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Detalles de la revista
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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 63 (2014): Edición 1-6 (December 2014)

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

37 Artículos
Acceso abierto

1. A genetic linkage map of Pinus massoniana based on SRAP, SSR and ESTP markers

Publicado en línea: 01 Jun 2017
Páginas: 1 - 8

Resumen

Abstract

Pinus massoniana (masson pine) is the most important native pine in southern China. High-density genetic maps have not been constructed for the species. In this study, a genetic linkage map with 251 markers (47 SSRs, 23 ESTPs and 181 SRAPs) was constructed using a F1 progeny mapping population derived from controlled pollination of two parents of different provenances. At LOD 7.0, a total of 17 linkage groups were constructed with twelve groups having nine or more markers and five other groups of two to four markers each. The total map length was 1,956 cM with an average of 8.4 cM among individual loci. The current linkage map represented 93% of the estimated genome length of 2,114 cM for masson pine. Such linkage map are useful for future genomic studies of masson pine including comparative mapping in Pinaceae and quantitative trait loci (QTL) mapping for economically important traits.

Palabras clave

  • Pinus massoniana
  • linkage map
  • SSR
  • SRAP
  • ESTP
Acceso abierto

Performance of Eucalyptus Clones in Auto and Allocompetition

Publicado en línea: 01 Jun 2017
Páginas: 9 - 14

Resumen

Abstract

This study was performed to estimate the abilities of eucalyptus clones to exercise as well as to tolerate competition and to compare their behaviors under auto- or allocompetition. Six commercial clones, belonging to PLANTAR S/A enterprise were evaluated for breast height circumference (BHC), total height (TH) and volume (VOL). At three locations of Minas Gerais, Brazil (two in Curvelo and one in Felixlândia) the clones were planted in two spaces. At 36 months of age each clone was evaluated for exercising and toleration competition amongst each other. The design for each experiment was similar to that of the nine-hole system; the center clone being under competition and the eight surrounding the center clone exercising competition. Each clone under competition was repeated eight times; therefore, for each spacing and location, six contiguous experiments were conducted. From the mean values; the parameters of ability to exercise competition (ci), ability to tolerate competition (tj), the specific competitive ability (sij) and the performance per se of the clones (aj) were estimated using a model similar to that of diallel crosses. The clones differed as to their ci, tj and aj. No one clone exhibited high and positive ci and tj. Regardless of location, spacing, or clone, the performance of autocompetition is similar to that of allocompetition. This indicates that a mixture of clones, if advantageous from the management or industrial point of view, may be performed without harm to the volume of wood produced.

Palabras clave

  • Eucalyptus
  • competition
  • mixture
  • clone
  • autocompetition
  • allocompetition
  • uniformity
Acceso abierto

Hybridizing ability and heterosis between Eucalyptus urophylla and E. tereticornis for growth and wood density over two environments

Publicado en línea: 01 Jun 2017
Páginas: 15 - 23

Resumen

Abstract

Interspecific hybrids of Eucalyptus urophylla × E. tereticornis in a factorial-mating design were used to analyze general hybridizing ability (GHA), specific hybridizing ability (SHA) and heterosis for height (H; 0.5, 1.5, 2.5, 4 and 7.5 years in age), diameter at breast height (D; ages 1.5, 2.5, 4 and 7.5) and wood density (WD; age 7.5) across two environments. The GHA variances were significant for all traits, and those of the SHA were also significant for most of the traits but with less magnitude, indicating the greater importance of additive gene effects in explaining the phenotypic variation among hybrids. The narrow-sense heritability (h2) and dominance (d2) estimates with hybrid growth and wood density ranged between 0.02±0.05 (d2 in D7.5) and 0.23±0.10 (d2 in H1.5) over the different ages, suggesting weak additive and dominant effects on these traits. Additive genetic correlations of growth with wood density were weak at age 7.5. Female general combining ability (GCA) based on maternal open-pollinated families was not necessarily a good indicator of GHA as their correlations were 0.48 (P=0.17), 0.65 (P=0.04) and -0.56 (P=0.10) for H7.5, D7.5 and WD7.5, respectively. A great proportion of hybrids showed positive female-parent heterosis (FPH) at age 7.5, with the highest relative FPH of 47.2% in D7.5. This study demonstrates the heterosis between inter-sectional species and could have implications for E. urophylla × E. tereticornis hybrid breeding.

Palabras clave

  • Hybridizing ability
  • heterosis
  • growth
  • wood density
  • Eucalyptus
Acceso abierto

Clonal Variation of Eucalypts in Susceptibility to Bacterial Wilt Detected by Using Different Inoculation Methods

Publicado en línea: 01 Jun 2017
Páginas: 24 - 31

Resumen

Palabras clave

  • Eucalypt
  • Ralstonia solanacearum
  • bacterial wilt
  • inoculation
  • clonal variation
  • repeatability
Acceso abierto

Experimental strategies for clonal eucalyptus

Publicado en línea: 01 Jun 2017
Páginas: 32 - 38

Resumen

Abstract

The success of any forestry operation depends on the careful choice of the clones to be planted. At existing yield levels, the differences among clones are becoming smaller, leading to the need to use experimental strategies for a more successful choice. To obtain information in regard to better experimental strategies, data from two clonal tests of eucalyptus were used. One of the tests consisted of 35 clones and another of 48 clones. In both tests, the experimental plot consisted of 100 plants at commercial spacing (12 m2 per plant). The trait wood volume was evaluated, taking the relative position of the plant in the plot as a reference. The data were evaluated by different means, and it was observed that the use of border plot in clonal tests in eucalyptus is not necessary. Experimental accuracy with 15 to 20 plants is similar in comparison to the plot with 100 plants.

Palabras clave

  • Eucalyptus
  • experimental precision
  • accuracy
  • plot size
Acceso abierto

Short note: Genetic diversity and differentiation in Ural populations of the aspen, Populus tremula L., as revealed by inter-simply sequence repeat (ISSR) markers

Publicado en línea: 01 Jun 2017
Páginas: 39 - 40

Resumen

Abstract

Genetic diversity and differentiation of six Populus tremula L. populations in the Ural mountains (Russia) were investigated using ISSR-markers. Analyses revealed relatively high genetic diversity and significant (p = 0.985) genetic isolation by distance of foothill and plain cis-Ural populations in the zone of forests with mixed coniferous and broad-leaved tree species. The genetic drift may be a factor that lead to comparatively low genetic variability and genetic singularities of isolated small populations of the aspen in dark coniferous taiga of the Ural mountains.

Palabras clave

  • inter-simply sequence repeat (ISSR) markers
  • genetic diversity
  • genetic differentiation
  • Populus tremula L.
  • Ural mountains
Acceso abierto

Variation and Stability in Female Strobili Production of a First-Generation Clonal Seed Orchard of Chinese Pine (Pinus tabuliformis)

Publicado en línea: 01 Jun 2017
Páginas: 41 - 46

Resumen

Abstract

Seed orchards of Chinese pine, Pinus tabuliformis, are in a transition period from first generation to advanced generation. During this crucial period, evaluation of seed production in seed orchards is essential. Female strobili production is an important factor in seed production. This study examined the variation and stability in female strobili production in a first-generation clonal seed orchard of Chinese pine in years 9, 10, 13, 14, 20 and 21 after grafting in 1974. The results showed significant variation in female strobili production among clones, years, and interactions between clones and years. Correlations in female strobili production between years were significant. The repeatability for female strobili production within the examined years ranged from 0.47 to 0.87. The relative stability of female strobili production varied among clones, with regression coefficients among individual clones and an environmental index ranging from 0.13 to 2.81. The productivity index in different clones ranged from -1.09 to 1.83. Yield stability of female strobili among clones could be estimated from female strobili production. Clones could be divided into three groups according to their stability and productivity parameters. The results of this research provide guidance for evaluating clones in existing seed orchards, as well as some basic information for seed orchard management and advanced-generation seed orchard establishment.

Palabras clave

  • Pinus tabuliformis
  • first generation
  • clonal seed orchard
  • female strobili production
  • variation
  • stability
  • productivity
  • seed orchard management
  • advanced-generation seed orchard establishment
Acceso abierto

Breeding triploid aspen and poplar clones for biomass production

Publicado en línea: 01 Jun 2017
Páginas: 47 - 58

Resumen

Abstract

Enriched diploid pollen was applied for in vitro pollinations and crossbreeding in the greenhouse to produce high performance triploid aspen and aspen hybrids for cultivation in medium rotation plantations. In addition to crossings within the section Populus, intersectional crossbreeding was performed to combine benefits of intersectional hybridization with those derived from triploidisation.

Both the enrichment of diploid pollen by size fractionation of naturally unreduced pollen and heat treatment of microspore mother cells resulted in a distinct increase of diploid pollen. Using this pollen, six triploid plants were obtained from in vitro pollinations and twenty from crossbreeding in the greenhouse. The triploid plants displayed a high variability in growth performance. Two clones from in vitro pollination and five from crossbreeding in the greenhouse were chosen to estimate growth characteristics. A first assessment of clone performance in an outdoor container test con - ducted over one growing season revealed two triploid clones with a same stem height and a significantly increased basal stem diameter in comparison to the fast-growing triploid reference clone “Astria”. Crossbreeding experiments also resulted in two fast-growing mixoploid clones, which have already been stable for several years.

All in all, in this study, crossbreeding using enriched diploid pollen is proved to be a reliable and applicable approach for an effective breeding of triploid poplars.

Palabras clave

  • Populus spp.
  • triploid
  • in vitro pollination
  • intersectional crossbreeding
  • diploid pollen
Acceso abierto

Molecular evolution of drought tolerance and wood strength related candidate genes in loblolly pine (Pinus taeda L.)

Publicado en línea: 01 Jun 2017
Páginas: 59 - 66

Resumen

Abstract

Loblolly pine (Pinus taeda L.) is an intensely studied species that has become a model system for conifers. It is one of the most important commercial crops in the southeastern United States and grows across a vast territory. Due to exposure to this current diverse environment and the fluctuating climatic conditions of the past, it has likely accumulated substantial variation in adaptive trait and wood strength related genes. We merged a set of newly collected and previously published genomic DNA sequence data and analyzed them for departures from neutrality in 32 drought tolerance and wood strength related candidate genes using neutrality tests, such as Tajima’s D, HKA, MK and nonsynonymous to synonymous substitutions ratio (Z-test). Three other major Southern pines closely related to P. taeda (Pinus echinata Mill., P. elliottii Engelm., and P. palustris Mill.) were used as outgroups in interspecific tests. In three loci (4-coumarate: CoA ligase, putative cell-wall protein and trans-cinnamate 4-hydroxylase 2) neutrality was rejected by both intra- and interspecific tests, consistent with purifying selection. Neutrality was also rejected in several other loci (alpha-tubulin, arabinogalactan 4, arabinogalactan 6, cinnamate 4-hydroxylase 1, cinnamoyl CoA reductase, cinnamyl alcohol dehydrogenase, caffeoyl CoA O-methyltransferase 1, early response to drought 3, glycine hydroxymethyltransferase, ABI1 protein phosphatase 2C-like, putative wall-associated protein kinase, and unknown gene ug_2-498); however, these results are difficult to interpret because only one of the tests proved significant. This study contributes to the ongoing discussion about natural selection in putative adaptive genes in loblolly pine. However, unambiguous interpretation of the results often remains problematic.

Palabras clave

  • loblolly pine
  • longleaf pine
  • shortleaf pine
  • slash pine
  • Australes
  • drought tolerance
  • wood strength
  • neutrality tests
  • SNP
  • natural selection
Acceso abierto

Growth response of European larch (Larix decidua Mill.) populations to climatic transfer A Novel Approach for Controlled Pollination in Casuarina equisetifolia

Publicado en línea: 01 Jun 2017
Páginas: 67 - 75

Resumen

Abstract

The study focuses on growth responses of Larix decidua provenances to climatic transfer based on a regional provenance experiment. This comprises a series of 5 trial plots situated in Germany and Slovakia, where 12 indigenous Sudetic and West-Carpathian larch provenances are planted. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. 1st and 2nd-order polynomial regressions were used for the identification of overall trends of growth performance and responses to transfer.

Sudetic provenances clearly outperformed the Carpathian ones on all test sites. When all provenances were considered jointly, height and breast-height diameter mostly showed significant monotonous geographical and climatic trends: the performance generally decreased with increasing altitude and precipitations and decreasing temperatures. The relationships between growth response and transfer rates (ecodistances) were mostly linear. However, when Sudetic and Carpathian provenances were considered separately, most significant response curves were unimodal. There is a very good correspondence between the responses in height and diameter growth within geographic groups, but the responses are not consistent between groups. Joint regression analysis showed that most provenances exhibited average stability. Stability indices are quite consistent between the response traits and did not show any association with the geographical position, climate of origin, or growth performance.

