bluuebunny/crossref_metadata_2025 huggingface dataset:
Chinese Tourists in Cracow, Poland: Their Profile, Expectations, and Perceptions
Authors: Guszkiewicz Paulina , Nessel Karolina
Published: June 2017

Introduction. In 2012, China became the largest spender in international tourism, benefiting many destinations worldwide. Even if for Poland it is not an important source market yet, the Polish authorities have undertaken some marketing activities in China. The main aim of the paper is to explore the profile, motivations, and perceptions of the Chinese tourists visiting Cracow. The secondary aim is to check the effectiveness of the marketing efforts dedicated to the Chinese market undertaken by Poland since 2010. Material and methods. Data for the study (n = 100) were collected using a paper survey in English carried out among mainland Chinese tourists in Cracow in 2015. Results. The Chinese usually visit Poland for the first time, often in transit. They are prompted by the information found online and by word of mouth. Their main reasons to come are tradition, culture, historical sites, landscapes, and low costs. These expectations are well fulfilled, and the tourists′ overall satisfaction is very high. The Chinese find Poland to be different from other Western European countries. For them, Poland is a remarkable, traditional, safe, and developing country. Yet, their knowledge about the destination is limited. The main problem encountered is the language barrier, both online and once on site. The marketing efforts undertaken by Poland in the Chinese market have had weak and ambivalent effects. Conclusions. In order to attract Chinese tourists, there is a need to intensify expenditure not only on promotion (mainly online) but also on the removal of language-based communication problems. There is also scope for expanding the tourist offer dedicated to Chinese tourists - both in Poland and in cooperation with other Central European countries.
Maintaining Sentiment Polarity in Translation of User-Generated Content
Authors: Lohar Pintu , Afli Haithem , Way Andy
Published: June 2017

The advent of social media has shaken the very foundations of how we share information, with Twitter, Facebook, and Linkedin among many well-known social networking platforms that facilitate information generation and distribution. However, the maximum 140-character restriction in Twitter encourages users to (sometimes deliberately) write somewhat informally in most cases. As a result, machine translation (MT) of user-generated content (UGC) becomes much more difficult for such noisy texts. In addition to translation quality being affected, this phenomenon may also negatively impact sentiment preservation in the translation process. That is, a sentence with positive sentiment in the source language may be translated into a sentence with negative or neutral sentiment in the target language. In this paper, we analyse both sentiment preservation and MT quality per se in the context of UGC, focusing especially on whether sentiment classification helps improve sentiment preservation in MT of UGC. We build four different experimental setups for tweet translation (i) using a single MT model trained on the whole Twitter parallel corpus, (ii) using multiple MT models based on sentiment classification, (iii) using MT models including additional out-of-domain data, and (iv) adding MT models based on the phrase-table fill-up method to accompany the sentiment translation models with an aim of improving MT quality and at the same time maintaining sentiment polarity preservation. Our empirical evaluation shows that despite a slight deterioration in MT quality, our system significantly outperforms the Baseline MT system (without using sentiment classification) in terms of sentiment preservation. We also demonstrate that using an MT engine that conveys a sentiment different from that of the UGC can even worsen both the translation quality and sentiment preservation.
Using Word Embeddings to Enforce Document-Level Lexical Consistency in Machine Translation
Authors: Garcia Eva Martínez , Creus Carles , España-Bonet Cristina , Màrquez Lluís
Published: June 2017

We integrate new mechanisms in a document-level machine translation decoder to improve the lexical consistency of document translations. First, we develop a document-level feature designed to score the lexical consistency of a translation. This feature, which applies to words that have been translated into different forms within the document, uses word embeddings to measure the adequacy of each word translation given its context. Second, we extend the decoder with a new stochastic mechanism that, at translation time, allows to introduce changes in the translation oriented to improve its lexical consistency. We evaluate our system on English–Spanish document translation, and we conduct automatic and manual assessments of its quality. The automatic evaluation metrics, applied mainly at sentence level, do not reflect significant variations. On the contrary, the manual evaluation shows that the system dealing with lexical consistency is preferred over both a standard sentence-level and a standard document-level phrase-based MT systems.
Continuous Learning from Human Post-Edits for Neural Machine Translation
Authors: Turchi Marco , Negri Matteo , Farajian M. Amin , Federico Marcello
Published: June 2017

Improving machine translation (MT) by learning from human post-edits is a powerful solution that is still unexplored in the neural machine translation (NMT) framework. Also in this scenario, effective techniques for the continuous tuning of an existing model to a stream of manual corrections would have several advantages over current batch methods. First, they would make it possible to adapt systems at run time to new users/domains; second, this would happen at a lower computational cost compared to NMT retraining from scratch or in batch mode. To attack the problem, we explore several online learning strategies to stepwise fine-tune an existing model to the incoming post-edits. Our evaluation on data from two language pairs and different target domains shows significant improvements over the use of static models.
Optimizing Tokenization Choice for Machine Translation across Multiple Target Languages
Authors: Zalmout Nasser , Habash Nizar
Published: June 2017

