

A genetic study of Pinus parviflora on Ulleung Island of Korea, Compared to P. parviflora of Japan and P. armandii of China

Publicado en línea: 05 Aug 2017
Páginas: 233 - 240

Resumen

Abstract

Pinus parviflora Siebold et Zucc. on Ulleung Island, Korea, has been proposed to be more closely related to P. armandii Franch. because both have long leaves and seeds that are either wingless or have very short wings. Randomly amplified polymorphic DNA (RAPD) markers using nine primers and sequence analysis of the trnG gene and the matK gene and morphological characteristics of seeds and cones were used to assess the genetic relatedness of this taxon on Ulleung Island with P. armandii in China and P. parviflora in Japan. This current study showed that Pinus armandii from China, P. parviflora from Japan, and P. parviflora populations of Ulleung Island formed distinct groups that were separated from each other. P. parviflora from Ulleung Island grouped with P. parviflora from Japan, rather than P. armandii from China based on the RAPD dendrogram and SNPs in matK. It is believed that P. parviflora on Ulleung Island is genetically well differentiated, indicating limited gene flow from Japan, although cones and seeds of P. parviflora on Ulleung Island are more similar to var. parviflora in southern Japan than P. armandii in central China. It seems that the entities that comprise P. parviflora exhibit widely overlapping ranges in morphological attributes except leaf length.

Palabras clave

  • RAPD
  • Single nucleotide polymorphisms
  • K gene
  • Ulleung Island
Acceso abierto

Genetic consequences of subtropical rainforest fragmentation on Macadamia tetraphylla (Proteaceae)

Publicado en línea: 05 Aug 2017
Páginas: 241 - 249

Resumen

Abstract

Habitat fragmentation can bring about a variety of gene-flow alterations in plant populations, potentially threatening adaptive potential and local persistence. It is expected that following habitat fragmentation an increased level of inbreeding will be evident. In addition, a reduction in genetic diversity and increased genetic differentiation is expected following severe or long term population bottlenecks. We examined population genetic parameters for the subtropical rainforest tree Macadamia tetraphylla (Proteaceae) at six field sites throughout its recently fragmented range, using four microsatellite loci. Genetic diversity (HE) of the juvenile cohort was significantly correlated with estimated population size. No significant difference was observed for genetic diversity between adult and juvenile cohorts, but juveniles, and not adults, exhibited significant population differentiation (θ =0.061; P<0.0001 and θ =0.016; P=0.23, respectively). A second, standardised measure of differentiation, ×′, yielded similarly large differences between the two cohorts, though higher estimates of differentiation overall (adults – θ′=0.034, juveniles – θ′=0.116). The coefficient of population inbreeding (f) was significant and positive in all juvenile, and four out of six adult, populations, and was significantly positively correlated with adult tree density, but not adult population size. Since fragmentation is relatively recent for this species, the population bottleneck must have been quite severe to have produced the observed patterns of population differentiation and genetic diversity. Fragmentation of forest across the study area over the last 100+ years has led to the genetic isolation of M. tetraphylla populations resulting in increased population divergence and likely eventual loss of genetic variation in future generations.

Palabras clave

  • subtropical rainforest
  • fragmentation
  • gene diversity
  • inbreeding coefficient
  • differentiation
  • microsatellites
Acceso abierto

Strong Genetic Control of High Wood Specific Gravity in Young Progenies of Pinus brutia: Potential of Early Selection for Industrial Plantations

Publicado en línea: 05 Aug 2017
Páginas: 249 - 258

Resumen

Abstract

To increase quality and amount of wood production in Turkish red pine (Pinus brutia Ten.), genetic control of wood specific gravity (WSG), tracheid length and growth traits was investigated in Ceyhan1A progeny trial by evaluating 168 families originated from six clonal Turkish red pine seed orchards. Wood samples were taken by destructive sampling during the rouging of this trial at the age of seven. Differences among the 168 families for mean WSG was large (ranged from 0.35 to 0.62), as indicated by high individual (0.42±0.07) and family mean (0.55±0.03) heritabilities. Family differences and high heritabilities were also observed for all growth traits and tracheid length. Genetic correlations between WSG and growth traits were insignificant (near zero), while low and insignificant negative phenotypic correlations among the same traits were also observed. Predicted genetic gain for single trait selection at age of seven was low for WSG (0.37%), but substantial for stem volume (8.4%) in phenotypic seed orchards. However, the first generation clonal seed orchards consisting of the best 30 clones yielded higher genetic gains (5.2% for WSG and 35% for stem volume). These preliminary results suggest that selection for wood characteristics and growth traits in Turkish pine could be practiced at early ages for short rotation (about 30 years) in industrial plantations.

Palabras clave

  • Wood Specific Gravity
  • Progeny Test
  • Heritabilities
  • Genetic and Phenotypic Correlations
  • Genetic Gain
Acceso abierto

Eucalyptus fastigata: its current status in New Zealand and breeding objectives for the future

Publicado en línea: 05 Aug 2017
Páginas: 259 - 266

Resumen

Abstract

Eucalyptus fastigata is currently the most promising species of eucalypt planted in New Zealand due to its better disease resistance and wood machinability. A breeding programme for E. fastigata was established in New Zealand in 1979 with the planting of a progeny/provenance trial series containing material collected from native Australian provenances and 2nd generation local land race material from New Zealand and South African populations. A second series containing additional Australian and South African material was planted in 1994.

Landrace material from New Zealand did not perform well compared to Australian and South African populations, suggesting early introductions to New Zealand originated from poor seed sources and/or suffered from inbreeding. Analysis of these trials has provided base genetic parameters for this species providing direction for the next generation of the breeding programme. Predicted genetic gains of 15% for tree form and diameter for the 1979 series, and gains of 8% for diameter and 12% for malformation for the 1994 series, indicate the potential for increases in both tree form and growth rate.

Palabras clave

  • Heritability
  • Genetic correlation
Acceso abierto

Threshold selection for rust resistance in hybrid poplar: Population response to mass selection

Publicado en línea: 05 Aug 2017
Páginas: 266 - 276

Resumen

Abstract

Eleven Populus × generosa populations were developed in the Pacific Northwest by annual controlled hybridization of P. deltoides and P. trichocarpa between 1991 and 2001. Mass selection for Melampsora leaf rust resistance was observed in the field as a threshold character in identifying seedling phenotypes for clonally replicated evaluation. The effectiveness of the approach was assessed for each annual population by comparing the distribution of phenotypes in unselected seedling populations with the distribution of selected genotypes in the clonal field tests established in successive years and evaluated at the approximate same level of disease severity using two selection thresholds corresponding to chlorotic and healthy tissue. Bi-directional selection was used as an initial check on the efficacy of the procedure and resulted in a wide separation in liability between the positive (0.06 threshold units (T.U.)) and negative (−2.45 T.U.) selection groups when tested as clones. The other 10 seedling populations that were subjected solely to directional selection exhibited a mean increase in incidence above the first selection threshold at the clonal stage (47 versus 81%) that was accompanied by an improvement in population liability (−0.06 versus 0.50 T.U.) and a reduction in population standard deviation (0.83 versus 0.54 T.U.). The change in liability was strongly related by polynomial regression to selection intensity and a grouping of populations based on infection-season precipitation (r2=0.98). The mean liability of four of the 10 seedling populations observed during years of high infection-season rainfall was six-fold lower than the mean liability of those populations observed during the other six years of lower infection-season rainfall (−0.12 T.U. versus −0.02 T.U., respectively), indicating that populations undergoing evaluation during years of heavy precipitation experienced more intense rust exposure. Moreover, quadratic functions showed that populations undergoing rust evaluation during years of high rainfall were more responsive to increases in selection intensity above the vertex of the function (i.e. 13.20 versus 3.43 T.U.). Realized heritability averaged 0.63 for all ten populations subjected solely to directional selection.