The results indicate that populations in different climates remain adapted to a common optimum, the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.

Palabras clave

  • Larix decidua
  • local adaptation
  • phenotypic plasticity
  • provenance research
  • climatic transfer
Acceso abierto

A Novel Approach for Controlled Pollination in Casuarina equisetifolia

Publicado en línea: 01 Jun 2017
Páginas: 76 - 80

Resumen

Abstract

Casuarina equisetifolia is an important tree species in the tropical and subtropical zones of Asia, Africa and the Pacific. There is an increasing interest in producing intra- and inter-specific hybrids of casuarina species. Conventional bagging controlled pollination method yielded very low fruit set and poor seed germination. High temperature and humidity in the pollination bags appeared to have instigated unfavorable conditions for pollination and fertilization mechanism. In this study, a novel approach was developed by conducting pollination in closed chambers which functioned like pollination bags. Fruit set and seed germination rate increased from 7.0% to 89.9%, and 8.1% to 51.8% respectively compared with the conventional bagging controlled pollination method. Based on the results, a controlled pollination glasshouse with 10 separated chambers has been designed to produce multiple hybrid combinations in a single pollination procedure.

Palabras clave

  • Casuarina equisetifolia
  • cross breeding
  • controlled pollination
  • fruit set
  • seed germination rate
  • pollination chambers
Acceso abierto

Hybridization and Genetic Diversity in Wild Apple (Malus sylvestris (L.) MILL.) from Various Regions in Germany and from Luxembourg

Publicado en línea: 01 Jun 2017
Páginas: 81 - 93

Resumen

Abstract

Malus sylvestris is the only apple species native to Central Europe. Its genetic integrity may be threatened by hybridization with the cultivated apple (Malus × domestica). A total of 883 genotypes, 477 putative wild apples in Germany and Luxembourg and 406 old to modern cultivars has been investigated. Wild apples growing in Germany originated from Rhineland-Palatinate, North Rhine-Westphalia, Saxony-Anhalt and Saxony. The genetic structure was analysed at ten isozyme marker loci, and morphology was studied by fruit size, leaf pubescence, and a complex morphological description performed in advance. A model-based cluster analysis applied to all nuclear data resulted in two clearly differentiated gene pools for putative wild and cultivated apples with moderate proportions of admixture in the wild group on average (0.138 total, 0.111 German sample). At the individual level, the percentages of both hybrids and feral cultivars together ranged from 2.3% in Rhineland-Palatinate to 28.8% in Luxembourg. The intraspecific variability in fruit diameter ranged from 21 to 40 mm, and that in leaf pubescence in autumn ranged from score 0 to score 1. No single morphological trait of a specimen appeared to be sufficient for identification. Even the correspondence between the complex morphological and complex genetic determinations for individuals did not exceed 93% in pure wilds and 64% in hybrids. Genetic variation in pure wild apple is high (species level: P = 90%, A/L = 3.1, He = 0.369). Allelic differentiation & was 0.089, pairwise genetic distance (d0) ranged from 0.065 to 0.148 among five samples. Correspondence between genetic and geographic distance of populations was observed to a certain extent.

Palabras clave

  • Malus sylvestris
  • Malus × domestica
  • introgression
  • gene flow
  • genetic variation
  • genetic differentiation
  • isozymes
  • morphology
  • conservation
  • biodiversity
Acceso abierto

Comparative assessment of SSR, ISSR and AFLP markers for characterization of selected genotypes of Himalayan Chir pine (Pinus roxburghii Sarg.) based on resin yield

Publicado en línea: 01 Jun 2017
Páginas: 94 - 108

Resumen

Abstract

A set of 19 SSR (Simple Sequence Repeats), 9 ISSR (Inter-Simple Sequence Repeats) and 5 AFLP (Amplified Fragment Length Polymorphism) primer combinations were used to evaluate the variability among 53 genotypes of Pinus roxburghii selected based on resin yield from the natural zone of occurrence of this species in Uttarakhand, India. The selected trees of pine varied in resin yield from 0.25 to 8 kg/year/tree. Based on the comparative assessment of SSR, ISSR and AFLP markers, SSR markers were found most polymorphic with an average PIC value of 0.327 and 2.42 alleles per marker, while ISSR markers showed the highest effective multiplex ratio (15.536) and marker index (4.958). AFLP markers showed the maximum resolving power (8.099) which was comparable to the resolving power (8.059) of ISSR markers. UPGMA-based dendrogram using SSR markers revealed more distinct grouping of genotypes on the basis of resin yield as compared to ISSR and AFLP markers. AMOVA by collection site revealed no significant variation among the populations. Whereas, AMOVA by resin yield using SSR, ISSR and AFLP markers revealed FST values to be 0.1096, 0.0483 and 0.2422 indicating moderate, low and great genetic differentiation among the groups. This clearly indicated that the variation at the molecular level was attributed to the resin yield and not the site of collection.

Palabras clave

  • genetic diversity
  • fixation index
  • AMOVA
  • PIC
Acceso abierto

Short Note: Isolation and Characterization of 12 Polymorphic Microsatellite Markers in Engelhardia roxburghiana (Juglandaceae)

Publicado en línea: 01 Jun 2017
Páginas: 109 - 112

Resumen

Abstract

Engelhardia roxburghiana is a common half evergreen tree with a wide distribution in southeast Asia. Despite its ecological and pharmaceutical values, its genetic diversity is poorly studied. Our objective was to develop nuclear microsatellite markers to investigate the level of genetic diversity within and among populations in the future. Using the microsatellite-enriched library and PCR-based screening method, 12 microsatellite markers were developed and showed polymorphism in a population. The number of alleles per locus for these 12 microsatellites ranged from four to 15. The observed and expected heterozygosities ranged from 0.358 to 0.897 and from 0.369 to 0.886, respectively. The developed microsatellites will be useful for studying genetic diversity and population structure in E. roxburghiana.

Palabras clave

  • DHS plot
  • DNA enriched libraries
  • genetic marker
  • genetic variation
  • Hardy-Weinberg equilibrium
  • linkage disequilibrium
  • marker development
  • microsatellite
  • population genetics
  • spatial genetic structure
  • subtropical China
Acceso abierto

Short note: Development, characterization and cross-amplification of eight EST-derived microsatellites in Salix

Publicado en línea: 01 Jun 2017
Páginas: 113 - 115

Resumen

Abstract

A set of eight simple sequence repeat (SSR) markers were developed from 707 Salix expressed sequence tags (ESTs) deposited in GenBank. Each of the EST-SSR amplicons was identical to the original EST, with sequence identity 60.90-96.03% and presence of the expected repeat motifs. Of the eight EST-SSR loci, five were polymorphic among 14 individuals of S. eriocephala, with the number of alleles per locus (Na), observed heterozygosity (Ho), expected heterozygosity (He) and polymorphic information content (PIC) being 2-7 (mean 4.8), 0.29-0.85 (mean 0.65), 0.25-0.84 (mean 0.65) and 0.21-0.78 (mean 0.58), respectively. High rates of crossspecies/ genus amplification were also observed within fourteen different species. The primer sequences for the eight EST-SSRs have been deposited in the Probe database of GenBank (IDs Pr031820546 - Pr031820553). The EST-SSRs developed herein would be a valuable addition of functional markers for genetics and breeding applications in a wide range of Salix species.

Palabras clave

  • Salix
  • Willow
  • Expressed sequence tag (EST)
  • Simple sequence repeat (SSR)
  • Microsatellites
Acceso abierto

Geographic Variation and Local Growth Superiority for Coastal Douglas-fir – Rotation-age Growth Performance in a Douglas-fir Provenance Test

Publicado en línea: 01 Jun 2017
Páginas: 116 - 124

Resumen

Abstract

Rotation-age growth performance of 16 provenances and local growth superiority were assessed from a rotation- age reciprocal coastal Douglas-fir [Pseudotsuga menziesii var. menziesii (Mirb.) Franco] provenance test established in the Pacific Northwest of America. Provenance differences for total volume per plot were highly significant. Due to the significant provenance × site interaction effect, the best provenances varied across planting sites in terms of rotation-age volume growth. Local provenance trees exhibited superior volume growth at two of the six planting sites. At the remaining four sites, local provenances performed equally well as average non-local provenances. At the three low-elevation (< 460 m) sites, low-elevation provenances performed significantly better than high-elevation provenances. By contrast, high- and low-elevation provenances had similar growth at the two high-elevation (> 800 m) sites. Southern provenances generally grew faster than northern provenances at the Oregon sites, while northern provenances performed better than southern provenances at the sites in British Columbia.

Regression analyses showed that although local growth superiority increased with the geographic distance between provenance’s origin and the test site in general (r=0.47, P<0.001), it only became obvious when the geographic distance is larger than 435 km in latitude or 370 m in elevation. Significant spatial autocorrelation was found via Mantel test, and geographically or climatically closely located provenances tended to have similar rotation-age volume growth.

The results suggested that breeding zones larger than the current second-cycle zones would lead to little loss of rotation-age total volume for coastal Douglas-fir in this region.

Palabras clave

  • Douglas-fir
  • provenance
  • rotation-age growth
  • local superiority
  • local adaptation
  • provenance × site interaction
  • breeding zone
Acceso abierto

In vitro Competition of Betula alnoides Pollens from Two Types of Habitats in a Heterogeneous Landscape in South China

Publicado en línea: 01 Jun 2017
Páginas: 125 - 132

Resumen

Abstract

Pollens of Betula alnoides were collected in its natural forests at two types of sites with soils originated from limestone (Site L) and granite (Site G) in a heterogeneous landscape at Jingxi County, Guangxi in 2010 to 2012 to investigate whether nutritional differences between the sites influenced its pollen competition. In vitro pollen germinations were conducted separately and in pairs for these samples as well as nutrient contents of pollens and soils were measured. There was no significant difference in total nitrogen, phosphorus, potassium and calcium contents of dried pollen and in efficient ones of aqueous extracts of pollens between two types of sites although the soil nutrient contents were quite different between them, and less remarkable correlation was found between these nutrient contents of soil and pollen. The results of pollen competition of B. alnoides were much diverse among three years, it seemed that pollen-pollen interaction did not depend on site type, and might vary according to genotype and/or combination of genotypes.

Palabras clave

  • Betula alnoides
  • genotype
  • habitat
  • heterogeneous landscape
  • in vitro
  • pollen competition
  • pollen germination
  • pollen nutrition
  • pollen tube growth
  • soil nutrition
Acceso abierto

Habitat fragmentation decreased the genetic variability of Trichilia elegans A. Juss. (Meliaceae) in southern Brazil

Publicado en línea: 01 Jun 2017
Páginas: 133 - 138

Resumen

Abstract

Habitat fragmentation and the creation of so-called edge effects may have different implications on flora and fauna, including complex genetic responses. This study aimed to analyze the genetic diversity in a local population of the shade tolerant tree Trichilia elegans A. Juss (Meliaceae), with emphasis to the evaluation of genetic variation towards an edge-interior gradient. The results of isoenzymes assays showed that the edge subpopulation experienced the highest allele loss, while fixed alleles increased towards the interior. The total polymorphic loci percentage was 76.67%, being higher in the Middle subpopulation, whilethe average sample size for a locus (N) and the mean number of alleles for a locus (Na) were significantly lower in the Edge subpopulation. The indices Ho, He and f showed good heterozygosity in the total population, indicating high genetic variability. The genetic distance Fst and Nm followed the same pattern, with Middle and Interior subpopulations showing higher similarity and the Edge as the farthest one, also showing less gene flow in relation to the others. Principal Coordinates Analysis (PCoA) allowed us to separate the three subpopulations with the first two axes explaining 65% of total variation, confirming that forest fragmentation affects the genetics of Trichilia elegans within the analyzed fragment.

Palabras clave

  • Isoenzymes
  • habitat fragmentation
  • allele frequency
  • gene flow
  • araucaria forest
Acceso abierto

Altitudinal genetic variation among native Pinus patula provenances: performance in two locations, seed zone delineation and adaptation to climate change

Publicado en línea: 01 Jun 2017
Páginas: 139 - 148

Resumen

Abstract

To select the genetic source of Pinus patula Shiede and Deppe seed best adapted to different native zones for reforestation, seedlings of 12 provenances native to a selected altitudinal gradient in Oaxaca, southern Mexico, were planted on two sites at contrasting altitudes (high 3000 m above sea level (masl) and low, 2500 masl) within the species natural distribution, and tested for growth in height at age 18, 24 and 36 months. Differences among provenances and between sites showed significance (p<0.05). Seedling growth showed a climatic and altitudinal pattern, in which seedlings from populations originating in low-middle altitudes had higher growth than populations originating in high altitudes, and from the extreme low altitude limit. Results were used to delineate climatic and altitudinal seed zones for contemporary and future climate zones in the decade centered in year 2030, using the average results of six climate-emissions scenarios. The results indicate that splitting the region into four seed zones is appropriate under contemporary climate scenarios with the following altitude limits: Zone 1, from 2300 to 2500 masl; Zone 2, 2500 to 2700 masl; Zone 3, 2700 to 2900 masl and Zone 4 from 2900 to 3100 masl. The equivalence on climatic intervals was also defined for mean annual temperature, precipitation and an annual aridity index (AAI). Values of contemporary AAI occurring at a given altitude by year 2030 were determined, with results suggesting that populations should be shifted 200 to 250 m attitudinally upward, through a program of assisted migration, to realign them to the future climate for which they are adapted.

