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Revista
eISSN
2509-8934
Publicado por primera vez
22 Feb 2016
Periodo de publicación
1 tiempo por año
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Volumen 69 (2020): Edición 1 (January 2020)

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

Buscar

20 Artículos
Acceso abierto

Development of EST microsatellite markers for the Tasmanian palaeoendemic conifer Lagarostrobos franklinii (Hook. f.) Quinn (Podocarpaceae)

Publicado en línea: 21 Jan 2020
Páginas: 1 - 5

Resumen

Abstract

Nuclear Expressed Sequence Tag (EST) microsatellite markers were developed for the Tasmanian palaeoendemic conifer Lagarostrobos franklinii (Hook.-f.) Quinn for genetic studies. RNAseq data was mined for EST microsatellites, and primer pairs were synthesised from 70 contigs with 50 producing amplification products. Of these 50, 10 reliably amplified and displayed polymorphism across 8 samples representing the entire species range. The genetic diversity of these 10 loci was then examined in three wild populations (84 samples). The number of alleles varied from two to thirteen per locus with the average number of alleles per population ranging between 3.0 – 4.7. Observed and expected heterozygosity ranged from 0.34 – 0.42 and 0.37 – 0.44, respectively. Marker cross-amplification was tested in the New Zealand sister species Manoao colensoi (Hook. f.) Molloy, but no markers amplified reliably, which possibly reflects the age of divergence between these species (~64 million years). These are the first microsatellite markers developed for the monotypic genus Lagarostrobos. They will be valuable for assessing the species extant genetic diversity, the impact of past climatic perturbations and human disturbance and the role of clonal propagation in recruitment.

Palabras clave

  • Lagarostrobos
  • Podocarpaceae
  • EST microsatellites
  • palaeoendemic
  • next generation sequencing
  • huon pine
  • Tasmania
Acceso abierto

Genetic control of coppice regrowth in Eucalyptus spp.

Publicado en línea: 04 Feb 2020
Páginas: 6 - 12

Resumen

Abstract

Forest companies prefer a coppice system as a silvicultural strategy owing to its economic and sustainability advantages compared to developing new plantations for second rotations. However, studies aiming to determine the selection of superior genetic material for this management strategy are scarce. In this study, we evaluated five clonal tests of Eucalyptus spp. located in Itatinga and Angatuba, São Paulo State, Brazil, to determine the genetic correlations and control of productivity for regrowth management in two rotations. The volume (m3) and survival of the Eucalyptus spp. clonal tests were determined for the two rotations at 5.5 years of age. The experiments were carried out in a randomized block design with six replicates, five plants per plot, and unbalanced treatments. The heritability in the normal scale (h^n2\hat h_n^2) for the survival ranged from 0.056 to 0.11, the heritability in the broad sense (h^g2\hat h_g^2) ranged from 0.205 to 0.334, and the genotypic correlation was positive and high (0.71-0.86), and statistically significant to the genetic means for the two rotations. The ranking of the best clones in the second rotation was similar (76 %) to their ranking in the first selection. Thus, for the evaluated material, there was no need for the second measurement to obtain accurate selection when managing a coppice system.

Palabras clave

  • coppice
  • quantitative genetics
  • tree breeding
  • urograndis
Acceso abierto

Chromosome Numbers in Gymnosperms - An Update

Publicado en línea: 03 Mar 2020
Páginas: 13 - 19

Resumen

Abstract

The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.

Palabras clave

  • gymnosperms
  • chromosome numbers
  • polyploidy
  • B-chromosome
  • sex chromosomes
Acceso abierto

Genetic structure of ural populations of Larix sibirica Ledeb. on the base of analysis of nucleotide polymorphism

Publicado en línea: 06 Apr 2020
Páginas: 20 - 28

Resumen

Abstract

Research on the state and dynamics of the gene pool (an important natural resource that determines the potential fitness of living organisms and, ultimately, their long-term survival) becomes an important problem in the context of increased anthropogenic environmental impact. They are especially important for key species of ecosystems of a global scale importance. Larix sibirica Ledeb., which spreads from the Western Siberia to the Russian North-West, is one of such forest tree species. We identified patterns of genetic structure of populations on the example of the species’ Western race on the Middle and Northern Urals. The analysis of nucleotide polymorphism of genes of ABA-inducible protein, MADS-box-transcription factor and of 4-kumarat: CoA ligase (a part of the gene) was used as a method. Evidences were obtained that a part of the populations previously formed a single large population. At the same time, populations with different gene pools were found. As a result, differences between populations within the region were more pronounced (fixation index FST = -0.021 – 0.260, total haplotype diversity Hd = 0.636 – 0.911; nucleotide diversity π = 0.005 – 0.009; number of mutations θW = 0.005 – 0.012) than in other parts of the race. Causes of this phenomenon are discussed. It was concluded that the larch forests with a unique gene pool and/or high genetic diversity should be objects of population-oriented forestry and conservation.

Palabras clave

  • Larix sibirica Ledeb
  • Urals
  • genetic structure
  • gene pool
  • populations
  • nucletide polymorphism
Acceso abierto

Gene-Targeted markers to assess genetic diversity and population structure within Tunisian Phoenix dactylifera L. cultivars

Publicado en línea: 22 Apr 2020
Páginas: 29 - 35

Resumen

Abstract

Genetic variability in date palm genotypes collected from different regions of southern Tunisia was analyzed using a Start Codon Targeted (SCoT) marker system. Thirty-one accessions collected from three locations were investigated. One hundred and nine amplicons were produced among which 84 % were polymorphic. The PIC value and the Rp values testified of the efficiency of used primers. The percentage of polymorphic loci (Pp) varied from 44.57 to 83.70 %, Nei‘s gene diversity (H) from 0.175 to 0.273 with a mean of 0.228, and Shannon‘s information index (I) values ranging from 0.257 to 0.409 with an average value of 0.338 were illustrated. The Tunisian date palm populations exhibited high genetic differentiation (GST = 0.319) and gene flow (Nm = 1.063). The AMOVA analysis presented 70 % of the variation within the population and 30 % of the variation between them. Phylogenetic analysis and the Bayesian clustering approach also revealed high genetic variation among genetic variants with a net divergence of the wild insular population of Kerkennah from other cultivars. The present investigation suggests the effectiveness of the SCoT marker system to estimate the genetic diversity of Phoenix dactylifera genotypes.

Palabras clave

  • Phoenix dactylifera
  • SCoT
  • Genetic diversity
  • AMOVA
  • Population structure
  • Tunisia
Acceso abierto

Repeatability of growth characteristics and wood properties for solid wood production from Eucalyptus camaldulensis half-sib families growing in Thailand

Publicado en línea: 26 May 2020
Páginas: 36 - 43

Resumen

Abstract

To promote solid wood production, the diameter at breast height, height, stress-wave velocity, surface-released strain, basic density and compressive strength parallel to the grain were measured for 10 half-sib families of 12-year-old Eucalyptus camaldulensis Dehnh. trees growing in Thailand. Based on the results, growth rates, correlations among measured properties, radial and among-family variations of wood properties, and their repeatability were evaluated. Diameter at breast height, height, and wood volume were exponentially increased at initial stage, and then gradually increased toward to 12 years after planting. The maximum current annual increment and mean annual increment in wood volume showed at age of 8 and 11years old, suggesting that rotation period for optimum productivity may be ranged from 8 to 11 years old. Wood with stable properties was found greater than 6 cm from the pith. These results indicate that 12-year-old E. camaldulensis trees had already reached the maturation stage. No significant correlations were found between growth characteristics and wood properties. Significant variances in the height, stress-wave velocity, and basic density were found among the 10 families. The F-values and repeatability of the wood properties in the outer wood were higher than those in the inner wood. These results indicate that the properties of the outer wood are closely related to genetic factors. Thus, to obtain superior E. camaldulensis trees for solid wood production, the family selection should be conducted using the outer wood of aged trees.