Palabras clave

  • genetic improvement
  • tree breeding
  • infection
  • leaf rust
Acceso abierto

Genetic variation between and within ex-situ native-provenance collections of Pinus radiata D. Don planted in Australia and New Zealand

Publicado en línea: 05 Aug 2017
Páginas: 276 - 285

Resumen

Abstract

A total of 1226 increment cores were sampled from two provenance trials of Pinus radiata D. Don planted in New Zealand (Kaingaroa) and Australia (Kangaroovale), to study variation and inheritance of wood density in selections from three mainland California natural populations: Año Nuevo, Monterey and Cambria. The study represents a back-to-back comparison of the same provenance and family material on contrasting sites between New Zealand and Australia. Monterey was significantly different to Año Nuevo and Cambria at Kaingaroa (p<0.05), and had slightly higher density, whereas all provenances were almost identical and not significantly different at Kangaroovale. However, there were significant differences for wood density at family level for Año Nuevo and Cambria at Kangaroovale. No significant provenance or family differences were detected for core length at either site. The estimates of heritability for wood density were all above 0.50 and generally higher at Kaingaroa than at Kangaroovale. Estimates of additive genetic correlations between wood density and core length were imprecise. Genotype × site interactions for density appeared minor (estimated type-B genetic correlation= 0.70) despite substantial differences in rainfall and soils. The similarity of Cambria to Año Nuevo for density is an interesting result because the genetic base of the present Australian and New Zealand plantations has been shown to be from Año Nuevo and Monterey. Infusion of Cambria material would increase the overall genetic base of the radiata pine breeding programs, with potential long-term benefits, despite the often disappointing growth performance of material collected from Cambria.

Palabras clave

  • provenance
  • genotype x environment interaction
  • breeding population
  • infusion
  • radiata pine
Acceso abierto

Primer Note: Microsatellite-AFLP development for Araucaria araucana (Mol.) K. Koch, an endangered conifer of Chilean and Argentinean native forests

Publicado en línea: 05 Aug 2017
Páginas: 285 - 288

Resumen

Abstract

Araucaria araucana (Mol.) K. Koch is one of the most important native species of Chile and Argentina, and also one of the most endangered. In this study, we report the development and characterization of a set of microsatellite markers in the species by means of the microsatellite-AFLP (M-AFLP) technique. A total of 25 M-AFLP derived bands, showing a typical microsatellite pattern, were selected and sequenced. Of these, 12 that contained microsatellite sequences, were used for primer extension. Six of the resulting SSR markers provided easily interpretable patterns and were used to investigate the level of genetic diversity in two populations of A. araucana. A total of 43 alleles were amplified. The mean overall loci of observed and expected heterozygosities for the Conguillio and Villa Araucaria populations were 0.322 and 0.443, respectively. The primers presented in this study may provide useful information for the establishment of a conservation strategy in the species.

Palabras clave

  • Microsatellite
  • endangered species
  • conservation
Acceso abierto

Transcript abundances of LIM transcription factor, 4CL, CAld5H and CesAs affect wood properties in Eucalyptus globulus

Publicado en línea: 05 Aug 2017
Páginas: 288 - 296

Resumen

Abstract

Eucalyptus globulus is the main hardwood species grown in pulpwood plantations in temperate regions of the world. We have cloned six genes influencing wood quality including the LIM domain transcription factor (LIM), 4-coumarate-CoA ligase (4CL), coniferaldehyde 5-hydroxylase (CAld5H) and the three catalytic units of cellulose synthase (CesA), from E. globulus. The transcript abundances of LIM in basal stems of ten independent E. globulus lines showed similar patterns to those of 4CL. We investigated the correlation between gene transcript abundances and wood qualities such as Klason lignin (KL) content, syringaldehyde/vanillin (S/V) ratio and holocellulose (HC) content. Expression of the LIM and 4CL were positively correlated with KL content. A highly significant positive correlation was observed between CAld5H expression and S/V ratio. Furthermore, a ratio of the sum of the transcript abundances of three CesA1, CesA2 and CesA3 to 4CL showed a positive correlation with a ratio of HC/KL content that positively correlated with the chemically extracted fiber content in this woody plant.

Palabras clave

  • LIM domain transcription factor
  • CAld5H
  • CesA
  • 4CL
38 Artículos
Acceso abierto

Stem breakage and forking in low and high elevation Pinus tecunumanii

Publicado en línea: 05 Aug 2017
Páginas: 1 - 8

Resumen

Palabras clave

  • Stem breakage
  • forking
  • low and high elevation
  • genotype*environment interaction
Acceso abierto

Heritabilities, Intertrait Genetic Correlations, G x E Interaction and Predicted Genetic Gains for Acoustic Velocity in Mid-rotation Coastal Douglas fir

Publicado en línea: 05 Aug 2017
Páginas: 8 - 18

Resumen

Abstract

Acoustic velocity (AV) data from 7,423 coastal Douglas-fir trees drawn from 347 wind-pollinated families on 14 sites, from four first-generation testing programs in the north Oregon Cascades, were analyzed. Families were measured on two or four sites at ages 23 to 41 years from seed using the Fakopp TreeSonic standingtree tool. Height (HT) and DBH data collected at ages 15 and 16 from seed, from all trees in the four programs (95,795 trees, 955 families), were used to calculate volume index (VOL = HT*DBH2) and stem taper (TAP = DBH/HT). All traits were analyzed using multivariate mixed model analyses.

Across-site individual narrow-sense heritabilities for AV2 ranged from 0.24 to 0.40 among first-generation programs, compared to 0.12 to 0.23 for HT, 0.10 to 0.16 for DBH, 0.11 to 0.20 for VOL and 0.14 to 0.17 for TAP.

Across-site type B correlations for AV2 ranged from 0.85 to 0.95, compared to 0.62 to 0.83 for HT, 0.60 to 0.74 for DBH, 0.67 to 0.78 for VOL and 0.66 to 0.79 for TAP. AV2 was negatively correlated with HT in three programs (rA = 0.17 to −0.28), and negatively correlated with DBH (−0.12 to −0.46), VOL (−0.05 to −0.44) and TAP (−0.09 to −0.40) in all four programs.

Selecting the top 10% of the families sampled based on AV2 gave predicted gains of 4.4% to 9.6% for AV2 and −9.3% to 10.6% for VOL. The adverse genetic correlations between AV2 and growth, and the losses in gain in AV2 from selection based on growth, may be overestimated by suppression of slower-growing families in these older tests.

Palabras clave

  • acoustic velocity
  • dbh
  • Douglas-fir
  • genetic correlation
  • genetic gain
  • height
  • heritability
  • taper
  • volume index
Acceso abierto

An Optimised Protocol for Fluorescent-dUTP Based SSR Genotyping and its Application to Genetic Mapping in Eucalyptus

Publicado en línea: 05 Aug 2017
Páginas: 18 - 25

Resumen

Abstract

Integration of fluorescent-dUTP in polymerase chain reaction (PCR) appears to be a sound method for fluorescence labelling of amplicons in genotyping with simple sequence repeats (SSRs) using an automated sequence analyser. However, the method has not been explored in terms of performance optimisation and cost control. In this paper, we optimised the protocol for fluorescent-dUTP based SSR genotyping in a case study with Eucalyptus. A combination of low dNTP concentration (25 μM each) in PCR reaction and a touchdown PCR programme contributed to increase dramatically the fluorescent intensity of SSR amplicons, thereby facilitating accurate and multiplexed scoring of SSR alleles. The usefulness of the optimised protocol was demonstrated in its application to genetic mapping of SSR loci onto E. urophylla and E. tereticornis linkage maps constructed previously. The protocol optimised here would provide a reliable and economical assay for sequencer-based SSR genotyping in a wide range of biological applications.

Palabras clave

  • Simple sequence repeats (SSRs)
  • genotyping
  • fluorescent-dUTP
  • genetic mapping
Acceso abierto

Two-dimensional penalized splines via Gibbs sampling to account for spatial variability in forest genetic trials with small amount of information available

Publicado en línea: 05 Aug 2017
Páginas: 25 - 35

Resumen

Abstract

Spatial environmental heterogeneity are well known characteristics of field forest genetic trials, even in small experiments (<1ha) established under seemingly uniform conditions and intensive site management. In such trials, it is commonly assumed that any simple type of experimental field design based on randomization theory, as a completely randomized design (CRD), should account for any of the minor site variability. However, most published results indicate that in these types of trials harbor a large component of the spatial variation which commonly resides in the error term. Here we applied a two-dimensional smoothed surface in an individual-tree mixed model, using tensor product of linear, quadratic and cubic B-spline bases with different and equal number of knots for rows and columns, to account for the environmental spatial variability in two relatively small (i.e., 576 m2 and 5,705 m2) forest genetic trials, with large multiple-tree contiguous plot configurations. In general, models accounting for site variability with a two-dimensional surface displayed a lower value of the deviance information criterion than the classical RCD. Linear B-spline bases may yield a reasonable description of the environmental variability, when a relatively small amount of information available. The mixed models fitting a smoothed surface resulted in a reduction in the posterior means of the error variance (σ2e), an increase in the posterior means of the additive genetic variance (σ2a) and heritability (h2HT), and an increase of 16.05% and 46.03% (for parents) or 11.86% and 44.68% (for offspring) in the accuracy of breeding values, respectively in the two experiments.