Palabras clave

  • Assisted migration
  • climate change
  • genetic differences
  • seed zoning
  • provenances
  • annual aridity index
  • Pinus patula
Acceso abierto

Spatial genetic structure in the very rare and species-rich Picea chihuahuana tree community (Mexico)

Publicado en línea: 01 Jun 2017
Páginas: 149 - 158

Resumen

Abstract

In natural plant populations, the spatial genetic structure (SGS) is occasionally associated with evolutionary and ecological features such as the mating system, individual fitness, inbreeding depression and natural selection of the species of interest. The very rare Mexican P. chihuahuana tree community covers an area no more than 300 ha and has been the subject of several studies concerning its ecology and population genetics. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. However, analysis of the fine-scale SGS in this special forest tree community has not yet been conducted, which might help enrich the above mentioned conservation programs. In this study, we examined the SGS of this community, mostly formed by P. chihuahuana Martínez, Pinus strobiformis Ehrenberg ex Schlechtendah, Pseudotsuga menziesii (Mirb.) Franco, and Populus tremuloides Michx, in 14 localities at both the fine and large scales, with the aim of obtaining a better understanding of evolutionary processes. We observed a non-significant autocorrelation in fine-scale SGS, suggesting that the genetic variants of all four tree species are randomly distributed in space within each sampled plot of 50 x 50 m. At the larger scale, the autocorrelation was highly significant for P. chihuahuana and P. menziesii, probably as a result of insufficient gene flow due to the extreme population isolation and small sizes. For these two species our results provided strong support for the theory of isolation by distance.

Palabras clave

  • Community genetics
  • AFLP
  • gene flow
  • selection
  • Sierra Madre Occidental
  • Pinus strobiformis Ehrenberg ex Schlechtendah
  • Pseudotsuga menziesii (Mirb.) Franco
  • Populus tremuloides Michx
Acceso abierto

Inference of allelic dosages and inheritance modes in tetraploids: a case study in Betula apoiensis with a putative hybrid origin

Publicado en línea: 01 Jun 2017
Páginas: 159 - 168

Resumen

Abstract

In tetraploids, inference of allelic dosages and inheritance modes is difficult due to the ambiguous number of allele copies and the variation between disomic and tetrasomic patterns. Considering the biases of amplification and the overlaps of stutter products in polymerase chain reactions, we inferred tetraploid genotypes at three nuclear microsatellite loci in progeny arrays from six reciprocal crosses among three parents of Betula apoiensis with a putative hybrid origin. In each cross, we assigned diploid genotypes to gametes on the basis of the tetraploid genotypes of the parents and their progeny and observed the frequencies of the gamete genotypes. Segregation patterns of the observed gamete genotypes indicated few null alleles in the progeny arrays and tetrasomic inheritance with rare double reduction. This mode of inheritance was consistent between genders and between mates in the crosses. This result suggests that our method to infer tetraploid genotypes in nuclear microsatellites is successful in family samples with few null alleles when the amplification biases and the stutter-product overlaps are accessed properly.

Palabras clave

  • Allelic configuration
  • Microsatellite
  • Polyploidy
  • Reciprocal cross
  • Segregation
Acceso abierto

Visible and near infrared hyperspectral imaging reveals significant differences in needle reflectance among Scots pine provenances

Publicado en línea: 01 Jun 2017
Páginas: 169 - 180

Resumen

Abstract

Genetic diversity is an important indicator of forest sustainability requiring particular attention and new methods to obtain fast and cheap estimates of genetic diversity. We assessed the differences in visible (VIS) and near infrared (NIR) spectral reflectance properties of detached shoots of several distant Scots pine provenances aiming to identify the most informative spectral wavebands and the seasonal time for the genetic diversity scoring. Shoots of five trees per provenance were sampled at two week intervals during the active growth and fall. The samples were scanned using a hyperspectral camera, equipped with a highly sensitive spectrometer capable of covering the spectral range of 400-1000 nm with a sampling interval of 0.6 nm. The ANOVAs revealed significant provenance effects on the spectral reflectance at variable spectral intervals depending on the sampling occasion. During the active growth, PCA identified the most informative wavebands over whole spectral range investigated. During the shoot/needle hardiness development, NIR was the most informative. Provenance ranking in spectral reflectance returned geographically interpretable pattern. We conclude that there are significant provenance attributable and interpretable differences in spectral reflectance of Scots pine needles providing a good opportunity for detecting this spectral variation with the hyperspectral imaging technique.

Palabras clave

  • Pinus sylvestris
  • forest inventory
  • genetic diversity
  • phenology
  • remote sensing
Acceso abierto

Novel nuclear microsatellites in the endangered neotropical timber tree Lecythis ampla (Lecythidaceae)

Publicado en línea: 01 Jun 2017
Páginas: 181 - 184

Resumen

Abstract

For the first time, nuclear microsatellite (nSSRs) primers were developed in the endangered tree species Lecythis ampla (Lecythidaceae) as molecular tools. An enrichment protocol with genomic DNA libraries for nSSRs was used to identify candidate loci. A large number of candidate loci were identified. Consecutively population genetic parameters of these loci were tested in two available populations. Eventually 17 microsatellite loci have been identified that show no or only low evidence for linkage disequilibrium, deviations from Hardy-Weinberg expectations or high levels of null alleles. These markers are apt for future molecular population studies.

Palabras clave

  • endangered species
  • genetic diversity
  • Lecythis ampla
  • Lecythidaceae
  • microsatellites
Acceso abierto

Genetic heterogeneity in age classes of naturally regenerated old growth forest of Picea abies (L.) Karst

Publicado en línea: 01 Jun 2017
Páginas: 185 - 190

Resumen

Abstract

The Białowiez·a Primeval Forest is located northeastern Poland. It is one of Europe’s most precious old growth forests in terms of abundance and richness of vegetation, retaining features of a primeval lowland forest which cannot be found anywhere else on the European continent. The aim of the study was to assess the genetic heterogeneity of the naturally regenerated Picea abies population using five chloroplast microsatellite markers. In total, 290 trees representing five age classes were studied. Clear patterns of genetic differentiation in relation to demographic substructuring were found within the population. The class of embryos exhibited the greatest genetic richness as evident from the highest number of alleles and haplotypes, the highest mean number of private alleles and haplotypes and the highest haplotype diversity. In the subsequent age classes, a significant decrease in the level of genetic variation was observed. Our data demonstrate that long-lived, highly outcrossing tree species growing in continuous stands can be genetically heterogeneous on a small geographic scale. The heterogeneity is related to age structure and it is likely due to the underlying mating system and selection processes.

Palabras clave

  • cpSSR markers
  • age dynamics
  • genetic diversity
  • Białowiez·a Primeval Forest
  • Picea abies
Acceso abierto

Genetic diversity of Picea likiangensis natural population at different altitudes revealed by EST-SSR markers

Publicado en línea: 01 Jun 2017
Páginas: 191 - 197

Resumen

Abstract

Altitude is thought to have greatly influenced current species distribution and their genetic diversity. However, it is unclear how different altitudes have affected the distribution and genetic diversity of Picea likiangensis, a dominant forestry species in the Qinghai-Tibetan Plateau region (QTP). In this study, we investigated the genetic diversity of Picea likiangensis populations which distributed in different altitudes of QTP using EST-SSR markers. The results suggested that this species has high genetic diversity at species level, with 100% of loci being polymorphic and an average Nei’s gene diversity (He) of 0.7186 and Shannon’s information index (I) of 1.5415. While the genetic diversity of Picea likiangensis at population level was lower than that at species level, with He and I being 0.6562 and 1.3742, respectively. The variation in genetic diversity of all four studied populations indicated a low-high-low pattern along the elevation gradients. The mid-elevation population (3050 m) was more genetically diverse than both low-elevation (2900 m) and high-elevation populations (3200 m and 3350 m). Nei’s genetic diversity (Fst = 0.0809) and AMOVA analysis (Phist = 0.1135) indicated that a low level of genetic differentiation among populations. Gene flow among populations was 2.8384, suggesting that high gene flow is a main factor leading to high levels of the genetic diversity among populations.

Palabras clave

  • Picea likiangensis
  • Genetic diversity
  • EST-SSR
  • Altitude
Acceso abierto

Genetic analysis of European common ash (Fraxinus excelsior L.) populations affected by ash dieback

Publicado en línea: 01 Jun 2017
Páginas: 198 - 212

Resumen

Abstract

European common ash is an important component of mixed forest ecosystems in Bavaria and is considered a valuable tree species under climate change. The first aim of the present study was to assess the genetic diversity within and between ash populations in Bavaria in comparison with neighboring regions. Because ash stands have been heavily attacked by ash shoot disease in the last few years, the second aim of the study was to detect genetic differences between susceptible and less susceptible trees (trees with defoliation up to 30%) within populations. Altogether 41 populations were investigated using nuclear and chloroplast microsatellites. The results showed high genetic variation within and high genetic differentiation between ash populations. Higher chloroplast microsatellite variation was detected instead populations from south-eastern Bavaria compared to other regions. The comparison of susceptible and less susceptible groups of individuals within each population revealed medium to high genetic differences in some cases. For the observed heterozygosity, higher values were found for the group of less susceptible trees compared to the group of all trees or to the group of susceptible trees within populations. This could be a first indication that individuals with a higher heterozygosity might be able to withstand ash dieback in a better way compared to homozygotic individuals. Within the group of less susceptible trees a relatively wide genetic base exists whereupon a future breeding programme can be built. Thus it is of utmost importance for the species to maintain less affected trees in order to keep the genetic potential for future adaptation processes within ash populations, seed production and regeneration.

Palabras clave

  • Fraxinus excelsior
  • genetic diversity
  • Hymenoscyphus fraxineus
  • nuclear microsatellites
  • chloroplast microsatellites
Acceso abierto

Comparison of allelic diversity between native gene resource plantings and selections in open-pollinated progeny test of Pinus radiata D. Don.

Publicado en línea: 01 Jun 2017
Páginas: 213 - 221

Resumen

Abstract

Genetic diversity within radiata pine first generation of open-pollinated selections (OPS) from the native resource stands was compared with that observed in native populations to monitor potential changes in genetic diversity during domestication. Genetic diversity was estimated using 58 single nucleotide polymorphisms (SNPs) from 8 expressed genes. Nucleotide diversity maintained in first generation of selections (OPS) (mean π = 0.0036; mean θw = 0.0058) was similar to that found within the native population material (mean π = 0.0043; mean for θw = 0.0065). Likewise, mean values for expected heterozygosity (HE) within and between native population material and OPS were similar (mean = 0.27 ± 0.04) and not significantly different (P = 0.068). Also, the overall distribution of allele frequency classes was not significantly different between native population material and OPS. These results point to no evidence of loss of diversity in OPS due to artificial selection. One possible reason is that the domestication of the OPS is at a very early stage. Another may be that artificial selection in the OPS was based on tree growth and form, not wood properties. The genes selected in this study are mostly involved in cell wall formation, thus genetic diversity of these genes should remain stable between natural population and OPS, unless there was a significant sampling bias in the OPS. Although the SNP information suggests similarities among mainland populations, results from quantitative genetic studies found large provenance differences for growth-, morphological-, stem-form traits, and disease resistance. Determining the threshold at which genetic diversity levels will be significantly reduced during selection should help breeders to make informed decisions regarding the intensity of selection in managed breeding populations as well as gene resource populations.

