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

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

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

Search

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

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

Search

42 Articles
Open Access

Genetic Variation Among and Within Populations in Swedish Species of Sorbus aucuparia L. and Prunus padus L. Assessed in a Nursery Trial

Published Online: 19 Oct 2017
Page range: 1 - 8

Abstract

Abstract

Seedlings originating from open-pollinated offspring of six and four populations of Prunus padus and Sorbus aucuparia, respectively, were studied with respect to phenology and growth traits for 3-4 years in a nursery. There were no replications at the population levels since the experiments should be converted to seedling seed orchards. Therefore, a special statistical model for analysis of the population effect was developed making use of neighbour performances. This model was also used for derivation of heritabilities. The heritabilities for phenology traits were in many cases high in P. padus, > 0.40, while they varied in the range 0.07-0.62 in S. aucuparia. The population effect was significant for all growth rhythm traits in P. padus and for a majority of traits in S. aucuparia. In both species the heritability for height decreased over time. Only bud flushing in P. padus indicated a relationship with population latitudinal origin in some cases. The genetic correlations between bud flushing different years were relatively strong in both species while the corresponding correlations for leaf colouring were moderate in P. padus and weak in S. aucuparia. In conclusion, the observed structure suggests that the pattern of seed dispersal may have an influence on the among- and within-population variation.

Keywords

  • P. padus
  • S. aucuparia
  • populations
  • half-sib families
  • nursery experiments
  • juvenile age
  • adaptive traits
  • growth rate
  • genetic variation
Open Access

Allozyme Variation in Different Species of Deciduous Oaks From Northwestern Italy

Published Online: 19 Oct 2017
Page range: 9 - 16

Abstract

Abstract

Allozyme variation was studied by electrophoresis at 11 loci in 14 populations of Quercus petraea, Q. robur, Q. cerris and Q. pubescens from Piedmont, northwestern Italy. The aim of the work was to characterize the genetic resources and to suggest effective measures for in situ preservation of biodiversity. As expected, most of the genetic variability was found at the within population level, and genetic differentiation accounted for about 14% of it. The study confirmed the low level of genetic variability among the species studied: only Q. cerris populations could be clearly distinguished. Q. pubescens could be separated from Q. petraea and Q. robur using Principal Coordinate Analysys. The latter was also found to be useful for separating Q. petraea and Q. robur populations. However, in mixed populations, the differentiation between the latter species was similar to that scored among populations belonging to the same species. A significant deviation from random mating was observed, although it was variable among species: Q. pubescens had the highest value for the inbreeding coefficient FIS (0.159).

Keywords

  • Allozyme variation
  • genetic diversity
  • heterozygosity
  • population differentiation
  • Quercus spp
Open Access

Identification of PCR-RFLP Haplotypes For Assessing Genetic Variation in the Green Oak Leaf Roller Tortrix viridana L. (Lepidoptera, Tortricidae)

Published Online: 19 Oct 2017
Page range: 17 - 24

Abstract

Abstract

PCR-RFLPs were performed to assess intraspecific variation in the green oak leaf roller, Tortrix viridana. The cytochrome oxidase I and II genes were amplified with universal and self designed primers, respectively, resulting in three PCR-fragments of 802 bp, 729 bp and 680 bp. 29 restrictions endonucleases were tested for variation in these PCR-patterns. Seven of these enzymes were chosen for further research. We found 13 haplotypes in four populations across a total of 436 individuals. In addition all haplotypes were sequenced. More single nucleotide substitutions were detected in the sequences, particularly in the middle of the cytochrome oxidase I gene, missed by the used restriction enzymes. For these markers intraspecific variation in T. viridana is high compared to other insect species. Furthermore we found differences in frequency of haplotypes among the investigated populations which induce that the markers developed so far are suitable for population genetic studies in T. viridana.

Keywords

  • Tortrix viridana
  • Quercus robur
  • PCR-RFLP
  • cytochrome oxidase
  • genetic variation
  • sequencing
Open Access

Assessment of AFLP-Based Genetic Variation in the Populations of Picea asperata

Published Online: 19 Oct 2017
Page range: 24 - 30

Abstract

Summary

Picea asperata Mast., which occurs in a restricted habitat in western China, has a wide ecological amplitude. In the present study, ten natural populations of P. asperata were studied using AFLP markers to investigate the population genetic structure and the level of genetic diversity. Of the 210 loci identified with two EcoRI/MseI primer combinations, 142 loci were found to be polymorphic. Yet, the level of genetic diversity observed within populations was quite low. The averages of NEI’s gene diversities (h) and Shannon's indices of diversity (I) calculated across populations equaled 0.156 and 0.227, respectively. The coefficient of gene differentiation among populations, based on the estimate GST and the unbiased estimate Φst, equaled 0.340 and 0.231, respectively. The mean genetic distance (D) between population pairs was 0.119 (range 0.050-0.156). Such high values indicate that there is significant differentiation among populations of P. asperata. Several factors could have contributed to the strong population differentiation, including relatively limited gene flow between populations (Nm = 0.968). Variation in environmental conditions and consequent selection pressures may be other factors attributing to the high level of genetic differentiation among populations. In addition, it was discovered that the geographic distances are not correlated with the genetic distances between the populations of P. asperata.

Keywords

  • AFLP markers
  • genetic structure
  • genetic diversity
  • Picea asperata Mast
Open Access

Variation and Correlations Among Stem Growth and Wood Traits of Calycophyllum spruceanum Benth. from the Peruvian Amazon

Published Online: 19 Oct 2017
Page range: 31 - 41

Abstract

Abstract

Calycophyllum spruceanum Benth. is an important tree for timber and energy in the western Amazon, with expanding national and international markets for its wood. There is relatively little information, however, about geographic variation in tree growth and wood properties, and correlations among these traits. The first provenance trial was established with farming communities in the Peruvian Amazon. Seven provenances, sampled from regions near the equator, were tested in three planting zones located in one watershed. Variation and correlations were investigated in stem growth at 30 and 42 months, wood density (in the lower and upper parts of the stem) and mean heat content of stem wood at 32 months. Stem height varied significantly among provenances and planting zones, but zones accounted for much more variation than provenances. Stem wood traits did not vary significantly among provenances. Wood density was greater in the lower than in the upper stem. Wood density in the upper stem and the difference in density between the lower and upper stem varied significantly among planting zones: density in the upper stem was lowest, and the difference in density between the lower and upper stem was largest in the zone where trees grew most rapidly. Phenotypic correlations between stem growth and wood density differed in sign among planting zones, suggesting that selecting fastgrowing trees could indirectly reduce wood density in environments where trees grow slowly, and increase the difference in wood density between the lower and upper stem in environments where trees grow very rapidly. Correlations between stem growth and wood heat content were stable across zones, and indicated that larger trees tended to have wood with higher heat content. Stem-wood heat content varied with provenance latitude/ longitude in the sample region, but none of the other traits varied clinally. Results indicate that there is potential to select faster-growing provenances at an early age, but this could affect wood density in certain environments.

Keywords

  • provenance
  • environment
  • height
  • diameter
  • wood density & heat content
Open Access

Chromosome Numbers of Four Nigerian Species of Cola Schott. & Endlicher (Sterculiaceae).

Published Online: 19 Oct 2017
Page range: 42 - 44

Abstract

Abstract

This paper reports the results of chromosome countings in four wild Cola species (Cola lateritia, C. ballayi, C. verticillata and C. gigantea). Cytological investigation of these species gave a constant mitotic chromosome counts of 2n = 4x = 40 for the first time. The karyotypes were found to consist mostly of metacentric and submetacentric chromosomes. In addition to confirming the chromosome numbers and ploidy levels in these species, the results also reveals high symmetry and homogeneity of the karyotypes with those of the cultivated species (C. nitida and C. acuminata) already reported. The similarity in chromosome morphology between the cultivated and wild species indicate their common origin and suggests the possibility of using these wild species as bridges for gene transfer in Cola breeding programmes involving interspecific hybridization.

Keywords

  • Cola
  • wild species
  • chromosome counts
  • karyotype
Open Access

Obituary Professor Dr. WOLFGANG LANGNER

Published Online: 19 Oct 2017
Page range: 45 - 45

Abstract

Open Access

Short Note: Cleistogamy in Eucalyptus tereticornis Sm. and its Genetic Implications

Published Online: 19 Oct 2017
Page range: 46 - 47

Abstract

Abstract

In a provenance cum progeny trial comprising 13 provenances and 91 families of Eucalyptus tereticornis Sm. of Australian and Papua New Guinean (PNG) origin, laid out in India in 2002, cleistogamy was found in a family emanating from CSIRO seed lot no. 13418, (tree no. DS000141) Sirinumu Sogeri Plat, PNG. This trait appears to be under genetic control, and presumably results in obligate selfing. This may lead to inbreeding depression in this family.

Keywords

  • Eucalyptus tereticornis
  • cleistogamy
  • inbreeding depression
  • autogamy
  • self-pollination
Open Access

Soil Temperature and Precipitation Affect the Rooting Ability of Dormant Hardwood Cuttings of Populus

Published Online: 19 Oct 2017
Page range: 47 - 58

Abstract

Abstract

In addition to genetic control, responses to environmental stimuli affect the success of rooting. Our objectives were to: 1) assess the variation in rooting ability among 21 Populus clones grown under varying soil temperatures and amounts of precipitation and 2) identify combinations of soil temperature and precipitation that promote rooting. The clones belonged to five genomic groups ([P. trichocarpa Torr. & Gray x P. deltoides Bartr. ex Marsh] x P. deltoides ‘BC’; P. deltoides ‘D’; P. deltoides x P. maximowiczii A. Henry ‘DM’; P. deltoides x P. nigra L. ‘DN’; P. nigra x P. maximowiczii ‘NM’). Cuttings, 20 cm long, were planted in Iowa and Minnesota, USA, in randomized complete blocks at 1.2- x 2.4-m spacing across three planting dates during 2001 and 2002. Soil temperatures were converted to belowground growing degree days (GDD) (base temperature = 10°C) accumulated over 14 days. Genomic groups responded similarly for root dry weight, number of roots, total root length, and mean root length, that increased as belowground GDD increased. Belowground GDD and precipitation governed rooting throughout the 14-d growing period. A minimum of four days above 14°C, along with sufficiently dispersed precipitation (e.g. no more than 3 d without a precipitation event), were needed to sustain aboveaverage rooting. Therefore, we recommend using a base temperature of 14°C for future models estimating belowground GDD in northern temperate zones.

Keywords

  • hybrid poplar
  • growing degree days
  • adventitious rooting
  • Populus deltoides
  • P. nigra
  • P. maximowiczii
  • P. trichocarpa
Open Access

Polyploidy in Gymnosperms: Revisited

Published Online: 19 Oct 2017
Page range: 59 - 69

Abstract

Abstract

There are only a few natural polyploids in gymnosperms. These have been reported in Ephera spp. (Gnetales), and Juniperus chinensis ‘Pfitzeriana’ (2n = 4x = 44), Fitzroya cupressoides (2n = 4x = 44), and the only hexaploid conifer Sequoia sempervirens (2n = 6x = 66) (Coniferales). Sporadic polyploids and aneuploids occur at a very low frequency in nurseries in conifers, but most of them show growth abnormalities, remain dwarf, and may not reach maturity. One exception is an autotetraploid tree of Larix decidua (2n = 4x = 48) that has survived in a private estate in Denmark. Colchicine-induced polyploids (colchiploids) have been produced in a several genera of conifers, including, Pinus, Picea, and Larix. These colchiploids (Co) were hybridized to untreated diploids to produce C1 and C2 generations to investigate their chromosome behavior. The colchiploids showed a wide range of chromosome variability, ranging from diploids, triploids, and tetraploids, and many were mixoploids. The colchiploids also show growth retardation, remain dwarf, and their future potential applications in forestry remains uncertain. However, genetic variability in the colchiploids still offers prospects for isolating genetically stable new genotypes. Even though polyploidy is rare in extant conifers, is it possible that ancient polyploidy or paleopolyploidy, that is prevalent in angiosperms, has also played a role in the evolution of conifers. In this paper we shall review the current status of polyploidy in gymnosperms.

Keywords

  • polyploidy
  • gymnosperms
  • conifers
  • coast redwood
  • alerce
  • ‘Pfitzer’ juniper
  • pines
  • genetic equilibrium
  • diploidization
  • colchiploids
  • ancient polyploidy
Open Access

Reproductive Success of Pollen Derived From Selected and Non-Selected Sources and its Impact on the Performance of Crops in a Nematode-Resistant Japanese Black Pine Seed Orchard

Published Online: 19 Oct 2017
Page range: 69 - 76

Abstract

Abstract

The reproductive success of pollen derived from selected and non-selected sources and its impact on the performance of orchard crops were evaluated, using five pairs of microsatellite markers, in a Japanese black pine (Pinus thunbergii Parl.) clonal seed orchard consisting of 16 nematode-resistant clones. The paternity of each open-pollinated seed was determined by comparing the genotypes of seeds from six clones (24 trees) with genotypes of the 16 orchard clones and two trees (N1, N2) representing other genotypes that had been inadvertently included in the orchard. Out of 384 seeds examined, the paternity of 316 seeds (82.3%) was assigned to the clones within the seed orchard. On average, the male reproductive success of orchard clones varied from 0.0% to 10.5%, and was significantly related to the male-flowering fecundity of each clone. It was not related to the synchrony of flowering phenology between mates. The expected proportions of seeds produced by clonal trees as a result of pollination by orchard clones, and by contaminating pollen originating from internal and external sources were estimated at 86.8%, 3.3% and 9.9%, respectively. Nematode-resistant seedlings of Japanese black pine were produced from surviving 2-yr seedlings that had previously been inoculated with pinewood nematode (Bursaphelenchus xylophilus). Without pollen contamination, the survival rate of seedlings produced by mating between resistant clones is expected to be 62.4%. However, in this orchard the figure was reduced to 57.5%, due to pollen contamination from both internal and external sources.