Palabras clave

  • genetics trials
  • spatial variability
  • tensor product of B-spline
  • error variance
  • genetic parameters
  • accuracy
Acceso abierto

Clonal Variation in Lateral and Basal Rooting of Populus Irrigated with Landfill Leachate

Publicado en línea: 05 Aug 2017
Páginas: 35 - 44

Resumen

Abstract

Successful establishment and productivity of Populus depends upon adventitious rooting from: 1) lateral roots that develop from either preformed or induced primordia and 2) basal roots that differentiate from callus at the base of the cutting in response to wounding. Information is needed for phytotechnologies about the degree to which Populus adventitious rooting is controlled by effects of individual genotypes, waste waters used as alternative fertigation sources, and their interactions. Our objective was to irrigate twelve Populus clones with well water (control) or municipal solid waste landfill leachate and to test for differences between initiation of lateral versus basal roots, as well as root growth rate and distributional trends for both root types. We evaluated number and length of lateral roots initiated from upper, middle, and lower thirds of the cutting, as well as basal callus roots. Overall, leachate irrigation affected lateral roots but not basal roots, and there was broad clonal variation between and within root types. On average, there were 129% more lateral than basal roots, which ranged from 3 to 27 (lateral) and 2 to 10 roots (basal). The percent advantage of number of roots from the middle portion of the cutting relative to other sections was 120% (upper), 193% (lower), and 24% (basal). Clones, treatments, and their interaction did not affect root growth rate, which ranged from 1.5 ± 0.6 to 3.4 ± 0.3 cm d−1, with a mean of 2.3 ± 0.2 cm d−1. These results contribute baseline information for clonal selection needed to establish Populus for phytotechnologies, energy, and fiber.

Palabras clave

  • forest genetics
  • tree improvement
  • phytotechnologies
  • hybrid poplar
  • root types
  • subsp.
Acceso abierto

Effect of genetic relatedness among parents on gain in salt tolerance in progeny of crosses of Eucalyptus occidentalis

Publicado en línea: 05 Aug 2017
Páginas: 45 - 55

Resumen

Abstract

Genetic diversity of a Eucalyptus occidentalis breeding population screened for salt and waterlogging tolerance was examined using eight microsatellite loci. Mating using an immature style ‘one stop pollination’ method between parents was carried out to produce progeny for testing under 500 mM salt waterlogging. The effect of parental genetic distance on seed production and early seedling survival was examined and inheritance of salt/or waterlogging tolerance was assessed by testing performance of progeny in comparison to parents. Diversity was moderate among the nine provenances and the families, and most of the diversity was distributed within rather than between families. Genetic relationships showed no structure in relation to provenance indicating any adaptation to saline environments has not affected genetic similarity. Breeding for salt and water tolerance may be achieved without decline in genetic diversity. There was a significant correlation between capsule production and parental genetic distance and a positive trend between increasing parental genetic distance and increasing number of germinated seeds/capsule, and seedling survival at 2 weeks and 9 months. These trends indicate expression of inbreeding depression in crosses between genetically similar parents. Heritability values, under 500 mM salt-waterlogging treatment, indicated that height had moderate heritability (h2 = 0.5). Crosses with the widest parental genetic distance produced progeny with considerable height increase above parents and this trend was evident even with moderate genetic distance indicating crossing at this level of differentiation may achieve optimum breeding gain.

Palabras clave

  • eucalypts
  • salt tolerance
  • genetic diversity
  • flat topped yate
  • microsatellite
  • inbreeding
Acceso abierto

Genetic structure and diversity of Polylepis australis (Rosaceae) tree populations from central Argentina: Implications for forest conservation

Publicado en línea: 05 Aug 2017
Páginas: 55 - 61

Resumen

Abstract

Worldwide, large areas of forest are being transformed to other land cover types and the resulting fragmented populations may suffer from restricted gene flow leading to genetic pauperization and increased inbreeding. To assess the genetic constitution of fragmented Polylepis australis mountain forests of central Argentina, analyses of the structure and diversity of ISSR markers were carried out for 90 trees distributed throughout five river basins with differing degrees of fragmentation. Overall, average polymorphism (P) ranged between 87.2 and 94.9% (95% criterion) while marker diversity index (M) varied between 0.35 and 0.39; values which are comparable with other wind-pollinated tree species. Analysis of molecular variance (AMOVA) revealed that most genetic variation occurred within river basins (97.8%), with only a little occurring between river basins (2.2%; ΦST = 0.02). In addition, Mantel’s test indicated that P. australis does not follow the usual pattern of isolation by distance; instead the UPGMA method showed that trees from the two most degraded river basins formed a group while trees from the three better preserved basins formed another. As such, either effective pollen flow has maintained high levels of genetic diversity, or present day genetic variability is a remnant of a recently fragmented ancestral panmictic population. We conclude that, at present, genetic degradation in P. australis populations of central Argentina is not as important as ecological degradation – such as soil loss, intensive browsing by livestock or increased frequencies of wildfires, and that genetic variability is still fully available for forest restoration.

Palabras clave

  • fragmentation
  • genetic diversity
  • Argentina
  • conservation
  • ISSR
Acceso abierto

Primer Note: Development of Highly Polymorphic Nuclear Microsatellite Markers for Hinoki (Chamaecyparis obtusa)

Publicado en línea: 05 Aug 2017
Páginas: 62 - 65

Resumen

Abstract

We developed 32 microsatellite markers from an enriched genomic DNA library of hinoki (Chamaecyparis obtusa), one of the most important Japanese forestry conifer species. From a total of 1,056 cloned plasmids, 96 sequence-specific primer pairs were designed from 110 candidate clones. We selected 32 primers that showed successful amplification and marked polymorphism and evaluated their characteristics using DNA from 38 C. obtusa elite trees planted in the Forest Tree Breeding Center. The markers were highly polymorphic, with the number of alleles ranging from 8 to 32 (mean: 20.09), and expected heterozygosity ranging from 0.811 to 0.958 (mean: 0.901). Progress in breeding projects and studies of the ecological genetics of this species can be expected through the use of this enlarged marker pool.

Palabras clave

  • microsatellites
  • forest tree breeding
  • genetic resources
  • ecological genetics
Acceso abierto

Short Note: Cross-Species Amplification and Characterization of Pinus Chloroplast Microsatellite Markers in Cedrus deodara Roxb.

Publicado en línea: 05 Aug 2017
Páginas: 65 - 69

Resumen

Abstract

The study reports the transferability of chloroplast microsatellite markers developed for Pinus species to Cedrus deodara. A total of 49 primer pairs (both nuclear and chloroplast) of Pinus species were tested in C. deodara out of which 21 chloroplast primers showed positive amplification and 20 were found polymorphic. The primers were screened on 100 adult trees of two natural populations of C. deodara. Using twenty cpSSR primers, a total of 64 variants were found which combined in 70 different haplotypes. The total haplotype diversity in two populations was 0.860 and 0.876 with a mean of 0.868. These sets of markers can further be used for population genetic studies and characterization in C. deodara for which no cpSSR markers have been reported till date.

Palabras clave

  • Cross-amplification
  • cpSSRs
  • micro satellite
  • genetic diversity
Acceso abierto

Genetic variation in tree growth, stem form and mortality of Guazuma crinita in slower- and faster-growing plantations in the Peruvian Amazon

Publicado en línea: 05 Aug 2017
Páginas: 70 - 78

Resumen

Abstract

Guazuma crinita is an important timber tree with a rotation age of 6–12 years in the Peruvian Amazon. A provenance/progeny test containing 200 families from seven locations (provenances) in the Aguaytía watershed of Peru was established in three zones in the Aguaytía watershed that differ in mean annual rainfall and soil fertility. Farmers managed the replications as plantations. Replications were divided into two groups at 24 months: faster- and slower-growing plantations. The faster-growing plantations were thinned at 32 months. The objectives of this paper are to determine if genetic variation in growth traits (tree height, stem diameter) is relatively greater in the faster-growing plantations, and if there are significant differences in tree mortality and stem bifurcations among provenances and families at 24, 36 and 48 months. Variation due to provenances and families and heritability of growth traits were consistently greater in the faster-growing plantations. At 48 months, heritability of growth traits was about twice as large in the faster- than in the slower-growing plantations. There were no significant interactions between zones and either provenances or families. Tree mortality and stem bifurcations in the faster-growing plantations generally did not differ significantly among families, but did differ significantly among provenances. Based on these results and considering its rotation age, we recommend that G. crinita families/trees could be selected at 48 months in the faster-growing plantations, the plantations could be transformed into seed orchards and the seed could be used for reforestation throughout the Aguaytía watershed. Results are compared with other tropical hardwoods.