Tokenization is very helpful for Statistical Machine Translation (SMT), especially when translating from morphologically rich languages. Typically, a single tokenization scheme is applied to the entire source-language text and regardless of the target language. In this paper, we evaluate the hypothesis that SMT performance may benefit from different tokenization schemes for different words within the same text, and also for different target languages. We apply this approach to Arabic as a source language, with five target languages of varying morphological complexity: English, French, Spanish, Russian and Chinese. Our results show that different target languages indeed require different source-language schemes; and a context-variable tokenization scheme can outperform a context-constant scheme with a statistically significant performance enhancement of about 1.4 BLEU points.
Neural Networks Classifier for Data Selection in Statistical Machine Translation
Authors: Peris Álvaro , Chinea-Ríos Mara , Casacuberta Francisco
Published: June 2017

Corpora are precious resources, as they allow for a proper estimation of statistical machine translation models. Data selection is a variant of the domain adaptation field, aimed to extract those sentences from an out-of-domain corpus that are the most useful to translate a different target domain. We address the data selection problem in statistical machine translation as a classification task. We present a new method, based on neural networks, able to deal with monolingual and bilingual corpora. Empirical results show that our data selection method provides slightly better translation quality, compared to a state-of-the-art method (cross-entropy), requiring substantially less data. Moreover, the results obtained are coherent across different language pairs, demonstrating the robustness of our proposal.
Historical Documents Modernization
Authors: Domingo Miguel , Chinea-Rios Mara , Casacuberta Francisco
Published: June 2017

Historical documents are mostly accessible to scholars specialized in the period in which the document originated. In order to increase their accessibility to a broader audience and help in the preservation of the cultural heritage, we propose a method to modernized these documents. This method is based in statistical machine translation, and aims at translating historical documents into a modern version of their original language. We tested this method in two different scenarios, obtaining very encouraging results.
Finite-State Back-Transliteration for Marathi
Authors: Ravishankar Vinit
Published: June 2017

In this paper, we describe the creation of an open-source, finite-state based system for back-transliteration of Latin text in the Indian language Marathi. We outline the advantages of our system and compare it to other existing systems, evaluate its recall, and evaluate the coverage of an open-source morphological analyser on our back-transliterated corpus.
Improving Machine Translation through Linked Data
Authors: Srivastava Ankit , Rehm Georg , Sasaki Felix
Published: June 2017

With the ever increasing availability of linked multilingual lexical resources, there is a renewed interest in extending Natural Language Processing (NLP) applications so that they can make use of the vast set of lexical knowledge bases available in the Semantic Web. In the case of Machine Translation, MT systems can potentially benefit from such a resource. Unknown words and ambiguous translations are among the most common sources of error. In this paper, we attempt to minimise these types of errors by interfacing Statistical Machine Translation (SMT) models with Linked Open Data (LOD) resources such as DBpedia and BabelNet. We perform several experiments based on the SMT system Moses and evaluate multiple strategies for exploiting knowledge from multilingual linked data in automatically translating named entities. We conclude with an analysis of best practices for multilingual linked data sets in order to optimise their benefit to multilingual and cross-lingual applications.
Current Status and Prospects for Organic Agriculture in Poland
Authors: Jezierska-Thöle Aleksandra , Gwiaździńska-Goraj Marta , Wiśniewski Łukasz
Published: June 2017

Organic farming is part of a sustainable development model; at the same time it is becoming a prerequisite for the multifunctional development of rural areas. The main aim of this study is to identify the state and analyse changes in the development of organic agriculture in Poland as well as to present the possibilities for its development. The time horizon of the study covers the years 2003 to 2015. The basis of the research was an analysis of the literature, the Report of the Chief Inspectorate of Trade Quality of Agriculture and Food (IJHARS), and national empirical research; it also includes an analysis of the results of surveys carried out on organic farms in the summer of 2016, as well as our own observations. The study showed that in the years 2003-2015 Poland saw a rapid increase in the number and area of organic farms due in part to the introduction of EU subsidies. Spatial analysis of the proportions of farms by voivodeship shows that in 2015 most were recorded in Warmia-Mazuria, Podlasie and West Pomerania. Similar to the increase in the number of organic farms, the years 2003-2015 saw an increased area of organic farmland. Poland is second in the world in terms of growth in the area of organic farms. In the years 2003-2014 the average size of an organic farm remained at about 25 ha and was higher than the average size of conventional farms (10 ha). In 2014 the crop structure was dominated by fodder plants (35.8%), and meadows and pastures (31.5%). In terms of livestock production, cattle and horses had the biggest share.
Productivism and Post-Productivism in the Olive Groves of Southern Spain
Authors: Martínez José Domingo Sánchez , Almonacid Antonio Garrido
Published: June 2017

This work examines changes in the cultivation of olive groves in the region of Andalusia since the accession of Spain to the European Common Market (1986). The first phase is marked by the triumph of productivism in which some of the basic elements of this model (specialisation and intensification) are overwhelming, according to the statistical sources used for this research, although the behaviour in terms of corporate concentration can be considered unique. Also notable, as we will explain later, are other less desirable effects of the process, which can currently be considered environmentally unsustainable. As the weaknesses and contradictions of the model have become evident, in the recent years - as a result of the new stimuli provided by the Common Agricultural Policy - more attention is paid to the opportunities offered by rural development. For the moment, the results of this approach have been limited, although the 2015-2020 planning period could be decisive for its reorientation.
Changes in the Spatial Organisation of Fruit Growing at the Beginning of the 21St Century: The Case of Grójec Poviat (Mazovia Voivodeship, Poland)
Authors: Wójcik Marcin , Traczyk Anna
Published: June 2017