Keywords

  • nematode-resistant
  • microsatellite
  • Pinus thunbergii
  • microsatellite
  • pollen contamination
  • reproductive success
  • seed orchard
Open Access

Seed Source Variation in Morphology, Germination and Seedling Growth of Jatropha curcas Linn. in Central India

Published Online: 19 Oct 2017
Page range: 76 - 80

Abstract

Abstract

The aim of the study was to determine source variation in Jatropha curcas seeds collected from ten locations in Central India. A significant seed source variation was observed in seed morphology (colour, size and weight), seed germination (viability, germination percent, germination energy, germination value) and seedling growth parameters (survival percentage, seedling height, collar diameter, leave/plant, and seedling biomass). The seed source of Chhindwara (M.P.) was found as the best source in comparison to others. The phenotypic and genotypic variance, their coefficient of variability and broad sense heritability also showed a sizeable variability. This offers a breeder ample scope to undertake screening and selection of seed sources for the desired traits. Further, high percentage of heritability coupled with moderate intensity of genetic gain, was observed for seed germination traits, which signifies that germination is under strong genetic control and good amount of heritable additive genetic component can be exploited for improvement of this species.

Keywords

  • Jatropha curcas
  • variation
  • seed source
  • variability
  • heritability
  • genetic gain
  • seed germination
  • germination energy
Open Access

Optimal Clone Number for Seed Orchards with Tested Clones

Published Online: 19 Oct 2017
Page range: 80 - 92

Abstract

Abstract

The optimal number of clones in seed orchards is discussed. A model is constructed to maximize a goodness criterion (“benefit”) for seed orchards. This criterion is a function of: 1) the number of tested genotypes available for selection and planted in seed orchard; 2) the contribution to pollination from: a) the ramet itself; b) the closest neighbors; c) the rest of the orchard and sources outside the orchard (contamination); 3) variation among genotypes for fertility; 4) frequency of selfing; 5) production of selfed genotypes; 6) gene diversity (= status number); 7) influence of contamination; 8) genetic variation among candidates; 9) correlation between selection criterion (e.g. height in progeny test) and value for forestry (e.g. production in forests from the orchard); and 10) the number of clones harvested. Numeric values of the entries are discussed, and values were chosen to be relevant for scenarios with Swedish conifers (focusing on Scots pine) and for loblolly pine. Benefit was maximized considering the number of clones. The optimum was 16 clones for the Swedish scenario, while less for the loblolly pine scenario. The optimum was rather broad, thus it is not essential to deploy the exact optimum, and an approximate optimum will do. A sensitivity analyses was performed to evaluate the importance of the likely uncertainty and variation in different entries. Quantification of the benefit of gene diversity is important. Other significant considerations are the genetic variance in the goal character and the ability to predict it, as well as the impact of selfing and the variation in reproductive success between clones. Twenty clones is suggested as a thumb rule for Swedish conifers.

Keywords

  • Gene diversity
  • selfing
  • pollination
  • genetic gain
  • clone number
  • seed orchard
Open Access

Genetic Gain and Diversity of Orchard Crops Under Alternative Management Options in a Clonal Seed Orchard of Pinus thunbergii

Published Online: 19 Oct 2017
Page range: 93 - 96

Abstract

Abstract

Genetic gain and diversity, expressed by status number, of seed crops from a clonal seed orchard of Pinus thunbergii were estimated considering selection, fertility variation and pollen contamination, and compared for different management alternatives (selective harvest, genetic thinning and combination of both options). Management variables included the proportion of clones left after selective harvest and/or genetic thinning. The impact on genetic gain and diversity of seed crops was quantified as a function of the quantity and quality of gene flow from outside the seed orchard. Genetic gain varied with the proportion of selected or thinned clones. Genetic thinning by means of truncation selection of clones resulted in a large decrease in status number, which was accompanied by greater genetic gain than achieved by selective harvest alone. As expected, gene flow from outside the seed orchard greatly increased status number of the seed crop at higher rates of pollen contamination under all management options. The formulae and results of the present study could be used for identifying favorable selection intensity and alternatives for orchard management.

Keywords

  • genetic gain
  • gene diversity
  • rouging
  • selective harvest
  • Japanese black pine
Open Access

Genetic Variation and Realized Genetic Gain From Black Pine Tree Improvement

Published Online: 19 Oct 2017
Page range: 96 - 104

Abstract

Summary

In 1978 a 10 ha clonal seed orchard of black pine (Pinus nigra Arnold) was established in the area of Koumani in the western part of Peleponnesos, Greece. The orchard comprises 52 clones derived from intensively selected plus trees in the natural forest of black pine of Peloponnesos. In 1991 three open pollinated progeny tests were established in Peloponnesos, proximal to the villages of Raches, Vlachokerasia and Vamvakou. Seedlings from 52 families including a commercial check (CC) were planted in each one of the three locations. Assessments were made when the trees were 4, 7 and 9 years respectively, with the following results. The variation among families for growth characteristics were highly significant in all locations examined. In the combined analyses of variance over the three locations, significant differences among families were also detected, while the family x location interaction effect was not significant. This indicates that the seed produced from the seed orchard can be freely used over the environments of the three experimental plantings, which are representative of the broad area of Peloponnesos. Narrow sense heritability estimates on individual tree basis (h2) were variable depending on the characteristic, age of assessment and the location of the experimental plantings. The estimates of h2 in Vlachokerasia for height (HT) were 0.21, 0.40 and 0.43 at the ages of 4, 7 and 9 years respectively. In Raches the corresponding h2 values for HT were nearly the same in all ages (0.29, 0.28 and 0.31 at 4, 7 and 9 years respectively) and stable but little higher (0.31, 0.28 and 0.31) at the Vamvakou experimental planting. The heritability values for HT estimated over the three location, were relatively low (0.25, 0.23 and 0.19) at the ages 4, 7 and 9 years respectively. Realized genetic gains were calculated for growth characteristics at the age of 9 years, by comparing the performance of the improved (selected) materials to unimproved materials (CC). For the first stage of selection (selection made in natural stands) gain of 6.0% for HT, 8.0% for diameter breast height (DBH) and 24% for volume were estimated. When 20% of the clones, with the lower breeding values are removed from the seed orchard (genetic thinning), an additional gain of 2% for HT, 3% for DBH and 8% for volume over the unrogued seed orchard is resulted. Thus, the total genetic gain from the genetically tested, first generation seed orchard of black pine at Koumani is estimated as 8% for HT, 11% for DBH and 32% for volume. These results indicate that improvement of black pine by selection, establishment of seed orchard and progeny testing the clones, is a very promising profitable operation.

Keywords

  • Pinus nigra
  • Variance
  • covariance
  • heritability
  • correlation
  • rogued seed orchard
  • genetic test
  • genetic base
  • realized gain
Open Access

Fertility Variation and Genetic Diversity in a Clonal Seed Orchard of Cryptomeria japonica

Published Online: 19 Oct 2017
Page range: 104 - 107

Abstract

Abstract

Clonal differences in fertility (expressed as the number of female and male strobili) were determined for three consecutive years (2002-2004) in a clonal seed orchard of sugi (Cryptomeria japonica D. Don) in Korea. Fertility varied among clones and among years producing three-year averages of 196 and 652 for female and male strobili per ramet, respectively. Correlation between female and male strobilus production was positive over the three years and statistically significant in 2003, a good flowering year. Based on the observed fertility variation, the status numbers (Ns, measure of genetic diversity) were calculated and varied from 25.6 to 31.7 among the three studied years. On average (pooled), relative status number was 86% of the census number (N). Variation in female fertility was higher than that in male fertility, and this variation was reflected on female and male parents’ status numbers. Pooled Ns estimated from the three years was higher than that for any single year, implying that genetic diversity would increase when seeds collected from different years are pooled.

Keywords

  • fertility variation
  • sibling coefficient
  • status number
  • effective number
  • flowering
  • sugi
Open Access

Resistance of Transgenic Hybrid Triploids in Populus tomentosa Carr. Against 3 Species of Lepidopterans Following Two Winter Dormancies Conferred by High Level Expression of Cowpea Trypsin Inhibitor Gene

Published Online: 19 Oct 2017
Page range: 108 - 116

Abstract

Abstract

Hybrid triploid poplars [(P. tomentosa x P. bolleana) x P. tomentosa] genetically engineered with cowpea trypsin inhibitor (CpTI) gene have been out-planted in field for two years. They were used to detect their efficacy against 3 species of poplar defoliators: forest tent capterpillar, Malacosoma disstria Hübner, gypsy moth, Lymantria dispar Linnaeus and willow moth, Stilpnotia candida Staudinger by using detached leaves and for the purpose of identifying the CpTI gene at the molecular level. Foliage of transgenic poplars elicited an increase in larval mortality rate and a decrease in foliage consumption, wet weight gains, faeces excretion, deposited pupae number and pupae weight, thus indicating its effectiveness in affecting the growth, development and fecundity of larvae rather than only directly killing them. PCR and Southern blotting analyses confirmed the stable incorporation of CpTI gene while proteinase inhibitory assays disclosed its high level expression in the two-field-season of transgenic trees. Efficacious insect resistance and higher content of CpTI in foliage were found in transgenic clone TG04, TG07, TG08 and TG71, demonstrating a correspondence between the insect resistance level and the CpTI content in the foliage of transgenic poplar.

Keywords

  • Populus tomentosa Carr.
  • CpTI gene
  • transgenic poplar
  • Lepidoptera
  • insect resistance
  • proteinase inhibitory assay
  • PCR
  • Southern blotting
Open Access

Population Genetic Survey of Populus cathayana Originating From Southeastern Qinghai-Tibetan Plateau of China Based on SSR Markers

Published Online: 19 Oct 2017
Page range: 116 - 122

Abstract

Abstract

In this study, the genetic diversity of Populus cathayana Rehd was investigated using microsatellite markers. In a total of 150 individuals collected from six natural populations in the southeastern part of the Qinghai-Tibetan Plateau in China, a high level of microsatellite polymorphism was detected. At the seven investigated microsatellite loci, the number of alleles per locus ranged from 5 to 16, with a mean of 11.3, the observed heterozygosities across populations ranged from 0.408 to 0.986, with a mean of 0.792, and the expected heterozygosities across populations ranged from 0.511 to 0.891, with a mean of 0.802. The proportion of genetic differentiation among populations accounted for 37.3% of the whole genetic diversity. The presence of such a high level of genetic diversity could be attributed to the features of the species and the habitats where the sampled populations occur: The southeastern part of the Qinghai-Tibetan Plateau is regarded as the natural distribution and variation center of the genus Populus in China. Variation in environmental conditions and selection pressures in different populations, and topographic dispersal barriers could be factors associated with the high level of genetic differentiation found among populations. The populations possessed significant heterozygosity excesses, which may be due to extensive population mixing at the local scale. The cluster analysis showed that the populations are not strictly grouped according to their geographic distances but the habitat characteristics also influence the divergence pattern. In addition, we suggest that population SHY should be regarded as an ecologically divergent species of P. cathayana.

Keywords

  • Genetic differentiation
  • Genetic diversity
  • Heterozygosity excess
  • Microsatellites
  • Populus cathayana
Open Access

Differentiating Groups of Abies Species With a Simple Molecular Marker

Published Online: 19 Oct 2017
Page range: 123 - 126

Abstract

Abstract

The unambiguous identification of closely related species is useful for many practical purposes in forest tree species. For example, international laws require timber identification and the control of the origin of forest reproductive material. In this paper, we present a mitochondrial DNA marker which can be used to differentiate among groups of fir species (Abies spp.). Eight Mediterranean and one North American fir species (used as reference) were analysed at the fourth intron of the NAD subunit 5 gene. A total of six different haplotypes was identified, one in the American Abies concolor, the other five in Mediterranean species. Two different haplotypes were found each in the widespread A. alba and in A. cephalonica, one haplotype being shared among the two species. A single species specific haplotype was found in the near-eastern A. cilicica. The two southwestern species A. pinsapo and A. numidica shared one haplotype. The fifth haplotype was shared by all remaining eastern Mediterranean firs, A. cephalonica, A. bornmuelleriana, A. equi-troiani, and A. nordmanniana. Differences in haplotype sequences were mainly due to large insertions/deletions. Agarose gel electrophoresis thus provides a fast, cheap and reliable diagnosis method for species or species group identification.

Keywords

  • Organelle DNA polymorphism
  • mitochondrial DNA
  • nad5-4
  • species differentiation
  • Abies (spec.).
Open Access

Evolution of Genome Size in Conifers

Published Online: 19 Oct 2017
Page range: 126 - 137

Abstract

Abstract

Conifers are the most widely distributed group of gymnosperms in the world. They have large genome size (1C-value) compared with most animal and plant species. The genome size ranges from ~6,500 Mb to ~37,000 Mb in conifers. How and why conifers have evolved such large genomes is not understood. The conifer genome contains ~75% highly repetitive DNA. Most of the repetitive DNA is composed of non-coding DNA, including ubiquitous transposable elements. Conifers have relatively larger rDNA repeat units, larger gene families generated by gene duplications, larger nuclear volume, and perhaps larger genes, as compared to angiosperm plants. These genomic components may partially account for the large genome size, as well as variation in genome size, in conifers. One of the major mechanisms for genome size expansion and evolution of species is polyploidy, which is widespread in angiosperms, but it is rare in conifers. There are only a few natural polyploids in one family of conifers, Cupressaceae. Other conifers, including well-studied pines, are nearly all diploids. Whether ancient polyploidy has played a role in the evolution of genome size in conifers still remains an open question. The mechanisms that account for the variation and evolution of genome size in conifers are addressed in this review.