Palabras clave

  • tree improvement
  • provenance/progeny test
  • environment
  • heritability
Acceso abierto

Selection Approaches in High-Elevation Coastal Douglas-fir in The Presence of GxE Interactions

Publicado en línea: 05 Aug 2017
Páginas: 79 - 84

Resumen

Abstract

Regeneration obligations in British Columbia for high-elevation coastal sites requires a secure seed supply of quality seed in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Consequently, a seed orchard is under development to supply seed after genetic testing and selection. For this purpose, 55 coastal Douglas-fir families were field-tested for 11 years on two contrasting high-elevation sites to examine differential growth performance and tolerance to cold conditions. Although heritabilities for growth on both sites were moderate at age 11, the higher elevation colder site had substantially slower growth and over 90% of the trees exhibited some form of cold damage to foliage, branches and stems; however, variation in this damage was not significant at the family level. Combined site analysis revealed a highly significant genotype by environment (GxE) component in height that could not be removed or reduced by using site-specific error variances or spatial analysis (i.e., GxE was primarily due to rank changes of families across the two sites). This was also reflected by a drop in heritability estimates obtained from the combined site analyses. In the presence of this type of GxE, independent culling, considering height a separate trait on each site, was employed to identify parents that were at a threshold breeding value of 5% or greater in growth superiority on both sites. Average breeding values for the selected parents, based on a combined site analysis, were around 5% above the trial mean for height at age 11. The use of independent culling, for situations where accurate genetic parameters are difficult to obtain, should be considered a practical alternative to more complex and error prone methods of selection.

Palabras clave

  • independent culling
  • spatial analysis
  • breeding value
Acceso abierto

Diagnosis of interspecific hybrids between Acacia mangium and A. auriculiformis using single nucleotide polymorphism (SNP) markers

Publicado en línea: 05 Aug 2017
Páginas: 85 - 92

Resumen

Abstract

This paper describes a diagnostic system to verify interspecific hybrids between Acacia mangium and A. auriculiformis using single nucleotide polymorphism (SNP) markers. Forty-eight DNA fragments were selected based on random amplified polymorphic DNAs (RAPD) amplified across 48 individuals from each parental species, and were transformed into 44 sequence-characterized amplified region (SCAR) markers. Five SNP markers that generated species-specific alleles for each species were selected from the 28 sequenced SCARs. A multiplex single nucleotide primer extension (SNuPE) analyses of the five SNPs using 40 A. mangium, 40 A. auriculiformis and 16 Acacia hybrids showed high discrimination power. This diagnostic system, with high discriminatory ability, provides a highly reliable and fast method for identifying interspecific hybrids of A. mangium and A. auriculiformis.

Palabras clave

  • interspecific hybrid
  • PCR
  • RAPD
  • SCAR
  • SNP
Acceso abierto

Short Note: Seven Genomic SSRs Revealed in Eucalyptus by Re-sequencing of DNA Sequences from GenBank

Publicado en línea: 05 Aug 2017
Páginas: 92 - 94

Resumen

Abstract

Seven genomic SSR markers of Eucalyptus were developed from DNA sequences of E. grandis deposited in GenBank. Their repeat motifs were revealed by resequencing with an individual tree of E. urophylla or E. tereticornis, and five out of the seven markers turned out to be heterozygous within the specific tree sequenced. The sequence identity ranged from 75.06% to 96.66%, with an average of 87.31%. These markers could be valuable in genetics studies in Eucalyptus. This report demonstrates the advantages of re-sequencing in developing SSR markers from publicly accessible databases.

Palabras clave

  • Simple sequence repeats (SSRs)
  • microsatellites
  • molecular markers
  • re-sequencing
Acceso abierto

Variations in biomass, nutrient contents and nutrient use efficiency among Chinese fir provenances

Publicado en línea: 05 Aug 2017
Páginas: 95 - 105

Resumen

Abstract

A provenance trial involving 16 Chinese fir provenances was established in southern China in 1979, and biomass, nutrient content and nutrient use efficiency were assessed at the age of 23. One-way analysis of variance revealed significant inter-provenance variation (p<0.0001) in measured variables. The mean total biomass ranged from 98.8±5.3 to 163.3±4.2 t ha−1, and the stemwood accounted for 47–65% of the total biomass, followed by roots (11–24%), stembark (7.4–13.7%), and needles and branches (< 10 %). Much of the nitrogen, phosphorus and potassium were stored in the needles, although the concentration varies among provenances. Whole-tree nutrient use efficiency varied from 115.4±2.1 to 180.2±1.02 g g−1, while efficiency in stemwood production ranged from 53.9±3.1 to 106.3±1.1 g g−1. Provenances did not display consistent variation in all measured variables, suggesting the need for multiple criteria for selection in future tree improvement program. In conclusion, the study reveals the existence of considerable variation in biomass production and nutrient use efficiency among Chinese fir provenances that can be exploited for selecting desirable genotypes for enhancing productivity of Chinese fir plantations.

Palabras clave

  • Biomass production
  • Tree improvement
  • forest nutrition
Acceso abierto

Genetic parameter estimates and parental selection in Eucalyptus longirostrata and Corymbia henryi populations tested in South Africa

Publicado en línea: 05 Aug 2017
Páginas: 105 - 113

Resumen

Abstract

The sub-tropical species, Eucalyptus longirostrata (formerly E. punctata var longirostrata) and Corymbia henryi were investigated as alternative species for growth on the Zululand coastal plain in South Africa. Provenance/progeny trials were established in 2001 at two sites, namely, Nyalazi and Kwambonambi. The seed material purchased from the Commonwealth Scientific and Industrial Research Organization in Australia in 2000 included six provenances of E. longirostrata and five provenances of C. henryi. Six-year diameter at breast height measurements were completed in 2007. Individual narrow-sense heritability coefficients for diameter growth varied from 0.30 to 0.58 for both species, with heritabilities being higher at the drier Nyalazi site. Heritabilities and breeding values were calculated prior to making selections in field. A total of 143 selections were made in the E. longirostrata trials, and 113 in the C. henryi trials during 2008. Predicted gains for the next generation range from 2.8 cm (20%) to 6.1 cm (61%) increase in diameter for E. longirostrata, and 3.4 cm (23%) to 5.4 cm (49%) increase for C. henryi, depending on site and selection scenario. Provenance differences were evident in E. longirostrata at both sites; however, there were no significant differences between the C. henryi provenances of Australian origin. The top families of both species performed better than the hybrid controls at the Nyalazi site, indicating that both E. longirostrata and C. henryi are viable alternative species for successful growth on the drier sites of the Zululand coastal plain.

Palabras clave

  • tree breeding
  • genetic parameters
  • heritability
  • genetic gains
  • BLUP
  • selection
Acceso abierto

Changes in Genetic Diversity of Whitebark Pine (Pinus albicaulis Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

Publicado en línea: 05 Aug 2017
Páginas: 113 - 123

Resumen

Abstract

We investigated the association of inbreeding and infection by the introduced disease white pine blister rust (caused by the fungus Cronartium ribicola J. C. Fisch) with genetic diversity of whitebark pine (Pinus albicaulis Engelm.) by genetically comparing cohorts of different ages in natural stands. Isozyme analysis of bud tissue was used to estimate expected and observed heterozygosity (He and Ho), and Wright’s fixation index (Fis) for three age cohorts (seedling, young, and mature), sampled from 14 sites in British Columbia, Oregon, Idaho, and Montana. Comparison of genetic diversity parameters among cohorts within a site was used to assess the extent and persistence of inbreeding with age, while comparisons of parameters among sites within a cohort were used to assess the impact of the disease on genetic diversity. Significant evidence of inbreeding (Fis >0) was found in all age cohorts. When sites were stratified by level of blister rust infection, differences in Fis and Ho among cohorts were only significant when level of infection was low. A significant negative association was found between level of blister rust infection and Ho in the mature cohort. This suggests that when differential selection due to blister rust is weak, more heterozygous individuals may be favored; however, more homozygous individuals may have higher fitness under higher blister rust levels

Palabras clave

  • whitebark pine
  • white pine blister rust
  • genetic diversity
  • isozymes
  • inbreeding
  • cohort analysis
  • heterozygosity
Acceso abierto

Genetic diversity of Anadenanthera colubrina Vell. (Brenan) var cebil, a tree species from the South American subtropical forest as revealed by cpSSR markers

Publicado en línea: 05 Aug 2017
Páginas: 123 - 132

Resumen

Abstract

Anadenanthera colubrina var cebil is a tree species native to the Upper Parana Atlantic Forest where human activities have severely impacted causing deep fragmentation. Microsatellites are not available in this species. Therefore, the first objective of this study was to generate chloroplast simple sequence repeats (cpSSR) by cross-species transfer. Understanding the evolutionary dynamics of subdivided populations is an important matter. In this way, a first approach to the characterization of the haplotypic diversity within and between populations as well as the genetic structure of native Argentinean populations were the main goals of this study.

