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2509-8934
Publicado por primera vez
22 Feb 2016
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Volumen 61 (2012): Edición 1-6 (December 2012)

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

Linkage map construction and QTL analysis for Betula platyphylla Suk using RAPD, AFLP, ISSR and SSR

Publicado en línea: 01 Aug 2017
Páginas: 1 - 9

Resumen

Abstract

A linkage map for Betula platyphylla Suk was constructed based on RAPD, ISSR, AFLP and SSR markers by a pseudo-testcross mapping strategy. A F1 segregating population including 80 progenies was obtained from the cross between two superior trees selected from Qinghai and Wangqing provenance, respectively. The paternal map was constructed with 282 markers consisting of 14 major and 15 minor (5 triplets and 10 doublets) linkage groups and spanning 1131 cM at an average distance of 4.0 cM between adjacent markers. The maternal map has 277 markers consisting of 15 major and 8 minor (5 triplets and 3 doublets) groups covering 1288 cM at an average distance of 4.6 cM between adjacent markers. In the same pedigree we investigated association of genetic markers with seedling stem height and circumference. The composite interval mapping was used to detect the number of quantitative trait loci and their position on the genetic linkage maps. Three QTLs (one on the male map and two on the female map) were found explaining 13.4%, 17.5% and 18.8% of the trait variation, respectively.

Palabras clave

  • silver birch
  • linkage map
  • RAPD
  • AFLP
  • ISSR
  • SSR
  • QTL
Acceso abierto

Influence of geographic distance and genetic dissimilarity among clones on flowering synchrony in a Teak (Tectona grandis Linn. f) clonal seed orchard

Publicado en línea: 01 Aug 2017
Páginas: 10 - 18

Resumen

Abstract

Influence of genetic dissimilarity among teak (Tectona grandis Linn. f.) clones on flowering synchrony was studied in a Clonal Seed Orchard (CSO) of teak in Karnataka, Southern India. Flowering phenology was monitored for all the 24 teak clones of the CSO and flowering synchrony between clones was assessed adopting a novel ‘overlap index’. Genetic dissimilarity among these clones was assessed adopting DNA based ISSR (Inter Simple Sequence Repeats) analysis. Large variation in the time of ‘flower initiation’ and of ‘peak flowering initiation’ was observed among the clones belonging to diverse sources, suggesting large asynchronous flowering. Cluster analysis based on ISSR marker indicated that the clones originating from a same source clustered together and there was a clear segregation based on their origin. Correlation analysis revealed a significant negative association between the average Jaccards’s dissimilarity index between pairs of clones and average peak flowering overlap index. Clones from geographically diverse regions had high genetic dissimilarity and also showed high flowering asynchrony within them.

Palabras clave

  • Provenance effect
  • genetic markers
  • flowering phenology
  • genetic distance
Acceso abierto

Gene exchange across a postglacial contact zone in Fraxinus excelsior L.

Publicado en línea: 01 Aug 2017
Páginas: 18 - 27

Resumen

Abstract

Hybridization between divergent lineages of common ash Fraxinus excelsior L. was studied in Slovakia and adjacent regions of Hungary, the Czech Republic and Poland in the contact zone between two postglacial colonization routes originating from different glacial refugia. Thirty-eight common ash populations were studied using a combination of 6 maternally inherited chloroplast microsatellite markers and 7 biparentally inherited nuclear microsatellites (nSSR). Two predominant chloroplast lineages were identified, between which the boundary was very sharp. Populations containing a mixture of different haplotypes were found only in the immediate proximity of the boundary. Bayesian analysis of population structure based on nSSR loci revealed the existence of two clusters, which largely coincided with chloroplast lineages. Both haplotype frequencies and proportions of clusters identified by the Bayesian analysis exhibited a clinal transition over the hybrid zone, with cline widths of 36 km for chloroplast haplotype frequencies (reflecting gene flow by seeds) and 275 km for Bayesian clusters based on nSSR (reflecting gene flow by pollen and seeds). Chloroplast haplotype diversity increased along the boundary between lineages not only because of admixture, but also due to the presence of rare haplotypes. In contrast, diversity at nuclear loci did not exhibit any geographical trend.

Palabras clave

  • Fraxinus excelsior L.
  • introgression
  • cline
  • postglacial colonization
Acceso abierto

Chloroplast DNA variation in planted and natural regenerated stands of black locust (Robinia pseudoacacia L.)

Publicado en línea: 01 Aug 2017
Páginas: 27 - 35

Resumen

Abstract

Black locust (Robinia pseudoacacia L.), native in mountainous regions in USA, is increasing in importance for forestry in many countries as a „multi-purpose tree“ associated with breeding efforts at the family and clonal levels. A few population genetic studies exist with nuclear, codominantly inherited markers. Here we present an additional marker type, the maternally inherited chloroplast haplotypes. The studied material included samples from the natural range and from artificial stands from three European countries as well as samples from a clone collection. Eleven haplotypes belonging to two clearly separated groups of related haplotypes were found using the PCR-RFLP method. The variation pattern of chloroplast haplotypes in artificial stands is strongly influenced by the local silvicultural management.

Palabras clave

  • Robinia pseudoacacia L.
  • cpDNA haplotypes
  • PCRRFLP
  • artificial populations
  • silvicultural management
Acceso abierto

Influence of altitude on seed and seedling characteristics in Quercus leucotrichophora A. Camus. ex. Bahadur

Publicado en línea: 01 Aug 2017
Páginas: 36 - 43

Resumen

Abstract

The present investigation was conducted to record variation of seed and seedling morphological characteristics and germination among eighteen provenances of Quercus leucotrichophora. These traits are important for improving the planting stock material in hand. Significant variations (p<0.05) were recorded for different morphological parameters of seed and seedling among the different provenances. Seed weight was the most variable character among morphological characteristics. Shoot/root ratio and root growth were more variable characters among the seedling traits. Altitude had significant positive relationship with seed weight, seed length and germination per cent. Soil pH was positively correlated with seed weight and germination. These parameters could be used as important criteria for seed source selection. Broad-sense heritability (h2) calculated for different seed and seedling traits showed a considerable portion of genetic variation suggesting the possibility of rapid genetic improvement of these traits. Furthermore, this variability appeared to be geographically structured and would be mainly genetically controlled. Thus the results of present study should be helpful for growing planting material of this potential tree species in afforestation of subtropical to temperate region of Garhwal Himalaya, India.

Palabras clave

  • Seed origin
  • seed dimensions
  • genetic variability
  • heritability
  • Quercus leucotrichophora seedling
  • growth characteristics
Acceso abierto

Isolating of a putative glyceraldehyde-3 phosphate dehydrogenase (GAPDH) from Calophyllum brasiliense, an important tropical forest tree

Publicado en línea: 01 Aug 2017
Páginas: 44 - 51

Resumen

Abstract

Calophyllum brasiliense Cambess. has characteristics that made it an excellent candidate model for ecogenomics in rain forest trees such as widespread natural occurrence and geographical patterns of adaptive genetic variation. Besides, it is also becoming a popular species for reforestation efforts in Brazil. Although, very little is known about its genetic diversity and the molecular mechanisms involved genetic adaptation traits. The first difficulty in launching genetic studies in a wild wood species is the lack of an optimized protocol for RNA and DNA isolation. In this work we built the essential framework for molecular genetics research with C. brasiliense comparing four distinct methods of RNA extraction from of three different tissues: leaves, stems and roots. We also were successful in the isolation of genomic DNA by an optimized CTAB method. Finally, degenerated oligonucleotide primers were designed for isolating of the glyceraldehyde-3 phosphate dehydrogenase (GAPDH) gene of C. brasiliense from the corresponding gene in closely related species. This gene is commonly used in plants as reference in expression gene analysis by Reverse Transcription Polymerase Chain Reaction (RT-PCR). Primers for RT-PCR were designed based on partial sequence obtained using degenerate primers designed. The optimized methods of RNA and DNA extraction combined with the identification, isolation and specific primer design for RT-PCR of a traditional Reference Gene provide the essential framework for molecular genetics research with C. brasiliense.

Palabras clave

  • Calophyllum brasiliense
  • gene expression
  • nucleic acid extraction
  • ecogenomics
Acceso abierto

Effect of monoclonal and assorted seedling rootstocks on long term growth and yield of Hevea clones

Publicado en línea: 01 Aug 2017
Páginas: 52 - 57

Resumen

Abstract

Seven Hevea brasiliensis clones were evaluated on two types of rootstocks, assorted seedling rootstocks (AR) and monoclonal rootstock (MR) over 19 years. Influence of rootstock on scion growth and rubber yield was assessed based on juvenile height, circumference of the main trunk (cm), number of branches, branching height and cumulative dry rubber yield (g per tree per tapping, conventionally abbreviated gt-1 t-1). Highest cumulative yield (g per tree per tapping) over the 12 years for which the trees were tapped was obtained from clone RRII 105 (MR: 1076 g per tree per tapping and AR: 497 g per tree per tapping), followed by RRII 203 (MR: 661; AR: 538), RRII 208 (MR: 477; AR: 486), RRII 118 (MR: 497; AR: 452). Gl 1 yielded the least, 219 g per tree per tapping (MR) and 378 g per tree per tapping (AR); GT1 produced 335 g per tree per tapping (MR) and 375 g per tree per tapping (AR). RRII 118 had the greatest circumference at age 19 (91.4 cm on MR) 88.8 on AR, followed by RRII 105 (MR: 87.4 cm AR: 89.2 cm) and GT 1 (MR: 88.5 cm; AR: 84.4cm). Effect of scion clone was significant (p<0.01) only for trunk circumference at opening, but not for cumulative rubber yield at age 11 (4 years after opening) or cumulative rubber yield at age 19 (12 years after opening). Most importantly, rootstock and clone × rootstock interaction did not significantly affect rubber yield or tree circumference at any evaluation time. There was no evidence to suggest that growth and yield of clones was influenced significantly by rootstock type.

Palabras clave

  • Natural rubber
  • rootstock-scion
  • Hevea brasiliensis
Acceso abierto

Early genetic evaluation of morphology and some wood properties of Tectona grandis L. clones

Publicado en línea: 01 Aug 2017
Páginas: 58 - 65

Resumen

Palabras clave

  • early evaluation
  • correlation genotypic
  • heritability
Acceso abierto

Diallel Crossing in Pinus cembra: V. Age Trends in Genetic Parameters and Genetic Gain for Height

Publicado en línea: 01 Aug 2017
Páginas: 66 - 79

Resumen

Abstract

A full diallel mating design (10 parents) was carried out in a Swiss stone pine panmictic population from the Carpathian Mountains. At age six, after nursery testing, the progenies were field planted to one site, using a completely randomized block design with 100 families, four replicates and a 15 tree row-plot per replication, spaced 2.5 × 2.5 m. Total and annual height of all individuals of this test was assessed at successive ages, between ages eight and 16. In addition, weight of 100 seeds and cotyledon number were considered in correlation analyses. Significant differences occurred in total height for general and specific combining ability effects. Variance components, heritabilities, genetic correlations and genetic gains on growth traits and survival at age 16 were estimated. Across the field testing period, GCA3) variance increased with time, accounting for 65% of plot mean phenotypic variance by age 16. In contrast, SCA variance declined as the progeny test aged accounting for only 9% by age 16. The time trend of the four heritability estimates for total height increased with age across the testing period reaching their highest level between age 14 and 16. Genetic correlations over time for total height rose from 0.85 at age two to 0.94 at age six and then leveled off across the field test indicating that if the goal is to improve 16-year height, early selection can be considered at age six. By selecting the best 10%, 15% and 20% of individuals within the best fullsib families, a genetic gain in total height of 12.4 %, 11.0% and 9.9% respectively, could be achieved at age 16. A higher gain can be obtained if the best general combiner parents are selected and intermated.

Palabras clave

  • Pinus cembra
  • diallel crossing
  • additive variance
  • dominance ratio
  • genetic effect
  • age-age genetic correlation
  • heritability
  • early selection
  • genetic gain
Acceso abierto

Clonal fertility variation and its effects on the effective population size in the seed orchard of dioecious species, Fraxinus rhynchophylla

Publicado en línea: 01 Aug 2017
Páginas: 79 - 84

Resumen

Abstract

The numbers of female and male flowers were assessed in a clonal seed orchard of Fraxinus rhynchophylla for four consecutive years from 2004 through 2007. The female and male flowers of the grafts from 48 clones were counted individually over the crown. Fertility variation was calculated by sibling coefficient that is related to the coefficient of variation in parental flower assessment. Estimated maternal and paternal fertilities were not constant but varied from year to year, and they were also found to be weakly correlated. The effective numbers of clones serving as male and female parents were calculated from the sibling coefficients of maternity and paternity. We applied two theoretical approaches to estimate the clonal effective population sizes based on 1) fertility variation (i.e., effective number of parents, N(c)) and 2) gender balance (effective population size, Nee) among parental genotypes. The values of Ne(c) were higher in the years with abundant flowering and seed production, while sibling coefficients were lower. On average (pooled), the maternal, paternal and clonal values of Ne(c) were calculated to be 17.3, 21.0 and 38.1 respectively. The Ne(c) for maternal gamete gene pool was ranged from 9.8 to 16.7. The values of Ne for paternal gamete gene pool were generally higher (ranged from 14.9 to 21.9) than those for maternal. When pooled, the Ne was 47.2 and the values of Ne were higher when the gender ratio was more balanced. An option of equal seed harvest might be good to mitigate fertility variation and to improve gene diversity of seeds.