Palabras clave

  • Growth rate
  • radial variation
  • among-family variation
  • stress-wave velocity
  • basic density
  • compressive strength parallel to the grain
Acceso abierto

Morphological and molecular characterization of a hybrid zone between Prosopis alba and P. nigra in the Chaco region of northwestern Argentina

Publicado en línea: 27 Jun 2020
Páginas: 44 - 54

Resumen

Abstract

The Gran Chaco is the largest dry forest in South America. One of the key taxa of this biome is the genus Prosopis (Fabaceae) which contains several economically important species. One of the characteristics of this genus is its natural capacity to exchange genetic information among congeneric species, generating zones of high morphological and genetic variability at contact points. The study and management of these contact areas can contribute to the dynamic conservation of these native genetic resources. In this study, we analysed three sites within a gradient of land aridity, where P. nigra and P. alba grow in sympatry and apparently hybridize. This is the first study performed in both, Prosopis pure sites and hybrid swarm, which includes a spatially explicit approach and simultaneously analyses fruit and leaf morphological variation, together with molecular information (microsatellites markers). We performed a multivariate morphological analysis, Bayesian genetic clustering and multivariate associations between genetic and morphological variability in the pure parental populations and in the hybrid swarm, considering possible spatial autocorrelation. Bayesian cluster analysis revealed two distinct groups corresponding to each species, differentiating the pure morphotypes from sites 1 and 2. Site 3, corresponding to the hybrid swarm, was composed of pure P. alba and P. nigra trees and hybrid individuals. We found morphological and molecular evidence of hybridization between P. alba and P. nigra, and detected novel phenotypes in the hybrid site.

Palabras clave

  • algarrobos
  • dry forest
  • hybridization
  • leaves
  • fruits
  • microsatellites
  • natural hybridization
  • variability
Acceso abierto

Genetic diversity and structure of Oriental and European beech populations from Iran and Europe

Publicado en línea: 13 Jul 2020
Páginas: 55 - 62

Resumen

Abstract

Genetic variation is a major component of plant development and adaptation, and recent studies have shown that genetic variation among plant species can have important ecological effects. Oriental beech (Fagus orientalis Lipsky) is a dominant tree species in the Hyrcanian forests, where it occupies approximately 18 % of the forested area. In this study, nine expressed sequence tag simple sequence repeat (EST-SSR) markers were used to determine the genetic diversity and structure of Iranian Oriental beech populations growing at different altitudes. We further compared the genetic structures of the Iranian populations to a F. orientalis and a Fagus sylvatica L. population from the hybrid zone of the two taxa in southeast Europe, and to a F. sylvatica population from central Europe. All populations showed a high genetic diversity, which was similar to other F. orientalis and F. sylvatica populations from Europe. The genetic differentiation among Iranian beech populations was very low. In contrast, distinct genetic differentiation was found between the Iranian populations and the analyzed European populations (F. orientalis and F. sylvatica). One EST-SSR was identified to differentiate (GST: 0.503) between F. orientalis and F. sylvatica with very pronounced allele frequency differences between taxa. Specifically, the Fagus sylvatica characteristic allele 189 was almost absent from all Iranian populations and present in low frequencies in F. orientalis populations from other regions. This study helps to extend the knowledge of genetic diversity and genetic structure of Iranian Oriental beech populations. It further gives insights into the genetic differentiation between F. orientalis populations from the center and the edge of the species’ distribution range as well as between Oriental and European beech.

Palabras clave

  • Genetic diversity
  • genetic structure
  • microsatellite
  • Fagaceae
  • Fagus orientalis
  • Fagus sylvatica
  • Hyrcanian forest
Acceso abierto

Marker-assisted selection in C. oleifera hybrid population

Publicado en línea: 13 Jul 2020
Páginas: 63 - 72

Resumen

Abstract

Marker-assisted selection (MAS) is implemented to improve Camellia oleifera yield and fruit attributes for meeting China’s increased demand for new varieties development. We conducted three-generational (G0, G1, and G2) hybridization (diallel mating) and selection experiment and used Sequence-Related Amplified Polymorphism (SRAP). SRAP markers to investigate their utility in a MAS framework. The utilized SRAP markers were instrumental in hybrid authenticity and the identification of matroclinal or patroclinal inheritance presence, thus guiding mating pair selection and direction (their role as male or females). Across the studied 3 generations, estimates of genetic diversity parameters showed steady increase with percentage increase of ((G0 to G1 and G1 to G2) 9.25 and 9.05: observed number of alleles; 3.12 and 7.80: means effective number of alleles; 12.35 and 22.34: Nei‘s gene diversity; and 14.21 and 21.77: Shannon‘s index), indicating lack of diversity reduction associated with selection. Estimates of genetic distance and their correlation with heterosis were useful in guiding selection of mating pairs for achieving the desired yield and fruit attributes (fruit diameter, height, weight, and index, peel thickness, number of seeds per fruit, seed weight per fruit, and seed rate). Most yield and fruit attributes exhibited high broad-sense heritability with increasing trend over generation intervals, indicating the increased potential of hybrid breeding for this species.

Palabras clave

  • C. oleifera
  • hybridization
  • marker-assisted selection
  • selection
  • heritability
  • heterosis
Acceso abierto

The influence of sexual dimorphism on the phenotypical properties of poplar

Publicado en línea: 07 Aug 2020
Páginas: 73 - 77

Resumen

Abstract

The influence of sexual dimorphism on commercial-biological traits of the most widespread poplar of the world Populus tremula L. in the Central forest-steppe of the European territory of Russia was studied. The analysis was made of the distribution of male and female clones in general, the effects of humidity, the richness of the soil, and surrounding vegetation on their productive capacity as well as core rot damage. The study presents survey results of 620 aspen plots spread out over an area of 823 hectares as well as more detailed data obtained from 3 pairs of test plots in which the indicators of male and female aspen stands were compared under identical or similar conditions. The study showed that the area of male aspen in the studied region is 4.5 times larger than that of females. The former prevail in drier and less fertile conditions while females gravitate towards more favorable growing conditions. The comparison of the productive capacity of male and female clones of the same age class, growing in identical or similar growing conditions showed that the height, diameter, and volume of the trunks were higher in male trees. Female aspen trees were less affected by core rot in the best conditions of growth, and male ones were more resistant at the worse ones.