Twenty four individuals from two populations of the Misiones province were studied and four cpSSR loci were tested. Two of them exhibited polymorphic patterns leading to the identification of 11 cpDNA haplotypes with high mean genetic diversity (GD=0.73). The minimum spanning network defined three clear groups which can be assigned to at least three subpopulations. AMOVA indicated that the total variance showed the highest percentage of variation (48%) within subpopulations with a fixation index (FST) statistically significant (FST=0.520; p<0.05). Brown’s two loci component analysis indicated that substructure population is present. Jost’s differentiation global index (Dest) was 0.049 while Dest pairwise comparison reflected a certain level of genetic structure.

The high diversity level detected in the adult trees of A. colubrina var cebil from the populations under study could be due to recent human influence. In this way, the reduction in population size caused a reduction in the number of trees leading to surviving trees showing the historical diversity of the populations analyzed.

Palabras clave

  • Upper Parana Atlantic Forest
  • Curupay
  • intraspecific genetic diversity
  • cpSSR cross-species transfer
Acceso abierto

Heritability of Yield and Secondary Traits in two populations of Para Rubber Tree (Hevea brasiliensis)

Publicado en línea: 05 Aug 2017
Páginas: 132 - 139

Resumen

Abstract

Heritability and interactions of yield and growth traits were assessed in Hevea brasiliensis using full-sib progenies and clonal populations. Using parent-offspring regression, annual mean rubber yield (ARY) and summer yield (SY) showed moderate to high heritability (ARY, h2 =34–56%; SY, h2 =36–52%). Among the yield components, girth exhibited low to moderate heritability (h2 =17–36%) while branching height showed low heritability (h2 =18%). Using forty clonal genotypes, annual mean rubber yield (H2=48%), rubber yield during peak period (H2=47%) and rubber yield during stress (or summer yield) (H2=44%) showed high estimates of heritability. Among the other yield components, except volume of latex during stress period (H2=40%), remaining yield components showed moderate estimates for heritability (H2=29–37%). Dry rubber content (DRC) based on annual mean showed very high heritability (H2=68%), followed by DRC during stress (H2=51%) and peak (H2=50%) periods. Latex flow rate based on annual mean and peak period data showed high heritability (H2=51%) followed by latex flow rate during stress period (H2=42%). Plugging indices of annual and stress period showed high heritability (H2=43%) than that of peak period (H2=25%). Regarding growth traits, girth showed high heritability (H2=50%) than girth increment (H2=32%). While bark thickness showed high heritability (H2=40%) length of tapping panel showed moderate heritability (H2=27%). Total chlorophyll content exhibited moderate heritability (H2=22%); chlorophyll pigment ratio showed low heritability (H2=5%). Based on parent-offspring analysis, annual mean rubber yield exhibited high genetic correlation with summer yield and girth. Annual mean rubber yield and summer yield were negatively correlated with branching height. Regarding phenotypic correlations among the forty clonal genotypes, annual mean rubber yield exhibited high correlation with latex volume, latex flow rate, DRC, girth and bark thickness. However, annual mean rubber yield was negatively correlated with yield depression under stress and plugging index. Rubber yield, volume and rate of flow of latex over the three periods, yield depression under stress, girth increment, annual mean plugging index and plugging index under stress showed high estimates of genetic advance. The high estimates of heritability for yield and its components coupled with their high genetic gain indicated that considerable improvement can be achieved for these traits through selection. Estimates for indirect selection efficiency were not optimal for indirect selection for yield using girth and summer yield.

Palabras clave

  • full-sibs
  • clonal population
  • latex yield
  • dry rubber content
  • girth
  • branching height
  • genotypic coefficient of variation
  • phenotypic coefficient of variation
  • parent-offspring regression
  • heritability
  • genetic correlation
  • phenotypic correlation
  • genetic gain
Acceso abierto

A combination of fruit and leaf morphology enables taxonomic classification of the complex Q. robur L. – Q. x rosacea Bechst. – Q. petraea (Matt.) Liebl. in autochthonous stands in Flanders

Publicado en línea: 05 Aug 2017
Páginas: 139 - 148

Resumen

Abstract

Hybrids between Quercus robur and Q. petraea have been a sought topic of many studies in Europe during the last decades. Here, leaf and fruit morphology were studied in five oak stands where both species occur naturally intermixed. The stands are relicts of old, possibly medieval coppice wood. Twenty two leaf characters and nine fruit characters were assessed on three leaves and three fruits per tree and for thirty trees per stand. A principal component analysis (PCA) resulted in a bimodal distribution with restricted overlap along the first component when both leaf and fruit data were processed together. For leaf and fruit data separately, the analysis produced only continuous clusters of trees. Two types of putative hybrids can be defined that either show a petiole length of the leaf (PL) according to Q. robur and a petiole length of the fruit (FP1) according to Q. petraea, or vice versa. These hybrids cluster within both groups of the PCA analysis, but not all are situated close to or in the intermediate area between the groups. A lowered mean relative number of developed acorns in the hybrid groups in comparison to their putative maternal parent, based on the assumption of matroclinal inheritance of PL, is observed. This might indicate a reduced ability for successful fertilisation in the hybrids. These results suggest the presence of putative hybrids and introgressed forms within the morphological distinct Q. robur and Q. petraea groups and argument for a taxonomically defined Q. x rosacea based on PL and FP1 limits.

Palabras clave

  • hybridisation
  • leaf and fruit morphology
  • number of undeveloped acorns
  • taxonomy
Acceso abierto

Competition Effects in a Young Sitka Spruce (Picea sitchensis, Bong. Carr) Clonal Trial

Publicado en línea: 05 Aug 2017
Páginas: 149 - 155

Resumen

Abstract

In the analysis of forestry experiments, there may be a need to adjust for competition between plots before predicting deployment performance in the field but there have been few attempts to investigate this. Our analysis looked at diameter data from a 19-year old Sitka spruce clonal trial growing in Scotland. Using a sequence of nested models, a likelihood ratio test indicated that fitting competition at both the genetic and residual level provided a significantly better fit than models which either ignored competition or fitted it at just the genetic or just the residual level. A strong negative genetic correlation of −0.93±0.05 was found between the direct genetic effects and competition effects. This was not significantly different from −1, indicating that competition is almost exactly proportional to the direct genetic effect and that a tree will exert a competitive effect which is closely related to its own genetic merit for size. At the residual level, the correlation between direct and competition effect was estimated as −0.17±0.03. We conclude that competition exists at both the genetic and environmental levels and including it in genetic evaluation systems gives a better prediction of future performance. Results also demonstrate that it is possible to obtain useful information about competition effects from a single-tree plot experiment.

Palabras clave

  • genetic variance
  • genetic prediction
  • single-plot design
  • local spatial trends
Acceso abierto

Induction of 2n pollen by colchicine in Populus × popularis and its triploids breeding

Publicado en línea: 05 Aug 2017
Páginas: 155 - 160

Resumen

Abstract

Induction of 2n pollen is a required technique for cultivating polyploid via sexual polyploidy. Orthogonal design or Taguchi Design was applied to select the best treatment process of 2n pollen induction in Populus × popularis from different levels of the meiosis stage of male flower buds, colchicine concentration, times of injection, and interval between injections. Flow cytometry and chromosome counting were used to identify the triploids from the offspring of P. × euramericana. (Dode) Guinier pollinated with induced pollen of P. × popularis. The results showed that high 2n pollen rate can be achieved by selecting the flower buds during diakinesis stage in meiosis, and then injecting 0.6% colchicine 4 times with 2 hours interval. The 2n pollen rate reached 62.10% by this process, and two triploids were obtained, which indicates that it is possible for cultivating triploids via 2n pollen induction by colchicine treatment in poplar. Results and protocol related to 2n pollen induction, polyploid identification and effect of 2n pollen in this study might be applicable in polyploidy breeding in section Aigeiros and Tacamahaca of poplar.