Palabras clave

  • status number
  • sibling coefficient
  • gene diversity
  • gender balance
  • equal seed harvest
  • Fraxinus rhynchophylla
Acceso abierto

High temperature-induced triploid production during embryo sac development in Populus

Publicado en línea: 01 Aug 2017
Páginas: 85 - 93

Resumen

Abstract

Triploid breeding plays an important role in cultivar improvement in the genus Populus L. A novel approach for triploid production with colchicine during embryo sac development was reported recently by Wang et al. (2010). In the present investigation, female catkins of Populus pseudo-simonii × P. nigra ‘Zheyin3#’ during embryo sac development were exposed to high temperature to assess the effectiveness of high temperature for induction of triploid production. In the progeny, 45 triploids were determined by both flow cytometric analysis and somatic chromosome counting. The period 66-72 h after pollination was the most suitable for high temperature-induced triploid production during embryo sac development in the ‘Zheyin3#’. Cytological analysis showed that the frequency of eight-nucleate embryo sacs rose at an increased rate during 66-78 h after pollination, which suggested that the third mitosis during embryo sac development could be the optimal stage for high temperature-induced triploid production. The highest frequency of triploid production was 40%, which was obtained in the 44°C for 2 h treatment 72 h after pollination. In view of both triploid number and production efficiency, treatments with 41°C for 4-6 h or with 44°C for 2 h during 66-72 h after pollination were both effective for triploid induction in ‘Zheyin3#’. Statistical analysis showed that the growth of triploids and diploids was not significantly different. However, highly significant differences were observed for all leaf characteristics. Finally, the significance of high temperature treatment in Populus triploid breeding programs is discussed.

Palabras clave

  • 2n egg
  • embryo sac development
  • high temperature
  • Populus
  • triploid
Acceso abierto

Physiological and Protein Responses to Drought in Four Pine Seedlings

Publicado en línea: 01 Aug 2017
Páginas: 93 - 103

Resumen

Abstract

Physiological and protein responses to drought stress in four pine seedlings, Pinus armandi Franch. (Pa), Pinus tabulaeformis Carr. (Pt), Pinus bungeana Zucc. ex Endl. (Pb) and Pinus sylvestris L. var. mongolica Litv. (Ps), were investigated using differential proteomics and water physiological indices. Firstly, the water physiological data showed that the decline rate of net photosynthesis rate, stomatal conductance, leaf water potential, turgor pressure except for under moderate drought stress was as follows: Pa>Ps>Pt>Pb. Pb and Pa always maintained the highest and lowest swelling pressure, respectively. Secondly, cluster analysis of 343 proteins indicated that the four pine species were classified into three groups with a genetic distance coefficient of 0.065. That is, five-needle-pine group (Pa), three-needle-pine group (Pb), two-needle-pine group (Pt and Ps), and the genetic distance between Pb and Pa was the farthest. The result was consistent with the declined rate in above physiological indices. Finally, for the differential proteomics analyzed, a total of 13 different proteins (P values < 0.01) changed significantly, the number of differentially expressed proteins was more in Pa (accounting for 46.2%) than the other three species, and 8 proteins were identified using matrix-assisted laser desorption/ionization time -of-flight mass spectrometry (MALDI-TOF-MS). These proteins are quite diverse in their functions and involved in photosynthesis, osmotic regulation and functioning as signal transduction. These results suggested that the sensitivities of the four pine species to drought were possibly related to genetic distance.

Palabras clave

  • drought stress
  • drought-resistance
  • proteomics
  • genetic distance
Acceso abierto

Developing breeding and deployment options for Douglas-fir in New Zealand: breeding for future forest conditions

Publicado en línea: 01 Aug 2017
Páginas: 104 - 115

Resumen

Abstract

Genetic improvement of Douglas-fir in New Zealand was initiated in 1955 with large provenance trials established in the late 1950’s. These trials illustrated that material from the coast of Oregon and California grew faster than other provenances tested. Further collections were made to evaluate provenance and familylevel performance from these two areas, and in 1996 additional trials were established at four low-altitude sites across New Zealand. Genotype×environment (GxE) interaction among these sites was found to be important for diameter at breast height (DBH), less important for stem straightness and malformation and not important for outerwood acoustic velocity (a surrogate for wood stiffness). Heritabilities were low to moderate for all growth traits, and very low for malformation. Heritability for needle cast due to Swiss needle cast, measured as needle retention on the one site where infection was relatively high, was moderate at 0.37, and was likely a major factor creating GxE interactions for growth among sites. The heritability of wood acoustic velocity was moderate to high at individual sites (0.26-0.74) and across sites (0.49). Individual- trait selection revealed the potential for good genetic gains to be made when selecting the top 20 families for diameter growth (an average of 10.7%), straightness (an average of 11.5%) and acoustic velocity (an average of 7.0%). When we examined predicted genetic gains while selecting for needle retention and/or DBH, we found that selecting for needle cast at the affected site did not compromise DBH gains at that site. Selecting for genotypes with low needle cast at the affected site did, however, reduce gains for DBH estimated across all sites. In order to maximise gains across the current Douglas-fir growing estate, a division of growing sites between those known and predicted to be affected by needle cast and those not affected would seem appropriate. This is particularly relevant given recent climate modelling work suggests that Swiss needle cast will become more important in the South Island, and even more destructive in the North Island of New Zealand. We suggest addressing differences in site through the development of separate deployment populations.

Palabras clave

  • Pseudotsuga menziesii
  • tree breeding
  • deployment
  • genotype x environment interaction
  • Swiss needle cast
Acceso abierto

Effect of Different Progeny Test Strategies in the Performance of Eucalypt Clones

Publicado en línea: 01 Aug 2017
Páginas: 116 - 120

Resumen

Abstract

The objective of the present study was to investigate whether the performance of an individual in clonal testing was affected by the location of the initial selection. The study also evaluated the effect of mass selection and BLUP (Best Linear Unbiased Prediction) on the performance of individuals in the progeny test and the clonal test. In the progeny test, 62 half-sib E. grandis families, 68 half-sib E. urophylla families and 62 full-sib families between E. grandis and E. urophylla, plus four checks were evaluated totaling 196 treatments. The experiments were carried out at three sites: Aracruz and São Mateus, in Espírito Santo State and Caravelas, Bahia State, Brazil. The 1000 best individuals were classified by mass selection and BLUP. In the clonal tests 257 clones were evaluated in two locations: Aracruz and Caravelas. In both the progeny test and the clonal test, two years after planting, the circumference at breast height and basic wood density were measured and the sum of standardized variables (Z) was estimated for simultaneous selection of both characteristics. The results indicated that the origin of the individual in a progeny test had a small effect on the performance of the clone when evaluated in other environments; the estimates of realized heritability and the linear regression coefficient were small in all the selection strategies. Thus, the correlation between the performance of trees selected in progeny tests and their respective clones in the clonal test was small.

Palabras clave

  • Plant breeding
  • selection strategies
  • realized heritability
  • Eucalyptus
Acceso abierto

Pollination methods, stigma receptivity and pollen tube growth in Eucalyptus argophloia

Publicado en línea: 01 Aug 2017
Páginas: 121 - 126

Resumen

Abstract

Eucalyptus argophloia Blakely (Western white gum) has shown potential as a commercial forestry timber species in marginal environments of north-eastern Australia. We measured early pollination success in Eucalyptus argophloia to compare pollination methods, determine the timing of stigma receptivity and compare fresh and stored pollen. Early pollination success was measured by counting pollen tubes in the style of E. argophloia 12 days after pollination. We compared the early pollination success of 1) Artificially Induced Protogyny (AIP), one-stop and three-stop methods of pollination; 2) flowers pollinated at 2 day intervals between 2 days before and 6 days after anthesis and 3) fresh pollen and pollen that had been stored for 9 months. Our results show significantly more pollen tubes from unpollinated AIP and AIP treatments than either the one-stop pollination or three-stop pollination treatments. This indicates that self-pollination occurs in the unpollinated AIP treatment. There was very little pollen tube growth in the one-stop method indicating that the three-stop method is the most suitable for this species. Stigma receptivity in E. argophloia commenced six days after anthesis and no pollen tube growth was observed prior to this. Fresh pollen resulted in pollen tube growth in the style whereas the stored pollen resulted in a total absence of pollen tube growth. We recommend that breeding programs incorporating E. argophloia as a female parent use the three-stop pollination method, and controlled pollination be carried out at least six days after anthesis using fresh pollen.

Palabras clave

  • one-stop pollination
  • three-stop pollination
  • artificially induced protogyny
  • stored pollen
Acceso abierto

GSCA: New Software and Algorithms to Analyse Diallel Mating Designs Based on Restricted Linear Model

Publicado en línea: 01 Aug 2017
Páginas: 126 - 132

Resumen

Palabras clave

  • Diallel mating design
  • restricted linear models
  • general combining ability
  • specific combining ability
  • least squares
Acceso abierto

Variation in Floral Phenological Synchronization in a Clonal Seed Orchard of Pinus tabuliformis in Northeast of China

Publicado en línea: 01 Aug 2017
Páginas: 133 - 142

Resumen

Abstract

Flowering phenology in an orchard is a crucial factor affecting the gene exchange among clones and consequently changing genetic composition of the seed crop. Pinus tabuliformis is now at the crucial period from first generation clonal seed orchards to advanced generation seed orchards in China. In this study, variation and stability in floral phenological synchronization of all the clones and possible mating pairs, in terms of an index of phenological overlap, were observed in a first generation clonal seed orchard which located in northeast of China. Results showed that significant variations occurred in the clones and mating pairs. This kind of variation was apparently related with temperature and humidity of the research site. With increasing age, levels of flowering synchronization were likely to rise in the clones and mating pairs. In general, the average flowering synchronization of male parents was slightly higher than that of female parents, female management in a seed orchard should be paied more attention. Flowering time was under strong genetic control and this genetic control was stronger in the female flowering process than of the males in terms of board sense heritability and year to year correlation analysis. Flowering synchronization of female parents was positively correlated between most years and can be a reliable reference for early and late predication in Pinus tabuliformis seed orchard during stage of initial seed harvest to stable seed production. According to their average levels of flowering synchronization, 49 clones in the first generation clonal seed orchard were divided into 11 different groups. Results of this paper provided the basic information for first generation seed orchard management and advanced seed orchard establishment of Pinus tabuliformis.

Palabras clave

  • Pinus tabuliformis
  • first generation
  • clonal seed orchard
  • reproductive synchronization
  • phenological overlap index
  • genetic variation
  • clonal repeatibility
  • seed orchard management
  • advanced seed orchard establishment
Acceso abierto

Optimisation of a multiplex PCR assay of nuclear microsatellite markers for population genetics and clone identification in Robinia pseudoacacia L.

Publicado en línea: 01 Aug 2017
Páginas: 142 - 148

Resumen

Abstract

Black locust (Robinia pseudoacacia L.) is a tree species native to North America. The multipurpose tree is cultivated worldwide, but causes problems due to its partially invasive character. The application of nuclear microsatellite loci has many aims in population genetic studies. Here we introduce a very cost-effective method for combining the information of 14 nuclear microsatellite loci into two multiplex PCR sets as a contribution to greater standardisation and more comparable results. Combined non-exclusion probabilities for clone identification using example populations are estimated at between 1.37*E-5 and 1.67*E-11, and for paternity analysis for 1.59*E-4. The detected weak linkage between some microsatellite loci is not considered to be a substantial restriction to the reliability of the set of markers in providing an appropriate method for fingerprinting and parentage analysis.

Palabras clave

  • Black locust
  • SSRs
  • multiplexing
  • population genetics
  • clone identification
  • paternity analysis
  • linkage
Acceso abierto

Microarray Analysis of Gene Expression in Triploid Black Poplar

Publicado en línea: 01 Aug 2017
Páginas: 148 - 157

Resumen

Abstract

Triploidy is a widespread phenomenon in cultivated and natural breeding plants and it can confer some growth advantages. Here, we analyzed genome-wide gene expression in triploid Populus euramericana (black poplar) using the Affymetrix poplar microarray to detect any possible correlation between triploid vigor and a unique gene expression profile. Among the 38,400 transcripts that were detected in triploid poplar, 1,564 and 2,015 genes were up- or downregulated, respectively, compared with the diploid. The majority of the upregulated genes in the triploid were associated with carbon and nitrogen metabolism, especially lignin and secondary metabolism. Other genes upregulated in the triploid included genes involved in sugar transport, and brassinosteroid (BR) and auxin metabolism. Downregulated genes were mostly related to the assembly and biosynthesis of ribosomes and the nucleosome macromolecular complex. The results suggested that BR and auxin levels were crucial in controlling sugar transport, photosynthesis and cell wall biosynthesis. Downregulated genes were associated with chromatin regulation in the triploid. The information from this analysis could provide an insight into the vigor of triploid poplar.

