Silvae Genetica

Published by JD Sauerlaender's Verlag
Online ISSN: 0037-5349
Publications
– Site mean values for extracted wood basic density (kg/m 3 ) of each five ring segment from bark (A) to pith (E) of the five island provenance families linking the two sampling sites. Significance of site differences indicated by ** p < 0.01, * p < 0.05.  
Article
Two progeny trials of native provenances of Pinus radiata, representing the 1978 seed collection, were assessed for wood density and standing tree acoustic velocity. One trial, planted in 1980 in southern New South Wales, Australia contains all five provenances. The second trial, planted in the same region in 1982 contains only the island provenances. Results for extracted wood density, assessed from pith to bark in 5 ring segments, and standing tree acoustic velocity, measured at age 24 or 26 years, are reported.Large differences between the mainland and island provenance were apparent for wood density and stiffness. The mainland provenances were very similar for density and followed the “normal” pattern of change with a gradual increase from the pith, followed by a plateauing around age 20. Neither of the island provenances followed this pattern of change in density: Cedros had stable density across the 4 inner most segments and Guadalupe had stable density for the inner two segments followed by a linear increase. Juvenile density was higher in both the island provenances than the mainland provenances. The island provenances differed from each other for standing tree acoustic velocity, with velocity being higher in Guadalupe provenance.Heritabilities for wood density and acoustic velocity (average 0.37) were higher than those for tree growth and form. Across the stem radius, heritability of density was variable with some segments having zero heritabilities in some provenances, particularly Cambria, Cedros and Guadalupe. Heritability for acoustic velocity was highest for Cambria and the island provenances. Within the mainland provenances, little difference was found between populations for either wood density or acoustic velocity. Density and standing tree acoustic velocity were negatively genetically correlated with tree diameter.Differences in provenance means were greater for acoustic velocity than for density in the outermost segment. Provenance rankings also differed, with the rankings for acoustic velocity being similar to those for density in the 2nd segment from the bark. The genetic correlations between density and velocity reached a maximum for 3rd segment. These results indicate that outerwood density is not the sole driver of acoustic velocity, and that the sound wave is perhaps not travelling through the outer most wood, but is penetrating some distance into the tree.
 
– Positioning of sensor probes and outerwood coring with a close-up of the TreeTap stress-wave timer inset (top- right).  
Article
Genetic parameters and genotype by environment interactions for wood properties of 13-year-old Pinus radiata were determined by sampling two progeny trials on contrasting sites in the southern slopes of New South Wales, Australia. Heritability of green and basic density were determined together with dynamic modulus of elasticity (MOE) measured using TreeTap.The phenotypic variance in MOE (CV 17-18%) was almost three times that of basic density. MOE and basic density were highly heritable at both sites (h2 0.57 & 0.79 for MOE & 0.59 and 0.85 for density). There was a moderately strong genetic correlation between MOE and basic density (0.64 across-sites). No genotype x environment interaction was detected in MOE or basic density. Basic density and MOE were lower on the warmer, lower rainfall site.
 
-Distribution curve of G ST per locus between Q. petraea and Q. robur populations.
-Distribution curve of G ST per locus among Q. petraea populations.
-Distribution curve of G ST per locus among Q. robur populations In each figure, loci were numbered in order of their G ST values. The dotted line separated the loci showing a differentiation superior to 10 % from the other loci.
Article
The aim of this study was to compare genetic diversity within and among Quercus spp. populations based on two contrasting types of nuclear markers. Seven mixed stands of Quercus petraea and Quercus robur were analysed using six highly polymorphic and codominantly inherited microsatellite markers as well as 155 dominant AFLP markers. Genetic differentiation and genetic diversity within each population were assessed. The intra- and inter-locus variances were calculated, and the results were used to compare the genetic diversity between populations. Both classes of markers revealed similar results: the genetic diversity within population and the genetic differentiation among populations is greater in Q. petraea than in Q. robur The genetic differentiation is generally higher when AFLP markers were used in comparison to microsatellites. For AFLPs, the inter-locus variance is always much higher than the intra-locus variance, and explains why it was not possible to distinguish populations using this marker system. Finally, no significant positive correlation was found between the level of within-population diversity assessed with the two markers.
 
Article
Cores extracted from trees to assess wood chemistry are generally not used to assess basic density in eucalypt pulpwood breeding programmes, as the meas-urement of basic density requires high temperature drying. However, both wood chemistry and air-dried density can be assessed on the same core. This study found that the inter-trait genetic correlation between core air-dried and basic density to be effectively equal to one in two Tasmanian Eucalyptus nitens progeny trials. This implies that selection for basic density could be undertaken using air-dried density with little or no reduction in genetic gain, thus negating the need to extract a separate core to assess basic density and wood chemistry. The adoption of this practice could considerably reduce the cost of assessing these traits in eucalypt breeding programmes.
 
– AFLP print of the six species studied in detail Ceiba pentandra, Maranthes panamensis, Eschweilera costaricensis, Lecythis ampla, Goethalsia meiantha and Laetia procera with the following primer combination EcoRI + CG /MseI + ACAA on leaf material (B) and cambium tissue (A).  
Article
The number of studies of tropical tree species that use molecular tools is increasing, most of which collect leaf tissue for genomic DNA extraction. In tropical trees the canopy is not only frequently inaccessible, but also, once reached, the leaf tissue is often heavily defended against herbivory by high concentrations of anti-predation compounds, which may inhibit downstream applications, particularly PCR. Cambium tissue, accessed directly from the tree trunk at ground level, offers a readily accessible resource that is less hampered by the presence of defensive chemicals than leaf tissue. Here we describe a simple method for obtaining tissue from the cambial zone for DNA extraction and test the applicability of the method in a range of tropical tree species. The method was used successfully to extract DNA from 11 species in nine families. A subset of the DNA extracts was tested in more detail and proved to be highly suitable for AFLP analysis.
 