Keywords

  • genome size
  • conifers
  • pines
  • polyploidy
  • paleopolyploidy
  • duplicate genes
  • repetitive DNA
  • retrotransposons
  • introns
  • genome evolution
Open Access

Lodgepole Pine and White Spruce Germination: Effects of Stratification and Simulated Aging

Published Online: 19 Oct 2017
Page range: 138 - 144

Abstract

Abstract

The effects of seed pre-treatment (stratification/prechilling) and simulated aging on germination parameters (germination capacity, speed and value and peak value) were evaluated for several seedlots originating from seed orchard clones of lodgepole pine (Pinus contorta var. latifolia DOUGL. ex LOUD.) and white spruce (Picea glauca (MOENCH) VOSS). Region of origin and stratification had little effect on white spruce, while stratification enhanced germination speed and completeness of lodgepole pine. Broad-sense heritability for germination parameters ranged from 70 to 97% (unstratified) and from 81 to 96% (stratified) for pine, and from 95 to 97% (unstratified) and from 93 to 97% (stratified) for spruce. Simulated aging (short-term storage at high temperature and relative humidity, approximating the physiological effects of long-term storage) resulted in rapid deterioration of white spruce, with very little germination after six days of aging. Lodgepole pine germination increased during the first several aging treatments relative to the control, but germination capacity decreased following twelve days of aging, and was very low after 18 days. White spruce was nondormant and responded primarily to moisture conditions, whereas pine was strongly influenced by maternal effects. These results can be incorporated for more efficacious nursery production practices for commercial reforestation seedling production as well as ex-situ gene conservation strategies.

Keywords

  • germination
  • Pinus contorta
  • Picea glauca
  • simulated aging
  • dormancy
  • stratification
  • broad-sense heritability
Open Access

Identification of Molecular Markers for Selected Wood Properties of Norway Spruce Picea abies L. (Karst.) II. Extractives Content

Published Online: 19 Oct 2017
Page range: 145 - 152

Abstract

Abstract

We describe the development of a SCAR-marker linked to low extractives content of Norway Spruce (Picea abies L [Karst.]) derived from AFLPs. In these analyses 57 different primer enzyme combinations were used in a bulked segregant analysis approach comparing individuals with high and low extractives content. A total of 14 polymorphic AFLP markers were detected between the pools. Five markers were selected for further analyses to verify their linkage to extractives content based on individuals used for pool constitution. One AFLP marker, found to be significant linked to low extractives content was converted into a SCAR marker for further validation. For this marker, a monomorphic band was obtained by using sets of nested primers or restriction site specific primers (RSS) which include the AFLP-restriction recognition site. The separation of the marker from unlinked size homologous marker-alleles was realized by a SSCP-approach. Validation of the marker on different full-sib families confirmed the usability to separate the classes for low and high extractives content of Picea abies.

Keywords

  • Bulked segregant analysis
  • AFLP
  • Molecular markers
  • Marker assisted selection (MAS)
  • Wood properties
  • Marker conversion
  • SCAR marker
Open Access

Impact of Clones in a Clonal Seed Orchard on the Variation of Seed Traits, Germination and Seedling Growth in Santalum album L.

Published Online: 19 Oct 2017
Page range: 153 - 160

Abstract

Summary

Clonal Seed Orchard (CSO) of Santalum album L. at Nallal, India consisting of 25 clones originated from different agro-climatic conditions of four southern states (Karnataka, Tamil Nadu, Kerala and Andhra Pradesh) was source of seeds for variability studies. There was vast variation in seed size, weight, germination, vigour and seedling growth of different clones over the years. Seed length, width and weight were positively correlated to each other but seed size had no effect on germination, Germination Value (GV), days taken for germination and early seedling growth. Effects of Clones were dominant and accounted for variation in germination rather than seed size. There was no consistency in the parameters studied in the two years. The impact of these genetic differences in handling of seed lots during bulking, grading and storage for mass propagation of nursery planting stock of S. album is also discussed.

Keywords

  • CSO
  • Santalum album
  • seed variability
  • clone
  • correlation and mass propagation
Open Access

Genetic Variation of Physical and Chemical Wood Properties of Eucalyptus globulus

Published Online: 19 Oct 2017
Page range: 160 - 166

Abstract

Abstract

This study considered the degree of genetic variation for diameter (DBH), basic density (BD), predicted pulp yield (PPY), fibre length (FL), microfibril angle (MFA) and cellulose content (CC) amongst eight subraces of Eucalyptus globulus growing in a field trial in NW Tasmania. There were significant subrace effects for BD, FL and CC. This variation affected the relative profitability of the subraces for pulp production. On average, the most profitable subraces (on NPV/ha over the base population mean) were Strzelecki Ranges ($862.04), Western Otways ($657.80) and Strzelecki Foothills ($576.81). The genetic control (heritability) of variation in DBH, FL and MFA was moderate (0.15 < h2< 0.27), while control for BD, PPY and CC was high (h2> 0.40). Genetic correlations between growth and wood properties were not statistically significant, except for DBHMFA (-0.86). Most genetic correlations amongst wood properties were outside the parametric space (< -1 or >1), but there were significant correlations between BDMFA (-0.70) and PPY-CC (0.82). The empirical response to selection on an index based on a pulp wood objective (which included volume and basic density) resulted in a gain of 4.3% for DBH, 7.9% for BD and marginal changes for all other traits, with a net impact in profit of $1,270/ha. However, future profit calculations will need to consider the effect of FL, MFA and CC on the economics of wood processing to fully evaluate the economic impact of breeding.

Keywords

  • BLUP
  • racial variation
  • heritability
  • genetic correlations
  • breeding
  • profit
Open Access

Early Assessment of First Year Height Data from Five Acacia mearnsii (black wattle) Sub-populations in South Africa using REML/BLUP

Published Online: 19 Oct 2017
Page range: 166 - 174

Abstract

Abstract

Recent research has shown, Acacia mearnsii (black wattle) to be a source of high quality pulp. This led to a change in the emphasis in the breeding programme at the Institute for Commercial Forestry Research, from improving bark yield and quality, to improving timber yield and quality while maintaining an acceptable bark quality. A Multiple Population Breeding Strategy was implemented to cater for these changes. Five sub-populations were established across different sites in KwaZulu- Natal and were determined by origin of seed. Each sub-population was established as a progeny trial with a seedling seed orchard adjacent to it. The management of the seed orchards will be determined according to the performance of the families within the progeny trials. This paper reports on the first year height measurements taken from the five sub-populations. The intention of this paper is not to base any selections from this data but rather to establish a set of analyses using REML/BLUP which will be used for future data analysis. This will also allow for future assessment of age-age correlations for the various traits being assessed and provide an appropriate decision-making tool, for selecting individuals for future generations.

Keywords

  • Acacia mearnsii
  • black wattle
  • BLUP
  • height measurements
  • REML
  • sub-populations
Open Access

Variation in Eucalyptus globulus LABILL. and E. nitens DEAN and MAIDEN in Susceptibility of Adult Foliage to Disease Caused by Mycosphaerella cryptica (COOKE) HANSF

Published Online: 19 Oct 2017
Page range: 174 - 184

Abstract

Summary

Severity of disease caused by Mycosphaerella cryptica (COOK) HANSF. was assessed on the adult foliage of Eucalyptus globulus LABILL. in two provenance trials (encompassing all four subspecies) and a progeny trial of E. globulus ssp. globulus LABILL. located in Victoria, Australia. Disease was relatively low in all trials (most trees with less than 15% crown severity), except for two provenances at one trial, Judbury (E. globulus ssp. globulus) and Mansfield (E. globulus ssp. bicostata), that had mean crown severities of approximately 25% and 40%, respectively. Eucalyptus globulus ssp. bicostata (MAIDEN et al.) KIRKPATR. was significantly (P < 0.01) more susceptible than E. globulus ssp. globulus, E. globulus ssp. pseudoglobulus (NAUDIN ex MAIDEN) KIRKPATR. and E. globulus ssp. maidenii (F. MUELL.) KIRKPATR., with subspecies maidenii significantly less diseased than all other subspecies. There was significant variation between provenances within subspecies globulus (P < 0.01) but not within subspecies pseudoglobulus, maidenii or bicostata. Subspecies globulus also showed significant (P < 0.01) variation between families. There was a moderate to high genetic correlation between disease of the adult foliage and disease of the juvenile foliage (caused by both M. cryptica and M. nubilosa (COOKE) HANSF.) assessed several years earlier, both at the provenance (rG = 0.67) and family (rG = 0.33) levels. Narrow sense heritability of disease of the adult foliage (M. cryptica) was low (h2 = 0.17), compared to that of the juvenile foliage (h2 = 0.35) and juvenile defoliation (h2 = 0.45) assessed previously. Selection for overall disease resistance (both adult- and juvenile-phase foliage) can be carried out more quickly and accurately at the juvenile stage when trees are 2-3 years old, potentially reducing the time required for resistant trees to be selected and deployed in the field. Mycosphaerella leaf disease on adult E. nitens (DEAN and MAIDEN) MAIDEN was also assessed in two provenance trials; however, there was very little disease observed and no significant differences were found between provenances.

Keywords

  • provenances
  • families
  • Mycosphaerella nubilosa
  • adult-juvenile leaf phase correlations
  • genetic parameters
Open Access

Genetic Gain and Gene Diversity Following Thinning in a Half-Sib Plantation

Published Online: 19 Oct 2017
Page range: 185 - 189

Abstract

Abstract

Status number, gene diversity, inbreeding coefficient and genetic gain were calculated following phenotypic rogueing of different intensities in a half-sib progeny plantation of Scots pine (Pinus sylvestris L.). Across most selection intensities the status number, gene diversity and genetic gain remained favorably high while the inbreeding coefficient was remarkably stable. It is suggested that phenotypic selection in half-sib progeny tests or plantations with unknown pedigrees, can be used to manage seed collection areas or as a component in low-input breeding without a fast build up of coancestry or inbreeding, provided the initial number of progenies of unrelated parents is sufficiently high and that a high number of these families are retained with a few individuals per family.

Keywords

  • half-sib plantation
  • status number
  • inbreeding
  • gene diversity
  • genetic gain
  • low-input breeding
  • seed collection area
  • Scots pine
Open Access

Cone Yield Characterization of a Stone Pine (Pinus pinea L.) Clone Bank

Published Online: 19 Oct 2017
Page range: 189 - 197

Abstract

Abstract

In spite of the use of the edible kernels of Stone pine (Pinus pinea L.) gathered from Mediterranean pine forests, the species remains a genuine forest tree that has never been domesticated as an orchard crop. In the last decades, some efforts have been made to select valuable genotypes for exploring the possibilities of Stone pine as an orchard crop. The present paper characterizes the cone yield of a grafted clone bank in order to elucidate the relevance of genetic and environment factors for seed-yield quantity and quality and for sequential transition rates of the development from pollinated conelets to ripe cones. Individual tree size and cone yield were separated in their genetic and environmental components, in order to estimate phenotypic, genetic and environmental correlations. A statistical model for logtransformed individual cone yield was adjusted, ranking the tested genotypes by their estimated clonal value after adjustment for tree size covariables. The degree of genetic determination for adjusted cone yield was estimated in 15%, the expected genetic gain by selection of the top 10% of tested genotypes would be 12%. Genetic correlation between genetic values for cone yield and cone and seed size were weak but significantly positive (r = 0.27 and 0.17), hence the lack of trade-offs between crop quantity and quality will allow a combined selection.

Keywords

  • Mediterranean stone pine
  • pine nuts
  • cone survival
  • degree of genetic determination
Open Access

Conservation Approaches For Autochthonous Woody Plants in Flanders

Published Online: 19 Oct 2017
Page range: 197 - 206

Abstract

Abstract

Autochthonous genetic resources of woody plants have become seriously endangered in Flanders because of the particularly low and fragmented forest cover, centuries of intensive forest use in this highly populated area and the wide-spread usage of non-autochthonous planting stock in reforestation and landscape plantings. Intraspecific hybridisation between remnant autochthonous populations and foreign genotypes, which can show inadequate adaptation, may influence the autochthonous genetic constitution and fitness in the long term. As several European countries face similar problems, the objective of this paper is to outline the conservation measures that are taken in Flanders. The central aim is to maintain and create the necessary conditions for natural and flexible evolution of the genetic diversity of autochthonous trees and shrubs. An inventory survey to locate remaining autochthonous populations was started in 1997 and will be completed in 2006. Relict populations are preserved in clonal banks. Central issues are the production of autochthonous planting stock through in situ seed collection, the approval of seed sources and stands and the creation of seed orchards. Conservation actions are discussed.