Palabras clave

  • Gene expression
  • Populus
  • microarray
  • triploid
Acceso abierto

Reconstructing explicit mating schemes in poplar hybrids – a case study in the Populus nigra L. – Populus × canadensis Moench complex

Publicado en línea: 01 Aug 2017
Páginas: 157 - 167

Resumen

Abstract

In the plant kingdom, a large percentage of taxa are known to interbreed. If these hybrids are fertile, introgressive gene flow may foster the development of hybrid swarms or even promote gene swamping. Our study focuses on the Eurasian black poplar (Populus nigra L.) which may be threatened by hybridization with the cultivated fertile Euramerican hybrid. Using a combination of taxa specific DNA markers from the chloroplast and the nuclear genome we set up a straightforward and cost efficient method for identification of all possible mating scenarios in the hybrid complex of P. nigra and its cultivar Populus × canadensis Moench. Within a mixed population, we analyzed seed collections from individual trees of both taxa as well as juveniles from natural regeneration for proportions of second-generation hybrids (F2 hybrids) and first generation backcrosses. While F2 hybrids were detected in the seeds only, first generation backcrosses occurred in seeds as well as in juveniles. Due to the meiotic segregation of alleles, a certain amount of such progeny may remain undetected. Based on Mendelian rules, we developed a scheme to adjust the observed proportion of hybrid progeny for these undetected cases. Moreover, the scheme can be used to iteratively add loci necessary to detect poplar hybrids beyond the second hybrid and first generation backcrosses. We questioned whether there is a risk of hybrid swarm formation or swamping of the P. nigra gene pool. We discuss the likelihood of such a scenario and draw conclusions for conservation issues while poplar plantations are increasingly appreciated as renewable resources.

Palabras clave

  • introgression
  • gene flow
  • hybrid swarm
  • SSR
  • P. × canadensis
  • diagnostic DNA markers
  • short rotation plantation.
Acceso abierto

Can Electrical Conductivity Predict Seed Germination of Three Pinus Species?

Publicado en línea: 01 Aug 2017
Páginas: 168 - 170

Resumen

Abstract

The potential of using the electrical conductivity method to predict seed germination of Pinus pinea, P. halepensis and P. nigra was investigated. Seed lots with low germination presented high conductivity values while those with high germination presented lower conductivity values after 48 hours of incubation. Based on linear regression analysis models with outlier remove analysis, high regression coefficients were obtained suggesting that it is possible to predict germination of the specific species through a quick electrical conductivity test.

Palabras clave

  • Electrical conductivity
  • germination
  • Pinus pinea
  • Pinus nigra
  • Pinus halepensis
Acceso abierto

Provenance Variation in Radial Increment and Wood Characteristics Revealed by 30 Years Old Norway Spruce Comparative Trials

Publicado en línea: 01 Aug 2017
Páginas: 170 - 178

Resumen

Abstract

The performance of 33 Norway spruce [Picea abies (L.) Karst.] seed sources from the Romanian Carpathians was evaluated with respect to growth and wood characteristics in comparative trials located at two different site conditions: Avrig- outside of the natural range of Norway spruce and Bret¸cu - within the natural range of this species. The radial increment (RI), latewood percentage (LWP) and conventional wood density (CWD) traits were evaluated at age 30 years after plantation. Phenotypic correlations between the evaluated traits, on the one hand, and between the same traits and the geographic gradients of the origin of seed sources, on the other hand, were calculated. Analysis of variance showed significant (p<0.01) differences between seed sources for RI, while for LWP and CWD, the differences were highly significant (p<0.001). These results suggest that selection at seed sources level could be possible. The test sites influence the LWP and CWD, while the RI is almost similar in both sites. For RI, the most valuable populations are situated in the Eastern and Western Romanian Carpathians. The highest LWP was registered for the Eastern Carpathian populations, while the lowest was recorded for the Western Carpathian populations. The Southern Carpathian populations, characterized by a lower growth rate, had higher values for wood density.

Palabras clave

  • Picea abies
  • radial increment
  • latewood
  • wood density
  • seed sources
  • comparative trials
Acceso abierto

Karyotype traits in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania

Publicado en línea: 01 Aug 2017
Páginas: 179 - 186

Resumen

Abstract

The description of the karyotype features and idiogram in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania, are reported here for the first time. The diploid chromosome number is 2n=2x=12, in agreement with the data published for the other species of the genus. The karyomorphological data show that the complements of the studied genotypes have small chromosomes (mean chromosome length is X̅±SE=2.56±0.10 μm, and mean length of haploid complements is X̅±SE=15.33±0.69 μm, with a range of variability comprised between 12.87-17.51 μm). The karyotypes are made up of six pairs of metacentric and submetacentric chromosomes, with an identical formula of the diploid complement: KF=2n=12=8m+ 2sm + 2sm-SAT. Satellites are located on the short arms of the chromosomes of pair III. The karyotypes show a relatively high level of intra-specific uniformity as well as similar symmetry patterns (R=1.29-1.53; TF%=38.78-41.57%; AsI%=54.54-57.61%; A1 = 0.24- 0.32; A2=0.08-0.16), belonging to 1A and 2A classes of symmetry. The small size of the chromosomes, the presence of only two chromosome morphometric types, and the preponderance of metacentrics confer a relatively high degree of symmetry to the karyotypes studied.

Palabras clave

  • Grindelia squarrosa
  • invasive plant
  • karyotype
  • mitotic chromosomes
  • satellites
  • asymmetry indexes
Acceso abierto

Early Selection for Improving Volume Growth in Coastal Douglas-fir Breeding Programs

Publicado en línea: 01 Aug 2017
Páginas: 186 - 198

Resumen

Abstract

Measurements on growth traits up to 41 years of age from 68 progeny sites in eight first-generation breeding zones of coastal Douglas-fir (Pseudotsuga menziesii [MIRB.] FRANCO var. menziesii) in the US Pacific Northwest were used to investigate age trends of genetic parameters and to determine optimum age of selection. Heritabilities and age-age genetic correlations were estimated using univariate or bivariate mixed model analyses. Heritability estimates tended to increase with age for both total growth and growth increment traits. The estimates showed different age trends among breeding zones, but the differences were generally small. Age-age genetic correlations for total growth traits fitted Lambeth’s model surprisingly well, despite the data being collected from multiple breeding zones. Using rotation-age (i.e., 50yr) volume as the selection criterion, the greatest correlated gains per year were achieved by making family selection at juvenile ages (i.e., 9 for height, 13 for diameter, and 11 for volume). Similar results were obtained for within-family selection except that the optimum ages of selection were 2~4 years later than that from family selection, i.e., 11 for height, 15 for diameter and volume. Early selection on total height was always more efficient and had earlier optimum ages than on other growth traits. The optimum ages of early family selection on total growth were 4~11 years earlier than on the corresponding growth increment traits. It was also evident that the optimum ages of selection occurred later for slow-growth trials than for fast-growing trials.

Palabras clave

  • Douglas-fir
  • growth
  • growth increment
  • early selection
  • selection efficiency
  • optimum age
  • heritability
  • age-age genetic correlation
Acceso abierto

Genetic Control of Growth Traits and Inheritance of Resistance to Bacterial Leaf Scorch in American Sycamore

Publicado en línea: 01 Aug 2017
Páginas: 198 - 206

Resumen

Abstract

Open-pollinated progeny tests of American sycamore (Platanus occidentalis L.), which included 55 open-pollinated families selected from several prior Westva - co progeny tests and seed orchards and six control-pollinated families were established in 2002 and 2003. The half-sibling families were planted at two sites in western Kentucky and southeastern Missouri. The six full-sibling families, generated from selections based on exhibition of parental disease resistance and susceptibility to a variety of diseases, were also planted near Stoneville, MS at the US Forest Service Center for Bottomland Hardwoods Research. All full-sibling families planted at the Stoneville site were inoculated in the fall 2002 with the leaf-scorch-causing bacterium, Xylella fastidiosa. Diameter and height data for trees of both half- and full-sibling families were recorded at ages three, five, seven, and nine at the various sites. Bacterial leaf scorch disease presence was also recorded as symptomatic or asymptomatic/ mildly symptomatic. Average family heritability across ages was 0.58, 0.50, and 0.55 for height, diameter, and volume, respectively, indicating that increased growth traits can be gained from family selection. In conjunction with derived age-age correlations, selection based on age-five data results in the greatest gain per unit time for age nine gains for half-sibling families. Breeding for bacterial leaf scorch resistance can also be successfully undertaken if proper selection and breeding of two resistant parents are undertaken which can result in a 4.5 fold decrease in the probability in symptoms of offspring by age nine. Results indicate a large potential for increased growth and disease resistance in American sycamore through traditional breeding.

Palabras clave

  • sycamore
  • selection
  • genetic gain
  • disease resistance
  • bacterial leaf scorch
Acceso abierto

Performance Evaluation of Shrub Willow Clones of North America and Yugoslavia Origins in Jilin, China

Publicado en línea: 01 Aug 2017
Páginas: 206 - 211

Resumen

Abstract

Demand for planting elite shrub willows as a resource for industrial use such as bioenergy and pulp has been increasing in Jilin province in northeast China. Toward this end, 12 elite willow clones, representing various species and origins, were imported from New York, USA, and planted at Lushui River, Jilin province. Two indigenous species were included in the test as the controls for comparison. This study was an evaluation of their performance in adaptation, growth potential, and wood traits after one rotation (three growing seasons). Results indicated that (1) all clones, but one, showed a parallel phenology to the control, had excellent survival (> 86%) and displayed good frost resistance; (2) compared to the control, most imported clones were comparable in main stem growth (height and diameter), but developed more stems and main roots; and (3) most imported clones had similar lignin, but higher cellulose content relative to the control. These results imply that some of the imported clones should be considered for further evaluation as good sources for both bioenergy and pulping. Based on cluster analysis, six clones were recommended for the upcoming scale-up site-clone trials for yield evaluation.

Palabras clave

  • adaptation
  • bioenergy
  • pulping
  • Salix
  • shrub willow
  • tree improvement
Acceso abierto

Gene flow in an overexploited population of Swietenia macrophylla King (Meliaceae) in the Bolivian Amazon

Publicado en línea: 01 Aug 2017
Páginas: 212 - 220

Resumen

Abstract

Pollen and seed movement among and within populations connect individuals and populations, and therefore are among the most important evolutionary processes determining the genetic structure of populations. Seven microsatellite loci were used to investigate the realized pollen dispersal and intra-population spatial genetic structure (SGS) in four permanent plots located in an overexploited big-leaf mahogany (Swietenia macrophylla King) population in the Bolivian Amazon. All adult trees found in the plots were mapped, sampled and genotyped. Seedlings were sampled below the canopy of reproductive trees. Private alleles in the sub-population of the adults and the seedlings were observed. The observed heterozygosity was significantly lower and fixation index was significantly higher for the seedlings (Ho=0.697, F=0.068) compared to the adults (Ho=0.761, F=-0.023). In one plot, seed immigration was observed (18%). Realized pollen immigration ranged among the plots from zero to 41% and selfing ranged from zero to 5.8%. We observed an average pollen dispersal distance from 75 to 255 m, with the maximum reaching 576 m. We found a significant SGS up to 150 m, showing that near neighbour individuals are relatives. The observed data on pollen- and seed dispersal provides important information for the sustainable management of the endangered mahogany species.

Palabras clave

  • Logging
  • mahogany
  • microsatellite loci
  • parentage analysis
  • tropical trees
Acceso abierto

Genetic diversity and differentiation of Chilean plantations of Pinus radiata D. Don using microsatellite DNA markers

Publicado en línea: 01 Aug 2017
Páginas: 221 - 228

Resumen

Abstract

Radiata pine (Pinus radiata D. Don) is the most important tree species in Chilean forest economy that was introduced to the country in 1892. Despite its economical end ecological relevance, no information about its genetic diversity is today available. Forty individuals of P. radiata, representing all populations in the Chilean radiata pine breeding program were genotyped with five microsatellite loci in order to determine genetic diversity and structure of Chilean plantations. The results of genetic diversity indicated that, after its introduction and mass planting, Chilean plantations of P. radiata has retained levels of genetic diversity similar to those of the natural populations of the species (HE=0.87, A=11.4). Genetic differentiation among populations (FST=0.04) was low, which means that the genetic variation present in radiata pine in Chile is partitioned among populations, indicating they are poorly differentiated. The structure analysis indicated the genetic base of the present plantations in Chile comes only from one provenance of the native populations. The genetic information provided important implications for the future breeding programs of P. radiata in Chile.

Palabras clave

  • Radiata pine
  • Chilean plantations
  • genetic diversity
  • population structure
  • molecular markers
Acceso abierto

Flowering phenology and germination ability of pollens for Acacia mangium and A. auriculiformis

Publicado en línea: 01 Aug 2017
Páginas: 228 - 236

Resumen

Abstract

A four-year investigation was conducted on the flowering phenology and germination ability of pollens from A. mangium and A. auriculiformis ramets to determine whether the flowering phenology and germination ability of pollens differed among clones or seed sources. The number of A. mangium and A. auriculiformis clones used was 19 and 23, collected from 17 and 8 seed sources, respectively. The flowering of each ramet was visually observed every three or four days for three seasons, with one season being from April to the following March, and the germination ability of pollens collected from the flowers was investigated at 1 day, 6 months, and 12 months after being stored at -18°C. The mean percentage of flowering per clone which was calculated by dividing the number of flowering ramets by the number of ramets used was low on A. mangium for each season, whereas it was more than 60% on A. auriculiformis for each season, with no significant variations among the seasons. The flowering initiation and flowering period also showed non-significant variations or differences among the seasons and among most of the clones within the seed sources. On the other hand, the percentage of flowering per clone, the flowering initiation, and the flowering period on A. auriculiformis showed significant variations and differences among the seed sources although those were similar on some seed sources. On both tree species, the germination rate of pollens per clone showed significant variations among clones, regardless of the seasons and number of days stored, and also among clones within seed sources for about half the cases. These results suggest that the flowering phenology is in some degree determined by a genetic factor such as the seed source, whereas the germination ability of pollens is mainly determined by a genetic factor in each clone.