This paper is meant to determine trends in changes in the organisation of fruit production at the beginning of the 21st century. It focuses on the determination of those trends as well as their circumstances. The analysis of changes in the organisation of fruit production was made using Grójec poviat as an example. The accession of Poland to the European Union resulted in the intensification of processes of specialisation and concentration in agriculture, due to which the area occupied by orchards started to grow systematically. With the growing area and the intensification of fruit crops, quantities of fruits produced also increased. Currently, Poland is one of the biggest fruit manufacturers in Europe, with Grójec poviat being the biggest producer in Poland.
Influence of cooling mode in relation to casting and extrusion parameters on mechanical properties of AA6082
Authors: Malej Simon , Terčelj Milan , Peruš Iztok , Kugler Goran
Published: June 2017

In this study, conditional average estimator neural networks (CAE NNs) were used for an analysis of the common influences of the cooling mode in relation to the ram speed, extrusion ratio, casting speed and casting temperature on the yield strength and the elongation of an extruded profile made from aluminium alloy (AA)6082. The obtained results from the analysis revealed very complex relationships between these parameters. In order to maximise the values for the yield strength and the elongation, the values for the ram speed, extrusion ratio, casting speed and casting temperature should be optimised in relation to the mode of cooling.
Basis and Statistical Design of the Passive HIV-1 Antibody Mediated Prevention (AMP) Test-of-Concept Efficacy Trials
Authors: Gilbert Peter B , Juraska Michal , deCamp Allan C. , Karuna Shelly , Edupuganti Srilatha , Mgodi Nyaradzo , Donnell Deborah J , Bentley Carter , Sista Nirupama , Andrew Philip , Isaacs Abby , Huang Yunda , Zhang Lily , Capparelli Edmund , Kochar Nidhi , Wang Jing , Eshleman Susan H , Mayer Kenneth H , Magaret Craig A , Hural John , Kublin James G , Gray Glenda , Montefiori David C , Gomez Margarita M , Burns David N , McElrath Julie , Ledgerwood Julie , Graham Barney S , Mascola John R , Cohen Myron , Corey Lawrence
Published: June 2017

Background

Anti-HIV-1 broadly neutralizing antibodies (bnAbs) have been developed as potential agents for prevention of HIV-1 infection. The HIV Vaccine Trials Network and the HIV Prevention Trials Network are conducting the Antibody Mediated Prevention (AMP) trials to assess whether, and how, intravenous infusion of the anti-CD4 binding site bnAb, VRC01, prevents HIV-1 infection. These are the first test-of-concept studies to assess HIV-1 bnAb prevention efficacy in humans.

Methods

The AMP trials are two parallel phase 2b HIV-1 prevention efficacy trials conducted in two cohorts: 2700 HIV-uninfected men and transgender persons who have sex with men in the United States, Peru, Brazil, and Switzerland; and 1500 HIV-uninfected sexually active women in seven countries in sub-Saharan Africa. Participants are randomized 1:1:1 to receive an intravenous infusion of 10 mg/kg VRC01, 30 mg/kg VRC01, or a control preparation every 8 weeks for a total of 10 infusions. Each trial is designed (1) to assess overall prevention efficacy (PE) pooled over the two VRC01 dose groups vs. control and (2) to assess VRC01 dose and laboratory markers as correlates of protection (CoPs) against overall and genotype- and phenotype-specific infection.

Results

Each AMP trial is designed to have 90 % power to detect PE > 0 % if PE is ≥ 60 %. The AMP trials are also designed to identify VRC01 properties (i. e., concentration and effector functions) that correlate with protection and to provide insight into mechanistic CoPs. CoPs are assessed using data from breakthrough HIV-1 infections, including genetic sequences and sensitivities to VRC01-mediated neutralization and Fc effector functions.

Conclusions

The AMP trials test whether VRC01 can prevent HIV-1 infection in two study populations. If affirmative, they will provide information for estimating the optimal dosage of VRC01 (or subsequent derivatives) and identify threshold levels of neutralization and Fc effector functions associated with high-level protection, setting a benchmark for future vaccine evaluation and constituting a bridge to other bnAb approaches for HIV-1 prevention.
1. A genetic linkage map of Pinus massoniana based on SRAP, SSR and ESTP markers
Authors: Chen Wenxia , Cao Mu , Wang Yuanxiu , Zhou Zhichun , Xu Li-An
Published: June 2017