Palabras clave

  • radiata pine
  • tree breeding
  • single nucleotide polymorphisms (SNPs)
  • allele frequency
  • genetic diversity
Acceso abierto

Promotion of resistance of black alder clones (Alnus glutinosa (L.) Gaertn.) against Phytophthora alni ssp. alni by cyclolipopeptide producing bacteria

Publicado en línea: 01 Jun 2017
Páginas: 222 - 229

Resumen

Palabras clave

  • in vitro
  • massetolide
  • Pseudomonas veronii PAZ1
  • tissue culture
  • viscosin
Acceso abierto

Three microsatellite multiplex PCR assays allowing high resolution genotyping of white spruce, Picea glauca

Publicado en línea: 01 Jun 2017
Páginas: 230 - 233

Resumen

Abstract

Fifteen previously published microsatellite primer pairs developed for and tested on Canadian white spruce were screened for amplification and polymorphy in Alaskan populations and tested for their suitability in PCR multiplexing. Eleven loci expressing polymorphisms ranging from 7 to 58 alleles were selected for development and optimization of three multiplex assays. Four natural stands containing a total of 1470 trees were used to characterize the selected loci and demonstrate their applicability for genotyping studies and parentage analysis. These assays can be used for studies focusing on population genetics, parentage analysis, provenance research, or individual genetic fingerprinting. The use of multiplex PCR facilitates large-scale studies by simultaneously enabling high resolution and reducing processing time and per sample cost.

Palabras clave

  • Picea glauca
  • SSR
  • fingerprinting
  • parentage analysis
  • population genetics
  • population structure
Acceso abierto

Investigating the Mendelian inheritance, genetic linkage, and genotypic disequilibrium for ten microsatellite loci of Araucaria angustifolia

Publicado en línea: 01 Jun 2017
Páginas: 234 - 239

Resumen

Abstract

Araucaria angustifolia is a dioecious and wind pollinated conifer that typically occurs in higher attitudes of Southern Brazil. After a significant reduction of its population during the twentieth century, public policies have enabled natural populations to recover. As new studies focus on the genetics of the species it is important to investigate Mendelian inheritance, genetic linkage, and genotypic disequilibrium for the microsatellite loci developed for the species. Here we analyze ten microsatellite loci developed for A. angustifolia by genotyping 295 adult trees and 13 open pollinated progenies from a forest fragment in Santa Catarina, Brazil. The likelihood G-test shows a perfect 1:1 Mendelian segregation for all ten loci, indicating that these molecular markers are genetic markers. Significant genetic linkage between pairwise loci was detected in only 3% of the tests, suggesting that these loci are not located in the same linkage groups within the chromosomes. However, genotypic disequilibrium was detected in 51% of pairwise loci for adult trees, probably due to the strong spatial genetic structure of the population. Our results indicate that the ten loci analyzed can be used in studies on genetic diversity and structure, mating system, and gene flow of the species.

Palabras clave

  • Araucaria
  • Conservation genetics
  • Microsatellites
  • pinheiro-do-paraná
  • Tropical tree species
Acceso abierto

Development and characterization of microsatellite loci for Cedrela fissilis Vell (Meliaceae), an endangered tropical tree species

Publicado en línea: 01 Jun 2017
Páginas: 240 - 243

Resumen

Abstract

The timber of the Neotropical tree Cedrela fissilis is used in construction, shipbuilding, carpentry and for medical purposes. In this study, polymorphic microsatellite (SSR) markers derived from an enriched genomic library were characterized using 120 adult trees from four different C. fissilis populations. No substantial genotypic linkage disequilibrium was detected among all possible pairs of SSR loci. The number of alleles per locus ranged from 2 to 20, the average allele number ranged from 8 to 9.7, depending on the population. The observed heterozygosity among the different SSR loci varied from 0.0 to 1.00 , the expected heterozygosity varied from 0.07 to 0.95 On the population level, the average observed and expected heterozygosities ranged from 0.50 to 0.63 and from 0.64 to 0.70, respectively. The average fixation index among populations ranged from 0.09 to 0.24. Thus, the SSR loci revealed high poly - morphism rates and can be used to study the genetic diversity,structure, mating system, and gene flow in C. fissilis.

Palabras clave

  • Cedar
  • Genetic diversity
  • Microsatellite markers
  • Neotropical tree species
Acceso abierto

Cytogenetic polymorphism of english oak (Quercus robur L.) seedlings from areas with different levels of anthropogenic pollution

Publicado en línea: 01 Jun 2017
Páginas: 245 - 252

Resumen

Abstract

Cytogenetic polymorphism of English oak seedlings from areas with different levels of anthropogenic pollution was studied. In each studied area, groups of seedlings with low, intermediate, and high level of mutations have been identified. Mutable groups were characterised by a high level of mitotic pathologies, broad spectrum of such pathologies (e.g., chromosome agglutination, asymmetric and tripolar mitoses). Impact of trees location near the freeway leads to variability increase of cytogenetic properties and domination of intermediate-mutable groups of seedlings.

Palabras clave

  • cytogenetic polymorphism
  • English oak
  • anthropogenic pollution
  • mitotic activity
  • pathologies of mitosis
  • nucleolar characteristics
Acceso abierto

Association mapping for resin yield in Pinus roxburghii Sarg. using microsatellite markers

Publicado en línea: 01 Jun 2017
Páginas: 253 - 266

Resumen

Abstract

Association mapping is a method for detection of gene effects based on linkage disequilibrium (LD) that complements QTL analysis in the development of tools for molecular plant breeding. A total of 240 genotypes of Pinus roxburghii (Himalayan Chir Pine) from a natural population in Chakrata division (Tiunee range), Uttarakhand (India) were evaluated for resin yield. Based on the phenotypic data and stable resin production in consecutive years, 53 genotypes were selected after excluding the individuals with similar resin production. The selected 53 individuals were best representatives of the variation in resin yield in Chakrata population which varied between 0.25 and 8.0 kg/tree/year and were used for genotyping and association analysis using SSR markers. Out of 80 primers initially screened, a total of 19 polymorphic SSRs (11 cpSSR and 8 nSSR) were used in the study. Model based clustering using 19 polymorphic SSR markers identified five subpopulations among these genotypes. LD was evaluated using the entire population. The squared allele frequency correlation, r2 was estimated for each pair of SSR loci. The comparison wise significance (p-values) of SSR marker pairs was determined by performing 100,000 permutations. The genetic divergence ranged from 50 to 100%. The UPGMA based hierarchial clustering grouped the genotypes in accordance with their resin yield. Model based clustering suggested the existence of five subpopulations in the sample. However, the distribution of P. roxburghii genotypes into five subpopulations had no correlation with their resin yield thus ruling out the possibility of any ancestral relationship among the genotypes with similar resin yield. AMOVA suggested that the variation among P. roxburghii genotypes at the molecular level was related with the variation in resin yield and not their site of collection thus highlighting the genetic basis of the trait. LD based association analysis revealed two chloroplast SSRs Pt71936 and Pt87268 and one nuclear SSR pm09a to be in significant association with resin yield. The two associated chloroplast SSRs showed significant LD (p<0.01). One of the chloroplast SSR Pt87268 showing association with resin yield was also found to be in significant LD with the nuclear SSR pm07, further showing the probability of this marker also to be associated with resin yield.

Palabras clave

  • Pinus roxburghii
  • SSR
  • association mapping
  • Linkage disequilibrium (LD)
Acceso abierto

Evaluation of the growth traits of Toxicodendron vernicifluum progeny based on their genetic groups assigned using new microsatellite markers

Publicado en línea: 01 Jun 2017
Páginas: 267 - 274

Resumen

Abstract

Toxicodendron vernicifluum (Stokes) F. A. Barkley is a tree species cultivated in Japan for production of Japanese lacquer. To facilitate the low-cost improvement of T. vernicifluum, we developed microsatellite markers for DNA fingerprinting and family and lineage reconstruction. Nine useful microsatellites were developed, with 3 to 23 alleles per locus and an expected heterozygosity of 0.162-0.838 based on a commercially planted population that included 783 offspring. Six clusters were detected in this population based on the Bayesian clustering method, and 93 half-sib families were identified using parentage and sibship assignment analysis based on a maximum likelihood method. Many members (40-96%) of large (≥10) half-sib families included specific clusters, and members from different families included the same clusters. The cluster effect for tree height was more significant than the half-sib family effect using a linear mixed model, although these effects were not significant for other traits (diameter at breast height and number of forked trunks). Based on the findings from pedigree reconstruction, backward selection for tree height seems possible. We discuss the direction of research for improving T. vernicifluum using our proposed approach.

Palabras clave

  • Backward selection
  • Bayesian clustering
  • Best unbiased linear predictor
  • Microsatellite
  • Pedigree reconstruction
  • Toxicodendron vernicifluum (Stokes) F.A. Barkley
Acceso abierto

Variation of the quantitative traits in a progeny test of Abies alba (Mill.) at the nursery stage

Publicado en línea: 01 Jun 2017
Páginas: 275 - 284

Resumen

Abstract

Fifty-one full-sib families were created using 11 parents in a silver fir seed orchard and a half-diallel mating design. The seeds of control-pollinated families were sown in a nursery in autumn 2007. Growth and branches traits were measured during nursery testing, and genetic parameters were estimated at the ages of 3, 4, 5, and 6 years. The additive and dominance genetic variances were major sources of genetic variance. Dominance variance was greater than additive variance at these early ages for all traits. However, the ratio of SCA/GCA variance decreased from 23 to 14 for total height and from 36 to 19 for root collar diameter. Broadsense family heritability is higher than individual heritability. Height and root collar diameter are the most heritable traits in silver fir. The time trend of the five heritability estimates for total height increased with age. Significant trait-trait genetic correlations were obtained. Age-age genetic correlations were very high, and they displayed increasing trends with age. The selection of the most valuable parents and most valuable individuals within the best families could maximise genetic gain in the second breeding generation of silver fir.

Palabras clave

  • Additive variance
  • non-additive variance
  • genetic correlations
  • genetic gain
  • heritability
  • silver fir
Acceso abierto

Analysis of absolute nuclear DNA content reveals a small genome and intra-specific variation in Cashew (Anacardium occidentale L.), Anacardiaceae

Publicado en línea: 01 Jun 2017
Páginas: 285 - 292

Resumen

Abstract

There are scanty data on genome size of Anacardiaceae, and none has been reported for cashew, Anacardium occidentale till date. This study aimed at determining the absolute nuclear DNA content (genome size) that could facilitate research into bio-systematics, genomics and genetic improvement of this important tropical tree crop species. Here, isolated nuclei of preparations from 43 cashew accessions selected across five growing regions were flow cytometrically analyzed for genome size determination using Solanum lycopersicum var. Stupicke with a genome size of 1.96 pg/2C as an internal reference standard.

Mean genome size was significantly different (P<0.01) across the 43 cashew accessions suggesting intra-specific variation (about 3.6% coefficient of variation) for absolute nuclear DNA content in this species, but with no evidence of endopolyploidy or endoreduplication. Flow cytometric analysis data presented here showed that absolute genome size of cashew is about 0.857 pg/2C (419 Mb/1C). However, there was a slight gradual increment in genome size from south to north gradient across sampled populations. The data also showed significant correlation (r=0.368, P<0.01) between nuclear DNA content (genome size) and phenotypic trait, nut weight. The results obtained here confirmed relatively small genome size in this tree species, almost twice genome size of diploid Arabidopsis thaliana but slightly lower than mango, Mangifera indica, a close relative in Anacardiaceae. Similarity in genome size between Mangifera indica and Anacardium occidentale could be a further proof of genetic relatedness between these two important species of Anacardiaceae.

Palabras clave

  • Anacardium occidentale
  • Cashew
  • Correlation analysis
  • Genome size
  • Nuclear DNA content
  • Nut weight
Acceso abierto

Phylogeography and genetic variability of the Arnica montana chemotypes in NW Iberian Peninsula

Publicado en línea: 01 Jun 2017
Páginas: 293 - 300

Resumen

Abstract

The threatened European species Arnica montana L. is a plant much appreciated in the pharmaceutical industry, Galicia (North-Western Spain) being one of the main supply regions. Two chemotypes based on the content of sesquiterpene lactones have been found in this area: a chemotype dominated by helenalins, common in Central Europe, and another dominated by dihydrohelenalins, only found currently in Galicia. The aim of this work was to analyse the phylogenetic relationships and genetic diversity of Arnica montana in Galicia and their concordance with previous biochemical and environmental information. Two polymorphic chloroplast markers were sequenced in individuals from populations showing significant biochemical differences and situated in different environments (heathland, hay-meadow and peatland). Three haplotypes, different from those previously described in Europe, were found in Galicia and our results suggest that one of them could be ancestral inside the species. Significant population differentiation was detected in the studied area but genetic diversity within populations was low, only showing variability in heathland populations. This study is the first one describing the genetic diversity of Arnica montana in the extreme SW of Europe. The results suggested the presence of two different genetic groups (one of them ancestral) and were congruent with the two chemotypes described. Plants from heathlands displayed the highest variability because the two chemotypes were present in them. Future design of conservation and economical management plans for this threatened species should take into account this genetic variability and prioritize further genetic and chemical characterizations across the distribution range of the species.