Palabras clave

  • Acacia hybrid
  • Acacia mangium
  • Acacia auriculiformis
  • Artificial pollination
  • Flowering phenology
  • Pollen germination
Acceso abierto

Statistical associations between morphology, physiology and AFLP DNA markers enable selection of a putative eucalypt hybrid able to tolerate salt affected floodplains

Publicado en línea: 01 Aug 2017
Páginas: 236 - 246

Resumen

Abstract

A naturally occurring putative hybrid between Eucalyptus largiflorens F. Muell and Eucalyptus gracilis F. Muell called Green Box tolerates saline conditions of the River Murray floodplains better than E. largiflorens. Revegetation strategies utilizing seedlings of Green Box have had limited success because only a few are Green Box and the majority are throw backs to E. gracilis and E. largiflorens. Therefore, the purpose of this study was to identify traits characteristic of Green Box and AFLP markers associated with the traits enabling selection at the seedling stage. This was done by non-linear canonical correlation analysis (OVERALS) to test for statistically significant associations between morphological and physiological traits with 232 AFLP markers from 9 primer combinations. OVERALS with all markers produced 1st and 2nd dimensions accounting for 80 and 74% of variation respectively. Green Box plants were placed intermediate between E. gracillis and E. largiflorens according to leaf colour, gloss and nitrogen with component loadings (lc) of 0.340, 0.615 and 0.294 respectively. A second approach of simple linear regression of morphological and physiological traits against all 232 AFLP markers singled out 17 with significance P<0.05. Thirteen of these were also identified by OVERALS. Four occurred with high frequency in Green Box and E. largiflorens distinguishing them from E. gracilis. In order to separate Green Box and E. largiflorens, the segregation of a further three markers can be used to align Green Box with E. gracilis. Therefore, the segregation of 7 markers can be utilized to select Green Box.

Palabras clave

  • Eucalyptus
  • Australia
  • salt
  • re-vegetation
  • hybrid selection
  • AFLP marker
Acceso abierto

Integration of EST-CAPS markers into genetic maps of Eucalyptus urophylla and E. tereticornis and their alignment with E. grandis genome sequence

Publicado en línea: 01 Aug 2017
Páginas: 247 - 255

Resumen

Abstract

A suite of 91 expressed sequence tag (EST) derived cleaved amplified polymorphic sequence (CAPS) markers were developed and used for enriching the genetic maps of Eucalyptus urophylla and E. tereticornis built previously based on random amplified polymorphic DNA (RAPD) markers. The EST-CAPS markers were highly similar to original ESTs, with sequence identity ranging from 92.5% to 100.0%. In linkage analysis, 48 and 42 EST-CAPSs were integrated into the genetic maps of E. urophylla and E. tereticornis, respectively, including 13 shared by both maps, while 14 were unmapped. For E. urophylla, the final map had a total length of 1789.5 cM and a mean interval between markers of 9.7 cM, being 284.9 cM larger and 1.3 cM less than those of the prior RAPD map, respectively. For E. tereticornis, the final map had a length of 1488.1 cM and a mean interval of 10.3 cM, being 452.4 and 0.2 cM more than the prior map, respectively. All the 77 newly mapped EST-CAPSs found each at least one homologue in the E. grandis genome sequence released recently, and conserved synteny and colinearity were observed between E. grandis genome and our linkage groups. The enriched maps would provide a set of useful markers for genome analysis, comparative mapping and fine-mapping of important genes located in conserved regions for the important tree genus Eucalyptus.

Palabras clave

  • Expressed sequence tag (EST)
  • cleaved amplified polymorphic sequence (CAPS)
  • genetic map
  • synteny
  • colinearity
  • Eucalyptus
Acceso abierto

Estimating coancestry within open-pollinated progenies of a dioecious species: the case study of Myracrodruon urundeuva

Publicado en línea: 01 Aug 2017
Páginas: 256 - 264

Resumen

Abstract

Understanding the coancestry coefficient within openpollinated progenies has long been an area of interest because of the implications of coancestry on estimates of additive genetic variation, variance effective size and the number of seed trees required for seed collection for ex situ conservation, tree breeding and environmental restoration. This study compares three methods to calculate the coancestry coefficient within open-pollinated progenies of the dioecious tree species, Myracrodruon urundeuva, using six microsatellite loci. The methods compared were: i) correlated mating model (CMM) (RITLAND, 1989); ii) TWOGENER method (SMOUSE et al., 2001) to estimate the differentiation among pollen pools (TGM); and iii) HARDY et al.’s 2004 method using the estimate of coancestry from LOISELLE et al. (1995) (HLM) and from RITLAND (1996) (HRM). The data analysis was based on four data sets: two populations were composed of 12 progenies, two of 24 progenies, and all progenies consisted of 15 plants. The coancestry estimated using CMM ranged among populations from 0.145 to 0.158, using TGM it ranged from 0.153 to 0.181, using HLM from 0.153 to 0.162, and HRM from 0.144 to 0.147. To investigate the bias of the estimates of true relatedness within progenies we simulated two half-sib and two full-sib populations. The most accurate method found in the study was CMM because the estimated values presented no bias for true half- or full-sib progenies and these values were very similar to those expected (0.125 and 0.25, respectively). These results have significant implications for breeding and conservation programs because coancestry-within-progenies is a key parameter in assessing the variance effective size.

Palabras clave

  • additive genetic variation
  • effective population size
  • kinship
  • mating system
Acceso abierto

Breeding status of tung tree (Vernicia sp.) in China, a multipurpose oilseed crop with industrial uses

Publicado en línea: 01 Aug 2017
Páginas: 265 - 270

Resumen

Abstract

As a developing country with the world’s largest population, China faces a serious challenge in satisfying its continuously increasing energy demands. Tung trees (Vernicia sp., especially V. fordii and V. montana), are multipurpose, perennial plants belonging to the Euphorbiaceae family. The unique chemical properties of tung seed oil make it one of the best known industrial drying oils. In this review, the breeding status of tung trees in China and some factors which limit the development of tung tree breeding will be summarised. Improvements in ecological performance and pathogen resistance, through to improved breeding methods, will help to rapidly expand the development and use of tung trees and their oil products in China. It is essential for tung tree breeding to advance in the future to keep pace with the increased demand.

Palabras clave

  • Tung tree
  • Vernicia spp.
  • eleostearic acid
  • bio-energy
  • cross-breeding
Acceso abierto

Evaluating Interior Spruce Seed Deployment with GIS-Based Modeling Using British Columbia’s Prince George Seed Planning Zone as a Model

Publicado en línea: 01 Aug 2017
Páginas: 271 - 279

Resumen

Abstract

The maintenance, protection, and conservation of forest genetic resources for economic, ecological and social benefits are daunting tasks. Understanding how reforestation materials are spatially and temporally deployed across the landscape is an integral component of forest genetic resources management. To improve the current understanding of how reforestation materials are deployed in British Columbia (BC), we developed a geographical information systems (GIS) method to track seed deployment across silviculture openings. Generally, reforestation materials can originate from either natural stand (wild seed collections) or orchards’ seed sources (improved seed); the latter are produced within the framework of specific tree improvement program designed for a particular species within a well-defined seed deployment area, commonly known as Seed Planning Zone (SPZ). In this paper, we present a GIS-based method for evaluating seed deployment patterns for interior spruce (Picea glauca and Picea engelmannii and their natural hybrids) within the Prince George SPZ. The evaluation period (1970-2004) is associated with wild stands and improved seed availability and the dynamic of each seed source proportionate contribution followed three distinct phases; namely, developing (1970-1987), immature (1988-1994), and mature (1995-2004) with a progressive increase of orchards’ seed use over time. The developed method is scalable across SPZs of the same species or multiple species, thus providing the means to: 1) temporally and spatially monitor improved and natural stands seed deployment over the landscape; and 2) identify areas of concerns where a particular seed source is over-represented which might pose an increased genetic vulnerability. The present study revealed that the current interior spruce orchard’s seed use within the Prince George SPZ is expected to exceed the provincial goal of performance target of 75% by 2014. Additionally, areas of excessive use of one seed orchard seed were identified.

Palabras clave

  • Geographical information system
  • Interior spruce
  • Seed Planning Zone
  • Wild stands and seed orchard seed
  • Deployment in time and space
Acceso abierto

Selection and validation of reference genes for real-time qRT-PCR normalization in different tissues of Eucalyptus tereticornis

Publicado en línea: 01 Aug 2017
Páginas: 280 - 286

Resumen

Abstract

Reference genes are generally used as endogenous normalization factor for relative quantification of target genes in quantitative real-time PCR (qRT-PCR). The present work aimed at identifying suitable reference genes for normalization of qRT-PCR data in tissues of Eucalyptus tereticornis. The expression levels of housekeeping genes like Actin (EtAct2), Isocitrate dehy - drogenase (EtIDH), ribosomal RNA (Et18s rRNA), SAND family protein (EtSAND), Histone protein (EtH2B), α-Tubulin (EtTUB), and eukaryotic initiation factor (EteIF4B) were studied to characterize their normalization stability in different tissues including young leaves, internodes, developing and mature xylem. The expression level of these genes was analyzed using different algorithms like geNorm, NormFinder and Best- Keeper. Among the seven reference genes analyzed, EtAct2 was expressed with less variance and was found to be the most stable reference gene across different tissues using all the three programs, while the least stable gene identified was EtH2B. Further, the normalization efficiency of the reference genes were assessed to predict the expression levels of three primary cell wall specific cellulose synthase transcripts (EtCesAs) in E. tereticornis tissues. The relative expression of EtCesA4, EtCesA5 and EtCesA6 was determined to be 3-19 fold higher in leaf and internode tissues when compared to developing and mature xylem tissues. This study will allow accurate normalization of qRT-PCR experiments across different tissues in E. tereticornis for future genomic research in this tropical eucalypt species.

Key words

  • Reference gene
  • selection
  • normalization
  • cellulose synthase gene
  • differential expression
  • qRT-PCR
  • Eucalyptus
Acceso abierto

Cross-Species Amplification of Microsatellite Loci for the Endangered Conifer, Taxus chinensis var. mairei (Taxaceae)

Publicado en línea: 01 Aug 2017
Páginas: 287 - 291

Resumen

Abstract

Being an economical and endangered species, microsatellite markers of Taxus chinensis var. mairei were very limited. We have developed a set of microsatellite markers, which was benefit for future genetic analysis of this rare species. Polymorphic loci were developed from congeneric species by cross-species amplification methods, and new primers were redesigned to test for potential null alleles. 15 loci showed polymorphism. The number of alleles per locus varied from 2 to 23 tested in 48 individuals. The observed heterozygosity (Ho) and expected heterozygosity (He) values ranged form 0.000 to 0.854 and 0.082 to 0.827, respectively. Newly redesigned primer confirmed that no null allele existed in most suspected loci. These microsatellite markers will be useful for future genetic analysis and conservation of this endangered species.

Palabras clave

  • cross-amplification
  • microsatellites
  • Taxus chinensis var. mairei
  • population genetics
  • genetic diversity
Acceso abierto

Insights in the chestnut genetic diversity in Canton Ticino (Southern Switzerland)

Publicado en línea: 01 Aug 2017
Páginas: 292 - 300

Resumen

Abstract

Castanea sativa Miller displays a high variability of morphological and ecological traits, vegetative and reproductive habits, nut morphology, wood characteristics, adaptability, and resistance to biotic and abiotic stresses. The present range of distribution of the species has been strongly influenced by human migrations and it is thought that Romans played a crucial role in the spread of the cultivation in Europe, although in some areas there is also evidence of local domestication and spontaneous spread of the tree after the last glacial period. In Switzerland chestnut stands are found mostly in the South (Canton Ticino), a region where the debate about the origin of the local germplasm, whether derived from the survival or spontaneous migration of C. sativa on the territory or due to the introduction of the tree during the Roman colonisation, is still open. This study aims contributing to depict the chestnut genetic situation of the species in Canton Ticino as a contribution to the debate about the native character of the species. The study area is located in Switzerland, on the southern slopes of the Alps, where 3 C. sativa populations were sampled and analysed at 9 SSR loci. Populations showed a high degree of diversity, as it is observed in most natural population of tree species: all nine SSR loci were polymorphic (no fixed alleles were detected), and genetic diversity, measured by expected heterozygosity, was high ranging in the populations between 0.647 and 0.721, on average. Results suggest that three homogeneous gene pools contributed to the formation of the 3 populations sampled. The genetic germplasm structuring of the analysed chestnut stands is very mild as confirmed by the relatively low level of genetic differentiation and divergence observed among sites.