Palabras clave

  • 2n pollen
  • poplar
  • polyploid breeding
  • colchicine
  • Orthogonal design
Acceso abierto

Short note: Development of Six EST-SSR Markers in Larch

Publicado en línea: 05 Aug 2017
Páginas: 161 - 163

Resumen

Abstract

Six simple sequence repeats (SSR) markers were developed from expressed sequence tags (ESTs) in the genus Larix. Based on evaluation with 49 L. kaempferi genotypes, the number of alleles per locus ranged from two to four, and the expected (He) and observed (Ho) heterozygosity values were 0.225−0.694 and 0.201−0.656, respectively. The inbreeding coffcient (FIS) for all loci were less than zero except that LAReSSR85 was 0.4383. All the six EST-SSR markers were transferable to L. gmelini, L. olgensis var Koreana, L. principisrupprechtii and L. olgensis. BlastX analysis showed that five of the EST-SSRs were homologous to known genes. The six EST-SSR markers developed here can be valuable for biological applications in Larix.

Palabras clave

  • Expressed sequence tag (EST)
  • Simple sequence repeats (SSRs)
  • cross-species transferability
Acceso abierto

Juvenile growth of provenances and open pollinated families of four Russian larch species (Larix Mill.) in Swedish field tests

Publicado en línea: 05 Aug 2017
Páginas: 165 - 177

Resumen

Abstract

Four Russian larch species; (Larix sukaczewii Dyl., L. sibirica Ledeb., L. gmelinii Rupr. and L. cajanderi Mayr.) were tested in combined provenance-progeny tests on three sites in Sweden. 29 provenances, two seed orchards and four seed stands-material were assessed for juvenile height growth and survival after five growing seasons in the field. Genetic parameters were also determined on the family level. The results show that provenances of L. sukaczewii originating from western Russia have the highest survival. Compared to the closely related L. sibirica, L. sukaczewii show better adaptation, a pattern that has also been observed in Finland and Iceland. Provenances of L. gmelinii from the Russian Far East demonstrate best juvenile height growth on all three sites. L. cajanderi from northern interior Siberia failed on all three sites. Both climatic and geographical variables showed strong correlation with survival and height. At this early evaluation it seems like provenances of L. sukaczewii can be transferred northward with satisfactory survival whereas southern transfer or transfer from strongly continental areas in Russia to the semi maritime climate in Sweden results in poor growth. CVA values suggested relatively high genetic variation in height for L. sukaczewii and L. sibirica. The heritabilities for height growth and survival were at this early evaluation generally low (h2 < 0.10) and often non-significant.

Palabras clave

  • provenance trials
  • half-sib families
  • heritability
  • height growth
  • genetic variation
  • climatic change
Acceso abierto

Early Realized Gains for Two-cycle Selection for Black Spruce and Their Implications for Testing Effort Allocation

Publicado en línea: 05 Aug 2017
Páginas: 178 - 186

Resumen

Abstract

Deployment of improved black spruce (Picea mariana (Mill.) B.S.P.) seedlots in New Brunswick (NB) is a standard silvicultural practice. Most plantations have been established using elite-stand seedlots in the 1980s, first-generation seedling seed orchard seedlots in the 1990s and thereafter second-generation clonal seed orchard seedlots. A large-plot realized gain test was established at six sites in NB to provide estimates of actual gains from planting these improved seedlots. The test compared four improved seedlots, representing seedlots collecting from an elite stand, a first-generation seed orchard, two second-generation orchards and a mix of eight elite full-sib families identified in second-generation testing populations, with one unimproved checklot. This paper presents height measurements taken on trees at age 5. Results indicate that realized genetic gains from two-cycle selection and breeding are reasonably high and, in general, the more improved the seedlot, the higher the gain. Planting the elite-stand or the first-generation orchard seedlot would produce a gain of about 10% (relative to the checklot) in 5-yr height and an additional 5.8% gain could be obtained from planting the second-generation orchard seedlot. Even higher gain could be obtained via the deployment of the elite full-sib families, which was estimated to be about 8.6% more than the deployment of the second-generation orchard seedlot. While the realized gain varied with site, the ranking of gain achieved for the different seedlots was similar between sites. The above information was further used to optimize testing efforts for realized gain tests. To detect a typical gain of 5 to 10% at a significance level of 0.05 with a predetermined power of 0.80, each test should include 5 to 10 blocks per site (the number of sites is fixed at 4) or 4 to 6 sites (the number of blocks per site is fixed at 6) paired with planting 36 to 49 trees per plot. These approximate numbers of sites and blocks per site should be modified, depending on the interactions of seedlot with site and with block within site.

Palabras clave

  • tree improvement
  • realized gain test
  • power analysis
  • seedlot deployment
Acceso abierto

Comparison of French and German sessile oak (Quercus petraea (Matt.) Liebl.) provenances

Publicado en línea: 05 Aug 2017
Páginas: 186 - 196

Resumen

Abstract

Provenances originating from French and German sessile oak seed sources were analysed 23 years after planting at nine different locations in Northwest Germany. In general, German provenances are better adapted to the prevailing conditions of the test sites showing a better survival. Differences between the provenances in measured growth characters (“DBH”, “height”) were less pronounced than in observed quality parameters (“form”, “crown”). Five of the German provenances showed a better stem form; only three French provenances exceeded the overall mean. Variation in phenotypic stability between provenances could be observed as well as rank changes of provenances measured at different ages. Observed variation in stability was mainly attributable to single provenances, however, no pattern of variation could be detected. Besides the German seed sources “Bundesgebiet”, “Spessart” and “Göhrde” some French provenances (“Reno Valdieu”, “Bertranges”, “Darney” and “Der”) can be recommended as substitute in low crop years.

Palabras clave

  • provenance
  • test
  • adaptation
  • stability
Acceso abierto

Genetic Variation and Tree Improvement of Konishii fir (Cunninghamia lanceolata (Lamb.) Hook. var. konishii) in Taiwan

Publicado en línea: 05 Aug 2017
Páginas: 196 - 205

Resumen

Abstract

We analyzed a 21-year old progeny test of Konishii fir (Cunninghamia lanceolata (Lamb.) Hook. var. konishii) involving 75 families. Tree height and diameter at breast height (DBH) were periodically recorded. At age 21, average height, DBH, and volume were 15.2 m, 20.2 cm, and 278 dm3, respectively. At this age, family accounted for 9, 12, and 11% of the total variance in height, DBH and volume, respectively. Also at age 21, individual tree heritability was 0.35, 0.49, and 0.45 for height, DBH and volume, respectively, and family heritability was 0.53, 0.69, and 0.66 for the three respective characteristics. The age trend for all genetic parameters was more stable for DBH than for height and volume. Family (backward) selection for DBH at age 21 resulted in a 9.6% gain and indirectly 5.1 and 21.0% gains for height and volume, respectively, compared to 5.2 and 20.1% gains for height and volume, respectively, when selection for these characteristics is done directly. DBH is an effective proxy trait for selection in growth. DBH is also less susceptible than height to typhoon damage, which frequently afflicts tree plantations in Taiwan. Therefore, DBH should be considered as the primary trait for selection for Konishii fir in Taiwan. Konishii fir is a genetically variable species despite its limited geographic range, and is fast growing which makes it a viable candidate species for tree improvement.