Palabras clave

  • aspen
  • sexual dimorphisms
  • distribution of male and female clones
  • productive capacity
  • the core rot
Acceso abierto

Development of novel Quercus rubra chloroplast genome CAPS markers for haplotype identification

Publicado en línea: 20 Aug 2020
Páginas: 78 - 85

Resumen

Abstract

Our main objective was to generate cost-effective chloroplast (cp) DNA markers that are easy to apply and to score. In combination with already published cpSSR markers they should increase haplotype resolution in populations. To discover new cpDNA markers, we sequenced 87-97 % of the entire chloroplast genome (except the second inverted repeat) of 8 trees representing different regions of the Quercus rubra L. natural range with 4,030X-6,297X coverage and assembled the genome sequences using the publicly available chloroplast genome of Quercus rubra L. as a reference. In total, 118 single nucleotide polymorphisms (SNPs) and 107 insertions or deletions (indels) were detected, and 15 cleaved amplified polymorphic sequence (CAPS) markers were developed for Q. rubra. Using these new markers together with five chloroplast microsatellite or simple sequence repeat (cpSSR) markers, we identified 10 haplotypes in our diversity panel of 19 Q. rubra populations. Specifically, two haplotypes based only on the cpSSR markers could now be separated in five haplotypes. These markers are useful to assess haplotype diversity with high resolution and are also transferable to a closely related species, Quercus ellipsoidalis E. J. Hill.

Palabras clave

  • Quercus rubra
  • oak
  • chloroplast genome
  • sequencing
  • SNP
  • indel
  • CAPS
  • SSR
Acceso abierto

Chloroplast microsatellites reveal genetic diversity and population structure in natural populations of Himalayan Cedar (Cedrus deodara (Roxb.) G. Don) in India

Publicado en línea: 24 Aug 2020
Páginas: 86 - 93

Resumen

Abstract

Himalayan cedar (Cedrus deodara) is one of the most important temperate timber species of Western Himalayas and is considered to be among the endangered conifer species in the region. Knowledge of genetic diversity and population structure will help guide gene conservation strategies for this species. Ten polymorphic chloroplast microsatellites (cpSSR) were used to study genetic diversity and population structure in twenty one natural populations of C. deodara throughout its entire distribution range in Western Himalayas. When alleles at each of the 10 loci were jointly analysed, 254 different haplotypes were identified among 1050 individuals. The cpSSRs indicate that C. deodara forests maintain a moderately high level of genetic diversity (mean h = 0.79 ). AMOVA analysis showed that most of the diversity in C. deodara occurs within populations. Bayesian analysis for population structure (BAPS) revealed spatial structuration of the variation (22 % of the total variation) and substructuring captured nineteen genetic clusters in the entire divisions of the populations. Most of the populations were clustered independently with minor admixtures. The distribution of genetic diversity and sub-structuring of C. deodara may be due to restricted gene flow due to geographic isolation, genetic drift, and natural selection. These findings indicated existence of genetically distinct and different high diversity and low diversity clusters, which are potential groups of populations that require attention for their conservation and management. The results are interpreted in context of future conservation plans for C. deodara.

Palabras clave

  • Cedrus deodara
  • chloroplast microsatellites
  • genetic diversity
  • haplotype
Acceso abierto

Usage of microsatellite markers for characterization of polyploids: a case study in reference to hexaploid bamboo species

Publicado en línea: 24 Aug 2020
Páginas: 94 - 97

Resumen

Abstract

Microsatellite markers are most valuable tools for characterization of plant genetic resources or population genetic analysis. Since they are codominant and allelic markers, utilizing them in polyploid species remained doubtful. In such cases, microsatellite markers are usually analyzed by treating them as dominant marker. In the current study, it has been showed that despite of losing the advantage of co-dominance, microsatellite markers are still powerful tool for genotyping of polyploid species because of availability of large number of reproducible alleles per locus. It has been studied by genotyping of nineteen sub populations of Dendrocalamus hamiltonii (hexaploid bamboo species) with seventeen polymorphic SSR primer pairs. Among these, ten primers gave typical banding pattern of microsatellite marker as expected in diploid species but rest seven gave unusual pattern i.e. more than two bands per locus per genotype. In such case genotyping data are generally analyzed by considering as dominant markers. Given these facts, data were analyzed in both ways as dominant and codominant. All the seventeen primer were first scored as non-allelic data and analyzed; later ten primer pairs giving standard banding pattern were analyzed as allelic data and the results were compared. The UPGMA clustering and genetic structure showed that results obtained with both the data sets were very similar, and therefore the SSR marker could be utilized to characterize polyploid species by considering them as dominant marker. The study is highly useful to widen the scope of SSR markers applications and beneficial to the researchers dealing with polyploid species.

Palabras clave

  • Microsatellite markers
  • dominant and codominant
  • Dendrocalamus hamiltonii
Acceso abierto

Cooperative Second-Cycle Breeding and Testing of Coastal Douglas-fir in the US Pacific Northwest: Strategy, Implementation, and Operational Aspects

Publicado en línea: 28 Aug 2020
Páginas: 98 - 107

Resumen

Abstract

The second cycle of cooperative breeding and testing of coastal Douglas-fir in western Oregon and Washington was started around 1992. By 2020 the bulk of testing is nearing completion, while the latest program in southern Oregon and NW California is scheduled to run through 2035. A total of 109 first-generation programs were consolidated into nine second- cycle breeding and testing cooperatives (with 15 testing zones); 136 tests are planned, of which 120 have already been established. Between five and eight tests are established per trial series. Trials established to date have contained from 50 to 283 full-sib crosses. In total, the Douglas-fir breeding effort will be comprised of over 2,900 crosses, of which 2,500 have already been established in the field. A total of about 349,000 test trees are to be planted, with over 310,000 already planted.

Tests typically get three main measurements when the trees are 3 (or 4), 7 and 12 years old from seed. (1) Age-3 or 4: progression of budburst, on a 1 to 5 rating score, when roughly 50 % of the seedlings have broken bud, on one or two sites per trial series. (2) Age-7: height (height pole), dbh, stem sinuosity in the second internode from the top, number of incidences of stem forking, number of incidences of ramicorn branching and (3) Age-12: height (vertex), dbh, stem sinuosity in the second internode from the top, number of incidences of stem forking, number of incidences of ramicorn branching, second flushing yes\no in current year, and wood acoustic velocity (in some trial series).

Palabras clave

  • Advanced-generation
  • Pseudotsuga menziesii
  • progeny testing
  • full-sib crosses
  • plantation
  • selection
  • tree breeding
Acceso abierto

Reinforced evidence on partial compatibility between Pinus sylvestris and Pinus mugo and on maternal inheritance of chloroplast DNA in the Pinus mugo × Pinus sylvestris cross

Publicado en línea: 05 Oct 2020
Páginas: 108 - 115

Resumen

Abstract

The crossability relationship between Scots pine (Pinus sylvestris L.) and mountain dwarf pine (Pinus mugo Turra) was tested under field conditions using an artificial pollination approach. There was partial compatibility between the parental species, as evidenced by the amount of filled seeds in their reciprocal crossings and in control variants from self-pollination, controlled intraspecific outcrossing and open pollination of mother trees. The crossability degree in P. sylvestris × P. mugo was characterised by the index 0.15, and the reciprocal crossing by the index 0.18. Crossability of P. sylvestris and P. mugo with their putative hybrid individuals was much higher; the number of filled seeds was comparable with that of the control variants. The reciprocal crossings of P. sylvestris and P. mugo species were highlighted by the opposite inheritance of their chloroplast DNA (cpDNA). The paternal cpDNA inheritance in P. sylvestris × P. mugo and maternal cpDNA inheritance in P. mugo × P. sylvestris was repeatedly confirmed using the cpDNA trnV-trnH/HinfI marker as well as the newly developed partial cpDNA trnV-trnH/AseI marker. The nature of the latter is described in terms of the nucleotide sequence.