Palabras clave

  • Castanea sativa
  • genetic diversity
  • chestnut population
  • DNA analysis
  • SSR
37 Artículos
Acceso abierto

Linkage map construction and QTL analysis for Betula platyphylla Suk using RAPD, AFLP, ISSR and SSR

Publicado en línea: 01 Aug 2017
Páginas: 1 - 9

Resumen

Abstract

A linkage map for Betula platyphylla Suk was constructed based on RAPD, ISSR, AFLP and SSR markers by a pseudo-testcross mapping strategy. A F1 segregating population including 80 progenies was obtained from the cross between two superior trees selected from Qinghai and Wangqing provenance, respectively. The paternal map was constructed with 282 markers consisting of 14 major and 15 minor (5 triplets and 10 doublets) linkage groups and spanning 1131 cM at an average distance of 4.0 cM between adjacent markers. The maternal map has 277 markers consisting of 15 major and 8 minor (5 triplets and 3 doublets) groups covering 1288 cM at an average distance of 4.6 cM between adjacent markers. In the same pedigree we investigated association of genetic markers with seedling stem height and circumference. The composite interval mapping was used to detect the number of quantitative trait loci and their position on the genetic linkage maps. Three QTLs (one on the male map and two on the female map) were found explaining 13.4%, 17.5% and 18.8% of the trait variation, respectively.

Palabras clave

  • silver birch
  • linkage map
  • RAPD
  • AFLP
  • ISSR
  • SSR
  • QTL
Acceso abierto

Influence of geographic distance and genetic dissimilarity among clones on flowering synchrony in a Teak (Tectona grandis Linn. f) clonal seed orchard

Publicado en línea: 01 Aug 2017
Páginas: 10 - 18

Resumen

Abstract

Influence of genetic dissimilarity among teak (Tectona grandis Linn. f.) clones on flowering synchrony was studied in a Clonal Seed Orchard (CSO) of teak in Karnataka, Southern India. Flowering phenology was monitored for all the 24 teak clones of the CSO and flowering synchrony between clones was assessed adopting a novel ‘overlap index’. Genetic dissimilarity among these clones was assessed adopting DNA based ISSR (Inter Simple Sequence Repeats) analysis. Large variation in the time of ‘flower initiation’ and of ‘peak flowering initiation’ was observed among the clones belonging to diverse sources, suggesting large asynchronous flowering. Cluster analysis based on ISSR marker indicated that the clones originating from a same source clustered together and there was a clear segregation based on their origin. Correlation analysis revealed a significant negative association between the average Jaccards’s dissimilarity index between pairs of clones and average peak flowering overlap index. Clones from geographically diverse regions had high genetic dissimilarity and also showed high flowering asynchrony within them.

Palabras clave

  • Provenance effect
  • genetic markers
  • flowering phenology
  • genetic distance
Acceso abierto

Gene exchange across a postglacial contact zone in Fraxinus excelsior L.

Publicado en línea: 01 Aug 2017
Páginas: 18 - 27

Resumen

Abstract

Hybridization between divergent lineages of common ash Fraxinus excelsior L. was studied in Slovakia and adjacent regions of Hungary, the Czech Republic and Poland in the contact zone between two postglacial colonization routes originating from different glacial refugia. Thirty-eight common ash populations were studied using a combination of 6 maternally inherited chloroplast microsatellite markers and 7 biparentally inherited nuclear microsatellites (nSSR). Two predominant chloroplast lineages were identified, between which the boundary was very sharp. Populations containing a mixture of different haplotypes were found only in the immediate proximity of the boundary. Bayesian analysis of population structure based on nSSR loci revealed the existence of two clusters, which largely coincided with chloroplast lineages. Both haplotype frequencies and proportions of clusters identified by the Bayesian analysis exhibited a clinal transition over the hybrid zone, with cline widths of 36 km for chloroplast haplotype frequencies (reflecting gene flow by seeds) and 275 km for Bayesian clusters based on nSSR (reflecting gene flow by pollen and seeds). Chloroplast haplotype diversity increased along the boundary between lineages not only because of admixture, but also due to the presence of rare haplotypes. In contrast, diversity at nuclear loci did not exhibit any geographical trend.

Palabras clave

  • Fraxinus excelsior L.
  • introgression
  • cline
  • postglacial colonization
Acceso abierto

Chloroplast DNA variation in planted and natural regenerated stands of black locust (Robinia pseudoacacia L.)

Publicado en línea: 01 Aug 2017
Páginas: 27 - 35

Resumen

Abstract

Black locust (Robinia pseudoacacia L.), native in mountainous regions in USA, is increasing in importance for forestry in many countries as a „multi-purpose tree“ associated with breeding efforts at the family and clonal levels. A few population genetic studies exist with nuclear, codominantly inherited markers. Here we present an additional marker type, the maternally inherited chloroplast haplotypes. The studied material included samples from the natural range and from artificial stands from three European countries as well as samples from a clone collection. Eleven haplotypes belonging to two clearly separated groups of related haplotypes were found using the PCR-RFLP method. The variation pattern of chloroplast haplotypes in artificial stands is strongly influenced by the local silvicultural management.

Palabras clave

  • Robinia pseudoacacia L.
  • cpDNA haplotypes
  • PCRRFLP
  • artificial populations
  • silvicultural management
Acceso abierto

Influence of altitude on seed and seedling characteristics in Quercus leucotrichophora A. Camus. ex. Bahadur

Publicado en línea: 01 Aug 2017
Páginas: 36 - 43

Resumen

Abstract

The present investigation was conducted to record variation of seed and seedling morphological characteristics and germination among eighteen provenances of Quercus leucotrichophora. These traits are important for improving the planting stock material in hand. Significant variations (p<0.05) were recorded for different morphological parameters of seed and seedling among the different provenances. Seed weight was the most variable character among morphological characteristics. Shoot/root ratio and root growth were more variable characters among the seedling traits. Altitude had significant positive relationship with seed weight, seed length and germination per cent. Soil pH was positively correlated with seed weight and germination. These parameters could be used as important criteria for seed source selection. Broad-sense heritability (h2) calculated for different seed and seedling traits showed a considerable portion of genetic variation suggesting the possibility of rapid genetic improvement of these traits. Furthermore, this variability appeared to be geographically structured and would be mainly genetically controlled. Thus the results of present study should be helpful for growing planting material of this potential tree species in afforestation of subtropical to temperate region of Garhwal Himalaya, India.

Palabras clave

  • Seed origin
  • seed dimensions
  • genetic variability
  • heritability
  • Quercus leucotrichophora seedling
  • growth characteristics
Acceso abierto

Isolating of a putative glyceraldehyde-3 phosphate dehydrogenase (GAPDH) from Calophyllum brasiliense, an important tropical forest tree

Publicado en línea: 01 Aug 2017
Páginas: 44 - 51

Resumen

Abstract

Calophyllum brasiliense Cambess. has characteristics that made it an excellent candidate model for ecogenomics in rain forest trees such as widespread natural occurrence and geographical patterns of adaptive genetic variation. Besides, it is also becoming a popular species for reforestation efforts in Brazil. Although, very little is known about its genetic diversity and the molecular mechanisms involved genetic adaptation traits. The first difficulty in launching genetic studies in a wild wood species is the lack of an optimized protocol for RNA and DNA isolation. In this work we built the essential framework for molecular genetics research with C. brasiliense comparing four distinct methods of RNA extraction from of three different tissues: leaves, stems and roots. We also were successful in the isolation of genomic DNA by an optimized CTAB method. Finally, degenerated oligonucleotide primers were designed for isolating of the glyceraldehyde-3 phosphate dehydrogenase (GAPDH) gene of C. brasiliense from the corresponding gene in closely related species. This gene is commonly used in plants as reference in expression gene analysis by Reverse Transcription Polymerase Chain Reaction (RT-PCR). Primers for RT-PCR were designed based on partial sequence obtained using degenerate primers designed. The optimized methods of RNA and DNA extraction combined with the identification, isolation and specific primer design for RT-PCR of a traditional Reference Gene provide the essential framework for molecular genetics research with C. brasiliense.

Palabras clave

  • Calophyllum brasiliense
  • gene expression
  • nucleic acid extraction
  • ecogenomics
Acceso abierto

Effect of monoclonal and assorted seedling rootstocks on long term growth and yield of Hevea clones

Publicado en línea: 01 Aug 2017
Páginas: 52 - 57

Resumen

Abstract

Seven Hevea brasiliensis clones were evaluated on two types of rootstocks, assorted seedling rootstocks (AR) and monoclonal rootstock (MR) over 19 years. Influence of rootstock on scion growth and rubber yield was assessed based on juvenile height, circumference of the main trunk (cm), number of branches, branching height and cumulative dry rubber yield (g per tree per tapping, conventionally abbreviated gt-1 t-1). Highest cumulative yield (g per tree per tapping) over the 12 years for which the trees were tapped was obtained from clone RRII 105 (MR: 1076 g per tree per tapping and AR: 497 g per tree per tapping), followed by RRII 203 (MR: 661; AR: 538), RRII 208 (MR: 477; AR: 486), RRII 118 (MR: 497; AR: 452). Gl 1 yielded the least, 219 g per tree per tapping (MR) and 378 g per tree per tapping (AR); GT1 produced 335 g per tree per tapping (MR) and 375 g per tree per tapping (AR). RRII 118 had the greatest circumference at age 19 (91.4 cm on MR) 88.8 on AR, followed by RRII 105 (MR: 87.4 cm AR: 89.2 cm) and GT 1 (MR: 88.5 cm; AR: 84.4cm). Effect of scion clone was significant (p<0.01) only for trunk circumference at opening, but not for cumulative rubber yield at age 11 (4 years after opening) or cumulative rubber yield at age 19 (12 years after opening). Most importantly, rootstock and clone × rootstock interaction did not significantly affect rubber yield or tree circumference at any evaluation time. There was no evidence to suggest that growth and yield of clones was influenced significantly by rootstock type.

Palabras clave

  • Natural rubber
  • rootstock-scion
  • Hevea brasiliensis
Acceso abierto

Early genetic evaluation of morphology and some wood properties of Tectona grandis L. clones

Publicado en línea: 01 Aug 2017
Páginas: 58 - 65

Resumen

Palabras clave

  • early evaluation
  • correlation genotypic
  • heritability
Acceso abierto

Diallel Crossing in Pinus cembra: V. Age Trends in Genetic Parameters and Genetic Gain for Height

Publicado en línea: 01 Aug 2017
Páginas: 66 - 79

Resumen

Abstract

A full diallel mating design (10 parents) was carried out in a Swiss stone pine panmictic population from the Carpathian Mountains. At age six, after nursery testing, the progenies were field planted to one site, using a completely randomized block design with 100 families, four replicates and a 15 tree row-plot per replication, spaced 2.5 × 2.5 m. Total and annual height of all individuals of this test was assessed at successive ages, between ages eight and 16. In addition, weight of 100 seeds and cotyledon number were considered in correlation analyses. Significant differences occurred in total height for general and specific combining ability effects. Variance components, heritabilities, genetic correlations and genetic gains on growth traits and survival at age 16 were estimated. Across the field testing period, GCA3) variance increased with time, accounting for 65% of plot mean phenotypic variance by age 16. In contrast, SCA variance declined as the progeny test aged accounting for only 9% by age 16. The time trend of the four heritability estimates for total height increased with age across the testing period reaching their highest level between age 14 and 16. Genetic correlations over time for total height rose from 0.85 at age two to 0.94 at age six and then leveled off across the field test indicating that if the goal is to improve 16-year height, early selection can be considered at age six. By selecting the best 10%, 15% and 20% of individuals within the best fullsib families, a genetic gain in total height of 12.4 %, 11.0% and 9.9% respectively, could be achieved at age 16. A higher gain can be obtained if the best general combiner parents are selected and intermated.

Palabras clave

  • Pinus cembra
  • diallel crossing
  • additive variance
  • dominance ratio
  • genetic effect
  • age-age genetic correlation
  • heritability
  • early selection
  • genetic gain
Acceso abierto

Clonal fertility variation and its effects on the effective population size in the seed orchard of dioecious species, Fraxinus rhynchophylla

Publicado en línea: 01 Aug 2017
Páginas: 79 - 84

Resumen

Abstract

The numbers of female and male flowers were assessed in a clonal seed orchard of Fraxinus rhynchophylla for four consecutive years from 2004 through 2007. The female and male flowers of the grafts from 48 clones were counted individually over the crown. Fertility variation was calculated by sibling coefficient that is related to the coefficient of variation in parental flower assessment. Estimated maternal and paternal fertilities were not constant but varied from year to year, and they were also found to be weakly correlated. The effective numbers of clones serving as male and female parents were calculated from the sibling coefficients of maternity and paternity. We applied two theoretical approaches to estimate the clonal effective population sizes based on 1) fertility variation (i.e., effective number of parents, N(c)) and 2) gender balance (effective population size, Nee) among parental genotypes. The values of Ne(c) were higher in the years with abundant flowering and seed production, while sibling coefficients were lower. On average (pooled), the maternal, paternal and clonal values of Ne(c) were calculated to be 17.3, 21.0 and 38.1 respectively. The Ne(c) for maternal gamete gene pool was ranged from 9.8 to 16.7. The values of Ne for paternal gamete gene pool were generally higher (ranged from 14.9 to 21.9) than those for maternal. When pooled, the Ne was 47.2 and the values of Ne were higher when the gender ratio was more balanced. An option of equal seed harvest might be good to mitigate fertility variation and to improve gene diversity of seeds.