Pinus massoniana (masson pine) is the most important native pine in southern China. High-density genetic maps have not been constructed for the species. In this study, a genetic linkage map with 251 markers (47 SSRs, 23 ESTPs and 181 SRAPs) was constructed using a F1 progeny mapping population derived from controlled pollination of two parents of different provenances. At LOD 7.0, a total of 17 linkage groups were constructed with twelve groups having nine or more markers and five other groups of two to four markers each. The total map length was 1,956 cM with an average of 8.4 cM among individual loci. The current linkage map represented 93% of the estimated genome length of 2,114 cM for masson pine. Such linkage map are useful for future genomic studies of masson pine including comparative mapping in Pinaceae and quantitative trait loci (QTL) mapping for economically important traits.
Hybridizing ability and heterosis between Eucalyptus urophylla and E. tereticornis for growth and wood density over two environments
Authors: Weng Q. , He X. , Li F. , Li M. , Yu X. , Shi J. , Gan S.
Published: June 2017

Interspecific hybrids of Eucalyptus urophylla × E. tereticornis in a factorial-mating design were used to analyze general hybridizing ability (GHA), specific hybridizing ability (SHA) and heterosis for height (H; 0.5, 1.5, 2.5, 4 and 7.5 years in age), diameter at breast height (D; ages 1.5, 2.5, 4 and 7.5) and wood density (WD; age 7.5) across two environments. The GHA variances were significant for all traits, and those of the SHA were also significant for most of the traits but with less magnitude, indicating the greater importance of additive gene effects in explaining the phenotypic variation among hybrids. The narrow-sense heritability (h2) and dominance (d2) estimates with hybrid growth and wood density ranged between 0.02±0.05 (d2in D7.5) and 0.23±0.10 (d2in H1.5) over the different ages, suggesting weak additive and dominant effects on these traits. Additive genetic correlations of growth with wood density were weak at age 7.5. Female general combining ability (GCA) based on maternal open-pollinated families was not necessarily a good indicator of GHA as their correlations were 0.48 (P=0.17), 0.65 (P=0.04) and -0.56 (P=0.10) for H7.5, D7.5and WD7.5, respectively. A great proportion of hybrids showed positive female-parent heterosis (FPH) at age 7.5, with the highest relative FPH of 47.2% in D7.5. This study demonstrates the heterosis between inter-sectional species and could have implications for E. urophylla × E. tereticornis hybrid breeding.
Molecular evolution of drought tolerance and wood strength related candidate genes in loblolly pine (Pinus taeda L.)
Authors: Koralewski T. E. , Brooks J. E. , Krutovsky Konstantin V.
Published: June 2017

Loblolly pine (Pinus taeda L.) is an intensely studied species that has become a model system for conifers. It is one of the most important commercial crops in the southeastern United States and grows across a vast territory. Due to exposure to this current diverse environment and the fluctuating climatic conditions of the past, it has likely accumulated substantial variation in adaptive trait and wood strength related genes. We merged a set of newly collected and previously published genomic DNA sequence data and analyzed them for departures from neutrality in 32 drought tolerance and wood strength related candidate genes using neutrality tests, such as Tajima’s D, HKA, MK and nonsynonymous to synonymous substitutions ratio (Z-test). Three other major Southern pines closely related to P. taeda (Pinus echinata Mill., P. elliottii Engelm., and P. palustris Mill.) were used as outgroups in interspecific tests. In three loci (4-coumarate: CoA ligase, putative cell-wall protein and trans-cinnamate 4-hydroxylase 2) neutrality was rejected by both intra- and interspecific tests, consistent with purifying selection. Neutrality was also rejected in several other loci (alpha-tubulin, arabinogalactan 4, arabinogalactan 6, cinnamate 4-hydroxylase 1, cinnamoyl CoA reductase, cinnamyl alcohol dehydrogenase, caffeoyl CoA O-methyltransferase 1, early response to drought 3, glycine hydroxymethyltransferase, ABI1 protein phosphatase 2C-like, putative wall-associated protein kinase, and unknown gene ug_2-498); however, these results are difficult to interpret because only one of the tests proved significant. This study contributes to the ongoing discussion about natural selection in putative adaptive genes in loblolly pine. However, unambiguous interpretation of the results often remains problematic.
Hybridization and Genetic Diversity in Wild Apple (Malus sylvestris (L.) MILL.) from Various Regions in Germany and from Luxembourg
Authors: Wagner Iris , Maurer W.D. , Lemmen P. , Schmitt H.P. , Wagner M. , Binder M. , Patzak P.
Published: June 2017

Malus sylvestris is the only apple species native to Central Europe. Its genetic integrity may be threatened by hybridization with the cultivated apple (Malus × domestica). A total of 883 genotypes, 477 putative wild apples in Germany and Luxembourg and 406 old to modern cultivars has been investigated. Wild apples growing in Germany originated from Rhineland-Palatinate, North Rhine-Westphalia, Saxony-Anhalt and Saxony. The genetic structure was analysed at ten isozyme marker loci, and morphology was studied by fruit size, leaf pubescence, and a complex morphological description performed in advance. A model-based cluster analysis applied to all nuclear data resulted in two clearly differentiated gene pools for putative wild and cultivated apples with moderate proportions of admixture in the wild group on average (0.138 total, 0.111 German sample). At the individual level, the percentages of both hybrids and feral cultivars together ranged from 2.3% in Rhineland-Palatinate to 28.8% in Luxembourg. The intraspecific variability in fruit diameter ranged from 21 to 40 mm, and that in leaf pubescence in autumn ranged from score 0 to score 1. No single morphological trait of a specimen appeared to be sufficient for identification. Even the correspondence between the complex morphological and complex genetic determinations for individuals did not exceed 93% in pure wilds and 64% in hybrids. Genetic variation in pure wild apple is high (species level: P = 90%, A/L = 3.1, He = 0.369). Allelic differentiation & was 0.089, pairwise genetic distance (d0) ranged from 0.065 to 0.148 among five samples. Correspondence between genetic and geographic distance of populations was observed to a certain extent.
Short note: Development, characterization and cross-amplification of eight EST-derived microsatellites in Salix
Authors: He X. , Zheng J. , Serapiglia M. , Smart L. , Shi S. , Wang B.
Published: June 2017