Palabras clave

  • Arnica montana
  • genetic variability
  • chloroplast DNA
  • sesquiterpene lactones
  • phylogeography
  • conservation
37 Artículos
Acceso abierto

1. A genetic linkage map of Pinus massoniana based on SRAP, SSR and ESTP markers

Publicado en línea: 01 Jun 2017
Páginas: 1 - 8

Resumen

Abstract

Pinus massoniana (masson pine) is the most important native pine in southern China. High-density genetic maps have not been constructed for the species. In this study, a genetic linkage map with 251 markers (47 SSRs, 23 ESTPs and 181 SRAPs) was constructed using a F1 progeny mapping population derived from controlled pollination of two parents of different provenances. At LOD 7.0, a total of 17 linkage groups were constructed with twelve groups having nine or more markers and five other groups of two to four markers each. The total map length was 1,956 cM with an average of 8.4 cM among individual loci. The current linkage map represented 93% of the estimated genome length of 2,114 cM for masson pine. Such linkage map are useful for future genomic studies of masson pine including comparative mapping in Pinaceae and quantitative trait loci (QTL) mapping for economically important traits.

Palabras clave

  • Pinus massoniana
  • linkage map
  • SSR
  • SRAP
  • ESTP
Acceso abierto

Performance of Eucalyptus Clones in Auto and Allocompetition

Publicado en línea: 01 Jun 2017
Páginas: 9 - 14

Resumen

Abstract

This study was performed to estimate the abilities of eucalyptus clones to exercise as well as to tolerate competition and to compare their behaviors under auto- or allocompetition. Six commercial clones, belonging to PLANTAR S/A enterprise were evaluated for breast height circumference (BHC), total height (TH) and volume (VOL). At three locations of Minas Gerais, Brazil (two in Curvelo and one in Felixlândia) the clones were planted in two spaces. At 36 months of age each clone was evaluated for exercising and toleration competition amongst each other. The design for each experiment was similar to that of the nine-hole system; the center clone being under competition and the eight surrounding the center clone exercising competition. Each clone under competition was repeated eight times; therefore, for each spacing and location, six contiguous experiments were conducted. From the mean values; the parameters of ability to exercise competition (ci), ability to tolerate competition (tj), the specific competitive ability (sij) and the performance per se of the clones (aj) were estimated using a model similar to that of diallel crosses. The clones differed as to their ci, tj and aj. No one clone exhibited high and positive ci and tj. Regardless of location, spacing, or clone, the performance of autocompetition is similar to that of allocompetition. This indicates that a mixture of clones, if advantageous from the management or industrial point of view, may be performed without harm to the volume of wood produced.

Palabras clave

  • Eucalyptus
  • competition
  • mixture
  • clone
  • autocompetition
  • allocompetition
  • uniformity
Acceso abierto

Hybridizing ability and heterosis between Eucalyptus urophylla and E. tereticornis for growth and wood density over two environments

Publicado en línea: 01 Jun 2017
Páginas: 15 - 23

Resumen

Abstract

Interspecific hybrids of Eucalyptus urophylla × E. tereticornis in a factorial-mating design were used to analyze general hybridizing ability (GHA), specific hybridizing ability (SHA) and heterosis for height (H; 0.5, 1.5, 2.5, 4 and 7.5 years in age), diameter at breast height (D; ages 1.5, 2.5, 4 and 7.5) and wood density (WD; age 7.5) across two environments. The GHA variances were significant for all traits, and those of the SHA were also significant for most of the traits but with less magnitude, indicating the greater importance of additive gene effects in explaining the phenotypic variation among hybrids. The narrow-sense heritability (h2) and dominance (d2) estimates with hybrid growth and wood density ranged between 0.02±0.05 (d2 in D7.5) and 0.23±0.10 (d2 in H1.5) over the different ages, suggesting weak additive and dominant effects on these traits. Additive genetic correlations of growth with wood density were weak at age 7.5. Female general combining ability (GCA) based on maternal open-pollinated families was not necessarily a good indicator of GHA as their correlations were 0.48 (P=0.17), 0.65 (P=0.04) and -0.56 (P=0.10) for H7.5, D7.5 and WD7.5, respectively. A great proportion of hybrids showed positive female-parent heterosis (FPH) at age 7.5, with the highest relative FPH of 47.2% in D7.5. This study demonstrates the heterosis between inter-sectional species and could have implications for E. urophylla × E. tereticornis hybrid breeding.

Palabras clave

  • Hybridizing ability
  • heterosis
  • growth
  • wood density
  • Eucalyptus
Acceso abierto

Clonal Variation of Eucalypts in Susceptibility to Bacterial Wilt Detected by Using Different Inoculation Methods

Publicado en línea: 01 Jun 2017
Páginas: 24 - 31

Resumen

Palabras clave

  • Eucalypt
  • Ralstonia solanacearum
  • bacterial wilt
  • inoculation
  • clonal variation
  • repeatability
Acceso abierto

Experimental strategies for clonal eucalyptus

Publicado en línea: 01 Jun 2017
Páginas: 32 - 38

Resumen

Abstract

The success of any forestry operation depends on the careful choice of the clones to be planted. At existing yield levels, the differences among clones are becoming smaller, leading to the need to use experimental strategies for a more successful choice. To obtain information in regard to better experimental strategies, data from two clonal tests of eucalyptus were used. One of the tests consisted of 35 clones and another of 48 clones. In both tests, the experimental plot consisted of 100 plants at commercial spacing (12 m2 per plant). The trait wood volume was evaluated, taking the relative position of the plant in the plot as a reference. The data were evaluated by different means, and it was observed that the use of border plot in clonal tests in eucalyptus is not necessary. Experimental accuracy with 15 to 20 plants is similar in comparison to the plot with 100 plants.

Palabras clave

  • Eucalyptus
  • experimental precision
  • accuracy
  • plot size
Acceso abierto

Short note: Genetic diversity and differentiation in Ural populations of the aspen, Populus tremula L., as revealed by inter-simply sequence repeat (ISSR) markers

Publicado en línea: 01 Jun 2017
Páginas: 39 - 40

Resumen

Abstract

Genetic diversity and differentiation of six Populus tremula L. populations in the Ural mountains (Russia) were investigated using ISSR-markers. Analyses revealed relatively high genetic diversity and significant (p = 0.985) genetic isolation by distance of foothill and plain cis-Ural populations in the zone of forests with mixed coniferous and broad-leaved tree species. The genetic drift may be a factor that lead to comparatively low genetic variability and genetic singularities of isolated small populations of the aspen in dark coniferous taiga of the Ural mountains.

Palabras clave

  • inter-simply sequence repeat (ISSR) markers
  • genetic diversity
  • genetic differentiation
  • Populus tremula L.
  • Ural mountains
Acceso abierto

Variation and Stability in Female Strobili Production of a First-Generation Clonal Seed Orchard of Chinese Pine (Pinus tabuliformis)

Publicado en línea: 01 Jun 2017
Páginas: 41 - 46

Resumen

Abstract

Seed orchards of Chinese pine, Pinus tabuliformis, are in a transition period from first generation to advanced generation. During this crucial period, evaluation of seed production in seed orchards is essential. Female strobili production is an important factor in seed production. This study examined the variation and stability in female strobili production in a first-generation clonal seed orchard of Chinese pine in years 9, 10, 13, 14, 20 and 21 after grafting in 1974. The results showed significant variation in female strobili production among clones, years, and interactions between clones and years. Correlations in female strobili production between years were significant. The repeatability for female strobili production within the examined years ranged from 0.47 to 0.87. The relative stability of female strobili production varied among clones, with regression coefficients among individual clones and an environmental index ranging from 0.13 to 2.81. The productivity index in different clones ranged from -1.09 to 1.83. Yield stability of female strobili among clones could be estimated from female strobili production. Clones could be divided into three groups according to their stability and productivity parameters. The results of this research provide guidance for evaluating clones in existing seed orchards, as well as some basic information for seed orchard management and advanced-generation seed orchard establishment.

Palabras clave

  • Pinus tabuliformis
  • first generation
  • clonal seed orchard
  • female strobili production
  • variation
  • stability
  • productivity
  • seed orchard management
  • advanced-generation seed orchard establishment
Acceso abierto

Breeding triploid aspen and poplar clones for biomass production

Publicado en línea: 01 Jun 2017
Páginas: 47 - 58

Resumen

Abstract

Enriched diploid pollen was applied for in vitro pollinations and crossbreeding in the greenhouse to produce high performance triploid aspen and aspen hybrids for cultivation in medium rotation plantations. In addition to crossings within the section Populus, intersectional crossbreeding was performed to combine benefits of intersectional hybridization with those derived from triploidisation.

Both the enrichment of diploid pollen by size fractionation of naturally unreduced pollen and heat treatment of microspore mother cells resulted in a distinct increase of diploid pollen. Using this pollen, six triploid plants were obtained from in vitro pollinations and twenty from crossbreeding in the greenhouse. The triploid plants displayed a high variability in growth performance. Two clones from in vitro pollination and five from crossbreeding in the greenhouse were chosen to estimate growth characteristics. A first assessment of clone performance in an outdoor container test con - ducted over one growing season revealed two triploid clones with a same stem height and a significantly increased basal stem diameter in comparison to the fast-growing triploid reference clone “Astria”. Crossbreeding experiments also resulted in two fast-growing mixoploid clones, which have already been stable for several years.

All in all, in this study, crossbreeding using enriched diploid pollen is proved to be a reliable and applicable approach for an effective breeding of triploid poplars.

Palabras clave

  • Populus spp.
  • triploid
  • in vitro pollination
  • intersectional crossbreeding
  • diploid pollen
Acceso abierto

Molecular evolution of drought tolerance and wood strength related candidate genes in loblolly pine (Pinus taeda L.)

Publicado en línea: 01 Jun 2017
Páginas: 59 - 66

Resumen

Abstract

Loblolly pine (Pinus taeda L.) is an intensely studied species that has become a model system for conifers. It is one of the most important commercial crops in the southeastern United States and grows across a vast territory. Due to exposure to this current diverse environment and the fluctuating climatic conditions of the past, it has likely accumulated substantial variation in adaptive trait and wood strength related genes. We merged a set of newly collected and previously published genomic DNA sequence data and analyzed them for departures from neutrality in 32 drought tolerance and wood strength related candidate genes using neutrality tests, such as Tajima’s D, HKA, MK and nonsynonymous to synonymous substitutions ratio (Z-test). Three other major Southern pines closely related to P. taeda (Pinus echinata Mill., P. elliottii Engelm., and P. palustris Mill.) were used as outgroups in interspecific tests. In three loci (4-coumarate: CoA ligase, putative cell-wall protein and trans-cinnamate 4-hydroxylase 2) neutrality was rejected by both intra- and interspecific tests, consistent with purifying selection. Neutrality was also rejected in several other loci (alpha-tubulin, arabinogalactan 4, arabinogalactan 6, cinnamate 4-hydroxylase 1, cinnamoyl CoA reductase, cinnamyl alcohol dehydrogenase, caffeoyl CoA O-methyltransferase 1, early response to drought 3, glycine hydroxymethyltransferase, ABI1 protein phosphatase 2C-like, putative wall-associated protein kinase, and unknown gene ug_2-498); however, these results are difficult to interpret because only one of the tests proved significant. This study contributes to the ongoing discussion about natural selection in putative adaptive genes in loblolly pine. However, unambiguous interpretation of the results often remains problematic.

Palabras clave

  • loblolly pine
  • longleaf pine
  • shortleaf pine
  • slash pine
  • Australes
  • drought tolerance
  • wood strength
  • neutrality tests
  • SNP
  • natural selection
Acceso abierto

Growth response of European larch (Larix decidua Mill.) populations to climatic transfer A Novel Approach for Controlled Pollination in Casuarina equisetifolia

Publicado en línea: 01 Jun 2017
Páginas: 67 - 75

Resumen

Abstract

The study focuses on growth responses of Larix decidua provenances to climatic transfer based on a regional provenance experiment. This comprises a series of 5 trial plots situated in Germany and Slovakia, where 12 indigenous Sudetic and West-Carpathian larch provenances are planted. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. 1st and 2nd-order polynomial regressions were used for the identification of overall trends of growth performance and responses to transfer.

Sudetic provenances clearly outperformed the Carpathian ones on all test sites. When all provenances were considered jointly, height and breast-height diameter mostly showed significant monotonous geographical and climatic trends: the performance generally decreased with increasing altitude and precipitations and decreasing temperatures. The relationships between growth response and transfer rates (ecodistances) were mostly linear. However, when Sudetic and Carpathian provenances were considered separately, most significant response curves were unimodal. There is a very good correspondence between the responses in height and diameter growth within geographic groups, but the responses are not consistent between groups. Joint regression analysis showed that most provenances exhibited average stability. Stability indices are quite consistent between the response traits and did not show any association with the geographical position, climate of origin, or growth performance.