Palabras clave

  • status number
  • sibling coefficient
  • gene diversity
  • gender balance
  • equal seed harvest
  • Fraxinus rhynchophylla
Acceso abierto

High temperature-induced triploid production during embryo sac development in Populus

Publicado en línea: 01 Aug 2017
Páginas: 85 - 93

Resumen

Abstract

Triploid breeding plays an important role in cultivar improvement in the genus Populus L. A novel approach for triploid production with colchicine during embryo sac development was reported recently by Wang et al. (2010). In the present investigation, female catkins of Populus pseudo-simonii × P. nigra ‘Zheyin3#’ during embryo sac development were exposed to high temperature to assess the effectiveness of high temperature for induction of triploid production. In the progeny, 45 triploids were determined by both flow cytometric analysis and somatic chromosome counting. The period 66-72 h after pollination was the most suitable for high temperature-induced triploid production during embryo sac development in the ‘Zheyin3#’. Cytological analysis showed that the frequency of eight-nucleate embryo sacs rose at an increased rate during 66-78 h after pollination, which suggested that the third mitosis during embryo sac development could be the optimal stage for high temperature-induced triploid production. The highest frequency of triploid production was 40%, which was obtained in the 44°C for 2 h treatment 72 h after pollination. In view of both triploid number and production efficiency, treatments with 41°C for 4-6 h or with 44°C for 2 h during 66-72 h after pollination were both effective for triploid induction in ‘Zheyin3#’. Statistical analysis showed that the growth of triploids and diploids was not significantly different. However, highly significant differences were observed for all leaf characteristics. Finally, the significance of high temperature treatment in Populus triploid breeding programs is discussed.

Palabras clave

  • 2n egg
  • embryo sac development
  • high temperature
  • Populus
  • triploid
Acceso abierto

Physiological and Protein Responses to Drought in Four Pine Seedlings

Publicado en línea: 01 Aug 2017
Páginas: 93 - 103

Resumen

Abstract

Physiological and protein responses to drought stress in four pine seedlings, Pinus armandi Franch. (Pa), Pinus tabulaeformis Carr. (Pt), Pinus bungeana Zucc. ex Endl. (Pb) and Pinus sylvestris L. var. mongolica Litv. (Ps), were investigated using differential proteomics and water physiological indices. Firstly, the water physiological data showed that the decline rate of net photosynthesis rate, stomatal conductance, leaf water potential, turgor pressure except for under moderate drought stress was as follows: Pa>Ps>Pt>Pb. Pb and Pa always maintained the highest and lowest swelling pressure, respectively. Secondly, cluster analysis of 343 proteins indicated that the four pine species were classified into three groups with a genetic distance coefficient of 0.065. That is, five-needle-pine group (Pa), three-needle-pine group (Pb), two-needle-pine group (Pt and Ps), and the genetic distance between Pb and Pa was the farthest. The result was consistent with the declined rate in above physiological indices. Finally, for the differential proteomics analyzed, a total of 13 different proteins (P values < 0.01) changed significantly, the number of differentially expressed proteins was more in Pa (accounting for 46.2%) than the other three species, and 8 proteins were identified using matrix-assisted laser desorption/ionization time -of-flight mass spectrometry (MALDI-TOF-MS). These proteins are quite diverse in their functions and involved in photosynthesis, osmotic regulation and functioning as signal transduction. These results suggested that the sensitivities of the four pine species to drought were possibly related to genetic distance.

Palabras clave

  • drought stress
  • drought-resistance
  • proteomics
  • genetic distance
Acceso abierto

Developing breeding and deployment options for Douglas-fir in New Zealand: breeding for future forest conditions

Publicado en línea: 01 Aug 2017
Páginas: 104 - 115

Resumen

Abstract

Genetic improvement of Douglas-fir in New Zealand was initiated in 1955 with large provenance trials established in the late 1950’s. These trials illustrated that material from the coast of Oregon and California grew faster than other provenances tested. Further collections were made to evaluate provenance and familylevel performance from these two areas, and in 1996 additional trials were established at four low-altitude sites across New Zealand. Genotype×environment (GxE) interaction among these sites was found to be important for diameter at breast height (DBH), less important for stem straightness and malformation and not important for outerwood acoustic velocity (a surrogate for wood stiffness). Heritabilities were low to moderate for all growth traits, and very low for malformation. Heritability for needle cast due to Swiss needle cast, measured as needle retention on the one site where infection was relatively high, was moderate at 0.37, and was likely a major factor creating GxE interactions for growth among sites. The heritability of wood acoustic velocity was moderate to high at individual sites (0.26-0.74) and across sites (0.49). Individual- trait selection revealed the potential for good genetic gains to be made when selecting the top 20 families for diameter growth (an average of 10.7%), straightness (an average of 11.5%) and acoustic velocity (an average of 7.0%). When we examined predicted genetic gains while selecting for needle retention and/or DBH, we found that selecting for needle cast at the affected site did not compromise DBH gains at that site. Selecting for genotypes with low needle cast at the affected site did, however, reduce gains for DBH estimated across all sites. In order to maximise gains across the current Douglas-fir growing estate, a division of growing sites between those known and predicted to be affected by needle cast and those not affected would seem appropriate. This is particularly relevant given recent climate modelling work suggests that Swiss needle cast will become more important in the South Island, and even more destructive in the North Island of New Zealand. We suggest addressing differences in site through the development of separate deployment populations.

Palabras clave

  • Pseudotsuga menziesii
  • tree breeding
  • deployment
  • genotype x environment interaction
  • Swiss needle cast
Acceso abierto

Effect of Different Progeny Test Strategies in the Performance of Eucalypt Clones

Publicado en línea: 01 Aug 2017
Páginas: 116 - 120

Resumen

Abstract

The objective of the present study was to investigate whether the performance of an individual in clonal testing was affected by the location of the initial selection. The study also evaluated the effect of mass selection and BLUP (Best Linear Unbiased Prediction) on the performance of individuals in the progeny test and the clonal test. In the progeny test, 62 half-sib E. grandis families, 68 half-sib E. urophylla families and 62 full-sib families between E. grandis and E. urophylla, plus four checks were evaluated totaling 196 treatments. The experiments were carried out at three sites: Aracruz and São Mateus, in Espírito Santo State and Caravelas, Bahia State, Brazil. The 1000 best individuals were classified by mass selection and BLUP. In the clonal tests 257 clones were evaluated in two locations: Aracruz and Caravelas. In both the progeny test and the clonal test, two years after planting, the circumference at breast height and basic wood density were measured and the sum of standardized variables (Z) was estimated for simultaneous selection of both characteristics. The results indicated that the origin of the individual in a progeny test had a small effect on the performance of the clone when evaluated in other environments; the estimates of realized heritability and the linear regression coefficient were small in all the selection strategies. Thus, the correlation between the performance of trees selected in progeny tests and their respective clones in the clonal test was small.

Palabras clave

  • Plant breeding
  • selection strategies
  • realized heritability
  • Eucalyptus
Acceso abierto

Pollination methods, stigma receptivity and pollen tube growth in Eucalyptus argophloia

Publicado en línea: 01 Aug 2017
Páginas: 121 - 126

Resumen

Abstract

Eucalyptus argophloia Blakely (Western white gum) has shown potential as a commercial forestry timber species in marginal environments of north-eastern Australia. We measured early pollination success in Eucalyptus argophloia to compare pollination methods, determine the timing of stigma receptivity and compare fresh and stored pollen. Early pollination success was measured by counting pollen tubes in the style of E. argophloia 12 days after pollination. We compared the early pollination success of 1) Artificially Induced Protogyny (AIP), one-stop and three-stop methods of pollination; 2) flowers pollinated at 2 day intervals between 2 days before and 6 days after anthesis and 3) fresh pollen and pollen that had been stored for 9 months. Our results show significantly more pollen tubes from unpollinated AIP and AIP treatments than either the one-stop pollination or three-stop pollination treatments. This indicates that self-pollination occurs in the unpollinated AIP treatment. There was very little pollen tube growth in the one-stop method indicating that the three-stop method is the most suitable for this species. Stigma receptivity in E. argophloia commenced six days after anthesis and no pollen tube growth was observed prior to this. Fresh pollen resulted in pollen tube growth in the style whereas the stored pollen resulted in a total absence of pollen tube growth. We recommend that breeding programs incorporating E. argophloia as a female parent use the three-stop pollination method, and controlled pollination be carried out at least six days after anthesis using fresh pollen.

Palabras clave

  • one-stop pollination
  • three-stop pollination
  • artificially induced protogyny
  • stored pollen
Acceso abierto

GSCA: New Software and Algorithms to Analyse Diallel Mating Designs Based on Restricted Linear Model

Publicado en línea: 01 Aug 2017
Páginas: 126 - 132

Resumen

Palabras clave

  • Diallel mating design
  • restricted linear models
  • general combining ability
  • specific combining ability
  • least squares
Acceso abierto

Variation in Floral Phenological Synchronization in a Clonal Seed Orchard of Pinus tabuliformis in Northeast of China

Publicado en línea: 01 Aug 2017
Páginas: 133 - 142

Resumen

Abstract

Flowering phenology in an orchard is a crucial factor affecting the gene exchange among clones and consequently changing genetic composition of the seed crop. Pinus tabuliformis is now at the crucial period from first generation clonal seed orchards to advanced generation seed orchards in China. In this study, variation and stability in floral phenological synchronization of all the clones and possible mating pairs, in terms of an index of phenological overlap, were observed in a first generation clonal seed orchard which located in northeast of China. Results showed that significant variations occurred in the clones and mating pairs. This kind of variation was apparently related with temperature and humidity of the research site. With increasing age, levels of flowering synchronization were likely to rise in the clones and mating pairs. In general, the average flowering synchronization of male parents was slightly higher than that of female parents, female management in a seed orchard should be paied more attention. Flowering time was under strong genetic control and this genetic control was stronger in the female flowering process than of the males in terms of board sense heritability and year to year correlation analysis. Flowering synchronization of female parents was positively correlated between most years and can be a reliable reference for early and late predication in Pinus tabuliformis seed orchard during stage of initial seed harvest to stable seed production. According to their average levels of flowering synchronization, 49 clones in the first generation clonal seed orchard were divided into 11 different groups. Results of this paper provided the basic information for first generation seed orchard management and advanced seed orchard establishment of Pinus tabuliformis.

Palabras clave

  • Pinus tabuliformis
  • first generation
  • clonal seed orchard
  • reproductive synchronization
  • phenological overlap index
  • genetic variation
  • clonal repeatibility
  • seed orchard management
  • advanced seed orchard establishment
Acceso abierto

Optimisation of a multiplex PCR assay of nuclear microsatellite markers for population genetics and clone identification in Robinia pseudoacacia L.

Publicado en línea: 01 Aug 2017
Páginas: 142 - 148

Resumen

Abstract

Black locust (Robinia pseudoacacia L.) is a tree species native to North America. The multipurpose tree is cultivated worldwide, but causes problems due to its partially invasive character. The application of nuclear microsatellite loci has many aims in population genetic studies. Here we introduce a very cost-effective method for combining the information of 14 nuclear microsatellite loci into two multiplex PCR sets as a contribution to greater standardisation and more comparable results. Combined non-exclusion probabilities for clone identification using example populations are estimated at between 1.37*E-5 and 1.67*E-11, and for paternity analysis for 1.59*E-4. The detected weak linkage between some microsatellite loci is not considered to be a substantial restriction to the reliability of the set of markers in providing an appropriate method for fingerprinting and parentage analysis.

Palabras clave

  • Black locust
  • SSRs
  • multiplexing
  • population genetics
  • clone identification
  • paternity analysis
  • linkage
Acceso abierto

Microarray Analysis of Gene Expression in Triploid Black Poplar

Publicado en línea: 01 Aug 2017
Páginas: 148 - 157

Resumen

Abstract

Triploidy is a widespread phenomenon in cultivated and natural breeding plants and it can confer some growth advantages. Here, we analyzed genome-wide gene expression in triploid Populus euramericana (black poplar) using the Affymetrix poplar microarray to detect any possible correlation between triploid vigor and a unique gene expression profile. Among the 38,400 transcripts that were detected in triploid poplar, 1,564 and 2,015 genes were up- or downregulated, respectively, compared with the diploid. The majority of the upregulated genes in the triploid were associated with carbon and nitrogen metabolism, especially lignin and secondary metabolism. Other genes upregulated in the triploid included genes involved in sugar transport, and brassinosteroid (BR) and auxin metabolism. Downregulated genes were mostly related to the assembly and biosynthesis of ribosomes and the nucleosome macromolecular complex. The results suggested that BR and auxin levels were crucial in controlling sugar transport, photosynthesis and cell wall biosynthesis. Downregulated genes were associated with chromatin regulation in the triploid. The information from this analysis could provide an insight into the vigor of triploid poplar.