Palabras clave

  • Pinus sylvestris
  • Pinus mugo
  • hybridisation
  • crossability
  • cpDNA
Acceso abierto

Development and Characterization of EST-SSR Markers for Juniperus squamata (Cupressaceae), an ecologically important conifer in Asian mountains

Publicado en línea: 10 Oct 2020
Páginas: 116 - 122

Resumen

Abstract

Juniperus squamata, an endemic conifer of Asia, is an important shrub ecologically and economically. Yet little is known about its genetic diversity and population structure due to lacking of highly polymorphic molecular markers. In this study, expressed sequence tag microsatellite markers (EST-SSR) were developed for Juniperus squamata. Illumina HiSeq data were used to reconstruct the transcriptome of this species by de novo assembly. Based on this transcriptome, 18 SSR markers were designed and successfully amplified. Just one locus was eliminated due to its detection of null alleles and the remaining 17 loci were polymorphic, generating five to 14 alleles per locus in J. squamata. Markers cross-amplification tests were successful in two closely related species of J. squamata. These markers will serve as a basis for further studies to assess the genetic diversity and population structure of J. squamata. As well, they could be useful in promoting sustainable forest management strategies for this species in the face of global climate change.

Palabras clave

  • Cupressaceae
  • microsatellite marker
  • Juniperus squamata
  • Juniperus tibetica
  • Juniperus saltuaria
  • transferability
Acceso abierto

Effect of witches’ broom mutation on growth of Pinus sibirica seedlings

Publicado en línea: 06 Nov 2020
Páginas: 123 - 129

Resumen

Abstract

Mutational witches’ brooms (WB) spontaneously arise in the tree crown. There are no male cones in Pinus sibirica WB and pollination always occurs with normal pollen. We studied 2-year-old seed progeny obtained from open-pollinated cones of WB and normal crown (NC) pines. There were significant morphological differences in two pairs of WB and NC families, while the third family pair studied showed barely pronounced differences. Segregation analysis of WB seed progeny based on needle length (growth trait) and total bud number (branching trait) revealed that about half of seedlings had a normal phenotype, while mutants were from 15.6 to 35.7 %. The rest seedlings could not be unambiguously identified, because they have not yet fully demonstrated the phenotype. Looking normal seedlings from WB families differed not only from mutants but also from NC progeny. Therefore, the mutation had some effect on both mutant seedlings and seedlings with a normal phenotype. Moreover, the denser was maternal WB the more differences were observed between WB and NC progeny.

Palabras clave

  • conifers
  • witches’ broom
  • seed progeny
  • morphology
  • branching
Acceso abierto

Clonal variation in phenological synchronization and cone production in a Pinus patula seed orchard

Publicado en línea: 18 Nov 2020
Páginas: 130 - 138

Resumen

Abstract

Synchronization between female receptiveness and pollen dispersal, and fecundity of clones influence effective population size and genetic diversity of germplasm produced in seed orchards. Our objective was to determine clonal variation in phenological synchronization and in cone production in a Pinus patula seed orchard. Two-year phenology data of female and male strobili from a sample of 31 clones, and of male strobili in trees from neighboring natural stands of the same species were used. Synchronization indices between female receptiveness and pollen release of the same clone (O̅ii), of other clones (O̅i P̅j), and of natural stands (O̅iNS) were calculated for each clone and averaged per precocity group (early, intermediate, and late). Genetic parameters for cone production of clones during three consecutive cone harvests were estimated, as was their relationship to precocity and synchronization index O̅iNS. Cone production showed a broad variation among clones and between years, with strong genetic control (H2c ≥ 0.80) and stable (rB ≥ 0.79) between yeas. There was wide clonal variation in synchronization indices, but no significant variation was found in most cases among precocity groups, neither were they consistent between years. Negative correlations [rp = -0.37 and -0.40 (P < 0.05)] in cone production per clone in two years with the O̅iNS index in the first year, indicated that the most prolific clones had lower synchronization with pollen release in natural stands in the orchard’s vicinity, and thus less risk of genetic contamination.

Palabras clave

  • Broad-sense heritability
  • clone fecundity
  • clonal stability
  • genetic contamination
  • genetic variation
  • Pinus patula
  • reproductive phenology
Acceso abierto

Genetic diversity of marginal populations of Populus euphratica Oliv. from highly fragmented river ecosystems

Publicado en línea: 17 Dec 2020
Páginas: 139 - 151

Resumen

Abstract

Populus euphratica Oliv. (Euphrates poplar) is one of the naturally distributed poplar species and limited to south and southwestern Turkey. The species possesses great importance for both renewable energy resources and persistence of a healthy river ecosystem. Due to increased habitat destructions and fragmentation by human activities, the distribution area of this species has become narrower. Hence, searching for potential genetic diversity present in species’ genetic resources is of great importance in terms of its resilience to changing environment as well as breeding and use. To explore genetic structure and diversity of Euphrates poplar, natural populations in the Göksu and Euphrates river ecosystems were studied with 21 microsatellite DNA loci. Results demonstrated reduced level of genetic diversity (Ho:0.44, uHe:0.45) and low differentiation among two river populations (FST= 0.07), suggesting a common origin. It appears that severe past reductions in population sizes have resulted in loss of genetic variation in the species. Native populations of this species in two rivers seemed to be marginal with continued gene pool shrinkage. Therefore, they are in great danger of collapsing, mainly because of continued habitat loss and fragmentation. Genetic data generated with the current study provide important information which could be useful for future restoration and conservation studies of the species.

Palabras clave

  • Populus euphratica
  • Microsatellite loci
  • genetic structure
  • genetic diversity
  • habitat fragmentation
Acceso abierto

Recent clonal reproduction of Cryptomeria japonica in a snowy region revealed by a survey of small-sized ramets

Publicado en línea: 17 Dec 2020
Páginas: 152 - 157

Resumen

Abstract

Clonal reproduction may contribute to population maintenance in areas where disturbance caused by snow limits tree recruitment. To understand the importance of clonal reproduction in the population dynamics of canopy tree species, it is necessary to determine the frequency of clonal reproduction in the early stages of seedling establishment. We found 106 ramets, including “small-sized” ramets of less than 5 cm in diameter at breast height, aggregated within 4 patches in a 70 × 50 m plot and also identified 20 genets among these ramets with the use of nuclear microsatellite markers. The size structure of the ramets revealed an inverse J-shaped distribution, suggesting that continuous recruitment of new ramets occurs. However, the number of intermediate-sized ramets (around 10 cm DBH) at the present study site was small, suggesting that most new ramets die while they are still small by pressure from heavy snow. Of the 20 genets, 12 included one or more small-sized ramets, which indicated recent recruitment. Of the 12 genets, 3 included only a single small-sized ramet, which suggested seedling recruitment, whereas the other 9 included multiple ramets (39 small-sized ramets in total), which indicated clonal recruitment. The frequency (9/12) and number (39/9) of recent clonal recruits suggest that clonal reproduction effectively maintains the population of Cryptomeria japonica in snowy regions.