Keywords

  • in situ conservation
  • ex situ conservation
  • autochthonous woody plants
  • seed orchards
  • forest reproductive material
  • clonal banks
  • regions of provenance
  • seed collection
  • natural populations
  • inventory
Open Access

Classification of Genus Acanthopanax in Korea and Genetic Diversity Using Allozymes

Published Online: 19 Oct 2017
Page range: 206 - 210

Abstract

Abstract

Genus Acanthopanax is a long-lived woody species that is primarily distributed throughout Asia. Many species of this genus are regarded as medically and ecologically important. We evaluated a representative sample of the nine taxa with allozymes to estimate genetic relationships within the genus. As some Korean populations were isolated and patchily distributed, they exhibited a low level of genetic diversity. The narrow geographic ranges, artificial distribution of habitats, and small population sizes are proposed as factors contributing to low genetic diversity. Acanthopanax seoulense was similar to A. sessiliflorus, while a cluster of the A. rufinerve population is distant from any other species. A. senticosus is closely related to A. seoulense and A. sessiliflorus, whereas other species (A. koreanum) are more distinct from the Korean populations. Korean species are clustered together and clearly differentiated from the Chinese and Russian Acanthopanax taxa, genus Acanthopanax

Keywords

  • Allozyme
  • Genetic relationships
  • Genus Acanthopanax
Open Access

Chromosome Microdissection, Cloning and Painting of the Chromosome 1 in Poplar (Populus tremula)

Published Online: 19 Oct 2017
Page range: 211 - 217

Abstract

Abstract

The chromosome microdissection, cloning and painting technology has evolved into an efficient tool for genomic research. Application of these techniques has rarely been applied for forest plants, largely due to the difficulty of chromosome preparation. The present study was performed to establish a method for single chromosome microdissection, cloning and painting in forest plants using poplar (Populus tremula) as a model. An individual chromosome 1 was microdissected from the metaphase spreads of poplar root-tip cells with fine glass needle controlled by a micromanipulator. The dissected chromosome was amplified in vitro by the Sau3A linker adaptor mediated PCR (LA-PCR) technique, by which 200bp to 3,000bp smear DNA fragments were obtained. Then, the second round PCR products from the single chromosome 1 were cloned into T-easy vectors to generate a DNA library of the chromosome 1. Approximately 3 x 105 recombinant clones were obtained. The second round PCR products were used as a complex probe mixture for fluorescent in situ hybridization (FISH) on the metaphase spreads of poplar. Hybridization signals were observed, mainly, along the entire chromosome 1, at the same time, signals were also present on telomeric and centromeric regions of other chromosomes. Therefore, this research suggests that chromosome microdissection, cloning and painting of the single small chromosome in forest plants are feasible.

Keywords

  • Chromosome painting
  • Fluorescent in situ hybridization (FISH)
  • Microdissection
  • Populus tremula
Open Access

Low Cost Improvement of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) By Application of The Breeding Seed Orchard Approach in Denmark

Published Online: 19 Oct 2017
Page range: 218 - 227

Abstract

Abstract

An evaluation of a seedling seed orchard in Denmark of Coastal Douglas-fir showed variation between open pollinated families in their susceptibility to windthrow, height and diameter growth, stem straightness, number of forks at age 10 and bud burst at age 9. Individual narrow-sense heritability was 0.63 for bud burst, 0.40 for height and diameter, respectively, 0.48 for stem straightness, 0.20 for number of forks and 0.17 for windthrow susceptibility. Fast growing families were characterised by late bud burst, and poorer stem straightness. The approach of using seedling seed orchards in Denmark is discussed in relation to genetic gains, genetic diversity and risk of inbreeding. Predicted gains concerning a reduction of windthrow susceptibility were poor due to low genetic variability. In multi-trait selection scenarios aiming to improve growth, stem straightness and reducing windthrow susceptibility, the approach of using seedling seed orchards demonstrated that it might be possible to obtain gains in height above 5% combined with significant improvements of stem straightness while retaining an effective population size above 50.

Keywords

  • heritability estimates
  • genetic correlation
  • growth
  • stem straightness
  • forking
  • windthrow
  • bud burst
  • genetic diversity
  • genetic gain
Open Access

Heritability and Correlations for Biomass Production and Allocation in White Spruce Seedlings

Published Online: 19 Oct 2017
Page range: 228 - 235

Abstract

Abstract

Tree growth is a multidimensional trait and families vary for components of growth such as height, diameter, foliage and roots. Therefore, variation in tree growth is better studied by analysing biomass production and allocation than simple traits. In addition, biomass is better linked to products such as pulp and wood energy than simple traits. We analysed biomass of 3-year old open-pollinated greenhouse seedlings of white spruce to determine (1) heritability for biomass production and allocation to shoot and root components, (2) correlations between biomass traits, and biomass traits with primary traits, and (3) correlation between biomass production in the greenhouse and height growth for the same families in the field. The study had a randomised complete block design with single-tree plots, 30 blocks and 58 open-pollinated families. Individual-tree heritability (hi2 ) and family mean heritability (hf2 ) ranged from 0.200 to 0.333 and 0.374 to 0.516 for green weight, respectively. Likewise, hi2 and hi2 ranged from 0.186 to 0.359 and 0.352 to 0.536 for dry weight, respectively. Genetic correlation (ra) between green and dry weight ranged from 0.943 to 1.015, while ra between shoot and root dry weight ranged from 0.947 to 0.955. In contrast, ra between biomass traits and field height ranged from -0.403 to -0.124. Thus, we conclude (1) variation in biomass production and allocation exhibited low genetic basis, (2) testing and selection for green or dry weight should lead to similar genotypes, (3) biomass allocation may not be easily altered by selection and breeding, and (4) indirect early selection based on seedling biomass

Keywords

  • Dry weight
  • early selection
  • genetic variation
  • heritability
  • Picea glauca
Open Access

Genetic Variation of Korean Pine (Pinus koraiensis Sieb. et Zucc.) at Allozyme and RAPD Markers in Korea, China and Russia

Published Online: 19 Oct 2017
Page range: 235 - 246

Abstract

Abstract

We studied and compared genetic variation of Korean pine (Pinus koraiensis Sieb. et Zucc.) from 12 natural populations in Korea, China, and Russian Far East using allozymes and random amplified polymorphic DNAs (RAPDs). Eighteen polymorphic allozyme loci and 38 polymorphic RAPD fragments were analyzed. The level of allozyme diversity (A = 1.95, P95 = 46.8%, Ho = 0.158, He = 0.169) and the degree of genetic differentiation (FST = 0.069) were comparable to those of other pines with similar life histories and ecological traits. Allozyme (He) as well as RAPD (Shannon’s index) variation decreased from south (Korea) to north (Russia), providing an evidence for the hypothesis of Korean pine’s northward migration. Differentiations among three different regions (Korea, China, and Russia) as well as among populations within regions were small. Substantial gene flow (Nm = 3.4) may be a partial explanation to this result. Clustering algorithms using various genetic distance measures showed some decisive geographic patterns at allozyme and RAPD level: the geographically close populations tended to be clustered together. On the other hand, two Chinese populations, Xobukho and Wangging, were grouped with the Russian populations rather than with the other Chinese populations. The Xiaoxing’anling and other mountains extended from north to south seemed to function as a barrier against gene flow between the Xobukho and Wangging (located east of the mountains) and the other Chinese P. koraiensis populations (located west of the mountains). The genetic diversities and differentiation estimated from RAPD data in Korean pine were congruent with those of allozymes.

Keywords

  • Pinus koraiensis
  • allozymes
  • RAPDs
  • genetic variation
  • Korea
  • China
  • Russian Far East
Open Access

Variation in Reproductive Phenology in a Pinus radiata D. Don Seed Orchard in Northern Spain

Published Online: 19 Oct 2017
Page range: 246 - 256

Abstract

Summary

Reproductive phenology was studied in a Pinus radiata seed orchard, located in northern Spain. Timing of flowering was determined on the basis of data recorded by visual observations made in 2000, 2001 and 2002. The genetic and environmental factors affecting female and male phenology, as well as reproductive synchronization, were studied. The dates of beginning of the receptive phase and pollen shedding varied greatly from year to year but the variation on the sum of degree-days was low. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity and pollen shedding were in most cases statistically significant. The time needed to reach flowering stages was under strong genetic control. Genetic control was stronger for the female than the male flowering process. However, correlations between years were stronger for male than for female flowering phenology. The male flowering clones that best synchronized with the females appeared to be those that started flowering earlier. The phenological overlap index varied greatly among clones, whether male or female, and also among years.

Keywords

  • flowering receptivity
  • pollen shedding
  • reproductive synchronization
  • flowering phenograms
  • cumulative growing degree-days
  • phenological overlap index
  • SYNCHRO.SAS programme
  • clonal repeatibility
  • progeny test
  • genetic variation
  • genetic parameters
  • quantitative traits
Open Access

Population Genetic Studies of Tree Populations in the Neotropics

Published Online: 19 Oct 2017
Page range: 257 - 257

Abstract

Open Access

Regional and Population-scale Influences on Genetic Diversity Partitioning within Costa Rican Populations of the Pioneer Tree Vochysia ferruginea Mart

Published Online: 19 Oct 2017
Page range: 258 - 264

Abstract

Abstract

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 (FST = 0.15) and within-population diversity high, though variable (Hs = 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.

Keywords

  • AFLP
  • chloroplast DNA
  • genetic diversity
  • gene flow
  • succession
Open Access

Sampling Tissue for DNA Analysis of Trees: Trunk Cambium as an Alternative to Canopy Leaves

Published Online: 19 Oct 2017
Page range: 265 - 269

Abstract

Abstract

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.

Keywords

  • DNA extraction
  • trees
  • tropical
  • cambium
  • AFLP
  • sample preservation
Open Access

Chloroplast DNA Variation of Carapa guianensis in the Amazon basin

Published Online: 19 Oct 2017
Page range: 270 - 274

Abstract

Abstract

Carapa guianensis is a widespread Neotropical tree species that produces a seed adapted for water dispersal. We conducted a pilot study of chloroplast DNA (cpDNA) variation in order to investigate the consequences of hydrochory on genetic diversity and geographic population structure in the lower Amazon basin. A survey of cpDNA haplotype variation reveals a strong regional structure, which suggests limited gene flow by seeds. Within site variation was detected only in one floodplain forest (varzea), suggesting that seed dispersal by water in these forests has the potential to mix maternal lineages. Several phylogeographic hypotheses are discussed with respect to these data.

Keywords

  • cpDNA
  • Amazonia
  • Amazon River
  • Carapa guianensis
  • seed dispersal
Open Access

Gene flow and mating system of the tropical tree Sextonia rubra

Published Online: 19 Oct 2017
Page range: 275 - 280

Abstract

Abstract

In this paper we report a study of the mating system and gene flow of Sextonia rubra, a hermaphroditic, insect pollinated tropical tree species with a geographic distribution in the Guyana Plateau and the Amazon. Using five microsatellites we analysed 428 seeds of 27 open pollinated families at the experimental site “Paracou” in French Guiana. We observed, compared to other tropical tree species, a high level of genetic diversity. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, tm, was 0.992 indicating nearly complete outcrossing. A significant level of biparental inbreeding and a small proportion of full-sibs were estimated for the 27 seed arrays. The differentiation of allelic frequencies among the pollen pools was ΦFT = 0.061. We estimated mean pollen dispersal distances between 65 m and 89 m according to the dispersal models used. The joint estimation of pollen dispersal and density of reproductive trees gave an effective density estimate of 2.1-2.2 trees/ha.

Keywords

  • Genetic diversity
  • gene flow
  • heterozygosity
  • microsatellites
  • mixed mating
  • tropical tree
  • twogener
Open Access

Contrasting Quantitative Traits and Neutral Genetic Markers for Genetic Resource Assessment of Mesoamerican Cedrela Odorata

Published Online: 19 Oct 2017
Page range: 281 - 292

Abstract

Abstract

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 (FST = 0.67 for the sampled Mesoamerican range) than for quantitative traits (QST = 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.

  • Key words: Cedrela odorata
  • FST
  • genetic differentiation
  • geographic variation
  • heritability
  • natural selection
  • quantitative traits
  • RAPD
  • QST
Open Access

Chloroplast and Total Genomic Diversity in the Endemic Costa Rican Tree Lonchocarpus costaricensis (J. D. Smith) Pittier (Papilionaceae)

Published Online: 19 Oct 2017
Page range: 293 - 300

Abstract

Abstract

In Mesoamerica, tropical dry forest is a highly threatened habitat, and species endemic to this environment are under extreme pressure. The tree species, Lonchocarpus costaricensis is endemic to the dry northwest of Costa Rica and southwest Nicaragua. It is a locally important species but, as land has been cleared for agriculture, populations have experienced considerable reduction and fragmentation. To assess current levels and distribution of genetic diversity in the species, a combination of chloroplast-specific (cpDNA) and whole genome DNA markers (amplified fragment length polymorphism, AFLP) were used to fingerprint 121 individual trees in 6 populations. Two cpDNA haplotypes were identified, distributed among populations such that populations at the extremes of the distribution showed lowest diversity. A large number (487) of AFLP markers were obtained and indicated that diversity levels were highest in the two coastal populations (Cobano, Matapalo, H = 0.23, 0.28 respectively). Population differentiation was low overall, FST = 0.12, although Matapalo was strongly differentiated from all other populations (FST = 0.16-0.22), apart from Cobano (FST = 0.11). Spatial genetic structure was present in both datasets at different scales: cpDNA was structured at a range-wide distribution scale, whilst AFLP data revealed genetic neighbourhoods on a population scale. In general, the habitat degradation of recent times appears not to have yet impacted diversity levels in mature populations. However, although no data on seed or saplings were collected, it seems likely that reproductive mechanisms in the species will have been affected by land clearance. It is recommended that efforts should be made to conserve the extant genetic resource base and further research undertaken to investigate diversity levels in the progeny generation.