A set of eight simple sequence repeat (SSR) markers were developed from 707 Salix expressed sequence tags (ESTs) deposited in GenBank. Each of the EST-SSR amplicons was identical to the original EST, with sequence identity 60.90-96.03% and presence of the expected repeat motifs. Of the eight EST-SSR loci, five were polymorphic among 14 individuals of S. eriocephala, with the number of alleles per locus (Na), observed heterozygosity (Ho), expected heterozygosity (He) and polymorphic information content (PIC) being 2-7 (mean 4.8), 0.29-0.85 (mean 0.65), 0.25-0.84 (mean 0.65) and 0.21-0.78 (mean 0.58), respectively. High rates of crossspecies/ genus amplification were also observed within fourteen different species. The primer sequences for the eight EST-SSRs have been deposited in the Probe database of GenBank (IDs Pr031820546 - Pr031820553). The EST-SSRs developed herein would be a valuable addition of functional markers for genetics and breeding applications in a wide range of Salix species.
Inference of allelic dosages and inheritance modes in tetraploids: a case study in Betula apoiensis with a putative hybrid origin
Authors: Nagamitsu Teruyoshi , Kawahara Takayuki , Kanazashi Ayako
Published: June 2017

In tetraploids, inference of allelic dosages and inheritance modes is difficult due to the ambiguous number of allele copies and the variation between disomic and tetrasomic patterns. Considering the biases of amplification and the overlaps of stutter products in polymerase chain reactions, we inferred tetraploid genotypes at three nuclear microsatellite loci in progeny arrays from six reciprocal crosses among three parents of Betula apoiensis with a putative hybrid origin. In each cross, we assigned diploid genotypes to gametes on the basis of the tetraploid genotypes of the parents and their progeny and observed the frequencies of the gamete genotypes. Segregation patterns of the observed gamete genotypes indicated few null alleles in the progeny arrays and tetrasomic inheritance with rare double reduction. This mode of inheritance was consistent between genders and between mates in the crosses. This result suggests that our method to infer tetraploid genotypes in nuclear microsatellites is successful in family samples with few null alleles when the amplification biases and the stutter-product overlaps are accessed properly.
Novel nuclear microsatellites in the endangered neotropical timber tree Lecythis ampla (Lecythidaceae)
Authors: Hernández G. , Konrad H. , Krumböck S. , Geburek Thomas
Published: June 2017

For the first time, nuclear microsatellite (nSSRs) primers were developed in the endangered tree species Lecythis ampla (Lecythidaceae) as molecular tools. An enrichment protocol with genomic DNA libraries for nSSRs was used to identify candidate loci. A large number of candidate loci were identified. Consecutively population genetic parameters of these loci were tested in two available populations. Eventually 17 microsatellite loci have been identified that show no or only low evidence for linkage disequilibrium, deviations from Hardy-Weinberg expectations or high levels of null alleles. These markers are apt for future molecular population studies.
Genetic heterogeneity in age classes of naturally regenerated old growth forest of Picea abies (L.) Karst
Authors: Wojnicka-Półtorak A. , Wachowiak W. , Prus-Głowacki W. , Celiński K. , Korczyk A.
Published: June 2017

The Białowiez·a Primeval Forest is located northeastern Poland. It is one of Europe’s most precious old growth forests in terms of abundance and richness of vegetation, retaining features of a primeval lowland forest which cannot be found anywhere else on the European continent. The aim of the study was to assess the genetic heterogeneity of the naturally regenerated Picea abies population using five chloroplast microsatellite markers. In total, 290 trees representing five age classes were studied. Clear patterns of genetic differentiation in relation to demographic substructuring were found within the population. The class of embryos exhibited the greatest genetic richness as evident from the highest number of alleles and haplotypes, the highest mean number of private alleles and haplotypes and the highest haplotype diversity. In the subsequent age classes, a significant decrease in the level of genetic variation was observed. Our data demonstrate that long-lived, highly outcrossing tree species growing in continuous stands can be genetically heterogeneous on a small geographic scale. The heterogeneity is related to age structure and it is likely due to the underlying mating system and selection processes.
Comparison of allelic diversity between native gene resource plantings and selections in open-pollinated progeny test of Pinus radiata D. Don.
Authors: Zhang L. , Huanqiong N. , Gapare Washington J. , Dillon S. K. , Li X. , Wu H. X.
Published: June 2017