Palabras clave

  • Clonal diversity
  • microsatellite marker
  • layering
  • seedling recruitment
  • conifer
20 Artículos
Acceso abierto

Development of EST microsatellite markers for the Tasmanian palaeoendemic conifer Lagarostrobos franklinii (Hook. f.) Quinn (Podocarpaceae)

Publicado en línea: 21 Jan 2020
Páginas: 1 - 5

Resumen

Abstract

Nuclear Expressed Sequence Tag (EST) microsatellite markers were developed for the Tasmanian palaeoendemic conifer Lagarostrobos franklinii (Hook.-f.) Quinn for genetic studies. RNAseq data was mined for EST microsatellites, and primer pairs were synthesised from 70 contigs with 50 producing amplification products. Of these 50, 10 reliably amplified and displayed polymorphism across 8 samples representing the entire species range. The genetic diversity of these 10 loci was then examined in three wild populations (84 samples). The number of alleles varied from two to thirteen per locus with the average number of alleles per population ranging between 3.0 – 4.7. Observed and expected heterozygosity ranged from 0.34 – 0.42 and 0.37 – 0.44, respectively. Marker cross-amplification was tested in the New Zealand sister species Manoao colensoi (Hook. f.) Molloy, but no markers amplified reliably, which possibly reflects the age of divergence between these species (~64 million years). These are the first microsatellite markers developed for the monotypic genus Lagarostrobos. They will be valuable for assessing the species extant genetic diversity, the impact of past climatic perturbations and human disturbance and the role of clonal propagation in recruitment.

Palabras clave

  • Lagarostrobos
  • Podocarpaceae
  • EST microsatellites
  • palaeoendemic
  • next generation sequencing
  • huon pine
  • Tasmania
Acceso abierto

Genetic control of coppice regrowth in Eucalyptus spp.

Publicado en línea: 04 Feb 2020
Páginas: 6 - 12

Resumen

Abstract

Forest companies prefer a coppice system as a silvicultural strategy owing to its economic and sustainability advantages compared to developing new plantations for second rotations. However, studies aiming to determine the selection of superior genetic material for this management strategy are scarce. In this study, we evaluated five clonal tests of Eucalyptus spp. located in Itatinga and Angatuba, São Paulo State, Brazil, to determine the genetic correlations and control of productivity for regrowth management in two rotations. The volume (m3) and survival of the Eucalyptus spp. clonal tests were determined for the two rotations at 5.5 years of age. The experiments were carried out in a randomized block design with six replicates, five plants per plot, and unbalanced treatments. The heritability in the normal scale (h^n2\hat h_n^2) for the survival ranged from 0.056 to 0.11, the heritability in the broad sense (h^g2\hat h_g^2) ranged from 0.205 to 0.334, and the genotypic correlation was positive and high (0.71-0.86), and statistically significant to the genetic means for the two rotations. The ranking of the best clones in the second rotation was similar (76 %) to their ranking in the first selection. Thus, for the evaluated material, there was no need for the second measurement to obtain accurate selection when managing a coppice system.

Palabras clave

  • coppice
  • quantitative genetics
  • tree breeding
  • urograndis
Acceso abierto

Chromosome Numbers in Gymnosperms - An Update

Publicado en línea: 03 Mar 2020
Páginas: 13 - 19

Resumen

Abstract

The present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.

Palabras clave

  • gymnosperms
  • chromosome numbers
  • polyploidy
  • B-chromosome
  • sex chromosomes
Acceso abierto

Genetic structure of ural populations of Larix sibirica Ledeb. on the base of analysis of nucleotide polymorphism

Publicado en línea: 06 Apr 2020
Páginas: 20 - 28

Resumen

Abstract

Research on the state and dynamics of the gene pool (an important natural resource that determines the potential fitness of living organisms and, ultimately, their long-term survival) becomes an important problem in the context of increased anthropogenic environmental impact. They are especially important for key species of ecosystems of a global scale importance. Larix sibirica Ledeb., which spreads from the Western Siberia to the Russian North-West, is one of such forest tree species. We identified patterns of genetic structure of populations on the example of the species’ Western race on the Middle and Northern Urals. The analysis of nucleotide polymorphism of genes of ABA-inducible protein, MADS-box-transcription factor and of 4-kumarat: CoA ligase (a part of the gene) was used as a method. Evidences were obtained that a part of the populations previously formed a single large population. At the same time, populations with different gene pools were found. As a result, differences between populations within the region were more pronounced (fixation index FST = -0.021 – 0.260, total haplotype diversity Hd = 0.636 – 0.911; nucleotide diversity π = 0.005 – 0.009; number of mutations θW = 0.005 – 0.012) than in other parts of the race. Causes of this phenomenon are discussed. It was concluded that the larch forests with a unique gene pool and/or high genetic diversity should be objects of population-oriented forestry and conservation.

Palabras clave

  • Larix sibirica Ledeb
  • Urals
  • genetic structure
  • gene pool
  • populations
  • nucletide polymorphism
Acceso abierto

Gene-Targeted markers to assess genetic diversity and population structure within Tunisian Phoenix dactylifera L. cultivars

Publicado en línea: 22 Apr 2020
Páginas: 29 - 35

Resumen

Abstract

Genetic variability in date palm genotypes collected from different regions of southern Tunisia was analyzed using a Start Codon Targeted (SCoT) marker system. Thirty-one accessions collected from three locations were investigated. One hundred and nine amplicons were produced among which 84 % were polymorphic. The PIC value and the Rp values testified of the efficiency of used primers. The percentage of polymorphic loci (Pp) varied from 44.57 to 83.70 %, Nei‘s gene diversity (H) from 0.175 to 0.273 with a mean of 0.228, and Shannon‘s information index (I) values ranging from 0.257 to 0.409 with an average value of 0.338 were illustrated. The Tunisian date palm populations exhibited high genetic differentiation (GST = 0.319) and gene flow (Nm = 1.063). The AMOVA analysis presented 70 % of the variation within the population and 30 % of the variation between them. Phylogenetic analysis and the Bayesian clustering approach also revealed high genetic variation among genetic variants with a net divergence of the wild insular population of Kerkennah from other cultivars. The present investigation suggests the effectiveness of the SCoT marker system to estimate the genetic diversity of Phoenix dactylifera genotypes.

Palabras clave

  • Phoenix dactylifera
  • SCoT
  • Genetic diversity
  • AMOVA
  • Population structure
  • Tunisia
Acceso abierto

Repeatability of growth characteristics and wood properties for solid wood production from Eucalyptus camaldulensis half-sib families growing in Thailand

Publicado en línea: 26 May 2020
Páginas: 36 - 43

Resumen

Abstract

To promote solid wood production, the diameter at breast height, height, stress-wave velocity, surface-released strain, basic density and compressive strength parallel to the grain were measured for 10 half-sib families of 12-year-old Eucalyptus camaldulensis Dehnh. trees growing in Thailand. Based on the results, growth rates, correlations among measured properties, radial and among-family variations of wood properties, and their repeatability were evaluated. Diameter at breast height, height, and wood volume were exponentially increased at initial stage, and then gradually increased toward to 12 years after planting. The maximum current annual increment and mean annual increment in wood volume showed at age of 8 and 11years old, suggesting that rotation period for optimum productivity may be ranged from 8 to 11 years old. Wood with stable properties was found greater than 6 cm from the pith. These results indicate that 12-year-old E. camaldulensis trees had already reached the maturation stage. No significant correlations were found between growth characteristics and wood properties. Significant variances in the height, stress-wave velocity, and basic density were found among the 10 families. The F-values and repeatability of the wood properties in the outer wood were higher than those in the inner wood. These results indicate that the properties of the outer wood are closely related to genetic factors. Thus, to obtain superior E. camaldulensis trees for solid wood production, the family selection should be conducted using the outer wood of aged trees.