Palabras clave

  • Gene expression
  • Populus
  • microarray
  • triploid
Acceso abierto

Reconstructing explicit mating schemes in poplar hybrids – a case study in the Populus nigra L. – Populus × canadensis Moench complex

Publicado en línea: 01 Aug 2017
Páginas: 157 - 167

Resumen

Abstract

In the plant kingdom, a large percentage of taxa are known to interbreed. If these hybrids are fertile, introgressive gene flow may foster the development of hybrid swarms or even promote gene swamping. Our study focuses on the Eurasian black poplar (Populus nigra L.) which may be threatened by hybridization with the cultivated fertile Euramerican hybrid. Using a combination of taxa specific DNA markers from the chloroplast and the nuclear genome we set up a straightforward and cost efficient method for identification of all possible mating scenarios in the hybrid complex of P. nigra and its cultivar Populus × canadensis Moench. Within a mixed population, we analyzed seed collections from individual trees of both taxa as well as juveniles from natural regeneration for proportions of second-generation hybrids (F2 hybrids) and first generation backcrosses. While F2 hybrids were detected in the seeds only, first generation backcrosses occurred in seeds as well as in juveniles. Due to the meiotic segregation of alleles, a certain amount of such progeny may remain undetected. Based on Mendelian rules, we developed a scheme to adjust the observed proportion of hybrid progeny for these undetected cases. Moreover, the scheme can be used to iteratively add loci necessary to detect poplar hybrids beyond the second hybrid and first generation backcrosses. We questioned whether there is a risk of hybrid swarm formation or swamping of the P. nigra gene pool. We discuss the likelihood of such a scenario and draw conclusions for conservation issues while poplar plantations are increasingly appreciated as renewable resources.

Palabras clave

  • introgression
  • gene flow
  • hybrid swarm
  • SSR
  • P. × canadensis
  • diagnostic DNA markers
  • short rotation plantation.
Acceso abierto

Can Electrical Conductivity Predict Seed Germination of Three Pinus Species?

Publicado en línea: 01 Aug 2017
Páginas: 168 - 170

Resumen

Abstract

The potential of using the electrical conductivity method to predict seed germination of Pinus pinea, P. halepensis and P. nigra was investigated. Seed lots with low germination presented high conductivity values while those with high germination presented lower conductivity values after 48 hours of incubation. Based on linear regression analysis models with outlier remove analysis, high regression coefficients were obtained suggesting that it is possible to predict germination of the specific species through a quick electrical conductivity test.

Palabras clave

  • Electrical conductivity
  • germination
  • Pinus pinea
  • Pinus nigra
  • Pinus halepensis
Acceso abierto

Provenance Variation in Radial Increment and Wood Characteristics Revealed by 30 Years Old Norway Spruce Comparative Trials

Publicado en línea: 01 Aug 2017
Páginas: 170 - 178

Resumen

Abstract

The performance of 33 Norway spruce [Picea abies (L.) Karst.] seed sources from the Romanian Carpathians was evaluated with respect to growth and wood characteristics in comparative trials located at two different site conditions: Avrig- outside of the natural range of Norway spruce and Bret¸cu - within the natural range of this species. The radial increment (RI), latewood percentage (LWP) and conventional wood density (CWD) traits were evaluated at age 30 years after plantation. Phenotypic correlations between the evaluated traits, on the one hand, and between the same traits and the geographic gradients of the origin of seed sources, on the other hand, were calculated. Analysis of variance showed significant (p<0.01) differences between seed sources for RI, while for LWP and CWD, the differences were highly significant (p<0.001). These results suggest that selection at seed sources level could be possible. The test sites influence the LWP and CWD, while the RI is almost similar in both sites. For RI, the most valuable populations are situated in the Eastern and Western Romanian Carpathians. The highest LWP was registered for the Eastern Carpathian populations, while the lowest was recorded for the Western Carpathian populations. The Southern Carpathian populations, characterized by a lower growth rate, had higher values for wood density.

Palabras clave

  • Picea abies
  • radial increment
  • latewood
  • wood density
  • seed sources
  • comparative trials
Acceso abierto

Karyotype traits in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania

Publicado en línea: 01 Aug 2017
Páginas: 179 - 186

Resumen

Abstract

The description of the karyotype features and idiogram in Grindelia squarrosa (Pursh) Dunal (Asteraceae), an invasive plant in Romania, are reported here for the first time. The diploid chromosome number is 2n=2x=12, in agreement with the data published for the other species of the genus. The karyomorphological data show that the complements of the studied genotypes have small chromosomes (mean chromosome length is X̅±SE=2.56±0.10 μm, and mean length of haploid complements is X̅±SE=15.33±0.69 μm, with a range of variability comprised between 12.87-17.51 μm). The karyotypes are made up of six pairs of metacentric and submetacentric chromosomes, with an identical formula of the diploid complement: KF=2n=12=8m+ 2sm + 2sm-SAT. Satellites are located on the short arms of the chromosomes of pair III. The karyotypes show a relatively high level of intra-specific uniformity as well as similar symmetry patterns (R=1.29-1.53; TF%=38.78-41.57%; AsI%=54.54-57.61%; A1 = 0.24- 0.32; A2=0.08-0.16), belonging to 1A and 2A classes of symmetry. The small size of the chromosomes, the presence of only two chromosome morphometric types, and the preponderance of metacentrics confer a relatively high degree of symmetry to the karyotypes studied.

Palabras clave

  • Grindelia squarrosa
  • invasive plant
  • karyotype
  • mitotic chromosomes
  • satellites
  • asymmetry indexes
Acceso abierto

Early Selection for Improving Volume Growth in Coastal Douglas-fir Breeding Programs

Publicado en línea: 01 Aug 2017
Páginas: 186 - 198

Resumen

Abstract

Measurements on growth traits up to 41 years of age from 68 progeny sites in eight first-generation breeding zones of coastal Douglas-fir (Pseudotsuga menziesii [MIRB.] FRANCO var. menziesii) in the US Pacific Northwest were used to investigate age trends of genetic parameters and to determine optimum age of selection. Heritabilities and age-age genetic correlations were estimated using univariate or bivariate mixed model analyses. Heritability estimates tended to increase with age for both total growth and growth increment traits. The estimates showed different age trends among breeding zones, but the differences were generally small. Age-age genetic correlations for total growth traits fitted Lambeth’s model surprisingly well, despite the data being collected from multiple breeding zones. Using rotation-age (i.e., 50yr) volume as the selection criterion, the greatest correlated gains per year were achieved by making family selection at juvenile ages (i.e., 9 for height, 13 for diameter, and 11 for volume). Similar results were obtained for within-family selection except that the optimum ages of selection were 2~4 years later than that from family selection, i.e., 11 for height, 15 for diameter and volume. Early selection on total height was always more efficient and had earlier optimum ages than on other growth traits. The optimum ages of early family selection on total growth were 4~11 years earlier than on the corresponding growth increment traits. It was also evident that the optimum ages of selection occurred later for slow-growth trials than for fast-growing trials.

Palabras clave

  • Douglas-fir
  • growth
  • growth increment
  • early selection
  • selection efficiency
  • optimum age
  • heritability
  • age-age genetic correlation
Acceso abierto

Genetic Control of Growth Traits and Inheritance of Resistance to Bacterial Leaf Scorch in American Sycamore

Publicado en línea: 01 Aug 2017
Páginas: 198 - 206

Resumen

Abstract

Open-pollinated progeny tests of American sycamore (Platanus occidentalis L.), which included 55 open-pollinated families selected from several prior Westva - co progeny tests and seed orchards and six control-pollinated families were established in 2002 and 2003. The half-sibling families were planted at two sites in western Kentucky and southeastern Missouri. The six full-sibling families, generated from selections based on exhibition of parental disease resistance and susceptibility to a variety of diseases, were also planted near Stoneville, MS at the US Forest Service Center for Bottomland Hardwoods Research. All full-sibling families planted at the Stoneville site were inoculated in the fall 2002 with the leaf-scorch-causing bacterium, Xylella fastidiosa. Diameter and height data for trees of both half- and full-sibling families were recorded at ages three, five, seven, and nine at the various sites. Bacterial leaf scorch disease presence was also recorded as symptomatic or asymptomatic/ mildly symptomatic. Average family heritability across ages was 0.58, 0.50, and 0.55 for height, diameter, and volume, respectively, indicating that increased growth traits can be gained from family selection. In conjunction with derived age-age correlations, selection based on age-five data results in the greatest gain per unit time for age nine gains for half-sibling families. Breeding for bacterial leaf scorch resistance can also be successfully undertaken if proper selection and breeding of two resistant parents are undertaken which can result in a 4.5 fold decrease in the probability in symptoms of offspring by age nine. Results indicate a large potential for increased growth and disease resistance in American sycamore through traditional breeding.

Palabras clave

  • sycamore
  • selection
  • genetic gain
  • disease resistance
  • bacterial leaf scorch
Acceso abierto

Performance Evaluation of Shrub Willow Clones of North America and Yugoslavia Origins in Jilin, China

Publicado en línea: 01 Aug 2017
Páginas: 206 - 211

Resumen

Abstract

Demand for planting elite shrub willows as a resource for industrial use such as bioenergy and pulp has been increasing in Jilin province in northeast China. Toward this end, 12 elite willow clones, representing various species and origins, were imported from New York, USA, and planted at Lushui River, Jilin province. Two indigenous species were included in the test as the controls for comparison. This study was an evaluation of their performance in adaptation, growth potential, and wood traits after one rotation (three growing seasons). Results indicated that (1) all clones, but one, showed a parallel phenology to the control, had excellent survival (> 86%) and displayed good frost resistance; (2) compared to the control, most imported clones were comparable in main stem growth (height and diameter), but developed more stems and main roots; and (3) most imported clones had similar lignin, but higher cellulose content relative to the control. These results imply that some of the imported clones should be considered for further evaluation as good sources for both bioenergy and pulping. Based on cluster analysis, six clones were recommended for the upcoming scale-up site-clone trials for yield evaluation.

Palabras clave

  • adaptation
  • bioenergy
  • pulping
  • Salix
  • shrub willow
  • tree improvement
Acceso abierto

Gene flow in an overexploited population of Swietenia macrophylla King (Meliaceae) in the Bolivian Amazon

Publicado en línea: 01 Aug 2017
Páginas: 212 - 220

Resumen

Abstract

Pollen and seed movement among and within populations connect individuals and populations, and therefore are among the most important evolutionary processes determining the genetic structure of populations. Seven microsatellite loci were used to investigate the realized pollen dispersal and intra-population spatial genetic structure (SGS) in four permanent plots located in an overexploited big-leaf mahogany (Swietenia macrophylla King) population in the Bolivian Amazon. All adult trees found in the plots were mapped, sampled and genotyped. Seedlings were sampled below the canopy of reproductive trees. Private alleles in the sub-population of the adults and the seedlings were observed. The observed heterozygosity was significantly lower and fixation index was significantly higher for the seedlings (Ho=0.697, F=0.068) compared to the adults (Ho=0.761, F=-0.023). In one plot, seed immigration was observed (18%). Realized pollen immigration ranged among the plots from zero to 41% and selfing ranged from zero to 5.8%. We observed an average pollen dispersal distance from 75 to 255 m, with the maximum reaching 576 m. We found a significant SGS up to 150 m, showing that near neighbour individuals are relatives. The observed data on pollen- and seed dispersal provides important information for the sustainable management of the endangered mahogany species.

Palabras clave

  • Logging
  • mahogany
  • microsatellite loci
  • parentage analysis
  • tropical trees
Acceso abierto

Genetic diversity and differentiation of Chilean plantations of Pinus radiata D. Don using microsatellite DNA markers

Publicado en línea: 01 Aug 2017
Páginas: 221 - 228

Resumen

Abstract

Radiata pine (Pinus radiata D. Don) is the most important tree species in Chilean forest economy that was introduced to the country in 1892. Despite its economical end ecological relevance, no information about its genetic diversity is today available. Forty individuals of P. radiata, representing all populations in the Chilean radiata pine breeding program were genotyped with five microsatellite loci in order to determine genetic diversity and structure of Chilean plantations. The results of genetic diversity indicated that, after its introduction and mass planting, Chilean plantations of P. radiata has retained levels of genetic diversity similar to those of the natural populations of the species (HE=0.87, A=11.4). Genetic differentiation among populations (FST=0.04) was low, which means that the genetic variation present in radiata pine in Chile is partitioned among populations, indicating they are poorly differentiated. The structure analysis indicated the genetic base of the present plantations in Chile comes only from one provenance of the native populations. The genetic information provided important implications for the future breeding programs of P. radiata in Chile.

Palabras clave

  • Radiata pine
  • Chilean plantations
  • genetic diversity
  • population structure
  • molecular markers
Acceso abierto

Flowering phenology and germination ability of pollens for Acacia mangium and A. auriculiformis

Publicado en línea: 01 Aug 2017
Páginas: 228 - 236

Resumen

Abstract

A four-year investigation was conducted on the flowering phenology and germination ability of pollens from A. mangium and A. auriculiformis ramets to determine whether the flowering phenology and germination ability of pollens differed among clones or seed sources. The number of A. mangium and A. auriculiformis clones used was 19 and 23, collected from 17 and 8 seed sources, respectively. The flowering of each ramet was visually observed every three or four days for three seasons, with one season being from April to the following March, and the germination ability of pollens collected from the flowers was investigated at 1 day, 6 months, and 12 months after being stored at -18°C. The mean percentage of flowering per clone which was calculated by dividing the number of flowering ramets by the number of ramets used was low on A. mangium for each season, whereas it was more than 60% on A. auriculiformis for each season, with no significant variations among the seasons. The flowering initiation and flowering period also showed non-significant variations or differences among the seasons and among most of the clones within the seed sources. On the other hand, the percentage of flowering per clone, the flowering initiation, and the flowering period on A. auriculiformis showed significant variations and differences among the seed sources although those were similar on some seed sources. On both tree species, the germination rate of pollens per clone showed significant variations among clones, regardless of the seasons and number of days stored, and also among clones within seed sources for about half the cases. These results suggest that the flowering phenology is in some degree determined by a genetic factor such as the seed source, whereas the germination ability of pollens is mainly determined by a genetic factor in each clone.