Article
Crown form is a visual characteristic having many component traits (branch thickness, branch angle, ramicorns, forks and uninodal/multinodal branch habit). Alternative methods of assessing each trait are evaluated in terms of their variance components and heritabilities in a progeny trial of Pinus radiata. A comparison is made between using one overall score for crown form and use of selection indices to combine traits. The efficiency of each alternative is compared in terms of the calculated selection response for each trait.For assessing branch diameter and branch angle a six point score was preferred to the use of a three or nine poInt score. The six point score resulted in large additive genetic variance and a higher heritability, giving good discrimination of genotypes without being confusing to the assessors. For ramicorns and forks, counting the actual numbers present resulted in higher heritabilities than scoring for their incidence. Calculated responses from selecting one tree in 100 on either a single crown form score or multitrait indices indicated that response in each component of crown form is greater for the indices.
 
– A map showing the location of the 30 populations of Cedrela odorata used in this study.  
– Cluster analyses of RAPD data for the seven C. odorata populations in the sub-set 1 (see methods).  
– Comparison of pair-wise Q ST and F ST estimates across the study populations for (a) Sub-set 1, (b) sub-set 2 and (c) and combined data. The solid line marks a 1:1 relationship for the correspondence between Q ST and F ST estimates, and the dotted lines are least square regression lines given for the ease of interpretation. See text for statistical tests.  
– Cluster analyses of quantitative traits in a greenhouse in Finland. Note that the clusters correspond to mesic (Almirante to Upala) and dry (Bacalar to Yucatan) environment populations. The morphological distances are based on Euclidean distances and the genetic distances on Nei's (1987) genetic distances.  
Article
We compared within-population variability and degree of population differentiation for neutral genetic markers (RAPDS) and eight quantitative traits in Central American populations of the endangered tree, Cedrela odorata. Whilst population genetic diversity for neutral markers (Shannon index) and quantitative traits (heritability, coefficient of additive genetic variation) were uncorrelated, both marker types revealed strong differentiation between populations from the Atlantic coast of Costa Rica and the rest of the species' distribution. The degree of interpopulation differentiation was higher for RAPD markers (F-ST 0.67 for the sampled Mesoamerican range) than for quantitative traits (Q(ST) = 0.30). Hence, the divergence in quantitative traits was lower than could have been achieved by genetic drift alone, suggesting that balancing selection for similar phenotypes in different populations of this species. Nevertheless, a comparison of pair-wise estimates of population differentiation in neutral genetic markers and quantitative traits revealed a strong positive correlation (r = 0.66) suggesting that, for C. odorata, neutral marker divergence could be used as a surrogate for adaptive gene divergence for conservation planning. The utility of this finding and suggested further work are discussed.
 
Article
Pith to bark density was measured on cores cut from 588 7-year-old Eucalyptus nitens trees. Heritability of ring density averaged 0.37 and was consistently higher than the heritability of earlywood or latewood density. Earlywood, latewood, and ring densities were highly genetically correlated. Age-age correlations for ring density declined with increasing age difference, and were moderately described by LAMBETH's (1980) relationship with log of age ratio. Disk and core densities were calculated as weighted averages of ring densities. Age-age correlations for disks and cores were higher and better described by LAMBETH's relationship than ring density correlations. Age-age correlations for growth assessed at 20 months, 4 years and 7 years were not well described by LAMBETH's relationship. Height, diameter, and volume were well correlated at age 7 years (rg> 0.9), as were disk density, core density, outer-ring density and Pilodyn penetration (rg> 0.9). Density showed a weak negative genetic relationship with diameter at age 7 years (rg = -0.2).
 
Article
Patterns of genetic variation for frost tolerance were studied in a first-generation breeding population of Eucalyptus nitens (DEANE and MAIDEN) MAIDEN. Winter hardened seeds were found to differ significantly in their frost tolerance at all three tested temperatures (-5.0C, - 6.5C and -8.0C). Provenance effects accounted for between 11% (at -5.0C) and 29% (at -8.0C) of the total variation. The most frost tolerant provenance was Northern NSW, with Toorongo being the least tolerant. Significant differences were also found between families within provenances and between seedlings within families. Family effects accounted for 14% to 22% of total variation and seedling effects accounted for 22% and 26% of the total variation. All five provenances were represented in the top seven ranked families. When each provenance was analysed separately, there were significant differences between families but no strong relationship was found with altitude of origin.
 
Article
When the performance of genotypes vary across an environmental gradient in a non-linear manner the matching of genotypes and sites is a complex problem. To overcome this breeding zones: aTe usually allocated so that sets of genotypes are used across different parts of the range to maximise production across all anticipated planting sites. Two different approaches to determining the number and constitution of these populations and the demarcation of their planting zone boundaries are contrasted. Both approaches use non-linear models to define the relationship between relative performance of a genotype and an environmental gradient. The approaches differ however, in the criterion used for choosing the populations. One approach will lead to a guaranteed minimum yield at each site whilst the other approach ma:lllmlSeS the expected yield over the total range of planting sites.
 