Palabras clave

  • Growth rate
  • radial variation
  • among-family variation
  • stress-wave velocity
  • basic density
  • compressive strength parallel to the grain
Acceso abierto

Morphological and molecular characterization of a hybrid zone between Prosopis alba and P. nigra in the Chaco region of northwestern Argentina

Publicado en línea: 27 Jun 2020
Páginas: 44 - 54

Resumen

Abstract

The Gran Chaco is the largest dry forest in South America. One of the key taxa of this biome is the genus Prosopis (Fabaceae) which contains several economically important species. One of the characteristics of this genus is its natural capacity to exchange genetic information among congeneric species, generating zones of high morphological and genetic variability at contact points. The study and management of these contact areas can contribute to the dynamic conservation of these native genetic resources. In this study, we analysed three sites within a gradient of land aridity, where P. nigra and P. alba grow in sympatry and apparently hybridize. This is the first study performed in both, Prosopis pure sites and hybrid swarm, which includes a spatially explicit approach and simultaneously analyses fruit and leaf morphological variation, together with molecular information (microsatellites markers). We performed a multivariate morphological analysis, Bayesian genetic clustering and multivariate associations between genetic and morphological variability in the pure parental populations and in the hybrid swarm, considering possible spatial autocorrelation. Bayesian cluster analysis revealed two distinct groups corresponding to each species, differentiating the pure morphotypes from sites 1 and 2. Site 3, corresponding to the hybrid swarm, was composed of pure P. alba and P. nigra trees and hybrid individuals. We found morphological and molecular evidence of hybridization between P. alba and P. nigra, and detected novel phenotypes in the hybrid site.

Palabras clave

  • algarrobos
  • dry forest
  • hybridization
  • leaves
  • fruits
  • microsatellites
  • natural hybridization
  • variability
Acceso abierto

Genetic diversity and structure of Oriental and European beech populations from Iran and Europe

Publicado en línea: 13 Jul 2020
Páginas: 55 - 62

Resumen

Abstract

Genetic variation is a major component of plant development and adaptation, and recent studies have shown that genetic variation among plant species can have important ecological effects. Oriental beech (Fagus orientalis Lipsky) is a dominant tree species in the Hyrcanian forests, where it occupies approximately 18 % of the forested area. In this study, nine expressed sequence tag simple sequence repeat (EST-SSR) markers were used to determine the genetic diversity and structure of Iranian Oriental beech populations growing at different altitudes. We further compared the genetic structures of the Iranian populations to a F. orientalis and a Fagus sylvatica L. population from the hybrid zone of the two taxa in southeast Europe, and to a F. sylvatica population from central Europe. All populations showed a high genetic diversity, which was similar to other F. orientalis and F. sylvatica populations from Europe. The genetic differentiation among Iranian beech populations was very low. In contrast, distinct genetic differentiation was found between the Iranian populations and the analyzed European populations (F. orientalis and F. sylvatica). One EST-SSR was identified to differentiate (GST: 0.503) between F. orientalis and F. sylvatica with very pronounced allele frequency differences between taxa. Specifically, the Fagus sylvatica characteristic allele 189 was almost absent from all Iranian populations and present in low frequencies in F. orientalis populations from other regions. This study helps to extend the knowledge of genetic diversity and genetic structure of Iranian Oriental beech populations. It further gives insights into the genetic differentiation between F. orientalis populations from the center and the edge of the species’ distribution range as well as between Oriental and European beech.

Palabras clave

  • Genetic diversity
  • genetic structure
  • microsatellite
  • Fagaceae
  • Fagus orientalis
  • Fagus sylvatica
  • Hyrcanian forest
Acceso abierto

Marker-assisted selection in C. oleifera hybrid population

Publicado en línea: 13 Jul 2020
Páginas: 63 - 72

Resumen

Abstract

Marker-assisted selection (MAS) is implemented to improve Camellia oleifera yield and fruit attributes for meeting China’s increased demand for new varieties development. We conducted three-generational (G0, G1, and G2) hybridization (diallel mating) and selection experiment and used Sequence-Related Amplified Polymorphism (SRAP). SRAP markers to investigate their utility in a MAS framework. The utilized SRAP markers were instrumental in hybrid authenticity and the identification of matroclinal or patroclinal inheritance presence, thus guiding mating pair selection and direction (their role as male or females). Across the studied 3 generations, estimates of genetic diversity parameters showed steady increase with percentage increase of ((G0 to G1 and G1 to G2) 9.25 and 9.05: observed number of alleles; 3.12 and 7.80: means effective number of alleles; 12.35 and 22.34: Nei‘s gene diversity; and 14.21 and 21.77: Shannon‘s index), indicating lack of diversity reduction associated with selection. Estimates of genetic distance and their correlation with heterosis were useful in guiding selection of mating pairs for achieving the desired yield and fruit attributes (fruit diameter, height, weight, and index, peel thickness, number of seeds per fruit, seed weight per fruit, and seed rate). Most yield and fruit attributes exhibited high broad-sense heritability with increasing trend over generation intervals, indicating the increased potential of hybrid breeding for this species.

Palabras clave

  • C. oleifera
  • hybridization
  • marker-assisted selection
  • selection
  • heritability
  • heterosis
Acceso abierto

The influence of sexual dimorphism on the phenotypical properties of poplar

Publicado en línea: 07 Aug 2020
Páginas: 73 - 77

Resumen

Abstract

The influence of sexual dimorphism on commercial-biological traits of the most widespread poplar of the world Populus tremula L. in the Central forest-steppe of the European territory of Russia was studied. The analysis was made of the distribution of male and female clones in general, the effects of humidity, the richness of the soil, and surrounding vegetation on their productive capacity as well as core rot damage. The study presents survey results of 620 aspen plots spread out over an area of 823 hectares as well as more detailed data obtained from 3 pairs of test plots in which the indicators of male and female aspen stands were compared under identical or similar conditions. The study showed that the area of male aspen in the studied region is 4.5 times larger than that of females. The former prevail in drier and less fertile conditions while females gravitate towards more favorable growing conditions. The comparison of the productive capacity of male and female clones of the same age class, growing in identical or similar growing conditions showed that the height, diameter, and volume of the trunks were higher in male trees. Female aspen trees were less affected by core rot in the best conditions of growth, and male ones were more resistant at the worse ones.