Genetic diversity within radiata pine first generation of open-pollinated selections (OPS) from the native resource stands was compared with that observed in native populations to monitor potential changes in genetic diversity during domestication. Genetic diversity was estimated using 58 single nucleotide polymorphisms (SNPs) from 8 expressed genes. Nucleotide diversity maintained in first generation of selections (OPS) (mean π = 0.0036; mean θw= 0.0058) was similar to that found within the native population material (mean π = 0.0043; mean for θw= 0.0065). Likewise, mean values for expected heterozygosity (HE) within and between native population material and OPS were similar (mean = 0.27 ± 0.04) and not significantly different (P = 0.068). Also, the overall distribution of allele frequency classes was not significantly different between native population material and OPS. These results point to no evidence of loss of diversity in OPS due to artificial selection. One possible reason is that the domestication of the OPS is at a very early stage. Another may be that artificial selection in the OPS was based on tree growth and form, not wood properties. The genes selected in this study are mostly involved in cell wall formation, thus genetic diversity of these genes should remain stable between natural population and OPS, unless there was a significant sampling bias in the OPS. Although the SNP information suggests similarities among mainland populations, results from quantitative genetic studies found large provenance differences for growth-, morphological-, stem-form traits, and disease resistance. Determining the threshold at which genetic diversity levels will be significantly reduced during selection should help breeders to make informed decisions regarding the intensity of selection in managed breeding populations as well as gene resource populations.
Promotion of resistance of black alder clones (Alnus glutinosa (L.) Gaertn.) against Phytophthora alni ssp. alni by cyclolipopeptide producing bacteria
Authors: Zaspel I. , Naujoks G. , Krüger L. , Pham L. H.
Published: June 2017

This study demonstrated the promotion of the ability of black alder clones to resist to Phytophthora alni ssp. alni with the cyclolipopeptide (CLP)-producing Pseudomonas veronii isolate PAZ1. The bacterial strain, isolated from an association with P. alni ssp. alni, and characterised by its production of the secondary metabolites viscosin and massetolides, possessed inhibitory ability against isolates of the oomycete tree pathogen in vitro. In plant experiments with alder clones in vitro, the treatment with living bacteria showed an earlier start of the rooting process and a promoted root and shoot growth. Compared to non-treated plants, the root system was improved by longer primary roots with abundant secondary roots. The treatment with a methanol extract prepared from strain PAZ1 had no comparable effect. After protective application of strain PAZ1 14 days before the pathogen, the disease incidence was lower and biomass production was higher than in the pathogen control. These results were completed by a greenhouse experiment for a period of 13 months. Bacteria application prior to the pathogen led to reduced Phytophthora incidence at two of five clones in the combined treatment.
Analysis of absolute nuclear DNA content reveals a small genome and intra-specific variation in Cashew (Anacardium occidentale L.), Anacardiaceae
Authors: Aliyu Olawe Mashood
Published: June 2017

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

Mean genome size was significantly different (P<0.01) across the 43 cashew accessions suggesting intra-specific variation (about 3.6% coefficient of variation) for absolute nuclear DNA content in this species, but with no evidence of endopolyploidy or endoreduplication. Flow cytometric analysis data presented here showed that absolute genome size of cashew is about 0.857 pg/2C (419 Mb/1C). However, there was a slight gradual increment in genome size from south to north gradient across sampled populations. The data also showed significant correlation (r=0.368, P<0.01) between nuclear DNA content (genome size) and phenotypic trait, nut weight. The results obtained here confirmed relatively small genome size in this tree species, almost twice genome size of diploid Arabidopsis thaliana but slightly lower than mango, Mangifera indica, a close relative in Anacardiaceae. Similarity in genome size between Mangifera indica and Anacardium occidentale could be a further proof of genetic relatedness between these two important species of Anacardiaceae.
How small and constrained is the genome size of angiosperm woody species
Authors: Ohri Deepak
Published: June 2017

Angiosperm hardwood species are generally considered to show an average smaller genome size with a narrow range of variation than their herbaceous counterparts. Various explanations pertaining to limitations of cell size exerted by wood fibers, the requirement of smaller stomata, longer generation time, large population size, etc., have been put forward to account for their small and constrained genome size. Yet studies done in the past several years show that genomically as well as evolutionarily, hardwoods are as diverse and active as their herbaceous counterparts. This is entirely supported by the presence of well developed inter and intraspecific polyploid series and natural triploidy in many genera. Polyploidy, in some instances has been shown to confer adaptability to arid and salt stress conditions and in colonization of new areas. Moreover, hardwoods also show reasonable amenability to the induced polyploidy which abruptly changes the balance between nuclear and cell size. Polyploidy has been induced in many hardwoods to restore fertility in interspecific hybrids and for the production of triploids.