Article
Breeding programs based on hybrids of tree species often have a need to unambiguously distinguish intraspecific and self progeny from hybrid progeny. The interspecific hybrid of P. elliottii var. elliottii (PEE) and P. caribaea var. hondurensis (PCH) is difficult to reliably distinguish from pure PEE based on morphology, especially at a young age. We examined the trnL-F intergenic spacer region of the paternally inherited chloroplast genome for a polymorphism that may distinguish these two taxa. Sequencing this region indicated there were two haplotypes, one which was specific to PEE, designated (+), the other designated (–), was shared by both taxa. This result was consistent with other studies which suggest past introgression of PCH into PEE. A PCR assay was developed to detect the PEE specific haplotype. This haplotype was found at a frequency of 0.6 in a sample of 22 PEE from a breeding population but was absent from a sample of 30 PCH parents. As expected, hybrids from crosses of PCH pollen donors and maternal (+) haplotype PEE had (–) haplotypes. In situations where the mother can be genotyped, and the pollen pool consists of maternal (self) or PCH pollen, this assay would unambiguously determine the hybrid status of offspring from 60 % of the PEE parents tested. Where paternal candidates include other PEE, the assay would conclusively identify non-hybrid progeny at a lower percentage determined by the frequency of the (+) haplotype in the pollen pool. The chloroplast trnL-F spacer assay would be useful for verifying hybrids from future seed orchards based on mother trees with (+) haplotype or for (+) haplotype mother trees in current orchards. The assay will also confirm suspected pure PEE individuals where they have a (+) haplotype but will be inconclusive where they have a (–) haplotype.
 
Article
A computer program creates permuted neighbourhood designs for second generation seed orchards which may include a high proportion of related clones. It maximizes panmixis, and ensures isolation of all related clones. It is fast, efficient and easy to use. Copies of the program are available from the author.
 
– A comprehensive consensus map for two Corymbia torelliana x citriodora subsp. variegata F 1 hybrids. The total map distance was 417 cM Kosambi, 47 framework and 9 accessory markers formed 12 Groups (LOD =>4; except CM12 (LOD 3)). Accessory markers are italicised and are reported at the framework loci that they were most strongly linked with their LOD and pair-wise distances. Groups CM11 and CM12 consisted of markers that segregated uniquely in the paternal or maternal parent respectively, and are highlighted with different shading. Groups CM1a&b and CM2a&b are linked at LOD 3 – indicated as separate groups but aligned vertically. Markers exhibiting segregation distortion are indicated by an asterisk ( ≤ 0.05). A marker quality rating (1 to 3) was suffixed to each loci, with 1 indicating the highest quality (see methods).  
– Pedigree of C. torelliana x C. citriodora subsp. variegata outbred F 2 mapping population. 1ct2-019 and 1ct2-011 were the C. torelliana maternal grandparents and 1cv2-018 and 1cv2025 the paternal C. citriodora subsp. variegata grandparents . (1ct2-011 x 1cv2-025)-A and (1ct2-019 x 1cv2-018)-A were the F 1 parents crossed to form the F 2 family.  
Article
The genus Corymbia is closely related to the genus Eucalyptus, and like Eucalyptus contains tree species that are important for sub-tropical forestry. Corymbia's close relationship with Eucalyptus suggests genetic studies in Corymbia should benefit from transfer of genetic information from its more intensively studied relatives. Here we report a genetic map for Corymbia spp. based on microsatellite markers identified de novo in Corymbia sp or transferred from Eucalyptus. A framework consensus map was generated from an outbred F2 population (n = 90) created by crossing two unrelated Corymbia torelliana x C. citriodora subsp. variegata F1 trees. The map had a total length of 367 cM (Kosambi) and was composed of 46 microsatellite markers distributed across 13 linkage groups (LOD 3). A high proportion of Eucalyptus microsatellites (90%) transferred to Corymbia. Comparative analysis between the Corymbia map and a published Eucalyptus map identified eight homeologous linkage groups in Corymbia with 13 markers mapping on one or both maps. Further comparative analysis was limited by low power to detect linkage due to low genome coverage in Corymbia , however, there was no convincing evidence for chromosomal structural differences because instances of non-synteny were associated with large distances on the Eucalyptus map. Segregation distortion was primarily restricted to a single linkage group and due to a deficit of hybrid genotypes, suggesting that hybrid inviability was one factor shaping the genetic composition of the F2 population in this inter-subgeneric hybrid. The conservation of microsatellite loci and synteny between Corymbia and Eucalyptus suggests there will be substantial value in exchanging information between the two groups.
 
Article
The neotropical pioneer species Vochysia ferruginea is locally important for timber and is being increasingly exploited. The sustainable utilisation of this species would benefit from an understanding of the level and partitioning of genetic diversity within remnant and secondary regrowth populations. We used data from total genome (amplified fragment length polymorphism, AFLP) and chloroplast genome markers to assay diversity levels within seven Costa Rican populations. Significant chloroplast differentiation between Atlantic and Pacific watersheds was observed, suggesting divergent historical origins for these populations. Contemporary gene flow, though extensive, is geographically constrained and a clear pattern of isolation by distance was detectable when an inter-population distance representing gene flow around the central Costa Rican mountain range was used. Overall population differentiation was low (F-ST = 0.15) and within-population diversity high, though variable (H-s=0.16-0.32), which fits with the overall pattern of population genetic structure expected for a widespread, outcrossed tropical tree. However genetic diversity was significantly lower and differentiation higher for recently colonised and disturbed populations compared to that at more established sites. Such a pattern seems indicative of a pioneer species undergoing repeated cycles of colonisation and succession.
 