Palabras clave

  • aspen
  • sexual dimorphisms
  • distribution of male and female clones
  • productive capacity
  • the core rot
Acceso abierto

Development of novel Quercus rubra chloroplast genome CAPS markers for haplotype identification

Publicado en línea: 20 Aug 2020
Páginas: 78 - 85

Resumen

Abstract

Our main objective was to generate cost-effective chloroplast (cp) DNA markers that are easy to apply and to score. In combination with already published cpSSR markers they should increase haplotype resolution in populations. To discover new cpDNA markers, we sequenced 87-97 % of the entire chloroplast genome (except the second inverted repeat) of 8 trees representing different regions of the Quercus rubra L. natural range with 4,030X-6,297X coverage and assembled the genome sequences using the publicly available chloroplast genome of Quercus rubra L. as a reference. In total, 118 single nucleotide polymorphisms (SNPs) and 107 insertions or deletions (indels) were detected, and 15 cleaved amplified polymorphic sequence (CAPS) markers were developed for Q. rubra. Using these new markers together with five chloroplast microsatellite or simple sequence repeat (cpSSR) markers, we identified 10 haplotypes in our diversity panel of 19 Q. rubra populations. Specifically, two haplotypes based only on the cpSSR markers could now be separated in five haplotypes. These markers are useful to assess haplotype diversity with high resolution and are also transferable to a closely related species, Quercus ellipsoidalis E. J. Hill.

Palabras clave

  • Quercus rubra
  • oak
  • chloroplast genome
  • sequencing
  • SNP
  • indel
  • CAPS
  • SSR
Acceso abierto

Chloroplast microsatellites reveal genetic diversity and population structure in natural populations of Himalayan Cedar (Cedrus deodara (Roxb.) G. Don) in India

Publicado en línea: 24 Aug 2020
Páginas: 86 - 93

Resumen

Abstract

Himalayan cedar (Cedrus deodara) is one of the most important temperate timber species of Western Himalayas and is considered to be among the endangered conifer species in the region. Knowledge of genetic diversity and population structure will help guide gene conservation strategies for this species. Ten polymorphic chloroplast microsatellites (cpSSR) were used to study genetic diversity and population structure in twenty one natural populations of C. deodara throughout its entire distribution range in Western Himalayas. When alleles at each of the 10 loci were jointly analysed, 254 different haplotypes were identified among 1050 individuals. The cpSSRs indicate that C. deodara forests maintain a moderately high level of genetic diversity (mean h = 0.79 ). AMOVA analysis showed that most of the diversity in C. deodara occurs within populations. Bayesian analysis for population structure (BAPS) revealed spatial structuration of the variation (22 % of the total variation) and substructuring captured nineteen genetic clusters in the entire divisions of the populations. Most of the populations were clustered independently with minor admixtures. The distribution of genetic diversity and sub-structuring of C. deodara may be due to restricted gene flow due to geographic isolation, genetic drift, and natural selection. These findings indicated existence of genetically distinct and different high diversity and low diversity clusters, which are potential groups of populations that require attention for their conservation and management. The results are interpreted in context of future conservation plans for C. deodara.

Palabras clave

  • Cedrus deodara
  • chloroplast microsatellites
  • genetic diversity
  • haplotype
Acceso abierto

Usage of microsatellite markers for characterization of polyploids: a case study in reference to hexaploid bamboo species

Publicado en línea: 24 Aug 2020
Páginas: 94 - 97

Resumen

Abstract

Microsatellite markers are most valuable tools for characterization of plant genetic resources or population genetic analysis. Since they are codominant and allelic markers, utilizing them in polyploid species remained doubtful. In such cases, microsatellite markers are usually analyzed by treating them as dominant marker. In the current study, it has been showed that despite of losing the advantage of co-dominance, microsatellite markers are still powerful tool for genotyping of polyploid species because of availability of large number of reproducible alleles per locus. It has been studied by genotyping of nineteen sub populations of Dendrocalamus hamiltonii (hexaploid bamboo species) with seventeen polymorphic SSR primer pairs. Among these, ten primers gave typical banding pattern of microsatellite marker as expected in diploid species but rest seven gave unusual pattern i.e. more than two bands per locus per genotype. In such case genotyping data are generally analyzed by considering as dominant markers. Given these facts, data were analyzed in both ways as dominant and codominant. All the seventeen primer were first scored as non-allelic data and analyzed; later ten primer pairs giving standard banding pattern were analyzed as allelic data and the results were compared. The UPGMA clustering and genetic structure showed that results obtained with both the data sets were very similar, and therefore the SSR marker could be utilized to characterize polyploid species by considering them as dominant marker. The study is highly useful to widen the scope of SSR markers applications and beneficial to the researchers dealing with polyploid species.

Palabras clave

  • Microsatellite markers
  • dominant and codominant
  • Dendrocalamus hamiltonii
Acceso abierto

Cooperative Second-Cycle Breeding and Testing of Coastal Douglas-fir in the US Pacific Northwest: Strategy, Implementation, and Operational Aspects

Publicado en línea: 28 Aug 2020
Páginas: 98 - 107

Resumen

Abstract

The second cycle of cooperative breeding and testing of coastal Douglas-fir in western Oregon and Washington was started around 1992. By 2020 the bulk of testing is nearing completion, while the latest program in southern Oregon and NW California is scheduled to run through 2035. A total of 109 first-generation programs were consolidated into nine second- cycle breeding and testing cooperatives (with 15 testing zones); 136 tests are planned, of which 120 have already been established. Between five and eight tests are established per trial series. Trials established to date have contained from 50 to 283 full-sib crosses. In total, the Douglas-fir breeding effort will be comprised of over 2,900 crosses, of which 2,500 have already been established in the field. A total of about 349,000 test trees are to be planted, with over 310,000 already planted.

Tests typically get three main measurements when the trees are 3 (or 4), 7 and 12 years old from seed. (1) Age-3 or 4: progression of budburst, on a 1 to 5 rating score, when roughly 50 % of the seedlings have broken bud, on one or two sites per trial series. (2) Age-7: height (height pole), dbh, stem sinuosity in the second internode from the top, number of incidences of stem forking, number of incidences of ramicorn branching and (3) Age-12: height (vertex), dbh, stem sinuosity in the second internode from the top, number of incidences of stem forking, number of incidences of ramicorn branching, second flushing yes\no in current year, and wood acoustic velocity (in some trial series).

Palabras clave

  • Advanced-generation
  • Pseudotsuga menziesii
  • progeny testing
  • full-sib crosses
  • plantation
  • selection
  • tree breeding
Acceso abierto

Reinforced evidence on partial compatibility between Pinus sylvestris and Pinus mugo and on maternal inheritance of chloroplast DNA in the Pinus mugo × Pinus sylvestris cross

Publicado en línea: 05 Oct 2020
Páginas: 108 - 115

Resumen

Abstract

The crossability relationship between Scots pine (Pinus sylvestris L.) and mountain dwarf pine (Pinus mugo Turra) was tested under field conditions using an artificial pollination approach. There was partial compatibility between the parental species, as evidenced by the amount of filled seeds in their reciprocal crossings and in control variants from self-pollination, controlled intraspecific outcrossing and open pollination of mother trees. The crossability degree in P. sylvestris × P. mugo was characterised by the index 0.15, and the reciprocal crossing by the index 0.18. Crossability of P. sylvestris and P. mugo with their putative hybrid individuals was much higher; the number of filled seeds was comparable with that of the control variants. The reciprocal crossings of P. sylvestris and P. mugo species were highlighted by the opposite inheritance of their chloroplast DNA (cpDNA). The paternal cpDNA inheritance in P. sylvestris × P. mugo and maternal cpDNA inheritance in P. mugo × P. sylvestris was repeatedly confirmed using the cpDNA trnV-trnH/HinfI marker as well as the newly developed partial cpDNA trnV-trnH/AseI marker. The nature of the latter is described in terms of the nucleotide sequence.