The results indicate that populations in different climates remain adapted to a common optimum, the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.

Palabras clave

  • Larix decidua
  • local adaptation
  • phenotypic plasticity
  • provenance research
  • climatic transfer
Acceso abierto

A Novel Approach for Controlled Pollination in Casuarina equisetifolia

Publicado en línea: 01 Jun 2017
Páginas: 76 - 80

Resumen

Abstract

Casuarina equisetifolia is an important tree species in the tropical and subtropical zones of Asia, Africa and the Pacific. There is an increasing interest in producing intra- and inter-specific hybrids of casuarina species. Conventional bagging controlled pollination method yielded very low fruit set and poor seed germination. High temperature and humidity in the pollination bags appeared to have instigated unfavorable conditions for pollination and fertilization mechanism. In this study, a novel approach was developed by conducting pollination in closed chambers which functioned like pollination bags. Fruit set and seed germination rate increased from 7.0% to 89.9%, and 8.1% to 51.8% respectively compared with the conventional bagging controlled pollination method. Based on the results, a controlled pollination glasshouse with 10 separated chambers has been designed to produce multiple hybrid combinations in a single pollination procedure.

Palabras clave

  • Casuarina equisetifolia
  • cross breeding
  • controlled pollination
  • fruit set
  • seed germination rate
  • pollination chambers
Acceso abierto

Hybridization and Genetic Diversity in Wild Apple (Malus sylvestris (L.) MILL.) from Various Regions in Germany and from Luxembourg

Publicado en línea: 01 Jun 2017
Páginas: 81 - 93

Resumen

Abstract

Malus sylvestris is the only apple species native to Central Europe. Its genetic integrity may be threatened by hybridization with the cultivated apple (Malus × domestica). A total of 883 genotypes, 477 putative wild apples in Germany and Luxembourg and 406 old to modern cultivars has been investigated. Wild apples growing in Germany originated from Rhineland-Palatinate, North Rhine-Westphalia, Saxony-Anhalt and Saxony. The genetic structure was analysed at ten isozyme marker loci, and morphology was studied by fruit size, leaf pubescence, and a complex morphological description performed in advance. A model-based cluster analysis applied to all nuclear data resulted in two clearly differentiated gene pools for putative wild and cultivated apples with moderate proportions of admixture in the wild group on average (0.138 total, 0.111 German sample). At the individual level, the percentages of both hybrids and feral cultivars together ranged from 2.3% in Rhineland-Palatinate to 28.8% in Luxembourg. The intraspecific variability in fruit diameter ranged from 21 to 40 mm, and that in leaf pubescence in autumn ranged from score 0 to score 1. No single morphological trait of a specimen appeared to be sufficient for identification. Even the correspondence between the complex morphological and complex genetic determinations for individuals did not exceed 93% in pure wilds and 64% in hybrids. Genetic variation in pure wild apple is high (species level: P = 90%, A/L = 3.1, He = 0.369). Allelic differentiation & was 0.089, pairwise genetic distance (d0) ranged from 0.065 to 0.148 among five samples. Correspondence between genetic and geographic distance of populations was observed to a certain extent.

Palabras clave

  • Malus sylvestris
  • Malus × domestica
  • introgression
  • gene flow
  • genetic variation
  • genetic differentiation
  • isozymes
  • morphology
  • conservation
  • biodiversity
Acceso abierto

Comparative assessment of SSR, ISSR and AFLP markers for characterization of selected genotypes of Himalayan Chir pine (Pinus roxburghii Sarg.) based on resin yield

Publicado en línea: 01 Jun 2017
Páginas: 94 - 108

Resumen

Abstract

A set of 19 SSR (Simple Sequence Repeats), 9 ISSR (Inter-Simple Sequence Repeats) and 5 AFLP (Amplified Fragment Length Polymorphism) primer combinations were used to evaluate the variability among 53 genotypes of Pinus roxburghii selected based on resin yield from the natural zone of occurrence of this species in Uttarakhand, India. The selected trees of pine varied in resin yield from 0.25 to 8 kg/year/tree. Based on the comparative assessment of SSR, ISSR and AFLP markers, SSR markers were found most polymorphic with an average PIC value of 0.327 and 2.42 alleles per marker, while ISSR markers showed the highest effective multiplex ratio (15.536) and marker index (4.958). AFLP markers showed the maximum resolving power (8.099) which was comparable to the resolving power (8.059) of ISSR markers. UPGMA-based dendrogram using SSR markers revealed more distinct grouping of genotypes on the basis of resin yield as compared to ISSR and AFLP markers. AMOVA by collection site revealed no significant variation among the populations. Whereas, AMOVA by resin yield using SSR, ISSR and AFLP markers revealed FST values to be 0.1096, 0.0483 and 0.2422 indicating moderate, low and great genetic differentiation among the groups. This clearly indicated that the variation at the molecular level was attributed to the resin yield and not the site of collection.

Palabras clave

  • genetic diversity
  • fixation index
  • AMOVA
  • PIC
Acceso abierto

Short Note: Isolation and Characterization of 12 Polymorphic Microsatellite Markers in Engelhardia roxburghiana (Juglandaceae)

Publicado en línea: 01 Jun 2017
Páginas: 109 - 112

Resumen

Abstract

Engelhardia roxburghiana is a common half evergreen tree with a wide distribution in southeast Asia. Despite its ecological and pharmaceutical values, its genetic diversity is poorly studied. Our objective was to develop nuclear microsatellite markers to investigate the level of genetic diversity within and among populations in the future. Using the microsatellite-enriched library and PCR-based screening method, 12 microsatellite markers were developed and showed polymorphism in a population. The number of alleles per locus for these 12 microsatellites ranged from four to 15. The observed and expected heterozygosities ranged from 0.358 to 0.897 and from 0.369 to 0.886, respectively. The developed microsatellites will be useful for studying genetic diversity and population structure in E. roxburghiana.

Palabras clave

  • DHS plot
  • DNA enriched libraries
  • genetic marker
  • genetic variation
  • Hardy-Weinberg equilibrium
  • linkage disequilibrium
  • marker development
  • microsatellite
  • population genetics
  • spatial genetic structure
  • subtropical China
Acceso abierto

Short note: Development, characterization and cross-amplification of eight EST-derived microsatellites in Salix

Publicado en línea: 01 Jun 2017
Páginas: 113 - 115

Resumen

Abstract

A set of eight simple sequence repeat (SSR) markers were developed from 707 Salix expressed sequence tags (ESTs) deposited in GenBank. Each of the EST-SSR amplicons was identical to the original EST, with sequence identity 60.90-96.03% and presence of the expected repeat motifs. Of the eight EST-SSR loci, five were polymorphic among 14 individuals of S. eriocephala, with the number of alleles per locus (Na), observed heterozygosity (Ho), expected heterozygosity (He) and polymorphic information content (PIC) being 2-7 (mean 4.8), 0.29-0.85 (mean 0.65), 0.25-0.84 (mean 0.65) and 0.21-0.78 (mean 0.58), respectively. High rates of crossspecies/ genus amplification were also observed within fourteen different species. The primer sequences for the eight EST-SSRs have been deposited in the Probe database of GenBank (IDs Pr031820546 - Pr031820553). The EST-SSRs developed herein would be a valuable addition of functional markers for genetics and breeding applications in a wide range of Salix species.

Palabras clave

  • Salix
  • Willow
  • Expressed sequence tag (EST)
  • Simple sequence repeat (SSR)
  • Microsatellites
Acceso abierto

Geographic Variation and Local Growth Superiority for Coastal Douglas-fir – Rotation-age Growth Performance in a Douglas-fir Provenance Test

Publicado en línea: 01 Jun 2017
Páginas: 116 - 124

Resumen

Abstract

Rotation-age growth performance of 16 provenances and local growth superiority were assessed from a rotation- age reciprocal coastal Douglas-fir [Pseudotsuga menziesii var. menziesii (Mirb.) Franco] provenance test established in the Pacific Northwest of America. Provenance differences for total volume per plot were highly significant. Due to the significant provenance × site interaction effect, the best provenances varied across planting sites in terms of rotation-age volume growth. Local provenance trees exhibited superior volume growth at two of the six planting sites. At the remaining four sites, local provenances performed equally well as average non-local provenances. At the three low-elevation (< 460 m) sites, low-elevation provenances performed significantly better than high-elevation provenances. By contrast, high- and low-elevation provenances had similar growth at the two high-elevation (> 800 m) sites. Southern provenances generally grew faster than northern provenances at the Oregon sites, while northern provenances performed better than southern provenances at the sites in British Columbia.

Regression analyses showed that although local growth superiority increased with the geographic distance between provenance’s origin and the test site in general (r=0.47, P<0.001), it only became obvious when the geographic distance is larger than 435 km in latitude or 370 m in elevation. Significant spatial autocorrelation was found via Mantel test, and geographically or climatically closely located provenances tended to have similar rotation-age volume growth.

The results suggested that breeding zones larger than the current second-cycle zones would lead to little loss of rotation-age total volume for coastal Douglas-fir in this region.

Palabras clave

  • Douglas-fir
  • provenance
  • rotation-age growth
  • local superiority
  • local adaptation
  • provenance × site interaction
  • breeding zone
Acceso abierto

In vitro Competition of Betula alnoides Pollens from Two Types of Habitats in a Heterogeneous Landscape in South China

Publicado en línea: 01 Jun 2017
Páginas: 125 - 132

Resumen

Abstract

Pollens of Betula alnoides were collected in its natural forests at two types of sites with soils originated from limestone (Site L) and granite (Site G) in a heterogeneous landscape at Jingxi County, Guangxi in 2010 to 2012 to investigate whether nutritional differences between the sites influenced its pollen competition. In vitro pollen germinations were conducted separately and in pairs for these samples as well as nutrient contents of pollens and soils were measured. There was no significant difference in total nitrogen, phosphorus, potassium and calcium contents of dried pollen and in efficient ones of aqueous extracts of pollens between two types of sites although the soil nutrient contents were quite different between them, and less remarkable correlation was found between these nutrient contents of soil and pollen. The results of pollen competition of B. alnoides were much diverse among three years, it seemed that pollen-pollen interaction did not depend on site type, and might vary according to genotype and/or combination of genotypes.

Palabras clave

  • Betula alnoides
  • genotype
  • habitat
  • heterogeneous landscape
  • in vitro
  • pollen competition
  • pollen germination
  • pollen nutrition
  • pollen tube growth
  • soil nutrition
Acceso abierto

Habitat fragmentation decreased the genetic variability of Trichilia elegans A. Juss. (Meliaceae) in southern Brazil

Publicado en línea: 01 Jun 2017
Páginas: 133 - 138

Resumen

Abstract

Habitat fragmentation and the creation of so-called edge effects may have different implications on flora and fauna, including complex genetic responses. This study aimed to analyze the genetic diversity in a local population of the shade tolerant tree Trichilia elegans A. Juss (Meliaceae), with emphasis to the evaluation of genetic variation towards an edge-interior gradient. The results of isoenzymes assays showed that the edge subpopulation experienced the highest allele loss, while fixed alleles increased towards the interior. The total polymorphic loci percentage was 76.67%, being higher in the Middle subpopulation, whilethe average sample size for a locus (N) and the mean number of alleles for a locus (Na) were significantly lower in the Edge subpopulation. The indices Ho, He and f showed good heterozygosity in the total population, indicating high genetic variability. The genetic distance Fst and Nm followed the same pattern, with Middle and Interior subpopulations showing higher similarity and the Edge as the farthest one, also showing less gene flow in relation to the others. Principal Coordinates Analysis (PCoA) allowed us to separate the three subpopulations with the first two axes explaining 65% of total variation, confirming that forest fragmentation affects the genetics of Trichilia elegans within the analyzed fragment.

Palabras clave

  • Isoenzymes
  • habitat fragmentation
  • allele frequency
  • gene flow
  • araucaria forest
Acceso abierto

Altitudinal genetic variation among native Pinus patula provenances: performance in two locations, seed zone delineation and adaptation to climate change

Publicado en línea: 01 Jun 2017
Páginas: 139 - 148

Resumen

Abstract

To select the genetic source of Pinus patula Shiede and Deppe seed best adapted to different native zones for reforestation, seedlings of 12 provenances native to a selected altitudinal gradient in Oaxaca, southern Mexico, were planted on two sites at contrasting altitudes (high 3000 m above sea level (masl) and low, 2500 masl) within the species natural distribution, and tested for growth in height at age 18, 24 and 36 months. Differences among provenances and between sites showed significance (p<0.05). Seedling growth showed a climatic and altitudinal pattern, in which seedlings from populations originating in low-middle altitudes had higher growth than populations originating in high altitudes, and from the extreme low altitude limit. Results were used to delineate climatic and altitudinal seed zones for contemporary and future climate zones in the decade centered in year 2030, using the average results of six climate-emissions scenarios. The results indicate that splitting the region into four seed zones is appropriate under contemporary climate scenarios with the following altitude limits: Zone 1, from 2300 to 2500 masl; Zone 2, 2500 to 2700 masl; Zone 3, 2700 to 2900 masl and Zone 4 from 2900 to 3100 masl. The equivalence on climatic intervals was also defined for mean annual temperature, precipitation and an annual aridity index (AAI). Values of contemporary AAI occurring at a given altitude by year 2030 were determined, with results suggesting that populations should be shifted 200 to 250 m attitudinally upward, through a program of assisted migration, to realign them to the future climate for which they are adapted.