Article
Data from 171 slash pine progeny tests, incorporating over 700 different families from more than 2100 first-generation parents and approximately 170000 trees, were used to estimate variance and covariance components by Restricted Maximum Likelihood (REML) in both single-site and paired-site analyses. From these REML estimates, genetic parameters (heritabilities, proportion of dominance, type B genetic correlations, and age-age genetic correlations) were estimated for resistance to fusiform rust infection at 4 to 15 years of age. Predictive models were developed for biased (single- site) heritability, unbiased (paired-site) heritability and the type B genetic correlation. Biased heritability exhibited a maximum of 0.20 at an average rust infection of 72%. Unbiased heritability estimates from paired- site analyses increased linearly with increasing average rust infection in the tests; however, in very few test pairs did the average rust infection exceed 75%, and extrapolation beyond 67% would be unreliable. Although genotype-environment interaction was present, it was of little consequence except at low rust infection levels. The proportion of dominance variance (when compared to the total phenotypic variance) was not related to rust infection levels or age, and across all tests and ages averaged 0.087 and 0.053 in single-site and paired-site analyses respectively. Since dominance variance was small relative to additive variance, except when rust infection levels were low, it was considered to be of little practical importance. Test age was not a significant factor affecting any genetic parameter examined, and all age-age genetic correlations were near +1.0. The results endorse the current brooding strategy, which is based on recurrent selection for general combining effects, and stresses the importance of restricting improvement efforts to sites with moderate to high rust infection levels.
 
– Map showing the sympatric distribution of C. variegata and C. henryi spotted gums in the east coast of Australia. The two locations sampled in this study are marked in large circles.  
Article
Population substructure and hybridization, among other factors, have the poten-tial to cause erroneous associations in linkage disequilibrium (LD) mapping. Two closely related spotted gum eucalypts, Corymbia variegata and C. henryi (Myrta-ceae) occur in sympatry in the east coast of Australia and potentially interbreed. They are morphologically similar but are distinguished as separate species based on capsule and foliage size. To determine whether they hybridize in nature and its implications for LD mapping, we investigated the level of molecular diver-gence between the two species at two sympatric locations separated by 300 kilometres. Very few individuals of intermediate morphology were identified, de-spite the two species occurring only metres apart. Analysis of genetic structure using 12 microsatellite loci showed that genetic differentiation between popu-lations of the same species at different locations (FST = 0.07 for both species; p = 0.0001) was significantly higher than that observed between species at each location (mean FST = 0.02 and 0.04 for Cherry tree and Bunyaville respectively; p = 0.0001; all Mann-Whitney U-test p ≤ 0.01). No species-specific alleles or significant allele frequency differences were detected within a site, suggesting recurrent local gene flow between the two species. The lack of significant allele frequency differences implies no population stratification along taxonomic lines. This suggested that there is little concern for cryptic hybridization when sampling from sites of sympatry for LD mapping.
 
Article
The construction of linkage maps based on RAPD markers using F1 intraprovenance cross in Eucalyptus globulus subsp. globulus is reported. Twenty-one microsatellite loci originating from E. globulus and four other Eucalyptus species were added to the RAPD maps. Linkages between microsatellites previous reported for E. grandis/E. urophylla were found to be conserved in E. globulus allowing confident assignment of homology for several linkage groups between maps of these species. Homology was also identifiable between most linkage groups of the two E. globulus parents based on microsatellites and RAPD loci segregating from both parents. At a LOD score threshold of 4.9 the male parent has 13 linkage groups covering 1013 cM with 101 framework markers ordered at LOD 3.0. The female parent has 11 linkage groups covering 701cM with 97 framework markers. On the female map there were more regions of segregation distortion than expected and genetic mechanisms to explain distorted segregation are discussed. Several linkages that arise between pairs of E. globulus linkage groups as the LOD score is reduced are supported by interspecific homologies identified using microsatellite loci.
 
Article
A breeding strategy involving inbreeding followed by crossbreeding of inbreds requires that the production of superior inbred lines must be possible, but crosses between lines should exhibit heterosis, inbreeding should not substantially delay reproduction, and early selection between lines to be effective. Age-age correlation and the effectiveness of early selection have been extensively reported for outcrossed populations of different species, but there are no reports for inbred populations. In this study, age-age correlations based on both family means and individual trees were investigated and compared in radiata pine populations with five different inbreeding levels (F = 0, 0.125, 0.25, 0.5 and 0.75). Trends in additive genetic variance, environmental variance, heritability and age-age additive genetic correlations were estimated from an outcrossed population (F = 0). For cross-sectional area at breast height, additive genetic variance increased from 3.7% at age 3 to 29.4% at age 5, remained at about 30% up to age 10, then declined to 15.6% at age 13.
 
Article
Thesis (M.S. in Genetics) - North Carolina State University. Bibliography: p. [28]-29.
 
Article
A gene recombination orchard attempts to maximize the spontaneous mating amongst all clones of interest in a breeding population. An algorithm enables designs for such an orchard to be completed quickly and efficiently.
 