Keywords

  • AFLPs
  • chloroplast DNA
  • genetic differentiation
  • genetic diversity
  • Lonchocarpus costaricensis
  • spatial genetic structuring
42 Articles
Open Access

Genetic Variation Among and Within Populations in Swedish Species of Sorbus aucuparia L. and Prunus padus L. Assessed in a Nursery Trial

Published Online: 19 Oct 2017
Page range: 1 - 8

Abstract

Abstract

Seedlings originating from open-pollinated offspring of six and four populations of Prunus padus and Sorbus aucuparia, respectively, were studied with respect to phenology and growth traits for 3-4 years in a nursery. There were no replications at the population levels since the experiments should be converted to seedling seed orchards. Therefore, a special statistical model for analysis of the population effect was developed making use of neighbour performances. This model was also used for derivation of heritabilities. The heritabilities for phenology traits were in many cases high in P. padus, > 0.40, while they varied in the range 0.07-0.62 in S. aucuparia. The population effect was significant for all growth rhythm traits in P. padus and for a majority of traits in S. aucuparia. In both species the heritability for height decreased over time. Only bud flushing in P. padus indicated a relationship with population latitudinal origin in some cases. The genetic correlations between bud flushing different years were relatively strong in both species while the corresponding correlations for leaf colouring were moderate in P. padus and weak in S. aucuparia. In conclusion, the observed structure suggests that the pattern of seed dispersal may have an influence on the among- and within-population variation.

Keywords

  • P. padus
  • S. aucuparia
  • populations
  • half-sib families
  • nursery experiments
  • juvenile age
  • adaptive traits
  • growth rate
  • genetic variation
Open Access

Allozyme Variation in Different Species of Deciduous Oaks From Northwestern Italy

Published Online: 19 Oct 2017
Page range: 9 - 16

Abstract

Abstract

Allozyme variation was studied by electrophoresis at 11 loci in 14 populations of Quercus petraea, Q. robur, Q. cerris and Q. pubescens from Piedmont, northwestern Italy. The aim of the work was to characterize the genetic resources and to suggest effective measures for in situ preservation of biodiversity. As expected, most of the genetic variability was found at the within population level, and genetic differentiation accounted for about 14% of it. The study confirmed the low level of genetic variability among the species studied: only Q. cerris populations could be clearly distinguished. Q. pubescens could be separated from Q. petraea and Q. robur using Principal Coordinate Analysys. The latter was also found to be useful for separating Q. petraea and Q. robur populations. However, in mixed populations, the differentiation between the latter species was similar to that scored among populations belonging to the same species. A significant deviation from random mating was observed, although it was variable among species: Q. pubescens had the highest value for the inbreeding coefficient FIS (0.159).

Keywords

  • Allozyme variation
  • genetic diversity
  • heterozygosity
  • population differentiation
  • Quercus spp
Open Access

Identification of PCR-RFLP Haplotypes For Assessing Genetic Variation in the Green Oak Leaf Roller Tortrix viridana L. (Lepidoptera, Tortricidae)

Published Online: 19 Oct 2017
Page range: 17 - 24

Abstract

Abstract

PCR-RFLPs were performed to assess intraspecific variation in the green oak leaf roller, Tortrix viridana. The cytochrome oxidase I and II genes were amplified with universal and self designed primers, respectively, resulting in three PCR-fragments of 802 bp, 729 bp and 680 bp. 29 restrictions endonucleases were tested for variation in these PCR-patterns. Seven of these enzymes were chosen for further research. We found 13 haplotypes in four populations across a total of 436 individuals. In addition all haplotypes were sequenced. More single nucleotide substitutions were detected in the sequences, particularly in the middle of the cytochrome oxidase I gene, missed by the used restriction enzymes. For these markers intraspecific variation in T. viridana is high compared to other insect species. Furthermore we found differences in frequency of haplotypes among the investigated populations which induce that the markers developed so far are suitable for population genetic studies in T. viridana.

Keywords

  • Tortrix viridana
  • Quercus robur
  • PCR-RFLP
  • cytochrome oxidase
  • genetic variation
  • sequencing
Open Access

Assessment of AFLP-Based Genetic Variation in the Populations of Picea asperata

Published Online: 19 Oct 2017
Page range: 24 - 30

Abstract

Summary

Picea asperata Mast., which occurs in a restricted habitat in western China, has a wide ecological amplitude. In the present study, ten natural populations of P. asperata were studied using AFLP markers to investigate the population genetic structure and the level of genetic diversity. Of the 210 loci identified with two EcoRI/MseI primer combinations, 142 loci were found to be polymorphic. Yet, the level of genetic diversity observed within populations was quite low. The averages of NEI’s gene diversities (h) and Shannon's indices of diversity (I) calculated across populations equaled 0.156 and 0.227, respectively. The coefficient of gene differentiation among populations, based on the estimate GST and the unbiased estimate Φst, equaled 0.340 and 0.231, respectively. The mean genetic distance (D) between population pairs was 0.119 (range 0.050-0.156). Such high values indicate that there is significant differentiation among populations of P. asperata. Several factors could have contributed to the strong population differentiation, including relatively limited gene flow between populations (Nm = 0.968). Variation in environmental conditions and consequent selection pressures may be other factors attributing to the high level of genetic differentiation among populations. In addition, it was discovered that the geographic distances are not correlated with the genetic distances between the populations of P. asperata.

Keywords

  • AFLP markers
  • genetic structure
  • genetic diversity
  • Picea asperata Mast
Open Access

Variation and Correlations Among Stem Growth and Wood Traits of Calycophyllum spruceanum Benth. from the Peruvian Amazon

Published Online: 19 Oct 2017
Page range: 31 - 41

Abstract

Abstract

Calycophyllum spruceanum Benth. is an important tree for timber and energy in the western Amazon, with expanding national and international markets for its wood. There is relatively little information, however, about geographic variation in tree growth and wood properties, and correlations among these traits. The first provenance trial was established with farming communities in the Peruvian Amazon. Seven provenances, sampled from regions near the equator, were tested in three planting zones located in one watershed. Variation and correlations were investigated in stem growth at 30 and 42 months, wood density (in the lower and upper parts of the stem) and mean heat content of stem wood at 32 months. Stem height varied significantly among provenances and planting zones, but zones accounted for much more variation than provenances. Stem wood traits did not vary significantly among provenances. Wood density was greater in the lower than in the upper stem. Wood density in the upper stem and the difference in density between the lower and upper stem varied significantly among planting zones: density in the upper stem was lowest, and the difference in density between the lower and upper stem was largest in the zone where trees grew most rapidly. Phenotypic correlations between stem growth and wood density differed in sign among planting zones, suggesting that selecting fastgrowing trees could indirectly reduce wood density in environments where trees grow slowly, and increase the difference in wood density between the lower and upper stem in environments where trees grow very rapidly. Correlations between stem growth and wood heat content were stable across zones, and indicated that larger trees tended to have wood with higher heat content. Stem-wood heat content varied with provenance latitude/ longitude in the sample region, but none of the other traits varied clinally. Results indicate that there is potential to select faster-growing provenances at an early age, but this could affect wood density in certain environments.

Keywords

  • provenance
  • environment
  • height
  • diameter
  • wood density & heat content
Open Access

Chromosome Numbers of Four Nigerian Species of Cola Schott. & Endlicher (Sterculiaceae).

Published Online: 19 Oct 2017
Page range: 42 - 44

Abstract

Abstract

This paper reports the results of chromosome countings in four wild Cola species (Cola lateritia, C. ballayi, C. verticillata and C. gigantea). Cytological investigation of these species gave a constant mitotic chromosome counts of 2n = 4x = 40 for the first time. The karyotypes were found to consist mostly of metacentric and submetacentric chromosomes. In addition to confirming the chromosome numbers and ploidy levels in these species, the results also reveals high symmetry and homogeneity of the karyotypes with those of the cultivated species (C. nitida and C. acuminata) already reported. The similarity in chromosome morphology between the cultivated and wild species indicate their common origin and suggests the possibility of using these wild species as bridges for gene transfer in Cola breeding programmes involving interspecific hybridization.

Keywords

  • Cola
  • wild species
  • chromosome counts
  • karyotype
Open Access

Obituary Professor Dr. WOLFGANG LANGNER

Published Online: 19 Oct 2017
Page range: 45 - 45

Abstract

Open Access

Short Note: Cleistogamy in Eucalyptus tereticornis Sm. and its Genetic Implications

Published Online: 19 Oct 2017
Page range: 46 - 47

Abstract

Abstract

In a provenance cum progeny trial comprising 13 provenances and 91 families of Eucalyptus tereticornis Sm. of Australian and Papua New Guinean (PNG) origin, laid out in India in 2002, cleistogamy was found in a family emanating from CSIRO seed lot no. 13418, (tree no. DS000141) Sirinumu Sogeri Plat, PNG. This trait appears to be under genetic control, and presumably results in obligate selfing. This may lead to inbreeding depression in this family.

Keywords

  • Eucalyptus tereticornis
  • cleistogamy
  • inbreeding depression
  • autogamy
  • self-pollination
Open Access

Soil Temperature and Precipitation Affect the Rooting Ability of Dormant Hardwood Cuttings of Populus

Published Online: 19 Oct 2017
Page range: 47 - 58

Abstract

Abstract

In addition to genetic control, responses to environmental stimuli affect the success of rooting. Our objectives were to: 1) assess the variation in rooting ability among 21 Populus clones grown under varying soil temperatures and amounts of precipitation and 2) identify combinations of soil temperature and precipitation that promote rooting. The clones belonged to five genomic groups ([P. trichocarpa Torr. & Gray x P. deltoides Bartr. ex Marsh] x P. deltoides ‘BC’; P. deltoides ‘D’; P. deltoides x P. maximowiczii A. Henry ‘DM’; P. deltoides x P. nigra L. ‘DN’; P. nigra x P. maximowiczii ‘NM’). Cuttings, 20 cm long, were planted in Iowa and Minnesota, USA, in randomized complete blocks at 1.2- x 2.4-m spacing across three planting dates during 2001 and 2002. Soil temperatures were converted to belowground growing degree days (GDD) (base temperature = 10°C) accumulated over 14 days. Genomic groups responded similarly for root dry weight, number of roots, total root length, and mean root length, that increased as belowground GDD increased. Belowground GDD and precipitation governed rooting throughout the 14-d growing period. A minimum of four days above 14°C, along with sufficiently dispersed precipitation (e.g. no more than 3 d without a precipitation event), were needed to sustain aboveaverage rooting. Therefore, we recommend using a base temperature of 14°C for future models estimating belowground GDD in northern temperate zones.

Keywords

  • hybrid poplar
  • growing degree days
  • adventitious rooting
  • Populus deltoides
  • P. nigra
  • P. maximowiczii
  • P. trichocarpa
Open Access

Polyploidy in Gymnosperms: Revisited

Published Online: 19 Oct 2017
Page range: 59 - 69

Abstract

Abstract

There are only a few natural polyploids in gymnosperms. These have been reported in Ephera spp. (Gnetales), and Juniperus chinensis ‘Pfitzeriana’ (2n = 4x = 44), Fitzroya cupressoides (2n = 4x = 44), and the only hexaploid conifer Sequoia sempervirens (2n = 6x = 66) (Coniferales). Sporadic polyploids and aneuploids occur at a very low frequency in nurseries in conifers, but most of them show growth abnormalities, remain dwarf, and may not reach maturity. One exception is an autotetraploid tree of Larix decidua (2n = 4x = 48) that has survived in a private estate in Denmark. Colchicine-induced polyploids (colchiploids) have been produced in a several genera of conifers, including, Pinus, Picea, and Larix. These colchiploids (Co) were hybridized to untreated diploids to produce C1 and C2 generations to investigate their chromosome behavior. The colchiploids showed a wide range of chromosome variability, ranging from diploids, triploids, and tetraploids, and many were mixoploids. The colchiploids also show growth retardation, remain dwarf, and their future potential applications in forestry remains uncertain. However, genetic variability in the colchiploids still offers prospects for isolating genetically stable new genotypes. Even though polyploidy is rare in extant conifers, is it possible that ancient polyploidy or paleopolyploidy, that is prevalent in angiosperms, has also played a role in the evolution of conifers. In this paper we shall review the current status of polyploidy in gymnosperms.

Keywords

  • polyploidy
  • gymnosperms
  • conifers
  • coast redwood
  • alerce
  • ‘Pfitzer’ juniper
  • pines
  • genetic equilibrium
  • diploidization
  • colchiploids
  • ancient polyploidy
Open Access

Reproductive Success of Pollen Derived From Selected and Non-Selected Sources and its Impact on the Performance of Crops in a Nematode-Resistant Japanese Black Pine Seed Orchard

Published Online: 19 Oct 2017
Page range: 69 - 76

Abstract

Abstract

The reproductive success of pollen derived from selected and non-selected sources and its impact on the performance of orchard crops were evaluated, using five pairs of microsatellite markers, in a Japanese black pine (Pinus thunbergii Parl.) clonal seed orchard consisting of 16 nematode-resistant clones. The paternity of each open-pollinated seed was determined by comparing the genotypes of seeds from six clones (24 trees) with genotypes of the 16 orchard clones and two trees (N1, N2) representing other genotypes that had been inadvertently included in the orchard. Out of 384 seeds examined, the paternity of 316 seeds (82.3%) was assigned to the clones within the seed orchard. On average, the male reproductive success of orchard clones varied from 0.0% to 10.5%, and was significantly related to the male-flowering fecundity of each clone. It was not related to the synchrony of flowering phenology between mates. The expected proportions of seeds produced by clonal trees as a result of pollination by orchard clones, and by contaminating pollen originating from internal and external sources were estimated at 86.8%, 3.3% and 9.9%, respectively. Nematode-resistant seedlings of Japanese black pine were produced from surviving 2-yr seedlings that had previously been inoculated with pinewood nematode (Bursaphelenchus xylophilus). Without pollen contamination, the survival rate of seedlings produced by mating between resistant clones is expected to be 62.4%. However, in this orchard the figure was reduced to 57.5%, due to pollen contamination from both internal and external sources.