Palabras clave

  • Assisted migration
  • climate change
  • genetic differences
  • seed zoning
  • provenances
  • annual aridity index
  • Pinus patula
Acceso abierto

Spatial genetic structure in the very rare and species-rich Picea chihuahuana tree community (Mexico)

Publicado en línea: 01 Jun 2017
Páginas: 149 - 158

Resumen

Abstract

In natural plant populations, the spatial genetic structure (SGS) is occasionally associated with evolutionary and ecological features such as the mating system, individual fitness, inbreeding depression and natural selection of the species of interest. The very rare Mexican P. chihuahuana tree community covers an area no more than 300 ha and has been the subject of several studies concerning its ecology and population genetics. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. However, analysis of the fine-scale SGS in this special forest tree community has not yet been conducted, which might help enrich the above mentioned conservation programs. In this study, we examined the SGS of this community, mostly formed by P. chihuahuana Martínez, Pinus strobiformis Ehrenberg ex Schlechtendah, Pseudotsuga menziesii (Mirb.) Franco, and Populus tremuloides Michx, in 14 localities at both the fine and large scales, with the aim of obtaining a better understanding of evolutionary processes. We observed a non-significant autocorrelation in fine-scale SGS, suggesting that the genetic variants of all four tree species are randomly distributed in space within each sampled plot of 50 x 50 m. At the larger scale, the autocorrelation was highly significant for P. chihuahuana and P. menziesii, probably as a result of insufficient gene flow due to the extreme population isolation and small sizes. For these two species our results provided strong support for the theory of isolation by distance.

Palabras clave

  • Community genetics
  • AFLP
  • gene flow
  • selection
  • Sierra Madre Occidental
  • Pinus strobiformis Ehrenberg ex Schlechtendah
  • Pseudotsuga menziesii (Mirb.) Franco
  • Populus tremuloides Michx
Acceso abierto

Inference of allelic dosages and inheritance modes in tetraploids: a case study in Betula apoiensis with a putative hybrid origin

Publicado en línea: 01 Jun 2017
Páginas: 159 - 168

Resumen

Abstract

In tetraploids, inference of allelic dosages and inheritance modes is difficult due to the ambiguous number of allele copies and the variation between disomic and tetrasomic patterns. Considering the biases of amplification and the overlaps of stutter products in polymerase chain reactions, we inferred tetraploid genotypes at three nuclear microsatellite loci in progeny arrays from six reciprocal crosses among three parents of Betula apoiensis with a putative hybrid origin. In each cross, we assigned diploid genotypes to gametes on the basis of the tetraploid genotypes of the parents and their progeny and observed the frequencies of the gamete genotypes. Segregation patterns of the observed gamete genotypes indicated few null alleles in the progeny arrays and tetrasomic inheritance with rare double reduction. This mode of inheritance was consistent between genders and between mates in the crosses. This result suggests that our method to infer tetraploid genotypes in nuclear microsatellites is successful in family samples with few null alleles when the amplification biases and the stutter-product overlaps are accessed properly.

Palabras clave

  • Allelic configuration
  • Microsatellite
  • Polyploidy
  • Reciprocal cross
  • Segregation
Acceso abierto

Visible and near infrared hyperspectral imaging reveals significant differences in needle reflectance among Scots pine provenances

Publicado en línea: 01 Jun 2017
Páginas: 169 - 180

Resumen

Abstract

Genetic diversity is an important indicator of forest sustainability requiring particular attention and new methods to obtain fast and cheap estimates of genetic diversity. We assessed the differences in visible (VIS) and near infrared (NIR) spectral reflectance properties of detached shoots of several distant Scots pine provenances aiming to identify the most informative spectral wavebands and the seasonal time for the genetic diversity scoring. Shoots of five trees per provenance were sampled at two week intervals during the active growth and fall. The samples were scanned using a hyperspectral camera, equipped with a highly sensitive spectrometer capable of covering the spectral range of 400-1000 nm with a sampling interval of 0.6 nm. The ANOVAs revealed significant provenance effects on the spectral reflectance at variable spectral intervals depending on the sampling occasion. During the active growth, PCA identified the most informative wavebands over whole spectral range investigated. During the shoot/needle hardiness development, NIR was the most informative. Provenance ranking in spectral reflectance returned geographically interpretable pattern. We conclude that there are significant provenance attributable and interpretable differences in spectral reflectance of Scots pine needles providing a good opportunity for detecting this spectral variation with the hyperspectral imaging technique.

Palabras clave

  • Pinus sylvestris
  • forest inventory
  • genetic diversity
  • phenology
  • remote sensing
Acceso abierto

Novel nuclear microsatellites in the endangered neotropical timber tree Lecythis ampla (Lecythidaceae)

Publicado en línea: 01 Jun 2017
Páginas: 181 - 184

Resumen

Abstract

For the first time, nuclear microsatellite (nSSRs) primers were developed in the endangered tree species Lecythis ampla (Lecythidaceae) as molecular tools. An enrichment protocol with genomic DNA libraries for nSSRs was used to identify candidate loci. A large number of candidate loci were identified. Consecutively population genetic parameters of these loci were tested in two available populations. Eventually 17 microsatellite loci have been identified that show no or only low evidence for linkage disequilibrium, deviations from Hardy-Weinberg expectations or high levels of null alleles. These markers are apt for future molecular population studies.

Palabras clave

  • endangered species
  • genetic diversity
  • Lecythis ampla
  • Lecythidaceae
  • microsatellites
Acceso abierto

Genetic heterogeneity in age classes of naturally regenerated old growth forest of Picea abies (L.) Karst

Publicado en línea: 01 Jun 2017
Páginas: 185 - 190

Resumen

Abstract

The Białowiez·a Primeval Forest is located northeastern Poland. It is one of Europe’s most precious old growth forests in terms of abundance and richness of vegetation, retaining features of a primeval lowland forest which cannot be found anywhere else on the European continent. The aim of the study was to assess the genetic heterogeneity of the naturally regenerated Picea abies population using five chloroplast microsatellite markers. In total, 290 trees representing five age classes were studied. Clear patterns of genetic differentiation in relation to demographic substructuring were found within the population. The class of embryos exhibited the greatest genetic richness as evident from the highest number of alleles and haplotypes, the highest mean number of private alleles and haplotypes and the highest haplotype diversity. In the subsequent age classes, a significant decrease in the level of genetic variation was observed. Our data demonstrate that long-lived, highly outcrossing tree species growing in continuous stands can be genetically heterogeneous on a small geographic scale. The heterogeneity is related to age structure and it is likely due to the underlying mating system and selection processes.

Palabras clave

  • cpSSR markers
  • age dynamics
  • genetic diversity
  • Białowiez·a Primeval Forest
  • Picea abies
Acceso abierto

Genetic diversity of Picea likiangensis natural population at different altitudes revealed by EST-SSR markers

Publicado en línea: 01 Jun 2017
Páginas: 191 - 197

Resumen

Abstract

Altitude is thought to have greatly influenced current species distribution and their genetic diversity. However, it is unclear how different altitudes have affected the distribution and genetic diversity of Picea likiangensis, a dominant forestry species in the Qinghai-Tibetan Plateau region (QTP). In this study, we investigated the genetic diversity of Picea likiangensis populations which distributed in different altitudes of QTP using EST-SSR markers. The results suggested that this species has high genetic diversity at species level, with 100% of loci being polymorphic and an average Nei’s gene diversity (He) of 0.7186 and Shannon’s information index (I) of 1.5415. While the genetic diversity of Picea likiangensis at population level was lower than that at species level, with He and I being 0.6562 and 1.3742, respectively. The variation in genetic diversity of all four studied populations indicated a low-high-low pattern along the elevation gradients. The mid-elevation population (3050 m) was more genetically diverse than both low-elevation (2900 m) and high-elevation populations (3200 m and 3350 m). Nei’s genetic diversity (Fst = 0.0809) and AMOVA analysis (Phist = 0.1135) indicated that a low level of genetic differentiation among populations. Gene flow among populations was 2.8384, suggesting that high gene flow is a main factor leading to high levels of the genetic diversity among populations.

Palabras clave

  • Picea likiangensis
  • Genetic diversity
  • EST-SSR
  • Altitude
Acceso abierto

Genetic analysis of European common ash (Fraxinus excelsior L.) populations affected by ash dieback

Publicado en línea: 01 Jun 2017
Páginas: 198 - 212

Resumen

Abstract

European common ash is an important component of mixed forest ecosystems in Bavaria and is considered a valuable tree species under climate change. The first aim of the present study was to assess the genetic diversity within and between ash populations in Bavaria in comparison with neighboring regions. Because ash stands have been heavily attacked by ash shoot disease in the last few years, the second aim of the study was to detect genetic differences between susceptible and less susceptible trees (trees with defoliation up to 30%) within populations. Altogether 41 populations were investigated using nuclear and chloroplast microsatellites. The results showed high genetic variation within and high genetic differentiation between ash populations. Higher chloroplast microsatellite variation was detected instead populations from south-eastern Bavaria compared to other regions. The comparison of susceptible and less susceptible groups of individuals within each population revealed medium to high genetic differences in some cases. For the observed heterozygosity, higher values were found for the group of less susceptible trees compared to the group of all trees or to the group of susceptible trees within populations. This could be a first indication that individuals with a higher heterozygosity might be able to withstand ash dieback in a better way compared to homozygotic individuals. Within the group of less susceptible trees a relatively wide genetic base exists whereupon a future breeding programme can be built. Thus it is of utmost importance for the species to maintain less affected trees in order to keep the genetic potential for future adaptation processes within ash populations, seed production and regeneration.

Palabras clave

  • Fraxinus excelsior
  • genetic diversity
  • Hymenoscyphus fraxineus
  • nuclear microsatellites
  • chloroplast microsatellites
Acceso abierto

Comparison of allelic diversity between native gene resource plantings and selections in open-pollinated progeny test of Pinus radiata D. Don.

Publicado en línea: 01 Jun 2017
Páginas: 213 - 221

Resumen

Abstract

Genetic diversity within radiata pine first generation of open-pollinated selections (OPS) from the native resource stands was compared with that observed in native populations to monitor potential changes in genetic diversity during domestication. Genetic diversity was estimated using 58 single nucleotide polymorphisms (SNPs) from 8 expressed genes. Nucleotide diversity maintained in first generation of selections (OPS) (mean π = 0.0036; mean θw = 0.0058) was similar to that found within the native population material (mean π = 0.0043; mean for θw = 0.0065). Likewise, mean values for expected heterozygosity (HE) within and between native population material and OPS were similar (mean = 0.27 ± 0.04) and not significantly different (P = 0.068). Also, the overall distribution of allele frequency classes was not significantly different between native population material and OPS. These results point to no evidence of loss of diversity in OPS due to artificial selection. One possible reason is that the domestication of the OPS is at a very early stage. Another may be that artificial selection in the OPS was based on tree growth and form, not wood properties. The genes selected in this study are mostly involved in cell wall formation, thus genetic diversity of these genes should remain stable between natural population and OPS, unless there was a significant sampling bias in the OPS. Although the SNP information suggests similarities among mainland populations, results from quantitative genetic studies found large provenance differences for growth-, morphological-, stem-form traits, and disease resistance. Determining the threshold at which genetic diversity levels will be significantly reduced during selection should help breeders to make informed decisions regarding the intensity of selection in managed breeding populations as well as gene resource populations.