Palabras clave

  • Acacia hybrid
  • Acacia mangium
  • Acacia auriculiformis
  • Artificial pollination
  • Flowering phenology
  • Pollen germination
Acceso abierto

Statistical associations between morphology, physiology and AFLP DNA markers enable selection of a putative eucalypt hybrid able to tolerate salt affected floodplains

Publicado en línea: 01 Aug 2017
Páginas: 236 - 246

Resumen

Abstract

A naturally occurring putative hybrid between Eucalyptus largiflorens F. Muell and Eucalyptus gracilis F. Muell called Green Box tolerates saline conditions of the River Murray floodplains better than E. largiflorens. Revegetation strategies utilizing seedlings of Green Box have had limited success because only a few are Green Box and the majority are throw backs to E. gracilis and E. largiflorens. Therefore, the purpose of this study was to identify traits characteristic of Green Box and AFLP markers associated with the traits enabling selection at the seedling stage. This was done by non-linear canonical correlation analysis (OVERALS) to test for statistically significant associations between morphological and physiological traits with 232 AFLP markers from 9 primer combinations. OVERALS with all markers produced 1st and 2nd dimensions accounting for 80 and 74% of variation respectively. Green Box plants were placed intermediate between E. gracillis and E. largiflorens according to leaf colour, gloss and nitrogen with component loadings (lc) of 0.340, 0.615 and 0.294 respectively. A second approach of simple linear regression of morphological and physiological traits against all 232 AFLP markers singled out 17 with significance P<0.05. Thirteen of these were also identified by OVERALS. Four occurred with high frequency in Green Box and E. largiflorens distinguishing them from E. gracilis. In order to separate Green Box and E. largiflorens, the segregation of a further three markers can be used to align Green Box with E. gracilis. Therefore, the segregation of 7 markers can be utilized to select Green Box.

Palabras clave

  • Eucalyptus
  • Australia
  • salt
  • re-vegetation
  • hybrid selection
  • AFLP marker
Acceso abierto

Integration of EST-CAPS markers into genetic maps of Eucalyptus urophylla and E. tereticornis and their alignment with E. grandis genome sequence

Publicado en línea: 01 Aug 2017
Páginas: 247 - 255

Resumen

Abstract

A suite of 91 expressed sequence tag (EST) derived cleaved amplified polymorphic sequence (CAPS) markers were developed and used for enriching the genetic maps of Eucalyptus urophylla and E. tereticornis built previously based on random amplified polymorphic DNA (RAPD) markers. The EST-CAPS markers were highly similar to original ESTs, with sequence identity ranging from 92.5% to 100.0%. In linkage analysis, 48 and 42 EST-CAPSs were integrated into the genetic maps of E. urophylla and E. tereticornis, respectively, including 13 shared by both maps, while 14 were unmapped. For E. urophylla, the final map had a total length of 1789.5 cM and a mean interval between markers of 9.7 cM, being 284.9 cM larger and 1.3 cM less than those of the prior RAPD map, respectively. For E. tereticornis, the final map had a length of 1488.1 cM and a mean interval of 10.3 cM, being 452.4 and 0.2 cM more than the prior map, respectively. All the 77 newly mapped EST-CAPSs found each at least one homologue in the E. grandis genome sequence released recently, and conserved synteny and colinearity were observed between E. grandis genome and our linkage groups. The enriched maps would provide a set of useful markers for genome analysis, comparative mapping and fine-mapping of important genes located in conserved regions for the important tree genus Eucalyptus.

Palabras clave

  • Expressed sequence tag (EST)
  • cleaved amplified polymorphic sequence (CAPS)
  • genetic map
  • synteny
  • colinearity
  • Eucalyptus
Acceso abierto

Estimating coancestry within open-pollinated progenies of a dioecious species: the case study of Myracrodruon urundeuva

Publicado en línea: 01 Aug 2017
Páginas: 256 - 264

Resumen

Abstract

Understanding the coancestry coefficient within openpollinated progenies has long been an area of interest because of the implications of coancestry on estimates of additive genetic variation, variance effective size and the number of seed trees required for seed collection for ex situ conservation, tree breeding and environmental restoration. This study compares three methods to calculate the coancestry coefficient within open-pollinated progenies of the dioecious tree species, Myracrodruon urundeuva, using six microsatellite loci. The methods compared were: i) correlated mating model (CMM) (RITLAND, 1989); ii) TWOGENER method (SMOUSE et al., 2001) to estimate the differentiation among pollen pools (TGM); and iii) HARDY et al.’s 2004 method using the estimate of coancestry from LOISELLE et al. (1995) (HLM) and from RITLAND (1996) (HRM). The data analysis was based on four data sets: two populations were composed of 12 progenies, two of 24 progenies, and all progenies consisted of 15 plants. The coancestry estimated using CMM ranged among populations from 0.145 to 0.158, using TGM it ranged from 0.153 to 0.181, using HLM from 0.153 to 0.162, and HRM from 0.144 to 0.147. To investigate the bias of the estimates of true relatedness within progenies we simulated two half-sib and two full-sib populations. The most accurate method found in the study was CMM because the estimated values presented no bias for true half- or full-sib progenies and these values were very similar to those expected (0.125 and 0.25, respectively). These results have significant implications for breeding and conservation programs because coancestry-within-progenies is a key parameter in assessing the variance effective size.

Palabras clave

  • additive genetic variation
  • effective population size
  • kinship
  • mating system
Acceso abierto

Breeding status of tung tree (Vernicia sp.) in China, a multipurpose oilseed crop with industrial uses

Publicado en línea: 01 Aug 2017
Páginas: 265 - 270

Resumen

Abstract

As a developing country with the world’s largest population, China faces a serious challenge in satisfying its continuously increasing energy demands. Tung trees (Vernicia sp., especially V. fordii and V. montana), are multipurpose, perennial plants belonging to the Euphorbiaceae family. The unique chemical properties of tung seed oil make it one of the best known industrial drying oils. In this review, the breeding status of tung trees in China and some factors which limit the development of tung tree breeding will be summarised. Improvements in ecological performance and pathogen resistance, through to improved breeding methods, will help to rapidly expand the development and use of tung trees and their oil products in China. It is essential for tung tree breeding to advance in the future to keep pace with the increased demand.

Palabras clave

  • Tung tree
  • Vernicia spp.
  • eleostearic acid
  • bio-energy
  • cross-breeding
Acceso abierto

Evaluating Interior Spruce Seed Deployment with GIS-Based Modeling Using British Columbia’s Prince George Seed Planning Zone as a Model

Publicado en línea: 01 Aug 2017
Páginas: 271 - 279

Resumen

Abstract

The maintenance, protection, and conservation of forest genetic resources for economic, ecological and social benefits are daunting tasks. Understanding how reforestation materials are spatially and temporally deployed across the landscape is an integral component of forest genetic resources management. To improve the current understanding of how reforestation materials are deployed in British Columbia (BC), we developed a geographical information systems (GIS) method to track seed deployment across silviculture openings. Generally, reforestation materials can originate from either natural stand (wild seed collections) or orchards’ seed sources (improved seed); the latter are produced within the framework of specific tree improvement program designed for a particular species within a well-defined seed deployment area, commonly known as Seed Planning Zone (SPZ). In this paper, we present a GIS-based method for evaluating seed deployment patterns for interior spruce (Picea glauca and Picea engelmannii and their natural hybrids) within the Prince George SPZ. The evaluation period (1970-2004) is associated with wild stands and improved seed availability and the dynamic of each seed source proportionate contribution followed three distinct phases; namely, developing (1970-1987), immature (1988-1994), and mature (1995-2004) with a progressive increase of orchards’ seed use over time. The developed method is scalable across SPZs of the same species or multiple species, thus providing the means to: 1) temporally and spatially monitor improved and natural stands seed deployment over the landscape; and 2) identify areas of concerns where a particular seed source is over-represented which might pose an increased genetic vulnerability. The present study revealed that the current interior spruce orchard’s seed use within the Prince George SPZ is expected to exceed the provincial goal of performance target of 75% by 2014. Additionally, areas of excessive use of one seed orchard seed were identified.

Palabras clave

  • Geographical information system
  • Interior spruce
  • Seed Planning Zone
  • Wild stands and seed orchard seed
  • Deployment in time and space
Acceso abierto

Selection and validation of reference genes for real-time qRT-PCR normalization in different tissues of Eucalyptus tereticornis

Publicado en línea: 01 Aug 2017
Páginas: 280 - 286

Resumen

Abstract

Reference genes are generally used as endogenous normalization factor for relative quantification of target genes in quantitative real-time PCR (qRT-PCR). The present work aimed at identifying suitable reference genes for normalization of qRT-PCR data in tissues of Eucalyptus tereticornis. The expression levels of housekeeping genes like Actin (EtAct2), Isocitrate dehy - drogenase (EtIDH), ribosomal RNA (Et18s rRNA), SAND family protein (EtSAND), Histone protein (EtH2B), α-Tubulin (EtTUB), and eukaryotic initiation factor (EteIF4B) were studied to characterize their normalization stability in different tissues including young leaves, internodes, developing and mature xylem. The expression level of these genes was analyzed using different algorithms like geNorm, NormFinder and Best- Keeper. Among the seven reference genes analyzed, EtAct2 was expressed with less variance and was found to be the most stable reference gene across different tissues using all the three programs, while the least stable gene identified was EtH2B. Further, the normalization efficiency of the reference genes were assessed to predict the expression levels of three primary cell wall specific cellulose synthase transcripts (EtCesAs) in E. tereticornis tissues. The relative expression of EtCesA4, EtCesA5 and EtCesA6 was determined to be 3-19 fold higher in leaf and internode tissues when compared to developing and mature xylem tissues. This study will allow accurate normalization of qRT-PCR experiments across different tissues in E. tereticornis for future genomic research in this tropical eucalypt species.

Key words

  • Reference gene
  • selection
  • normalization
  • cellulose synthase gene
  • differential expression
  • qRT-PCR
  • Eucalyptus
Acceso abierto

Cross-Species Amplification of Microsatellite Loci for the Endangered Conifer, Taxus chinensis var. mairei (Taxaceae)

Publicado en línea: 01 Aug 2017
Páginas: 287 - 291

Resumen

Abstract

Being an economical and endangered species, microsatellite markers of Taxus chinensis var. mairei were very limited. We have developed a set of microsatellite markers, which was benefit for future genetic analysis of this rare species. Polymorphic loci were developed from congeneric species by cross-species amplification methods, and new primers were redesigned to test for potential null alleles. 15 loci showed polymorphism. The number of alleles per locus varied from 2 to 23 tested in 48 individuals. The observed heterozygosity (Ho) and expected heterozygosity (He) values ranged form 0.000 to 0.854 and 0.082 to 0.827, respectively. Newly redesigned primer confirmed that no null allele existed in most suspected loci. These microsatellite markers will be useful for future genetic analysis and conservation of this endangered species.

Palabras clave

  • cross-amplification
  • microsatellites
  • Taxus chinensis var. mairei
  • population genetics
  • genetic diversity
Acceso abierto

Insights in the chestnut genetic diversity in Canton Ticino (Southern Switzerland)

Publicado en línea: 01 Aug 2017
Páginas: 292 - 300

Resumen

Abstract

Castanea sativa Miller displays a high variability of morphological and ecological traits, vegetative and reproductive habits, nut morphology, wood characteristics, adaptability, and resistance to biotic and abiotic stresses. The present range of distribution of the species has been strongly influenced by human migrations and it is thought that Romans played a crucial role in the spread of the cultivation in Europe, although in some areas there is also evidence of local domestication and spontaneous spread of the tree after the last glacial period. In Switzerland chestnut stands are found mostly in the South (Canton Ticino), a region where the debate about the origin of the local germplasm, whether derived from the survival or spontaneous migration of C. sativa on the territory or due to the introduction of the tree during the Roman colonisation, is still open. This study aims contributing to depict the chestnut genetic situation of the species in Canton Ticino as a contribution to the debate about the native character of the species. The study area is located in Switzerland, on the southern slopes of the Alps, where 3 C. sativa populations were sampled and analysed at 9 SSR loci. Populations showed a high degree of diversity, as it is observed in most natural population of tree species: all nine SSR loci were polymorphic (no fixed alleles were detected), and genetic diversity, measured by expected heterozygosity, was high ranging in the populations between 0.647 and 0.721, on average. Results suggest that three homogeneous gene pools contributed to the formation of the 3 populations sampled. The genetic germplasm structuring of the analysed chestnut stands is very mild as confirmed by the relatively low level of genetic differentiation and divergence observed among sites.

Palabras clave

  • Castanea sativa
  • genetic diversity
  • chestnut population
  • DNA analysis
  • SSR

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