Article
A full-length cDNA encoding sedoheptulose-1,7-bisphosphatase (SBPase; EC 3.1.3.37) was cloned from mulberry (Morus alba var. multicaulis) by rapid amplification of cDNA ends (RACE). The cDNA consisted of 1,527 nucleotides with an open reading frame (ORF) of 1,179 nucleotides encoding a 393 amino acid protein of approximately 42.6 kDa. Sequence comparison analysis showed that mulberry SBPase (MSBPase) had high homology to other plant counterparts. Phylogenetic and molecular evolutionary analysis revealed that MSBPase fell into plant SBPase group. Moreover, SBPase and fructose-1,6-bisphosphatase (FBPase; EC 3.1.3.11) shared 28-32% identical residues, suggesting that the two enzymes originated from the same evolution branch. Molecular modeling indicated that each subunit of MSB-Pase was composed of α-helices and β-sheets joined by turns and loops, and folded into a structure of hexahedron shape which was very similar to FBPase.
 
Article
Spiral grain measured at ring number 6 or 8 from the pith on 13-years old ramets coming from 191 Sitka spruce clones tested at 4 sites showed a broad sense heritability on single tree level from 0.36 to 0.54. Standard deviations were in the interval from 1.61 to 1.97 degrees and the mean was on all sites about 5 degrees to the left. Predicted genetic gains equal to about 2 degrees reduction of spiral grain in the juvenile wood seems realistic even with moderate selection intensities. Genetic correlations with height, diameter, stem form and pilodyn were small or absent, and almost no genotype-environment interaction was present. Individual broad sense heritabilities for heights and diameters were moderate to low ranging from 0.08 to 0.81 and with coefficients of variation about 0.30. Moderate genotype-environment interaction was present for the 2 traits with genetic correlations across sites ranging from 0.57 to 0.85. Pilodyn had a moderate heritability about 0.32 and a coefficient of variation about 8%. The genetic correlation with diameter was 0.53 and with height 0.22 so the density must be taken in consideration when selecting for growth in Sitka spruce. The broad sense heritability for stem form using a scale from 1 to 9 was 0.37 and the coefficient of variation 0.22. Positive, but moderate genetic correlations with diameter and height was present, 0.27 and 0.21 respectively. Pilodyn and stem form were only measured in one trial.
 
Article
After the nursery testing, twelve Swiss stone pine (Pinus cembra L.) provenances from the Alps and Carpathian Mountains were planted out at two sites located at high elevation in the Southern and Northern Carpathians. Total height growth (H), annual height growth (h), root collar diameter (RCD), branches per whorl (BW) and survival (SV) were measured and analyzed. Analysis of variance showed highly significant (p < 0.01; p < 0.001) differences between provenances for all traits, except survival, suggesting that selection at the provenance level could be possible. Also, over locations analysis revealed significant genotype x environment interaction, demonstrating that some provenances react differently to environmental conditions and, selection should take this into account. The phenotypic coefficient of variation was moderate for growth and high for number of branches per whorl suggesting that selection within provenance can also be applied. Finding of significant and highly significant age-age and trait-trait phenotypic correlations indicated that early and indirect selection in Swiss stone pine species is possible. According to DUNCAN'S multiple range test the best performing provenances of the two mountain ranges were selected for operational planting and breeding programmes. The results of this study validate that a very slow growing species, such as Swiss stone pine may still possess very high genetic variation in growth rate; consequently, this trait can be improved. Finally, an attempt has been made to develop a seed transfer guidelines for the species by using the pattern of geographic variation as a basis.
 
Article
Schima superba is a common dominant tree species in evergreen broad-leaved forest in subtropical China. Despite its multiple usages in wood industry, reforestation and traditional Chinese medicine, its genetic diversity is poorly studied. To help studying its genetic diversity and structure in the future, after microsatellite enrichment and screening, we identified 16 microsatellites in S. superba. These markers showed polymorphism in three populations. The number of alleles per locus ranged from 3 to 32 with a mean of 14. Within populations, the observed and unbiased expected heterozygosities ranged from 0.048 to 0.926 and from 0.048 to 0.949, respectively. The newly developed 16 microsatellites will be useful for investigating the genetic diversity and structure from large scale patterns to fine-scale structures in this species.
 
Article
A 7 x 4 factorial crossing was performed between Pinus strobus (female) and R peuce (male) to combine the rapid growth of P. strobus with high resistance of F1 peuce to blister-rust. The resulting 28 families were artificially inoculated at age two and planted in the field at age 6. Nine traits were measured at age 17. The results indicated that: (1) the effects of female parents were highly significant for growth traits and blister-rust resistance, whereas the male parents had highly significant effects only on growth traits; (2) the hybrid performance was intermediate between the two parent species, in all traits; (3) highly significant positive correlations were found among growth traits, but no significant correlations were foundbetween any growth trait and blister-rust resistance; (4) good general combiners, not only for growth but for blister-rust resistance, too, were found among eastern white pine parents as three of 11 parents had positive significant gca effects for blister-rust resistance and five for volume growth; and (5) a genetic gain of 9.5% in blister-rust resistance and 18.3% in volume growth could be achieved.
 