Palabras clave

  • Pinus sylvestris
  • Pinus mugo
  • hybridisation
  • crossability
  • cpDNA
Acceso abierto

Development and Characterization of EST-SSR Markers for Juniperus squamata (Cupressaceae), an ecologically important conifer in Asian mountains

Publicado en línea: 10 Oct 2020
Páginas: 116 - 122

Resumen

Abstract

Juniperus squamata, an endemic conifer of Asia, is an important shrub ecologically and economically. Yet little is known about its genetic diversity and population structure due to lacking of highly polymorphic molecular markers. In this study, expressed sequence tag microsatellite markers (EST-SSR) were developed for Juniperus squamata. Illumina HiSeq data were used to reconstruct the transcriptome of this species by de novo assembly. Based on this transcriptome, 18 SSR markers were designed and successfully amplified. Just one locus was eliminated due to its detection of null alleles and the remaining 17 loci were polymorphic, generating five to 14 alleles per locus in J. squamata. Markers cross-amplification tests were successful in two closely related species of J. squamata. These markers will serve as a basis for further studies to assess the genetic diversity and population structure of J. squamata. As well, they could be useful in promoting sustainable forest management strategies for this species in the face of global climate change.

Palabras clave

  • Cupressaceae
  • microsatellite marker
  • Juniperus squamata
  • Juniperus tibetica
  • Juniperus saltuaria
  • transferability
Acceso abierto

Effect of witches’ broom mutation on growth of Pinus sibirica seedlings

Publicado en línea: 06 Nov 2020
Páginas: 123 - 129

Resumen

Abstract

Mutational witches’ brooms (WB) spontaneously arise in the tree crown. There are no male cones in Pinus sibirica WB and pollination always occurs with normal pollen. We studied 2-year-old seed progeny obtained from open-pollinated cones of WB and normal crown (NC) pines. There were significant morphological differences in two pairs of WB and NC families, while the third family pair studied showed barely pronounced differences. Segregation analysis of WB seed progeny based on needle length (growth trait) and total bud number (branching trait) revealed that about half of seedlings had a normal phenotype, while mutants were from 15.6 to 35.7 %. The rest seedlings could not be unambiguously identified, because they have not yet fully demonstrated the phenotype. Looking normal seedlings from WB families differed not only from mutants but also from NC progeny. Therefore, the mutation had some effect on both mutant seedlings and seedlings with a normal phenotype. Moreover, the denser was maternal WB the more differences were observed between WB and NC progeny.

Palabras clave

  • conifers
  • witches’ broom
  • seed progeny
  • morphology
  • branching
Acceso abierto

Clonal variation in phenological synchronization and cone production in a Pinus patula seed orchard

Publicado en línea: 18 Nov 2020
Páginas: 130 - 138

Resumen

Abstract

Synchronization between female receptiveness and pollen dispersal, and fecundity of clones influence effective population size and genetic diversity of germplasm produced in seed orchards. Our objective was to determine clonal variation in phenological synchronization and in cone production in a Pinus patula seed orchard. Two-year phenology data of female and male strobili from a sample of 31 clones, and of male strobili in trees from neighboring natural stands of the same species were used. Synchronization indices between female receptiveness and pollen release of the same clone (O̅ii), of other clones (O̅i P̅j), and of natural stands (O̅iNS) were calculated for each clone and averaged per precocity group (early, intermediate, and late). Genetic parameters for cone production of clones during three consecutive cone harvests were estimated, as was their relationship to precocity and synchronization index O̅iNS. Cone production showed a broad variation among clones and between years, with strong genetic control (H2c ≥ 0.80) and stable (rB ≥ 0.79) between yeas. There was wide clonal variation in synchronization indices, but no significant variation was found in most cases among precocity groups, neither were they consistent between years. Negative correlations [rp = -0.37 and -0.40 (P < 0.05)] in cone production per clone in two years with the O̅iNS index in the first year, indicated that the most prolific clones had lower synchronization with pollen release in natural stands in the orchard’s vicinity, and thus less risk of genetic contamination.

Palabras clave

  • Broad-sense heritability
  • clone fecundity
  • clonal stability
  • genetic contamination
  • genetic variation
  • Pinus patula
  • reproductive phenology
Acceso abierto

Genetic diversity of marginal populations of Populus euphratica Oliv. from highly fragmented river ecosystems

Publicado en línea: 17 Dec 2020
Páginas: 139 - 151

Resumen

Abstract

Populus euphratica Oliv. (Euphrates poplar) is one of the naturally distributed poplar species and limited to south and southwestern Turkey. The species possesses great importance for both renewable energy resources and persistence of a healthy river ecosystem. Due to increased habitat destructions and fragmentation by human activities, the distribution area of this species has become narrower. Hence, searching for potential genetic diversity present in species’ genetic resources is of great importance in terms of its resilience to changing environment as well as breeding and use. To explore genetic structure and diversity of Euphrates poplar, natural populations in the Göksu and Euphrates river ecosystems were studied with 21 microsatellite DNA loci. Results demonstrated reduced level of genetic diversity (Ho:0.44, uHe:0.45) and low differentiation among two river populations (FST= 0.07), suggesting a common origin. It appears that severe past reductions in population sizes have resulted in loss of genetic variation in the species. Native populations of this species in two rivers seemed to be marginal with continued gene pool shrinkage. Therefore, they are in great danger of collapsing, mainly because of continued habitat loss and fragmentation. Genetic data generated with the current study provide important information which could be useful for future restoration and conservation studies of the species.

Palabras clave

  • Populus euphratica
  • Microsatellite loci
  • genetic structure
  • genetic diversity
  • habitat fragmentation
Acceso abierto

Recent clonal reproduction of Cryptomeria japonica in a snowy region revealed by a survey of small-sized ramets

Publicado en línea: 17 Dec 2020
Páginas: 152 - 157

Resumen

Abstract

Clonal reproduction may contribute to population maintenance in areas where disturbance caused by snow limits tree recruitment. To understand the importance of clonal reproduction in the population dynamics of canopy tree species, it is necessary to determine the frequency of clonal reproduction in the early stages of seedling establishment. We found 106 ramets, including “small-sized” ramets of less than 5 cm in diameter at breast height, aggregated within 4 patches in a 70 × 50 m plot and also identified 20 genets among these ramets with the use of nuclear microsatellite markers. The size structure of the ramets revealed an inverse J-shaped distribution, suggesting that continuous recruitment of new ramets occurs. However, the number of intermediate-sized ramets (around 10 cm DBH) at the present study site was small, suggesting that most new ramets die while they are still small by pressure from heavy snow. Of the 20 genets, 12 included one or more small-sized ramets, which indicated recent recruitment. Of the 12 genets, 3 included only a single small-sized ramet, which suggested seedling recruitment, whereas the other 9 included multiple ramets (39 small-sized ramets in total), which indicated clonal recruitment. The frequency (9/12) and number (39/9) of recent clonal recruits suggest that clonal reproduction effectively maintains the population of Cryptomeria japonica in snowy regions.

Palabras clave

  • Clonal diversity
  • microsatellite marker
  • layering
  • seedling recruitment
  • conifer

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