Furthermore, some cases studied show that genome size variation in hardwoods can be as variable as that of herbaceous species. Genome size has been shown to vary remarkably both at homoploid level as well as by polyploidy in certain genera. In the same way, the genome size is not correlated with the habit in certain groups having both herbaceous and woody taxa. This point is further proved by the presence of secondary and insular woody habit in certain cases where either the transition to woodiness is not followed by any diminution in the genome size, or the genome size of insular woody species may be even more than that of the congeneric herbaceous species. This shows that woody habit does not by itself put any constraints on the genome size either at homoploid or at polyploidy levels. The genome size in fact, not only varies significantly in many congeneric woody species but also may not show any correlation with the habit when woody and herbaceous species are compared in some narrow taxonomic groups studied.
Near rotation-length performance of selected hybrid larch in Central Maine, U.S.A
Authors: Greenwood M. S. , Roth Brian E. , Maass D. , Irland L. C.
Published: June 2017

Twenty-two year measurements of a test of inter- and intraspecific larch hybrids among European (E), Japanese (J) and tamarack (T) parents growing in central Maine reveal significant hybrid vigor, especially among crosses involving J and E parents. The mean heights and diameters of all the interspecific crosses between J and E parents exceeded those of intraspecific crosses among either of the parents. The mean height after 22 years for all 17 JxE and ExJ crosses was 19.2 m (63 feet), which compares favorably with heights of loblolly pine plantations at age 25 growing in the southeastern USA, where site index ranged from 12.2 m to 24.4 m (40 and 80 feet respectively). In addition the mean height of these larch crosses was 30% greater than that of a control hybrid seed lot of German origin. Crosses between E and T parents also performed well, but exhibited relatively poor form, and seed set was very low. Seed set and viability for crosses between J and E were as good as intraspecific parental crosses. Therefore propagation of hybrid larch crosses via controlled pollination and rooted cuttings is feasible, and the potential benefits of larch plantations for Maine’s forest economy are briefly discussed.
Differentiation of six Eucalyptus trees grown in Mexico by ITS and six chloroplast barcoding markers
Authors: Fladung M. , Schroeder H. , Wehenkel C. , Kersten B.
Published: June 2017

Different species of the genus Eucalyptus, originally native to Australia, are being cultivated in different parts of the world due to their fast growth and beneficial wood properties. In Mexico, probably up to 25 different Eucalyptus species (many of them with unknown species declaration) were introduced early in the 20th century. Many Eucalyptus species are cross compatible and information about provenances of the single eucalypt species is rare. In this study, an experimental plantation established in 1984 and located in Northeast of Mexico was chosen as example to re-assign the species name of six randomly selected Eucalyptus trees growing in this plantation. First, a phylogenetic tree was constructed from complete chloroplast sequences of 31 Eucalyptus species available in the NCBI database. The phylogenetic tree includes three of the nine Eucalyptus species known to be introduced to Mexico, namely E. camaldulensis, E. saligna and E. grandis, which belong to a clade named “Symphyomyrts”. By employing combined BLASTN and UPGMA analyses of six chloroplast (cp) regions, three of the six unknown eucalypt samples (Euc4, 5, 6) cluster together with E. microtheca and E. cladocalyx, whereas the other three (Euc1, 2, 3) were more similar to a group containing E. camaldulensis, E. grandis and E. saligna. UPGMA analysis of the ITS region overall shows the same rough clustering, but provide more detailed information for two samples being most likely assigned to E. camaldulensis.
Expression of three phenylpropanoid pathway genes in Scots pine (Pinus sylvestris L.) in open-pollinated families with differing relative wood densities during early and late wood formation
Authors: Kanberga-Silina K. , Jansons A. , Rungis Dainis
Published: June 2017

Wood volume and quality are the most important aspects of commercial forestry production, and studies of wood formation are important in order to increase the value and efficiency of forestry production. The phenylpropanoid pathway produces various compounds with diverse functions both for plant defence against biotic and abiotic stress as well as structural development. One of the main roles is monolignol production for lignin biosynthesis, which is a crucial aspect of wood formation. For this study three candidate genes involved in lignin biosynthesis were selected: phenylalanine ammonialyase (PAL1), cinnamyl alcohol dehydrogenase (CAD) and cinnamoyl-CoA reductase (CCR). Candidate gene expression was analysed in selected individuals with high and low wood density from open-pollinated Scots pine families during early wood (EW) and late wood (LW) formation and correlation between expression of these genes, total lignin content, and wood density was determined. Wood density values for analysed trees were similar within tree families but differed significantly between families with high and low wood density (p=1,06E-20). Wood density was slightly negatively correlated with lignin content (r=-0.36, p=0.038), but only in individuals in the high density wood group. In trees with low wood density, expression of the CAD gene was significantly lower in late wood formation compared to early wood (p=0.00179). In trees with high wood density, expression of the PAL1 gene was five times higher during early wood formation compared to late wood formation. A positive correlation was detected between PAL1 and CCR gene expression during early wood formation (r=0.804) and late wood formation (r=0.466).
PCR-RFLP analysis of cpDNA in Gigantochloa scortechinii (Poaceae: Bambuseae) in Peninsular Malaysia and implications for the use of cpDNA markers in systematic studies
Authors: Dhanendiren N. , Ong H.Y. , Khoo G. , Wong K.M. , Goh W.L.
Published: June 2017