Palabras clave

  • Konishii fir
  • genetic variation
  • tree improvement
  • Taiwan
Acceso abierto

The effectiveness of phenotypic selection in natural populations: a case study from the Peruvian Amazon

Publicado en línea: 05 Aug 2017
Páginas: 205 - 209

Resumen

Abstract

Phenotypic selection is commonly used in agroforestry, both in genetic improvement and as a component of “good practice” in seed collection. In the first case, the aim is to secure genetic gain. In the second case, selection is used to ensure that seed supplies meet given minimum quality standards, or that poor quality sources are avoided. Here we examine the effectiveness of phenotypic selection in natural forest stands of the Amazonian timber and multipurpose tree Calycophyllum spruceanum Benth.. We ask (a) whether mothertrees with high estimated annual height and diameter increments had faster growing progeny than mothertrees with low values; (b) whether forked mother-trees tended to have higher proportions of forked progeny than unforked trees; (c) whether spatially isolated mother-trees tend to produce slower growing progeny than mother-trees growing together with conspecifics. In each case, we found no evidence of differences between the respective groups. We offer explanations for these findings and discuss their implications for tree improvement and seed collection.

Palabras clave

  • progeny-test
  • tree domestication
  • tree improvement
  • seed collection
  • tropical rainforest
Acceso abierto

Genetic Variation in Needle Epicuticular Wax Characteristics in Pinus Pinceana Seedlings

Publicado en línea: 05 Aug 2017
Páginas: 210 - 215

Resumen

Abstract

Seedlings from each of 12 Pinus pinceana populations from throughout the species’ range in Mexico were evaluated in a common-garden test to (1) determine the level of genetic variation and genetic structure of epicuticular needle wax quantity, (2) examine differences in wax chemical composition, and (3) seek evidence for an adaptive response in wax composition and quantity across environmental and geographic gradients. Regions and populations within regions showed high variation (38.2% and 10.5%, respectively, of the total variation) in wax quantity. Epicuticular wax recovered from primary needles of P. pinceana comprised eight classes. Secondary alcohols (71.7%) were the major homologs identified by gas chromatography. Seedlings from the northern region were separated based on wax composition from seedlings from the central and southern regions by canonical discriminant analysis. A strong differentiation among regions (QSTR=0.571) and populations within regions (QSTP(R)=0.384) was observed for wax quantity. Data on wax quantity and chemical composition indicate that physicochemical characteristics of epicuticular wax may show adaptation of P. pinceana to local environments.

Palabras clave

  • environmental adaptation
  • epicuticular wax characteristics
  • genetic variation
  • physicochemical characteristics
  • selection
Acceso abierto

Microsatellite-based Genotyping of the Commercial Eucalyptus Clones Cultivated in China

Publicado en línea: 05 Aug 2017
Páginas: 216 - 223

Resumen

Abstract

A proper identification of clones is necessary in clonal forestry and will help to protect the legitimate interests of breeders, growers and industry. Twenty-four of the Eucalyptus clones most widely cultivated in China were analyzed using a set of 24 microsatellite markers to develop their DNA-based fingerprints and exploit the genetic variations. A total of 286 alleles were detected, averaging at 11.9 alleles per marker locus. All the microsatellites were polymorphic among the clones investigated. The observed heterozygosity (Ho) varied with locus between 0.500 and 1.000 with a mean of 0.885. The 24 clones could be uniquely fingerprinted based on their multilocus genotypes at a minimum of three loci (Embra169, Embra72 and Embra2). The dendrogram constructed from the genotypic similarity coefficients separated the 24 clones into three groups, matching essentially the historically known or speculated clonal origins. Clones T13, Guanglin-5 and Guanglin-9 turned out to be full siblings of cross DH32 while the DH201-2 sampled here appeared to be mislabelled.

Palabras clave

  • Microsatellite
  • clone
  • genotyping
  • genetic variation
Acceso abierto

Density and wood biomass development in whole-tree analyses of Scots pine, and aspects on heritability estimates

Publicado en línea: 05 Aug 2017
Páginas: 224 - 232

Resumen

Abstract

Twelve trees in a 36 year old full-sib progeny plantation, testing a part of the Scots pine breeding population, were analysed for wood density and the width of the earlywood and latewood sections in each annual ring. Wood samples (stem discs) were taken with 1 m intervals along the stem and the analyses covered thus the whole stem. Based on these data, the biomass of the earlywood and latewood of each annual ring in each 1 meter stem section was estimated. Latewood density increased from pith to bark while it decreased from stem base to top. Earlywood density was of similar size both radially and vertically. The biomass in each annual ring increased until around ring number 10 from pith for both wood types. For earlywood it then decreased while it remained quite constant for latewood. Latewood biomass decreased more rapidly towards the top of the tree than earlywood biomass. Heritabilities for earlywood and latewood in each annual ring at breast height (estimated in the same material in a previous study) were related to the corresponding biomasses to indirectly estimate overall heritability for wood density valid for the whole stem. The analyses indicate that the decrease in heritability for latewood density and increase for earlywood density, from the pith to bark, is compensated by the increase in latewood biomass in relation to earlywood biomass. Thus, the heritability of the latewood density and earlywood density seems to have the same influence on the overall heritability for density in the whole stem.

Palabras clave

  • wood density
  • biomass
  • stem
  • earlywood
  • latewood
  • heritability
  • selection
  • genetic improvement
Acceso abierto

A genetic study of Pinus parviflora on Ulleung Island of Korea, Compared to P. parviflora of Japan and P. armandii of China

Publicado en línea: 05 Aug 2017
Páginas: 233 - 240

Resumen

Abstract

Pinus parviflora Siebold et Zucc. on Ulleung Island, Korea, has been proposed to be more closely related to P. armandii Franch. because both have long leaves and seeds that are either wingless or have very short wings. Randomly amplified polymorphic DNA (RAPD) markers using nine primers and sequence analysis of the trnG gene and the matK gene and morphological characteristics of seeds and cones were used to assess the genetic relatedness of this taxon on Ulleung Island with P. armandii in China and P. parviflora in Japan. This current study showed that Pinus armandii from China, P. parviflora from Japan, and P. parviflora populations of Ulleung Island formed distinct groups that were separated from each other. P. parviflora from Ulleung Island grouped with P. parviflora from Japan, rather than P. armandii from China based on the RAPD dendrogram and SNPs in matK. It is believed that P. parviflora on Ulleung Island is genetically well differentiated, indicating limited gene flow from Japan, although cones and seeds of P. parviflora on Ulleung Island are more similar to var. parviflora in southern Japan than P. armandii in central China. It seems that the entities that comprise P. parviflora exhibit widely overlapping ranges in morphological attributes except leaf length.

Palabras clave

  • RAPD
  • Single nucleotide polymorphisms
  • K gene
  • Ulleung Island
Acceso abierto

Genetic consequences of subtropical rainforest fragmentation on Macadamia tetraphylla (Proteaceae)

Publicado en línea: 05 Aug 2017
Páginas: 241 - 249

Resumen

Abstract

Habitat fragmentation can bring about a variety of gene-flow alterations in plant populations, potentially threatening adaptive potential and local persistence. It is expected that following habitat fragmentation an increased level of inbreeding will be evident. In addition, a reduction in genetic diversity and increased genetic differentiation is expected following severe or long term population bottlenecks. We examined population genetic parameters for the subtropical rainforest tree Macadamia tetraphylla (Proteaceae) at six field sites throughout its recently fragmented range, using four microsatellite loci. Genetic diversity (HE) of the juvenile cohort was significantly correlated with estimated population size. No significant difference was observed for genetic diversity between adult and juvenile cohorts, but juveniles, and not adults, exhibited significant population differentiation (θ =0.061; P<0.0001 and θ =0.016; P=0.23, respectively). A second, standardised measure of differentiation, ×′, yielded similarly large differences between the two cohorts, though higher estimates of differentiation overall (adults – θ′=0.034, juveniles – θ′=0.116). The coefficient of population inbreeding (f) was significant and positive in all juvenile, and four out of six adult, populations, and was significantly positively correlated with adult tree density, but not adult population size. Since fragmentation is relatively recent for this species, the population bottleneck must have been quite severe to have produced the observed patterns of population differentiation and genetic diversity. Fragmentation of forest across the study area over the last 100+ years has led to the genetic isolation of M. tetraphylla populations resulting in increased population divergence and likely eventual loss of genetic variation in future generations.