Keywords

  • nematode-resistant
  • microsatellite
  • Pinus thunbergii
  • microsatellite
  • pollen contamination
  • reproductive success
  • seed orchard
Open Access

Seed Source Variation in Morphology, Germination and Seedling Growth of Jatropha curcas Linn. in Central India

Published Online: 19 Oct 2017
Page range: 76 - 80

Abstract

Abstract

The aim of the study was to determine source variation in Jatropha curcas seeds collected from ten locations in Central India. A significant seed source variation was observed in seed morphology (colour, size and weight), seed germination (viability, germination percent, germination energy, germination value) and seedling growth parameters (survival percentage, seedling height, collar diameter, leave/plant, and seedling biomass). The seed source of Chhindwara (M.P.) was found as the best source in comparison to others. The phenotypic and genotypic variance, their coefficient of variability and broad sense heritability also showed a sizeable variability. This offers a breeder ample scope to undertake screening and selection of seed sources for the desired traits. Further, high percentage of heritability coupled with moderate intensity of genetic gain, was observed for seed germination traits, which signifies that germination is under strong genetic control and good amount of heritable additive genetic component can be exploited for improvement of this species.

Keywords

  • Jatropha curcas
  • variation
  • seed source
  • variability
  • heritability
  • genetic gain
  • seed germination
  • germination energy
Open Access

Optimal Clone Number for Seed Orchards with Tested Clones

Published Online: 19 Oct 2017
Page range: 80 - 92

Abstract

Abstract

The optimal number of clones in seed orchards is discussed. A model is constructed to maximize a goodness criterion (“benefit”) for seed orchards. This criterion is a function of: 1) the number of tested genotypes available for selection and planted in seed orchard; 2) the contribution to pollination from: a) the ramet itself; b) the closest neighbors; c) the rest of the orchard and sources outside the orchard (contamination); 3) variation among genotypes for fertility; 4) frequency of selfing; 5) production of selfed genotypes; 6) gene diversity (= status number); 7) influence of contamination; 8) genetic variation among candidates; 9) correlation between selection criterion (e.g. height in progeny test) and value for forestry (e.g. production in forests from the orchard); and 10) the number of clones harvested. Numeric values of the entries are discussed, and values were chosen to be relevant for scenarios with Swedish conifers (focusing on Scots pine) and for loblolly pine. Benefit was maximized considering the number of clones. The optimum was 16 clones for the Swedish scenario, while less for the loblolly pine scenario. The optimum was rather broad, thus it is not essential to deploy the exact optimum, and an approximate optimum will do. A sensitivity analyses was performed to evaluate the importance of the likely uncertainty and variation in different entries. Quantification of the benefit of gene diversity is important. Other significant considerations are the genetic variance in the goal character and the ability to predict it, as well as the impact of selfing and the variation in reproductive success between clones. Twenty clones is suggested as a thumb rule for Swedish conifers.

Keywords

  • Gene diversity
  • selfing
  • pollination
  • genetic gain
  • clone number
  • seed orchard
Open Access

Genetic Gain and Diversity of Orchard Crops Under Alternative Management Options in a Clonal Seed Orchard of Pinus thunbergii

Published Online: 19 Oct 2017
Page range: 93 - 96

Abstract

Abstract

Genetic gain and diversity, expressed by status number, of seed crops from a clonal seed orchard of Pinus thunbergii were estimated considering selection, fertility variation and pollen contamination, and compared for different management alternatives (selective harvest, genetic thinning and combination of both options). Management variables included the proportion of clones left after selective harvest and/or genetic thinning. The impact on genetic gain and diversity of seed crops was quantified as a function of the quantity and quality of gene flow from outside the seed orchard. Genetic gain varied with the proportion of selected or thinned clones. Genetic thinning by means of truncation selection of clones resulted in a large decrease in status number, which was accompanied by greater genetic gain than achieved by selective harvest alone. As expected, gene flow from outside the seed orchard greatly increased status number of the seed crop at higher rates of pollen contamination under all management options. The formulae and results of the present study could be used for identifying favorable selection intensity and alternatives for orchard management.

Keywords

  • genetic gain
  • gene diversity
  • rouging
  • selective harvest
  • Japanese black pine
Open Access

Genetic Variation and Realized Genetic Gain From Black Pine Tree Improvement

Published Online: 19 Oct 2017
Page range: 96 - 104

Abstract

Summary

In 1978 a 10 ha clonal seed orchard of black pine (Pinus nigra Arnold) was established in the area of Koumani in the western part of Peleponnesos, Greece. The orchard comprises 52 clones derived from intensively selected plus trees in the natural forest of black pine of Peloponnesos. In 1991 three open pollinated progeny tests were established in Peloponnesos, proximal to the villages of Raches, Vlachokerasia and Vamvakou. Seedlings from 52 families including a commercial check (CC) were planted in each one of the three locations. Assessments were made when the trees were 4, 7 and 9 years respectively, with the following results. The variation among families for growth characteristics were highly significant in all locations examined. In the combined analyses of variance over the three locations, significant differences among families were also detected, while the family x location interaction effect was not significant. This indicates that the seed produced from the seed orchard can be freely used over the environments of the three experimental plantings, which are representative of the broad area of Peloponnesos. Narrow sense heritability estimates on individual tree basis (h2) were variable depending on the characteristic, age of assessment and the location of the experimental plantings. The estimates of h2 in Vlachokerasia for height (HT) were 0.21, 0.40 and 0.43 at the ages of 4, 7 and 9 years respectively. In Raches the corresponding h2 values for HT were nearly the same in all ages (0.29, 0.28 and 0.31 at 4, 7 and 9 years respectively) and stable but little higher (0.31, 0.28 and 0.31) at the Vamvakou experimental planting. The heritability values for HT estimated over the three location, were relatively low (0.25, 0.23 and 0.19) at the ages 4, 7 and 9 years respectively. Realized genetic gains were calculated for growth characteristics at the age of 9 years, by comparing the performance of the improved (selected) materials to unimproved materials (CC). For the first stage of selection (selection made in natural stands) gain of 6.0% for HT, 8.0% for diameter breast height (DBH) and 24% for volume were estimated. When 20% of the clones, with the lower breeding values are removed from the seed orchard (genetic thinning), an additional gain of 2% for HT, 3% for DBH and 8% for volume over the unrogued seed orchard is resulted. Thus, the total genetic gain from the genetically tested, first generation seed orchard of black pine at Koumani is estimated as 8% for HT, 11% for DBH and 32% for volume. These results indicate that improvement of black pine by selection, establishment of seed orchard and progeny testing the clones, is a very promising profitable operation.

Keywords

  • Pinus nigra
  • Variance
  • covariance
  • heritability
  • correlation
  • rogued seed orchard
  • genetic test
  • genetic base
  • realized gain
Open Access

Fertility Variation and Genetic Diversity in a Clonal Seed Orchard of Cryptomeria japonica

Published Online: 19 Oct 2017
Page range: 104 - 107

Abstract

Abstract

Clonal differences in fertility (expressed as the number of female and male strobili) were determined for three consecutive years (2002-2004) in a clonal seed orchard of sugi (Cryptomeria japonica D. Don) in Korea. Fertility varied among clones and among years producing three-year averages of 196 and 652 for female and male strobili per ramet, respectively. Correlation between female and male strobilus production was positive over the three years and statistically significant in 2003, a good flowering year. Based on the observed fertility variation, the status numbers (Ns, measure of genetic diversity) were calculated and varied from 25.6 to 31.7 among the three studied years. On average (pooled), relative status number was 86% of the census number (N). Variation in female fertility was higher than that in male fertility, and this variation was reflected on female and male parents’ status numbers. Pooled Ns estimated from the three years was higher than that for any single year, implying that genetic diversity would increase when seeds collected from different years are pooled.

Keywords

  • fertility variation
  • sibling coefficient
  • status number
  • effective number
  • flowering
  • sugi
Open Access

Resistance of Transgenic Hybrid Triploids in Populus tomentosa Carr. Against 3 Species of Lepidopterans Following Two Winter Dormancies Conferred by High Level Expression of Cowpea Trypsin Inhibitor Gene

Published Online: 19 Oct 2017
Page range: 108 - 116

Abstract

Abstract

Hybrid triploid poplars [(P. tomentosa x P. bolleana) x P. tomentosa] genetically engineered with cowpea trypsin inhibitor (CpTI) gene have been out-planted in field for two years. They were used to detect their efficacy against 3 species of poplar defoliators: forest tent capterpillar, Malacosoma disstria Hübner, gypsy moth, Lymantria dispar Linnaeus and willow moth, Stilpnotia candida Staudinger by using detached leaves and for the purpose of identifying the CpTI gene at the molecular level. Foliage of transgenic poplars elicited an increase in larval mortality rate and a decrease in foliage consumption, wet weight gains, faeces excretion, deposited pupae number and pupae weight, thus indicating its effectiveness in affecting the growth, development and fecundity of larvae rather than only directly killing them. PCR and Southern blotting analyses confirmed the stable incorporation of CpTI gene while proteinase inhibitory assays disclosed its high level expression in the two-field-season of transgenic trees. Efficacious insect resistance and higher content of CpTI in foliage were found in transgenic clone TG04, TG07, TG08 and TG71, demonstrating a correspondence between the insect resistance level and the CpTI content in the foliage of transgenic poplar.

Keywords

  • Populus tomentosa Carr.
  • CpTI gene
  • transgenic poplar
  • Lepidoptera
  • insect resistance
  • proteinase inhibitory assay
  • PCR
  • Southern blotting
Open Access

Population Genetic Survey of Populus cathayana Originating From Southeastern Qinghai-Tibetan Plateau of China Based on SSR Markers

Published Online: 19 Oct 2017
Page range: 116 - 122

Abstract

Abstract

In this study, the genetic diversity of Populus cathayana Rehd was investigated using microsatellite markers. In a total of 150 individuals collected from six natural populations in the southeastern part of the Qinghai-Tibetan Plateau in China, a high level of microsatellite polymorphism was detected. At the seven investigated microsatellite loci, the number of alleles per locus ranged from 5 to 16, with a mean of 11.3, the observed heterozygosities across populations ranged from 0.408 to 0.986, with a mean of 0.792, and the expected heterozygosities across populations ranged from 0.511 to 0.891, with a mean of 0.802. The proportion of genetic differentiation among populations accounted for 37.3% of the whole genetic diversity. The presence of such a high level of genetic diversity could be attributed to the features of the species and the habitats where the sampled populations occur: The southeastern part of the Qinghai-Tibetan Plateau is regarded as the natural distribution and variation center of the genus Populus in China. Variation in environmental conditions and selection pressures in different populations, and topographic dispersal barriers could be factors associated with the high level of genetic differentiation found among populations. The populations possessed significant heterozygosity excesses, which may be due to extensive population mixing at the local scale. The cluster analysis showed that the populations are not strictly grouped according to their geographic distances but the habitat characteristics also influence the divergence pattern. In addition, we suggest that population SHY should be regarded as an ecologically divergent species of P. cathayana.

Keywords

  • Genetic differentiation
  • Genetic diversity
  • Heterozygosity excess
  • Microsatellites
  • Populus cathayana
Open Access

Differentiating Groups of Abies Species With a Simple Molecular Marker

Published Online: 19 Oct 2017
Page range: 123 - 126

Abstract

Abstract

The unambiguous identification of closely related species is useful for many practical purposes in forest tree species. For example, international laws require timber identification and the control of the origin of forest reproductive material. In this paper, we present a mitochondrial DNA marker which can be used to differentiate among groups of fir species (Abies spp.). Eight Mediterranean and one North American fir species (used as reference) were analysed at the fourth intron of the NAD subunit 5 gene. A total of six different haplotypes was identified, one in the American Abies concolor, the other five in Mediterranean species. Two different haplotypes were found each in the widespread A. alba and in A. cephalonica, one haplotype being shared among the two species. A single species specific haplotype was found in the near-eastern A. cilicica. The two southwestern species A. pinsapo and A. numidica shared one haplotype. The fifth haplotype was shared by all remaining eastern Mediterranean firs, A. cephalonica, A. bornmuelleriana, A. equi-troiani, and A. nordmanniana. Differences in haplotype sequences were mainly due to large insertions/deletions. Agarose gel electrophoresis thus provides a fast, cheap and reliable diagnosis method for species or species group identification.

Keywords

  • Organelle DNA polymorphism
  • mitochondrial DNA
  • nad5-4
  • species differentiation
  • Abies (spec.).
Open Access

Evolution of Genome Size in Conifers

Published Online: 19 Oct 2017
Page range: 126 - 137

Abstract

Abstract

Conifers are the most widely distributed group of gymnosperms in the world. They have large genome size (1C-value) compared with most animal and plant species. The genome size ranges from ~6,500 Mb to ~37,000 Mb in conifers. How and why conifers have evolved such large genomes is not understood. The conifer genome contains ~75% highly repetitive DNA. Most of the repetitive DNA is composed of non-coding DNA, including ubiquitous transposable elements. Conifers have relatively larger rDNA repeat units, larger gene families generated by gene duplications, larger nuclear volume, and perhaps larger genes, as compared to angiosperm plants. These genomic components may partially account for the large genome size, as well as variation in genome size, in conifers. One of the major mechanisms for genome size expansion and evolution of species is polyploidy, which is widespread in angiosperms, but it is rare in conifers. There are only a few natural polyploids in one family of conifers, Cupressaceae. Other conifers, including well-studied pines, are nearly all diploids. Whether ancient polyploidy has played a role in the evolution of genome size in conifers still remains an open question. The mechanisms that account for the variation and evolution of genome size in conifers are addressed in this review.