Article
The results of the IUPRO Grand-fir provenance experiment in northern and central Germany at age 18/19 are presented for height, diameter, volume and losses. The experiment was planted on 13 sites, 12 of which are included here. The provenances represent the coastal part of the natural range in British Columbia, Washington and Oregon quite well. From the continental part only 3 Idaho provenances are included. In addition to 41 IUFRO provenances 22 other provenances are included, 5 from Vancouver Island and the rest from Oregon, where 11 represent elevational transsects. In height growth low and mean elevation provenances from northern Washington, from Vancouver Island, Coastal Southern Washington, and North Oregon are performing best. The same is true for diameter growth and volume with a slightly better performance of Oregon sources in diameter due to the higher losses in the Oregon provenances. Differences between test sites are considerable and explain roughly 2 thirds of total variation for quantitative characters. They are most drastic for losses, where also more rank change occur between provenances than for height and diameter. Volume differences of provenances range from 30% to 176% of standard provenances mean. An overall ranking including height, diameter, and losses shows that 7 Washington provenances, 3 B. C. provenances and 1 Oregon provenance surpass the overall mean by at least 10 %. Correlations with earlier measurements of the same experiment demonstrate that early selection is not very precise and that indirect selection would not have been possible with the characters under consideration.
 
-Idiograms showing localization of 5S (hatched) and 18S-25S (solid black) ribosomal genes on chromosomes of Castanopsis acuminatissima (a), C. armata (b), C. cerabrina (c), C. diversifolia (d), C. indica (e), Lithocarpus polystachyus (f), Quercus kerrii (g), and Q. lenticellatus (h). Each chromosome represents a homologous pair, and the vertical scale bar represents 5 µm. Chromosome pairs were identified and arranged on the basis of chromosome length and arm ratio (LEVAN et al., 1964). The measurements were made on digital images of chromosomes which were captured with the maximum resolution of 12 megapixels. 
Article
Fifteen species of Fagaceae from Chiang Mai province, northern Thailand, were investigated: eight Castanopsis, four Lithocarpus and three Quercus species. The species were generally diploid with the chromosome number 2n = 24, and the basic number x = 12 was confirmed in some species with meiosis. One tree belonging to Q. lenticellatus had 2n = 14. Chromosomal mapping of the highly repetitive 18S-25S and 5S ribosomal genes by fluorescence in situ hybridisation (FISH) was performed. Most species (from all three genera) showed four 18S-25S rDNA sites (two pairs: one subterminal major and one paracentromeric/intercalary minor loci) and two 5S rDNA sites (one pair: paracentromeric locus). Quercus kerrii also had two pairs of 18S-25S rDNA sites, but both were subterminal major loci. Two species, C. argentea and Q. brandisianus, only had one pair of 18S-25S rDNA sites. Two species, C. calathiformis and L. vestitus, showed an odd number of (unpaired) sites, and this indicated hybrid origin and/or polyploidy. Polyploid cells were detected in these species. The ribosomal gene maps based on both sequences together were genus-specific. In Castanopsis, the 18S-25S and the 5S genes were localized on three different chromosome pairs, and comprised species-specific maps. On the other hand, the ribosomal genes in Lithocarpus and Quercus were found only on two chromosome pairs, because one of the two 18S-25S rDNA loci was localized on the same chromosome as the 5S rDNA locus. The FISH markers may be used to clarify discrepancies arising from morphological assessments.
 
Article
79 provenances from 3 blocks in a 17-year-old IUFRO 1964/1968 Picea abies (L.) KARST. provenance trial in southern Sweden were chosen for special measurements. The provenances originated from 11 zones in eastern Europe and southern Scandinavia and belonged all to the most fast-growing half of provenances. Carpathian provenances had the highest stem volume and dry weight and harvest index. Provenances from the Baltic States and Belarus combine high growth, high basic density and low incidence of spike knots. Provenances from southern Scandinavia had rather thin branches and high wood density but very low stem volume. The zonal variation in root anchorage could be attributed to variation in tree size. Partial correlations eliminating effects of zones showed that stems with high volume had poor form, thick branches and low basic density but high harvest index.
 
Article
Isoenzyme-polymorphisms of Norway spruce populations from the spruce regions of Central and Southeastern Europe were compared with those from Northern and Northeastern Europe. To do this, the electrophoretically detectable genetic variation was assayed at 19 coding gene loci (10 enzyme systems) for 15 provenances of the international IUFRO provenance-testing programme of 1964/1968. The results can be summarized as follows: 1. For the gene loci SKDH-A, IDH-A, LAP-A and GDH-A some alleles showed a marked geographic pattern. 2. The measures of genetic diversity as the mean number of alleles per locus (A/L), the proportion of polymorphic loci (P%), the expected heterozygosity (He) and the hypothetical gametic multilocus-diversity according to Gregorius (1978) all showed lower values in Southern and Central than in Northern and Northeastern Europe. Thereby, the genetic variation within the populations increased in going from the southwest to the north or northeast, although two provenances from the Balkans showed higher values as well. Hence, the conclusions of other authors could be confirmed. 3. For most provenances significant to highly significant correlations were found between the genetic distances and the geographic distances of the provenances. 4. The subpopulation differentiation (Dj), i.e. the genetic distance between each individual provenance and the complement of all other provenances, was highest for the most southerly provenances (Southwestern France and Northern Greece) and one Eastern Russian provenance. In the discussion of the results it is pointed out that, along the altitude gradients and depending on the geographic latitude, numerous ecological adaptations advantageous for the species have arisen during the reinvasion into the Central European area after the last Ice Age. Thus, despite limited genetic variation at the experimentally accessible gene loci, the Norway spruce in Central Europe has demonstrated a good adaptive capacity.
 