Gigantochloa is a paleotropical woody bamboo genus that has been widely cultivated in SE Asia because of its usefulness. Recent studies have shown that species of this genus enter into an introgression complex with other genera of the same subtribe Bambusinae. Within G. scortechinii, a common species indigenous to Malay Peninsula and common in Peninsular Malaysia, two distinct chloroplast DNA (cpDNA) lineages, the Gombak- and Langat-type, were recovered. We report the development of a PCR-based restriction fragment length polymorphism (RFLP) marker for depicting the genetic differentiation in G. scortechinii based on cpDNA. We determined a cpDNA region and its corresponding restriction enzyme which can produce different RFLP profiles for the two cpDNA lineages. Our design was verified with empirical studies. The Gombak-type was the dominant cpDNA genotype for G. scortechinii in Peninsular Malaysia. Implications for the continued use of cpDNA markers in systematic studies are discussed.
Genetic diversity and spatial genetic structure in populations of Orbignya phalerata Mart. under different exploitation intensities in the Brazilian savanna
Authors: Ibanes Bruna , Sebbenn A.M. , Azevedo V.C.R. , Moreno M.A. , Gandara F.B. , Tambarussi E.V. , Ferraz E.M. , Damasceno-Silva K.J. , Lima P. S.C. , Carvalhaes M.A.
Published: June 2017

Genetic studies in tropical tree species have found signs of decreased genetic diversity and increased levels of inbreeding and spatial genetic structure (SGS) in fragmented and exploited populations. The aim of this paper was to investigate genetic diversity, structure, and intrapopulation SGS using eight microsatellite loci for three Orbignya phalerata populations that have undergone different intensities of seed harvesting. From each population, we georeferenced and sampled 30 seedlings, 30 juveniles, and 30 adult trees. The total number of alleles over all loci (k), and observed (Ho) and expected heterozygosity (He) presented lower values for the population experiencing more intense fruit harvesting than less heavily exploited populations, suggesting that fruit harvesting may decrease genetic diversity. Null alleles were detected in practically all loci among seedlings, juveniles, and adults in all populations, indicating that the estimates of Ho, He, and fixation index (F) are biased. When corrected for null alleles (FNull), the fixation index decreased for all samples, resulting in significantly higher than zero results for seedlings of all populations, but not for juveniles and adults of all populations. The comparison of FNullvalues between cohorts in the most heavily exploited population (ESP) suggests that inbred individuals are eliminated between seedling and adult stages. Significant SGS was detected up to 60 m in all populations, which indicates short distance seed dispersal. Genetic differentiation (G’ST) between pairwise populations was related to spatial distance between populations, with the greatest difference between more distant populations.
Mating system variation among populations, individuals and within and among fruits in Bertholletia excelsa
Authors: Wadt L.H.O. , Baldoni A. B. , Silva V. S. , Campos T. , Martins K. , Azevedo V.C.R. , Mata L.R. , Botin A.A. , Hoogerheide E.S. S. , Tonini H. , Sebbenn Alexandre M.
Published: June 2017

The aim of this study was to investigate variation in mating system among three Brazilian Amazon populations of the tree Bertholletia excelsa with different levels of anthropogenic interventions. We collected open-pollinated seeds from one natural population, remnant trees dispersed in a pasture, and trees from a plantation. Outcrossing rate not varied among the populations and indicates that all seeds were originated from outcrossing (tm=1.0). Mating among relatives was significant higher in the plantation than forest and pasture populations, probably due the fact that many trees are related in the plantation. Correlated mating was significantly higher in pasture (rp=0.47) and plantation (rp=0.51) than in the natural population (rp=0.22), suggesting that trees in natural population are pollinated by a higher number of pollen donors. The paternity correlation was significantly higher within (rp(w)=0.41) than among fruits (rp(a)=0.18), showing a higher probability to find full-sibs within than among fruits. The fixation index was generally lower in seed trees than in their seedlings, suggesting selection for heterozygous individuals from seedling to adult stages. Progeny arrays collected from the natural population had a lower proportion of pairwise full-sibs than in pasture and plantation and higher variance effective size (2.75) than trees in pasture (2.15) and plantations (2.22). Results highlight that seed collections for conservation, breeding and reforestation programs preferentially should be carried out in natural populations due low proportion highest variance effective size within progeny.
PCR-based detection of single sequence variants from a natural collection of the non-model tree species European Aspen Populus tremula (L.)
Authors: Winkler S. , Linke K. , Gscheidel N. , Meyer M. , Krabel Doris
Published: June 2017

In the present study we present and discuss the identification of species-specific SNPs to rule out any experimental influence of species-specific primer design (Populus tremula vs. the closely related model-species Populus trichocarpa) on the detectability of SNPs. Applying a species-optimized method, partial sequences of 14 genes involved in xylem cell development, xylogenesis, pectin formation, and drought stress reaction were analyzed at the genomic level. About 3 Mb of sequence information were generated by Sanger sequencing technology and 258 sequence variants were identified. 15 out of these represent insertions /deletions located exclusively in non-coding regions and the remaining 243 are SNPs found in coding and non-coding regions of candidate genes.

The introduction of a species-specific SNP detection pipeline will help to detect nucleotide variants in P. tremula and to conduct association mapping in natural P. tremula populations.