Keywords

  • genome size
  • conifers
  • pines
  • polyploidy
  • paleopolyploidy
  • duplicate genes
  • repetitive DNA
  • retrotransposons
  • introns
  • genome evolution
Open Access

Lodgepole Pine and White Spruce Germination: Effects of Stratification and Simulated Aging

Published Online: 19 Oct 2017
Page range: 138 - 144

Abstract

Abstract

The effects of seed pre-treatment (stratification/prechilling) and simulated aging on germination parameters (germination capacity, speed and value and peak value) were evaluated for several seedlots originating from seed orchard clones of lodgepole pine (Pinus contorta var. latifolia DOUGL. ex LOUD.) and white spruce (Picea glauca (MOENCH) VOSS). Region of origin and stratification had little effect on white spruce, while stratification enhanced germination speed and completeness of lodgepole pine. Broad-sense heritability for germination parameters ranged from 70 to 97% (unstratified) and from 81 to 96% (stratified) for pine, and from 95 to 97% (unstratified) and from 93 to 97% (stratified) for spruce. Simulated aging (short-term storage at high temperature and relative humidity, approximating the physiological effects of long-term storage) resulted in rapid deterioration of white spruce, with very little germination after six days of aging. Lodgepole pine germination increased during the first several aging treatments relative to the control, but germination capacity decreased following twelve days of aging, and was very low after 18 days. White spruce was nondormant and responded primarily to moisture conditions, whereas pine was strongly influenced by maternal effects. These results can be incorporated for more efficacious nursery production practices for commercial reforestation seedling production as well as ex-situ gene conservation strategies.

Keywords

  • germination
  • Pinus contorta
  • Picea glauca
  • simulated aging
  • dormancy
  • stratification
  • broad-sense heritability
Open Access

Identification of Molecular Markers for Selected Wood Properties of Norway Spruce Picea abies L. (Karst.) II. Extractives Content

Published Online: 19 Oct 2017
Page range: 145 - 152

Abstract

Abstract

We describe the development of a SCAR-marker linked to low extractives content of Norway Spruce (Picea abies L [Karst.]) derived from AFLPs. In these analyses 57 different primer enzyme combinations were used in a bulked segregant analysis approach comparing individuals with high and low extractives content. A total of 14 polymorphic AFLP markers were detected between the pools. Five markers were selected for further analyses to verify their linkage to extractives content based on individuals used for pool constitution. One AFLP marker, found to be significant linked to low extractives content was converted into a SCAR marker for further validation. For this marker, a monomorphic band was obtained by using sets of nested primers or restriction site specific primers (RSS) which include the AFLP-restriction recognition site. The separation of the marker from unlinked size homologous marker-alleles was realized by a SSCP-approach. Validation of the marker on different full-sib families confirmed the usability to separate the classes for low and high extractives content of Picea abies.

Keywords

  • Bulked segregant analysis
  • AFLP
  • Molecular markers
  • Marker assisted selection (MAS)
  • Wood properties
  • Marker conversion
  • SCAR marker
Open Access

Impact of Clones in a Clonal Seed Orchard on the Variation of Seed Traits, Germination and Seedling Growth in Santalum album L.

Published Online: 19 Oct 2017
Page range: 153 - 160

Abstract

Summary

Clonal Seed Orchard (CSO) of Santalum album L. at Nallal, India consisting of 25 clones originated from different agro-climatic conditions of four southern states (Karnataka, Tamil Nadu, Kerala and Andhra Pradesh) was source of seeds for variability studies. There was vast variation in seed size, weight, germination, vigour and seedling growth of different clones over the years. Seed length, width and weight were positively correlated to each other but seed size had no effect on germination, Germination Value (GV), days taken for germination and early seedling growth. Effects of Clones were dominant and accounted for variation in germination rather than seed size. There was no consistency in the parameters studied in the two years. The impact of these genetic differences in handling of seed lots during bulking, grading and storage for mass propagation of nursery planting stock of S. album is also discussed.

Keywords

  • CSO
  • Santalum album
  • seed variability
  • clone
  • correlation and mass propagation
Open Access

Genetic Variation of Physical and Chemical Wood Properties of Eucalyptus globulus

Published Online: 19 Oct 2017
Page range: 160 - 166

Abstract

Abstract

This study considered the degree of genetic variation for diameter (DBH), basic density (BD), predicted pulp yield (PPY), fibre length (FL), microfibril angle (MFA) and cellulose content (CC) amongst eight subraces of Eucalyptus globulus growing in a field trial in NW Tasmania. There were significant subrace effects for BD, FL and CC. This variation affected the relative profitability of the subraces for pulp production. On average, the most profitable subraces (on NPV/ha over the base population mean) were Strzelecki Ranges ($862.04), Western Otways ($657.80) and Strzelecki Foothills ($576.81). The genetic control (heritability) of variation in DBH, FL and MFA was moderate (0.15 < h2< 0.27), while control for BD, PPY and CC was high (h2> 0.40). Genetic correlations between growth and wood properties were not statistically significant, except for DBHMFA (-0.86). Most genetic correlations amongst wood properties were outside the parametric space (< -1 or >1), but there were significant correlations between BDMFA (-0.70) and PPY-CC (0.82). The empirical response to selection on an index based on a pulp wood objective (which included volume and basic density) resulted in a gain of 4.3% for DBH, 7.9% for BD and marginal changes for all other traits, with a net impact in profit of $1,270/ha. However, future profit calculations will need to consider the effect of FL, MFA and CC on the economics of wood processing to fully evaluate the economic impact of breeding.

Keywords

  • BLUP
  • racial variation
  • heritability
  • genetic correlations
  • breeding
  • profit
Open Access

Early Assessment of First Year Height Data from Five Acacia mearnsii (black wattle) Sub-populations in South Africa using REML/BLUP

Published Online: 19 Oct 2017
Page range: 166 - 174

Abstract

Abstract

Recent research has shown, Acacia mearnsii (black wattle) to be a source of high quality pulp. This led to a change in the emphasis in the breeding programme at the Institute for Commercial Forestry Research, from improving bark yield and quality, to improving timber yield and quality while maintaining an acceptable bark quality. A Multiple Population Breeding Strategy was implemented to cater for these changes. Five sub-populations were established across different sites in KwaZulu- Natal and were determined by origin of seed. Each sub-population was established as a progeny trial with a seedling seed orchard adjacent to it. The management of the seed orchards will be determined according to the performance of the families within the progeny trials. This paper reports on the first year height measurements taken from the five sub-populations. The intention of this paper is not to base any selections from this data but rather to establish a set of analyses using REML/BLUP which will be used for future data analysis. This will also allow for future assessment of age-age correlations for the various traits being assessed and provide an appropriate decision-making tool, for selecting individuals for future generations.

Keywords

  • Acacia mearnsii
  • black wattle
  • BLUP
  • height measurements
  • REML
  • sub-populations
Open Access

Variation in Eucalyptus globulus LABILL. and E. nitens DEAN and MAIDEN in Susceptibility of Adult Foliage to Disease Caused by Mycosphaerella cryptica (COOKE) HANSF

Published Online: 19 Oct 2017
Page range: 174 - 184

Abstract

Summary

Severity of disease caused by Mycosphaerella cryptica (COOK) HANSF. was assessed on the adult foliage of Eucalyptus globulus LABILL. in two provenance trials (encompassing all four subspecies) and a progeny trial of E. globulus ssp. globulus LABILL. located in Victoria, Australia. Disease was relatively low in all trials (most trees with less than 15% crown severity), except for two provenances at one trial, Judbury (E. globulus ssp. globulus) and Mansfield (E. globulus ssp. bicostata), that had mean crown severities of approximately 25% and 40%, respectively. Eucalyptus globulus ssp. bicostata (MAIDEN et al.) KIRKPATR. was significantly (P < 0.01) more susceptible than E. globulus ssp. globulus, E. globulus ssp. pseudoglobulus (NAUDIN ex MAIDEN) KIRKPATR. and E. globulus ssp. maidenii (F. MUELL.) KIRKPATR., with subspecies maidenii significantly less diseased than all other subspecies. There was significant variation between provenances within subspecies globulus (P < 0.01) but not within subspecies pseudoglobulus, maidenii or bicostata. Subspecies globulus also showed significant (P < 0.01) variation between families. There was a moderate to high genetic correlation between disease of the adult foliage and disease of the juvenile foliage (caused by both M. cryptica and M. nubilosa (COOKE) HANSF.) assessed several years earlier, both at the provenance (rG = 0.67) and family (rG = 0.33) levels. Narrow sense heritability of disease of the adult foliage (M. cryptica) was low (h2 = 0.17), compared to that of the juvenile foliage (h2 = 0.35) and juvenile defoliation (h2 = 0.45) assessed previously. Selection for overall disease resistance (both adult- and juvenile-phase foliage) can be carried out more quickly and accurately at the juvenile stage when trees are 2-3 years old, potentially reducing the time required for resistant trees to be selected and deployed in the field. Mycosphaerella leaf disease on adult E. nitens (DEAN and MAIDEN) MAIDEN was also assessed in two provenance trials; however, there was very little disease observed and no significant differences were found between provenances.

Keywords

  • provenances
  • families
  • Mycosphaerella nubilosa
  • adult-juvenile leaf phase correlations
  • genetic parameters
Open Access

Genetic Gain and Gene Diversity Following Thinning in a Half-Sib Plantation

Published Online: 19 Oct 2017
Page range: 185 - 189

Abstract

Abstract

Status number, gene diversity, inbreeding coefficient and genetic gain were calculated following phenotypic rogueing of different intensities in a half-sib progeny plantation of Scots pine (Pinus sylvestris L.). Across most selection intensities the status number, gene diversity and genetic gain remained favorably high while the inbreeding coefficient was remarkably stable. It is suggested that phenotypic selection in half-sib progeny tests or plantations with unknown pedigrees, can be used to manage seed collection areas or as a component in low-input breeding without a fast build up of coancestry or inbreeding, provided the initial number of progenies of unrelated parents is sufficiently high and that a high number of these families are retained with a few individuals per family.

Keywords

  • half-sib plantation
  • status number
  • inbreeding
  • gene diversity
  • genetic gain
  • low-input breeding
  • seed collection area
  • Scots pine
Open Access

Cone Yield Characterization of a Stone Pine (Pinus pinea L.) Clone Bank

Published Online: 19 Oct 2017
Page range: 189 - 197

Abstract

Abstract

In spite of the use of the edible kernels of Stone pine (Pinus pinea L.) gathered from Mediterranean pine forests, the species remains a genuine forest tree that has never been domesticated as an orchard crop. In the last decades, some efforts have been made to select valuable genotypes for exploring the possibilities of Stone pine as an orchard crop. The present paper characterizes the cone yield of a grafted clone bank in order to elucidate the relevance of genetic and environment factors for seed-yield quantity and quality and for sequential transition rates of the development from pollinated conelets to ripe cones. Individual tree size and cone yield were separated in their genetic and environmental components, in order to estimate phenotypic, genetic and environmental correlations. A statistical model for logtransformed individual cone yield was adjusted, ranking the tested genotypes by their estimated clonal value after adjustment for tree size covariables. The degree of genetic determination for adjusted cone yield was estimated in 15%, the expected genetic gain by selection of the top 10% of tested genotypes would be 12%. Genetic correlation between genetic values for cone yield and cone and seed size were weak but significantly positive (r = 0.27 and 0.17), hence the lack of trade-offs between crop quantity and quality will allow a combined selection.

Keywords

  • Mediterranean stone pine
  • pine nuts
  • cone survival
  • degree of genetic determination
Open Access

Conservation Approaches For Autochthonous Woody Plants in Flanders

Published Online: 19 Oct 2017
Page range: 197 - 206

Abstract

Abstract

Autochthonous genetic resources of woody plants have become seriously endangered in Flanders because of the particularly low and fragmented forest cover, centuries of intensive forest use in this highly populated area and the wide-spread usage of non-autochthonous planting stock in reforestation and landscape plantings. Intraspecific hybridisation between remnant autochthonous populations and foreign genotypes, which can show inadequate adaptation, may influence the autochthonous genetic constitution and fitness in the long term. As several European countries face similar problems, the objective of this paper is to outline the conservation measures that are taken in Flanders. The central aim is to maintain and create the necessary conditions for natural and flexible evolution of the genetic diversity of autochthonous trees and shrubs. An inventory survey to locate remaining autochthonous populations was started in 1997 and will be completed in 2006. Relict populations are preserved in clonal banks. Central issues are the production of autochthonous planting stock through in situ seed collection, the approval of seed sources and stands and the creation of seed orchards. Conservation actions are discussed.