Palabras clave

  • radiata pine
  • tree breeding
  • single nucleotide polymorphisms (SNPs)
  • allele frequency
  • genetic diversity
Acceso abierto

Promotion of resistance of black alder clones (Alnus glutinosa (L.) Gaertn.) against Phytophthora alni ssp. alni by cyclolipopeptide producing bacteria

Publicado en línea: 01 Jun 2017
Páginas: 222 - 229

Resumen

Palabras clave

  • in vitro
  • massetolide
  • Pseudomonas veronii PAZ1
  • tissue culture
  • viscosin
Acceso abierto

Three microsatellite multiplex PCR assays allowing high resolution genotyping of white spruce, Picea glauca

Publicado en línea: 01 Jun 2017
Páginas: 230 - 233

Resumen

Abstract

Fifteen previously published microsatellite primer pairs developed for and tested on Canadian white spruce were screened for amplification and polymorphy in Alaskan populations and tested for their suitability in PCR multiplexing. Eleven loci expressing polymorphisms ranging from 7 to 58 alleles were selected for development and optimization of three multiplex assays. Four natural stands containing a total of 1470 trees were used to characterize the selected loci and demonstrate their applicability for genotyping studies and parentage analysis. These assays can be used for studies focusing on population genetics, parentage analysis, provenance research, or individual genetic fingerprinting. The use of multiplex PCR facilitates large-scale studies by simultaneously enabling high resolution and reducing processing time and per sample cost.

Palabras clave

  • Picea glauca
  • SSR
  • fingerprinting
  • parentage analysis
  • population genetics
  • population structure
Acceso abierto

Investigating the Mendelian inheritance, genetic linkage, and genotypic disequilibrium for ten microsatellite loci of Araucaria angustifolia

Publicado en línea: 01 Jun 2017
Páginas: 234 - 239

Resumen

Abstract

Araucaria angustifolia is a dioecious and wind pollinated conifer that typically occurs in higher attitudes of Southern Brazil. After a significant reduction of its population during the twentieth century, public policies have enabled natural populations to recover. As new studies focus on the genetics of the species it is important to investigate Mendelian inheritance, genetic linkage, and genotypic disequilibrium for the microsatellite loci developed for the species. Here we analyze ten microsatellite loci developed for A. angustifolia by genotyping 295 adult trees and 13 open pollinated progenies from a forest fragment in Santa Catarina, Brazil. The likelihood G-test shows a perfect 1:1 Mendelian segregation for all ten loci, indicating that these molecular markers are genetic markers. Significant genetic linkage between pairwise loci was detected in only 3% of the tests, suggesting that these loci are not located in the same linkage groups within the chromosomes. However, genotypic disequilibrium was detected in 51% of pairwise loci for adult trees, probably due to the strong spatial genetic structure of the population. Our results indicate that the ten loci analyzed can be used in studies on genetic diversity and structure, mating system, and gene flow of the species.

Palabras clave

  • Araucaria
  • Conservation genetics
  • Microsatellites
  • pinheiro-do-paraná
  • Tropical tree species
Acceso abierto

Development and characterization of microsatellite loci for Cedrela fissilis Vell (Meliaceae), an endangered tropical tree species

Publicado en línea: 01 Jun 2017
Páginas: 240 - 243

Resumen

Abstract

The timber of the Neotropical tree Cedrela fissilis is used in construction, shipbuilding, carpentry and for medical purposes. In this study, polymorphic microsatellite (SSR) markers derived from an enriched genomic library were characterized using 120 adult trees from four different C. fissilis populations. No substantial genotypic linkage disequilibrium was detected among all possible pairs of SSR loci. The number of alleles per locus ranged from 2 to 20, the average allele number ranged from 8 to 9.7, depending on the population. The observed heterozygosity among the different SSR loci varied from 0.0 to 1.00 , the expected heterozygosity varied from 0.07 to 0.95 On the population level, the average observed and expected heterozygosities ranged from 0.50 to 0.63 and from 0.64 to 0.70, respectively. The average fixation index among populations ranged from 0.09 to 0.24. Thus, the SSR loci revealed high poly - morphism rates and can be used to study the genetic diversity,structure, mating system, and gene flow in C. fissilis.

Palabras clave

  • Cedar
  • Genetic diversity
  • Microsatellite markers
  • Neotropical tree species
Acceso abierto

Cytogenetic polymorphism of english oak (Quercus robur L.) seedlings from areas with different levels of anthropogenic pollution

Publicado en línea: 01 Jun 2017
Páginas: 245 - 252

Resumen

Abstract

Cytogenetic polymorphism of English oak seedlings from areas with different levels of anthropogenic pollution was studied. In each studied area, groups of seedlings with low, intermediate, and high level of mutations have been identified. Mutable groups were characterised by a high level of mitotic pathologies, broad spectrum of such pathologies (e.g., chromosome agglutination, asymmetric and tripolar mitoses). Impact of trees location near the freeway leads to variability increase of cytogenetic properties and domination of intermediate-mutable groups of seedlings.

Palabras clave

  • cytogenetic polymorphism
  • English oak
  • anthropogenic pollution
  • mitotic activity
  • pathologies of mitosis
  • nucleolar characteristics
Acceso abierto

Association mapping for resin yield in Pinus roxburghii Sarg. using microsatellite markers

Publicado en línea: 01 Jun 2017
Páginas: 253 - 266

Resumen

Abstract

Association mapping is a method for detection of gene effects based on linkage disequilibrium (LD) that complements QTL analysis in the development of tools for molecular plant breeding. A total of 240 genotypes of Pinus roxburghii (Himalayan Chir Pine) from a natural population in Chakrata division (Tiunee range), Uttarakhand (India) were evaluated for resin yield. Based on the phenotypic data and stable resin production in consecutive years, 53 genotypes were selected after excluding the individuals with similar resin production. The selected 53 individuals were best representatives of the variation in resin yield in Chakrata population which varied between 0.25 and 8.0 kg/tree/year and were used for genotyping and association analysis using SSR markers. Out of 80 primers initially screened, a total of 19 polymorphic SSRs (11 cpSSR and 8 nSSR) were used in the study. Model based clustering using 19 polymorphic SSR markers identified five subpopulations among these genotypes. LD was evaluated using the entire population. The squared allele frequency correlation, r2 was estimated for each pair of SSR loci. The comparison wise significance (p-values) of SSR marker pairs was determined by performing 100,000 permutations. The genetic divergence ranged from 50 to 100%. The UPGMA based hierarchial clustering grouped the genotypes in accordance with their resin yield. Model based clustering suggested the existence of five subpopulations in the sample. However, the distribution of P. roxburghii genotypes into five subpopulations had no correlation with their resin yield thus ruling out the possibility of any ancestral relationship among the genotypes with similar resin yield. AMOVA suggested that the variation among P. roxburghii genotypes at the molecular level was related with the variation in resin yield and not their site of collection thus highlighting the genetic basis of the trait. LD based association analysis revealed two chloroplast SSRs Pt71936 and Pt87268 and one nuclear SSR pm09a to be in significant association with resin yield. The two associated chloroplast SSRs showed significant LD (p<0.01). One of the chloroplast SSR Pt87268 showing association with resin yield was also found to be in significant LD with the nuclear SSR pm07, further showing the probability of this marker also to be associated with resin yield.

Palabras clave

  • Pinus roxburghii
  • SSR
  • association mapping
  • Linkage disequilibrium (LD)
Acceso abierto

Evaluation of the growth traits of Toxicodendron vernicifluum progeny based on their genetic groups assigned using new microsatellite markers

Publicado en línea: 01 Jun 2017
Páginas: 267 - 274

Resumen

Abstract

Toxicodendron vernicifluum (Stokes) F. A. Barkley is a tree species cultivated in Japan for production of Japanese lacquer. To facilitate the low-cost improvement of T. vernicifluum, we developed microsatellite markers for DNA fingerprinting and family and lineage reconstruction. Nine useful microsatellites were developed, with 3 to 23 alleles per locus and an expected heterozygosity of 0.162-0.838 based on a commercially planted population that included 783 offspring. Six clusters were detected in this population based on the Bayesian clustering method, and 93 half-sib families were identified using parentage and sibship assignment analysis based on a maximum likelihood method. Many members (40-96%) of large (≥10) half-sib families included specific clusters, and members from different families included the same clusters. The cluster effect for tree height was more significant than the half-sib family effect using a linear mixed model, although these effects were not significant for other traits (diameter at breast height and number of forked trunks). Based on the findings from pedigree reconstruction, backward selection for tree height seems possible. We discuss the direction of research for improving T. vernicifluum using our proposed approach.

Palabras clave

  • Backward selection
  • Bayesian clustering
  • Best unbiased linear predictor
  • Microsatellite
  • Pedigree reconstruction
  • Toxicodendron vernicifluum (Stokes) F.A. Barkley
Acceso abierto

Variation of the quantitative traits in a progeny test of Abies alba (Mill.) at the nursery stage

Publicado en línea: 01 Jun 2017
Páginas: 275 - 284

Resumen

Abstract

Fifty-one full-sib families were created using 11 parents in a silver fir seed orchard and a half-diallel mating design. The seeds of control-pollinated families were sown in a nursery in autumn 2007. Growth and branches traits were measured during nursery testing, and genetic parameters were estimated at the ages of 3, 4, 5, and 6 years. The additive and dominance genetic variances were major sources of genetic variance. Dominance variance was greater than additive variance at these early ages for all traits. However, the ratio of SCA/GCA variance decreased from 23 to 14 for total height and from 36 to 19 for root collar diameter. Broadsense family heritability is higher than individual heritability. Height and root collar diameter are the most heritable traits in silver fir. The time trend of the five heritability estimates for total height increased with age. Significant trait-trait genetic correlations were obtained. Age-age genetic correlations were very high, and they displayed increasing trends with age. The selection of the most valuable parents and most valuable individuals within the best families could maximise genetic gain in the second breeding generation of silver fir.

Palabras clave

  • Additive variance
  • non-additive variance
  • genetic correlations
  • genetic gain
  • heritability
  • silver fir
Acceso abierto

Analysis of absolute nuclear DNA content reveals a small genome and intra-specific variation in Cashew (Anacardium occidentale L.), Anacardiaceae

Publicado en línea: 01 Jun 2017
Páginas: 285 - 292

Resumen

Abstract

There are scanty data on genome size of Anacardiaceae, and none has been reported for cashew, Anacardium occidentale till date. This study aimed at determining the absolute nuclear DNA content (genome size) that could facilitate research into bio-systematics, genomics and genetic improvement of this important tropical tree crop species. Here, isolated nuclei of preparations from 43 cashew accessions selected across five growing regions were flow cytometrically analyzed for genome size determination using Solanum lycopersicum var. Stupicke with a genome size of 1.96 pg/2C as an internal reference standard.

Mean genome size was significantly different (P<0.01) across the 43 cashew accessions suggesting intra-specific variation (about 3.6% coefficient of variation) for absolute nuclear DNA content in this species, but with no evidence of endopolyploidy or endoreduplication. Flow cytometric analysis data presented here showed that absolute genome size of cashew is about 0.857 pg/2C (419 Mb/1C). However, there was a slight gradual increment in genome size from south to north gradient across sampled populations. The data also showed significant correlation (r=0.368, P<0.01) between nuclear DNA content (genome size) and phenotypic trait, nut weight. The results obtained here confirmed relatively small genome size in this tree species, almost twice genome size of diploid Arabidopsis thaliana but slightly lower than mango, Mangifera indica, a close relative in Anacardiaceae. Similarity in genome size between Mangifera indica and Anacardium occidentale could be a further proof of genetic relatedness between these two important species of Anacardiaceae.

Palabras clave

  • Anacardium occidentale
  • Cashew
  • Correlation analysis
  • Genome size
  • Nuclear DNA content
  • Nut weight
Acceso abierto

Phylogeography and genetic variability of the Arnica montana chemotypes in NW Iberian Peninsula

Publicado en línea: 01 Jun 2017
Páginas: 293 - 300

Resumen

Abstract

The threatened European species Arnica montana L. is a plant much appreciated in the pharmaceutical industry, Galicia (North-Western Spain) being one of the main supply regions. Two chemotypes based on the content of sesquiterpene lactones have been found in this area: a chemotype dominated by helenalins, common in Central Europe, and another dominated by dihydrohelenalins, only found currently in Galicia. The aim of this work was to analyse the phylogenetic relationships and genetic diversity of Arnica montana in Galicia and their concordance with previous biochemical and environmental information. Two polymorphic chloroplast markers were sequenced in individuals from populations showing significant biochemical differences and situated in different environments (heathland, hay-meadow and peatland). Three haplotypes, different from those previously described in Europe, were found in Galicia and our results suggest that one of them could be ancestral inside the species. Significant population differentiation was detected in the studied area but genetic diversity within populations was low, only showing variability in heathland populations. This study is the first one describing the genetic diversity of Arnica montana in the extreme SW of Europe. The results suggested the presence of two different genetic groups (one of them ancestral) and were congruent with the two chemotypes described. Plants from heathlands displayed the highest variability because the two chemotypes were present in them. Future design of conservation and economical management plans for this threatened species should take into account this genetic variability and prioritize further genetic and chemical characterizations across the distribution range of the species.

Palabras clave

  • Arnica montana
  • genetic variability
  • chloroplast DNA
  • sesquiterpene lactones
  • phylogeography
  • conservation

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