Article
This study involves polymix families of coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. men-ziesii) that were created by crossing parents selected from the Cascade, Longview, Twin Harbors and Vail wild populations of western Washington State. Eight to 10 female parents from each population were crossed using pollen-mixes of males from either the same or different populations. In 1985 these polymix families were planted across six genetic tests located in Cascade, Longview and Twin Harbors (two tests per region). Variance components are reported for over-bark breast-height diameter measured at 21 years (DBH21). Genotype x environment (GE) interactions involving different wild populations of Douglas-fir accounted for little variation in DBH21 across the western Washington regions studied. Interaction involving female parents nested within populations was the most important GE effect; explaining 2% of total variation in DBH21. However, this interaction was of limited practical importance since the superior female parents for DBH21 generally showed good stability across tests. Results from this study support selection of superior coastal Douglas-fir genotypes that can produce strong, stable growth across a range of site environments encountered in western Washington.
 
Article
This study was carried out to determine the extent of variation in seed traits and oil content among 24 seeds sources of Jatropha curcas from 8 countries in Asia, Africa and Papua New Guinea. There were marked differences in the length (range 15.88-19 mm), breadth (10.20-11.71 mm), thickness (7.95-9.37 mm) and volume index of seed (1337-2000 mm(3)), weight of seed (42.67-80.20 g) and kernel (18.44-51.04 g), kernel/seed ratio (0.43-0.66), and oil content in seed (18.08-37.89%) and kernel (34.02-59.09%). In general, seeds from Laos, Mali, Papua New Guinea, Philippines and Thailand were larger and heavier than sources from China and India, but contained lower oil content in seed and kernel. Principal component analysis revealed that seed and kernel weight and oil content in whole seed and in kernel were useful characteristics in explaining the variation pattern among seed sources. Seven out of the 24 seed sources investigated in this study are considered promising for planting for oil-seed production. This study underpins the importance of selecting suitable seed sources for commercial plantation establishment of J. curcas.
 
Article
Four hundred and sixty individual families of Pinus radiata, representing all provenances and populations in a 1978 seed collection, plus a local seed orchard control, were planted together in 1980 in a large trial in southern New South Wales, Australia. Provenance means and genetic parameters for growth measured at ages 3, 8 and 26 years plus stem straightness, branch angle and nodality at age 26 years are reported. Large provenance differences were apparent for all traits. The two island provenances, Cedros and Guadalupe, were significantly inferior to the mainland provenances and, due to competition effects, very few trees survived to age 26. Within the mainland provenances, the performance of Año Nuevo and Monterey was almost identical with Cambria being less vigorous. The best performing seedlot for all traits was the local control. Differences between populations within the mainland provenances were apparent for diameter at age 26 within Año Nuevo and Cambria but not Monterey. Año Nuevo also showed population differences for stem straightness. Heritabilities for early growth were similar within Año Nuevo and Monterey but by age 26, the heritability for diameter was higher in Monterey. Within Cambria, heritabilities for growth and tree form at age 26 were close to zero. Genetic correlations between traits showed similar patterns for each of the mainland provenances, with the exception of correlations with stem straightness within Año Nuevo. Results are discussed in light of recent molecular studies of genetic architecture, levels of inbreeding in the native stands and possible effects of this inbreeding.
 
Article
The Chinese fir (Cunninghamia lanceolata) is a very important plantation species that is mainly distributed in Southern China. However, genomic analyses of C. lanceolata have lagged significantly behind those of other conifer species due to a lack of suitable markers. To address this issue, we examined 27,666,670 reads from C. lanceolata transcriptome sequences recorded in the SRA database. Assembly produced 35,633 contigs, 1,822 (5.11%) of which contained one or more SSRs. In total, 2,156 SSRs were identified, giving an average SSR density of 68.4 SSRs/Mb. The most common SSR types were tri-SSRs (41.7%), followed by hexa-(29.8%), penta-(12.7%), di-(11.1%) and tetra-(4.7%) SSRs. EST-SSR markers based on the 1,822 SSR-containing contigs were developed using the CMiB pipeline and primer pairs were designed to target 35 loci. Polymorphism was observed in 28 of these loci, for which the number of alleles per locus ranged from 3 to 12 over 16 plus-tree individuals. The observed heterozygosity (Ho), expected heterozygosity (He) and fixation index (FIS) values for the targeted loci ranged from 0.125 to 0.938, 0.225 to 0.891 and -0.368 to 0.456, respectively. The corres - ponding PIC values ranged from 0.210 to 0.881, with an average of 0.573. Some of these markers have since been used in our ongoing genetic diversity analyses of C. lanceolata. To our knowledge, this is the first analysis of SSRs and EST-SSR markers in C. lanceolata, and the identified EST-SSR markers will be useful in future genetic analyses of C. lanceolata and related species.
 
Article
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.
 