Palabras clave

  • subtropical rainforest
  • fragmentation
  • gene diversity
  • inbreeding coefficient
  • differentiation
  • microsatellites
Acceso abierto

Strong Genetic Control of High Wood Specific Gravity in Young Progenies of Pinus brutia: Potential of Early Selection for Industrial Plantations

Publicado en línea: 05 Aug 2017
Páginas: 249 - 258

Resumen

Abstract

To increase quality and amount of wood production in Turkish red pine (Pinus brutia Ten.), genetic control of wood specific gravity (WSG), tracheid length and growth traits was investigated in Ceyhan1A progeny trial by evaluating 168 families originated from six clonal Turkish red pine seed orchards. Wood samples were taken by destructive sampling during the rouging of this trial at the age of seven. Differences among the 168 families for mean WSG was large (ranged from 0.35 to 0.62), as indicated by high individual (0.42±0.07) and family mean (0.55±0.03) heritabilities. Family differences and high heritabilities were also observed for all growth traits and tracheid length. Genetic correlations between WSG and growth traits were insignificant (near zero), while low and insignificant negative phenotypic correlations among the same traits were also observed. Predicted genetic gain for single trait selection at age of seven was low for WSG (0.37%), but substantial for stem volume (8.4%) in phenotypic seed orchards. However, the first generation clonal seed orchards consisting of the best 30 clones yielded higher genetic gains (5.2% for WSG and 35% for stem volume). These preliminary results suggest that selection for wood characteristics and growth traits in Turkish pine could be practiced at early ages for short rotation (about 30 years) in industrial plantations.

Palabras clave

  • Wood Specific Gravity
  • Progeny Test
  • Heritabilities
  • Genetic and Phenotypic Correlations
  • Genetic Gain
Acceso abierto

Eucalyptus fastigata: its current status in New Zealand and breeding objectives for the future

Publicado en línea: 05 Aug 2017
Páginas: 259 - 266

Resumen

Abstract

Eucalyptus fastigata is currently the most promising species of eucalypt planted in New Zealand due to its better disease resistance and wood machinability. A breeding programme for E. fastigata was established in New Zealand in 1979 with the planting of a progeny/provenance trial series containing material collected from native Australian provenances and 2nd generation local land race material from New Zealand and South African populations. A second series containing additional Australian and South African material was planted in 1994.

Landrace material from New Zealand did not perform well compared to Australian and South African populations, suggesting early introductions to New Zealand originated from poor seed sources and/or suffered from inbreeding. Analysis of these trials has provided base genetic parameters for this species providing direction for the next generation of the breeding programme. Predicted genetic gains of 15% for tree form and diameter for the 1979 series, and gains of 8% for diameter and 12% for malformation for the 1994 series, indicate the potential for increases in both tree form and growth rate.

Palabras clave

  • Heritability
  • Genetic correlation
Acceso abierto

Threshold selection for rust resistance in hybrid poplar: Population response to mass selection

Publicado en línea: 05 Aug 2017
Páginas: 266 - 276

Resumen

Abstract

Eleven Populus × generosa populations were developed in the Pacific Northwest by annual controlled hybridization of P. deltoides and P. trichocarpa between 1991 and 2001. Mass selection for Melampsora leaf rust resistance was observed in the field as a threshold character in identifying seedling phenotypes for clonally replicated evaluation. The effectiveness of the approach was assessed for each annual population by comparing the distribution of phenotypes in unselected seedling populations with the distribution of selected genotypes in the clonal field tests established in successive years and evaluated at the approximate same level of disease severity using two selection thresholds corresponding to chlorotic and healthy tissue. Bi-directional selection was used as an initial check on the efficacy of the procedure and resulted in a wide separation in liability between the positive (0.06 threshold units (T.U.)) and negative (−2.45 T.U.) selection groups when tested as clones. The other 10 seedling populations that were subjected solely to directional selection exhibited a mean increase in incidence above the first selection threshold at the clonal stage (47 versus 81%) that was accompanied by an improvement in population liability (−0.06 versus 0.50 T.U.) and a reduction in population standard deviation (0.83 versus 0.54 T.U.). The change in liability was strongly related by polynomial regression to selection intensity and a grouping of populations based on infection-season precipitation (r2=0.98). The mean liability of four of the 10 seedling populations observed during years of high infection-season rainfall was six-fold lower than the mean liability of those populations observed during the other six years of lower infection-season rainfall (−0.12 T.U. versus −0.02 T.U., respectively), indicating that populations undergoing evaluation during years of heavy precipitation experienced more intense rust exposure. Moreover, quadratic functions showed that populations undergoing rust evaluation during years of high rainfall were more responsive to increases in selection intensity above the vertex of the function (i.e. 13.20 versus 3.43 T.U.). Realized heritability averaged 0.63 for all ten populations subjected solely to directional selection.

Palabras clave

  • genetic improvement
  • tree breeding
  • infection
  • leaf rust
Acceso abierto

Genetic variation between and within ex-situ native-provenance collections of Pinus radiata D. Don planted in Australia and New Zealand

Publicado en línea: 05 Aug 2017
Páginas: 276 - 285

Resumen

Abstract

A total of 1226 increment cores were sampled from two provenance trials of Pinus radiata D. Don planted in New Zealand (Kaingaroa) and Australia (Kangaroovale), to study variation and inheritance of wood density in selections from three mainland California natural populations: Año Nuevo, Monterey and Cambria. The study represents a back-to-back comparison of the same provenance and family material on contrasting sites between New Zealand and Australia. Monterey was significantly different to Año Nuevo and Cambria at Kaingaroa (p<0.05), and had slightly higher density, whereas all provenances were almost identical and not significantly different at Kangaroovale. However, there were significant differences for wood density at family level for Año Nuevo and Cambria at Kangaroovale. No significant provenance or family differences were detected for core length at either site. The estimates of heritability for wood density were all above 0.50 and generally higher at Kaingaroa than at Kangaroovale. Estimates of additive genetic correlations between wood density and core length were imprecise. Genotype × site interactions for density appeared minor (estimated type-B genetic correlation= 0.70) despite substantial differences in rainfall and soils. The similarity of Cambria to Año Nuevo for density is an interesting result because the genetic base of the present Australian and New Zealand plantations has been shown to be from Año Nuevo and Monterey. Infusion of Cambria material would increase the overall genetic base of the radiata pine breeding programs, with potential long-term benefits, despite the often disappointing growth performance of material collected from Cambria.

Palabras clave

  • provenance
  • genotype x environment interaction
  • breeding population
  • infusion
  • radiata pine
Acceso abierto

Primer Note: Microsatellite-AFLP development for Araucaria araucana (Mol.) K. Koch, an endangered conifer of Chilean and Argentinean native forests

Publicado en línea: 05 Aug 2017
Páginas: 285 - 288

Resumen

Abstract

Araucaria araucana (Mol.) K. Koch is one of the most important native species of Chile and Argentina, and also one of the most endangered. In this study, we report the development and characterization of a set of microsatellite markers in the species by means of the microsatellite-AFLP (M-AFLP) technique. A total of 25 M-AFLP derived bands, showing a typical microsatellite pattern, were selected and sequenced. Of these, 12 that contained microsatellite sequences, were used for primer extension. Six of the resulting SSR markers provided easily interpretable patterns and were used to investigate the level of genetic diversity in two populations of A. araucana. A total of 43 alleles were amplified. The mean overall loci of observed and expected heterozygosities for the Conguillio and Villa Araucaria populations were 0.322 and 0.443, respectively. The primers presented in this study may provide useful information for the establishment of a conservation strategy in the species.

Palabras clave

  • Microsatellite
  • endangered species
  • conservation
Acceso abierto

Transcript abundances of LIM transcription factor, 4CL, CAld5H and CesAs affect wood properties in Eucalyptus globulus

Publicado en línea: 05 Aug 2017
Páginas: 288 - 296

Resumen

Abstract

Eucalyptus globulus is the main hardwood species grown in pulpwood plantations in temperate regions of the world. We have cloned six genes influencing wood quality including the LIM domain transcription factor (LIM), 4-coumarate-CoA ligase (4CL), coniferaldehyde 5-hydroxylase (CAld5H) and the three catalytic units of cellulose synthase (CesA), from E. globulus. The transcript abundances of LIM in basal stems of ten independent E. globulus lines showed similar patterns to those of 4CL. We investigated the correlation between gene transcript abundances and wood qualities such as Klason lignin (KL) content, syringaldehyde/vanillin (S/V) ratio and holocellulose (HC) content. Expression of the LIM and 4CL were positively correlated with KL content. A highly significant positive correlation was observed between CAld5H expression and S/V ratio. Furthermore, a ratio of the sum of the transcript abundances of three CesA1, CesA2 and CesA3 to 4CL showed a positive correlation with a ratio of HC/KL content that positively correlated with the chemically extracted fiber content in this woody plant.

Palabras clave

  • LIM domain transcription factor
  • CAld5H
  • CesA
  • 4CL

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