Keywords

  • in situ conservation
  • ex situ conservation
  • autochthonous woody plants
  • seed orchards
  • forest reproductive material
  • clonal banks
  • regions of provenance
  • seed collection
  • natural populations
  • inventory
Open Access

Classification of Genus Acanthopanax in Korea and Genetic Diversity Using Allozymes

Published Online: 19 Oct 2017
Page range: 206 - 210

Abstract

Abstract

Genus Acanthopanax is a long-lived woody species that is primarily distributed throughout Asia. Many species of this genus are regarded as medically and ecologically important. We evaluated a representative sample of the nine taxa with allozymes to estimate genetic relationships within the genus. As some Korean populations were isolated and patchily distributed, they exhibited a low level of genetic diversity. The narrow geographic ranges, artificial distribution of habitats, and small population sizes are proposed as factors contributing to low genetic diversity. Acanthopanax seoulense was similar to A. sessiliflorus, while a cluster of the A. rufinerve population is distant from any other species. A. senticosus is closely related to A. seoulense and A. sessiliflorus, whereas other species (A. koreanum) are more distinct from the Korean populations. Korean species are clustered together and clearly differentiated from the Chinese and Russian Acanthopanax taxa, genus Acanthopanax

Keywords

  • Allozyme
  • Genetic relationships
  • Genus Acanthopanax
Open Access

Chromosome Microdissection, Cloning and Painting of the Chromosome 1 in Poplar (Populus tremula)

Published Online: 19 Oct 2017
Page range: 211 - 217

Abstract

Abstract

The chromosome microdissection, cloning and painting technology has evolved into an efficient tool for genomic research. Application of these techniques has rarely been applied for forest plants, largely due to the difficulty of chromosome preparation. The present study was performed to establish a method for single chromosome microdissection, cloning and painting in forest plants using poplar (Populus tremula) as a model. An individual chromosome 1 was microdissected from the metaphase spreads of poplar root-tip cells with fine glass needle controlled by a micromanipulator. The dissected chromosome was amplified in vitro by the Sau3A linker adaptor mediated PCR (LA-PCR) technique, by which 200bp to 3,000bp smear DNA fragments were obtained. Then, the second round PCR products from the single chromosome 1 were cloned into T-easy vectors to generate a DNA library of the chromosome 1. Approximately 3 x 105 recombinant clones were obtained. The second round PCR products were used as a complex probe mixture for fluorescent in situ hybridization (FISH) on the metaphase spreads of poplar. Hybridization signals were observed, mainly, along the entire chromosome 1, at the same time, signals were also present on telomeric and centromeric regions of other chromosomes. Therefore, this research suggests that chromosome microdissection, cloning and painting of the single small chromosome in forest plants are feasible.

Keywords

  • Chromosome painting
  • Fluorescent in situ hybridization (FISH)
  • Microdissection
  • Populus tremula
Open Access

Low Cost Improvement of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) By Application of The Breeding Seed Orchard Approach in Denmark

Published Online: 19 Oct 2017
Page range: 218 - 227

Abstract

Abstract

An evaluation of a seedling seed orchard in Denmark of Coastal Douglas-fir showed variation between open pollinated families in their susceptibility to windthrow, height and diameter growth, stem straightness, number of forks at age 10 and bud burst at age 9. Individual narrow-sense heritability was 0.63 for bud burst, 0.40 for height and diameter, respectively, 0.48 for stem straightness, 0.20 for number of forks and 0.17 for windthrow susceptibility. Fast growing families were characterised by late bud burst, and poorer stem straightness. The approach of using seedling seed orchards in Denmark is discussed in relation to genetic gains, genetic diversity and risk of inbreeding. Predicted gains concerning a reduction of windthrow susceptibility were poor due to low genetic variability. In multi-trait selection scenarios aiming to improve growth, stem straightness and reducing windthrow susceptibility, the approach of using seedling seed orchards demonstrated that it might be possible to obtain gains in height above 5% combined with significant improvements of stem straightness while retaining an effective population size above 50.

Keywords

  • heritability estimates
  • genetic correlation
  • growth
  • stem straightness
  • forking
  • windthrow
  • bud burst
  • genetic diversity
  • genetic gain
Open Access

Heritability and Correlations for Biomass Production and Allocation in White Spruce Seedlings

Published Online: 19 Oct 2017
Page range: 228 - 235

Abstract

Abstract

Tree growth is a multidimensional trait and families vary for components of growth such as height, diameter, foliage and roots. Therefore, variation in tree growth is better studied by analysing biomass production and allocation than simple traits. In addition, biomass is better linked to products such as pulp and wood energy than simple traits. We analysed biomass of 3-year old open-pollinated greenhouse seedlings of white spruce to determine (1) heritability for biomass production and allocation to shoot and root components, (2) correlations between biomass traits, and biomass traits with primary traits, and (3) correlation between biomass production in the greenhouse and height growth for the same families in the field. The study had a randomised complete block design with single-tree plots, 30 blocks and 58 open-pollinated families. Individual-tree heritability (hi2 ) and family mean heritability (hf2 ) ranged from 0.200 to 0.333 and 0.374 to 0.516 for green weight, respectively. Likewise, hi2 and hi2 ranged from 0.186 to 0.359 and 0.352 to 0.536 for dry weight, respectively. Genetic correlation (ra) between green and dry weight ranged from 0.943 to 1.015, while ra between shoot and root dry weight ranged from 0.947 to 0.955. In contrast, ra between biomass traits and field height ranged from -0.403 to -0.124. Thus, we conclude (1) variation in biomass production and allocation exhibited low genetic basis, (2) testing and selection for green or dry weight should lead to similar genotypes, (3) biomass allocation may not be easily altered by selection and breeding, and (4) indirect early selection based on seedling biomass

Keywords

  • Dry weight
  • early selection
  • genetic variation
  • heritability
  • Picea glauca
Open Access

Genetic Variation of Korean Pine (Pinus koraiensis Sieb. et Zucc.) at Allozyme and RAPD Markers in Korea, China and Russia

Published Online: 19 Oct 2017
Page range: 235 - 246

Abstract

Abstract

We studied and compared genetic variation of Korean pine (Pinus koraiensis Sieb. et Zucc.) from 12 natural populations in Korea, China, and Russian Far East using allozymes and random amplified polymorphic DNAs (RAPDs). Eighteen polymorphic allozyme loci and 38 polymorphic RAPD fragments were analyzed. The level of allozyme diversity (A = 1.95, P95 = 46.8%, Ho = 0.158, He = 0.169) and the degree of genetic differentiation (FST = 0.069) were comparable to those of other pines with similar life histories and ecological traits. Allozyme (He) as well as RAPD (Shannon’s index) variation decreased from south (Korea) to north (Russia), providing an evidence for the hypothesis of Korean pine’s northward migration. Differentiations among three different regions (Korea, China, and Russia) as well as among populations within regions were small. Substantial gene flow (Nm = 3.4) may be a partial explanation to this result. Clustering algorithms using various genetic distance measures showed some decisive geographic patterns at allozyme and RAPD level: the geographically close populations tended to be clustered together. On the other hand, two Chinese populations, Xobukho and Wangging, were grouped with the Russian populations rather than with the other Chinese populations. The Xiaoxing’anling and other mountains extended from north to south seemed to function as a barrier against gene flow between the Xobukho and Wangging (located east of the mountains) and the other Chinese P. koraiensis populations (located west of the mountains). The genetic diversities and differentiation estimated from RAPD data in Korean pine were congruent with those of allozymes.

Keywords

  • Pinus koraiensis
  • allozymes
  • RAPDs
  • genetic variation
  • Korea
  • China
  • Russian Far East
Open Access

Variation in Reproductive Phenology in a Pinus radiata D. Don Seed Orchard in Northern Spain

Published Online: 19 Oct 2017
Page range: 246 - 256

Abstract

Summary

Reproductive phenology was studied in a Pinus radiata seed orchard, located in northern Spain. Timing of flowering was determined on the basis of data recorded by visual observations made in 2000, 2001 and 2002. The genetic and environmental factors affecting female and male phenology, as well as reproductive synchronization, were studied. The dates of beginning of the receptive phase and pollen shedding varied greatly from year to year but the variation on the sum of degree-days was low. In general, the flowering periods of the different clones overlapped. The clonal differences in the phenology of receptivity and pollen shedding were in most cases statistically significant. The time needed to reach flowering stages was under strong genetic control. Genetic control was stronger for the female than the male flowering process. However, correlations between years were stronger for male than for female flowering phenology. The male flowering clones that best synchronized with the females appeared to be those that started flowering earlier. The phenological overlap index varied greatly among clones, whether male or female, and also among years.

Keywords

  • flowering receptivity
  • pollen shedding
  • reproductive synchronization
  • flowering phenograms
  • cumulative growing degree-days
  • phenological overlap index
  • SYNCHRO.SAS programme
  • clonal repeatibility
  • progeny test
  • genetic variation
  • genetic parameters
  • quantitative traits
Open Access

Population Genetic Studies of Tree Populations in the Neotropics

Published Online: 19 Oct 2017
Page range: 257 - 257

Abstract

Open Access

Regional and Population-scale Influences on Genetic Diversity Partitioning within Costa Rican Populations of the Pioneer Tree Vochysia ferruginea Mart

Published Online: 19 Oct 2017
Page range: 258 - 264

Abstract

Abstract

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 (FST = 0.15) and within-population diversity high, though variable (Hs = 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.

Keywords

  • AFLP
  • chloroplast DNA
  • genetic diversity
  • gene flow
  • succession
Open Access

Sampling Tissue for DNA Analysis of Trees: Trunk Cambium as an Alternative to Canopy Leaves

Published Online: 19 Oct 2017
Page range: 265 - 269

Abstract

Abstract

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.

Keywords

  • DNA extraction
  • trees
  • tropical
  • cambium
  • AFLP
  • sample preservation
Open Access

Chloroplast DNA Variation of Carapa guianensis in the Amazon basin

Published Online: 19 Oct 2017
Page range: 270 - 274

Abstract

Abstract

Carapa guianensis is a widespread Neotropical tree species that produces a seed adapted for water dispersal. We conducted a pilot study of chloroplast DNA (cpDNA) variation in order to investigate the consequences of hydrochory on genetic diversity and geographic population structure in the lower Amazon basin. A survey of cpDNA haplotype variation reveals a strong regional structure, which suggests limited gene flow by seeds. Within site variation was detected only in one floodplain forest (varzea), suggesting that seed dispersal by water in these forests has the potential to mix maternal lineages. Several phylogeographic hypotheses are discussed with respect to these data.

Keywords

  • cpDNA
  • Amazonia
  • Amazon River
  • Carapa guianensis
  • seed dispersal
Open Access

Gene flow and mating system of the tropical tree Sextonia rubra

Published Online: 19 Oct 2017
Page range: 275 - 280

Abstract

Abstract

In this paper we report a study of the mating system and gene flow of Sextonia rubra, a hermaphroditic, insect pollinated tropical tree species with a geographic distribution in the Guyana Plateau and the Amazon. Using five microsatellites we analysed 428 seeds of 27 open pollinated families at the experimental site “Paracou” in French Guiana. We observed, compared to other tropical tree species, a high level of genetic diversity. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGener approach. The estimated multilocus outcrossing rate, tm, was 0.992 indicating nearly complete outcrossing. A significant level of biparental inbreeding and a small proportion of full-sibs were estimated for the 27 seed arrays. The differentiation of allelic frequencies among the pollen pools was ΦFT = 0.061. We estimated mean pollen dispersal distances between 65 m and 89 m according to the dispersal models used. The joint estimation of pollen dispersal and density of reproductive trees gave an effective density estimate of 2.1-2.2 trees/ha.

Keywords

  • Genetic diversity
  • gene flow
  • heterozygosity
  • microsatellites
  • mixed mating
  • tropical tree
  • twogener
Open Access

Contrasting Quantitative Traits and Neutral Genetic Markers for Genetic Resource Assessment of Mesoamerican Cedrela Odorata

Published Online: 19 Oct 2017
Page range: 281 - 292

Abstract

Abstract

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 (FST = 0.67 for the sampled Mesoamerican range) than for quantitative traits (QST = 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.

  • Key words: Cedrela odorata
  • FST
  • genetic differentiation
  • geographic variation
  • heritability
  • natural selection
  • quantitative traits
  • RAPD
  • QST
Open Access

Chloroplast and Total Genomic Diversity in the Endemic Costa Rican Tree Lonchocarpus costaricensis (J. D. Smith) Pittier (Papilionaceae)

Published Online: 19 Oct 2017
Page range: 293 - 300

Abstract

Abstract

In Mesoamerica, tropical dry forest is a highly threatened habitat, and species endemic to this environment are under extreme pressure. The tree species, Lonchocarpus costaricensis is endemic to the dry northwest of Costa Rica and southwest Nicaragua. It is a locally important species but, as land has been cleared for agriculture, populations have experienced considerable reduction and fragmentation. To assess current levels and distribution of genetic diversity in the species, a combination of chloroplast-specific (cpDNA) and whole genome DNA markers (amplified fragment length polymorphism, AFLP) were used to fingerprint 121 individual trees in 6 populations. Two cpDNA haplotypes were identified, distributed among populations such that populations at the extremes of the distribution showed lowest diversity. A large number (487) of AFLP markers were obtained and indicated that diversity levels were highest in the two coastal populations (Cobano, Matapalo, H = 0.23, 0.28 respectively). Population differentiation was low overall, FST = 0.12, although Matapalo was strongly differentiated from all other populations (FST = 0.16-0.22), apart from Cobano (FST = 0.11). Spatial genetic structure was present in both datasets at different scales: cpDNA was structured at a range-wide distribution scale, whilst AFLP data revealed genetic neighbourhoods on a population scale. In general, the habitat degradation of recent times appears not to have yet impacted diversity levels in mature populations. However, although no data on seed or saplings were collected, it seems likely that reproductive mechanisms in the species will have been affected by land clearance. It is recommended that efforts should be made to conserve the extant genetic resource base and further research undertaken to investigate diversity levels in the progeny generation.

Keywords

  • AFLPs
  • chloroplast DNA
  • genetic differentiation
  • genetic diversity
  • Lonchocarpus costaricensis
  • spatial genetic structuring

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