– Spatial distribution of Picea abies trees in seed orchard of Dubrava Forest Enterprise in 1999. Symbols indicate trees planted in 1964 to 1965. Encircled numbers show clonal assignment. Based on RAMANAUSKAS and GRADECKAS (1967).  
– Over 3 m long crack on stem of Picea abies in seed orchard of Dubrava Forest Enterprise. Stem area affected by the crack is marked with paint (photo from 1987).  
– Three 10 cm to 15 cm long closed scars on stem of Picea abies in seed orchard of Dubrava Forest Enterprise. Their margins are marked with paint (photo from 1987).  
Article
A study was carried out during 1987 to 1999 in seed orchard of Picea abies (L.) Karst. located in central Lithuania to estimate differences in diameter growth, occurrence of stem cracks, bark beetle (Dendroctonus micans Kug.) attacks, tree dieback and fungal infections among 20 different clones. Those were represented by 1333 clonal grafts that, at the time of the study, were 36-year-old. The results had shown: 1) significant differences in diameter growth among the different clones; 2) significant differences in the occurrence of stem cracks among the different clones; 3) significant positive relationship between average diameter at breast height (d.b.h.) of the clone and amount of trees with the stem cracks within the clone (r = 0.511; p < 0.05); 4) that within the clone, trees of larger d.b.h. are more likely to have cracked stems. Analysis of the data by chi-squared tests revealed four significant (p < 0.000001) relationships: 1) in trees that possessed stem cracks occurrence of the dieback (66 dead out of 197, or 33.5%) was much higher than in trees without cracks (44 dead out of 1136, or 3.9%); 2) in trees that possessed stem cracks frequency of D. micans attack was much higher (52 attacked out of 197, or 26.4%) than in trees without cracks (10 attacked out of 1136, or 0.9%); 3) the survival rate of trees with the stem cracks that were attacked by D. micans was much lower (2 survived out of 52, or 3.8%) than survival rate of trees with the stem cracks that were not attacked by D. micans (129 survived out of 145, or 89.0%); 4) the trees that suffered both from stem cracks and D. micans attack were less likely to survive (2 survived out of 52, or 3.8%) than sound-looking ones which were attacked by the bark beetle (9 survived out of 10, or 90%). Among the fungal species, Sarea resinae Kuntze and Sarea difformis Fr. were the most common ones and were frequently found both in sound-looking stems and in stems with cracks.
 
Article
Five genetic tests involving 70 somatic clones of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were planted March-April 1999 in Weyerhaeuser plantations across western Washington and Oregon states, USA. Four of the tests are in Longview and Twin Harbors regions of Washington, and one test is in Springfield, Oregon. Each test is based on single-tree plots with 12 randomized complete-blocks. The 70 coastal Douglas-fir clones were propagated by somatic embryogenesis from two full-sib families that had the same female parent. Results are reported for survival, height, diameter at breast-height (DBH) and volume growth at 5 1/2-years. These tests provide evidence of acceptable growth and survival of somatic trees of coastal Douglas-fir across a range of site conditions. Height had a clonal heritability of 0.25 ± 0.01, DBH 0.21 ± 0.01 and volume 0.20 ± 0.01. The growth traits were all strongly genetically associated with clonal correlations of 0.92 to 0.99. Clonal performance for growth proved quite stable across tests with an overall between-test correlation of 0.84 ± 0.04. There was little variance due to clone x test interactions.
 
Article
The insecticidal activity and the influence of transgenic hybrid poplar clone 741 carrying a Bacillus thuringensis gene (BtCry1Ac) and the arrowhead proteinase inhibitor gene (API) on the growth and development of different defoliating insects were tested during two years. The transgene expression stability during this period was documented. Bioassays of transgenic poplar clone 741 on the larvae of Gypsy moth [Lymantria dispar (Linnaeus)], Scarce Chocolatetip [Clostera anachoreta (Fabricius)] and other defoliating insects were carried out annually. The results showed that three transgenic subclones tested had a high resistance against these insects, but the insecticidal activity was different between years and with different insect species. Transgenic expression was generally stable during the 4 years. The insecticidal activity on the first larvae stage was obvious and decreased gradually with the development of the larvae (instar stage). Growth and development of the surviving larvae was seriously inhibited and delayed and in some cases could not even complete their development. Nevertheless feeding of transgenic poplar leaves could not kill the pests entirely. Proper planting strategies are necessary in order to prolong and optimize their resistance against the pests.
 
Article
Based on the well-established knowledge that important spread of H. annosum is performed through spore infection of stumps and subsequent spread of mycelium to neighboring trees at points of root contact, an inoculation experiment was established in three adjacent fully pedigreed 17-year old Norway spruce field trials. In June 1995, every third row was cut and stump-inoculated with conidia belonging to the two contrasting types, P and S. 5 years later the remaining trees were evaluated by clear-cutting and mapping of rot occurrence. 34% of the trees were attacked. For each host-tree, the most likely source of infestation (i.e. possible inoculated donor-stump 5 years earlier) was evaluated based on orientation of the rot on the stump surface supplemented with samples of re-isolation of H. annosum of the two types. According to these estimates, the tested S-type turned out to be more aggressive towards Norway spruce than the tested P-type. Genetic variation in resistance was most convincingly detected in the most informative trial F175B. The pattern of genetic variation in the two roles as donor and host seems to differ. However, genetic variation was also expressed as general resistance, which is defined as the combined effect of donor stump, living host and across the two tested types of H. annosum. No indication of host x pathogen interaction was detected. This evidence combined with the general experience that resistance against root rot pathogens usually is partial and based on the cumulative effects of several genes, suggests that sustainable genetic gains in relative resistance may be obtainable in breeding programs of Norway spruce. The developed experimental set-up represents a useful concept for screening existing genetic trials for field resistance within a time scale of 5-6 years.
 
Top-cited authors
Yousry A El-Kassaby
  • University of British Columbia - Vancouver
Dag Lindgren
  • Swedish University of Agricultural Sciences
Bradley M. Potts
  • University of Tasmania
Rowland David Burdon
  • Scion (New Zealand Forest Research Institute Ltd)
Nuno M. G. Borralho
  • RAIZ - Instituto de Investigação da Floresta e do Papel