rss_2.0Silvae Genetica FeedSciendo RSS Feed for Silvae Genetica Genetica Feed growth performance and genetic parameters on Korean pine in Northeastern China<abstract> <title style='display:none'>Abstract</title> <p>Korean pine (<italic>Pinus koraiensis</italic>) is an economically valuable species owing to its excellent timber quality and nuts useful for various purposes. But few studies have been made on growth performance, and aspects combining the genetic gain and classification method on phenotypic similarity in the selection process of superior families. Thus, the present study aimed at analyzing the genetic variation and highlight suitable morphological traits for family selection; establishing trait correlations and families’ ordination based on similarities in phenotypic characters, and selecting elite families and suitable parent trees. Full-sib families from 28 crosses established in randomized complete block design from Naozhi orchard in Northeast China were used, and 11 morphological traits were investigated. Significant differences were observed among families for all traits. The traits coefficients of variation ranged from 6.07 to 56.25 % and from 0.029 to 15.213 % in phenotype and genotypic variation, respectively. A moderate level of inherited genetic control was observed (broad sense heritability H<sub>2</sub>, varied from 0.155 to 0.438). Traits related to stem growth were highly positively correlated to each other whereas crown traits showed a weak correlation with stem traits (Pearson correlation r, ranged from -0.161 to 0.956). Based on multi-trait comprehensive analysis, we selected six elite families and six parents, which resulted in a genetic gain of 5.6 %, 16.9 %, and 36.4 % in tree height, diameter at breast height, and volume, respectively. These results make a theoretical basis for selecting excellent families and establish orchards of Korean pine from improved seeds.</p> </abstract>ARTICLEtrue diversity and structure of Siberian Stone Pine ( Du Tour) populations<abstract> <title style='display:none'>Abstract</title> <p>Siberian stone pine (<italic>Pinus sibirica</italic> Du Tour) is a key component of the Eurasian boreal forest ecosystems. However, due to the ongoing climatic changes and anthropogenic activities, the habitats of the species are constantly degrading and reducing. To these reasons, exploring the genetic resources of the species and determining the genetic diversity and structure of today’s populations is essential. In this study, we assessed genetic diversity and differentiation in six Siberian stone pine populations from different forest zones in Middle Siberia. Based on seven microsatellite nuclear markers (nSSR), moderate level of genetic diversity (<italic>He</italic>=0.455) was detected. A population structure analysis divided the six Siberian stone pine populations into two groups. Southernmost populations were distinguished from the others. Analysis of molecular variance (AMOVA) showed that only 2 % of the genetic variation occurred among populations. Our findings suggest that extensive gene flow may prevent genetic differentiation among Siberian stone pine populations. Hence, further genetic diversity estimation with additional loci is needed for crucial insight into the gene pool of Siberian stone pine populations.</p> </abstract>ARTICLEtrue the gene pools of Cypriot oaks: no evidence of intersectional hybridization<abstract> <title style='display:none'>Abstract</title> <p>In our study, we performed a population genetic analysis in all three native oak species of Cyprus and addressed whether two intermediate individuals arose from intersectional hybridization between <italic>Quercus coccifera</italic> ssp. <italic>calliprinos</italic> and <italic>Q. infectoria</italic> ssp. <italic>veneris</italic>. For this purpose, we successfully tested chloroplast and nuclear microsatellites initially developed for other oak species. We identified a set of markers that can be efficiently used for species identification and study of hybridization. Haplotypes based on the chloroplast microsatellites could resolve different maternal lineages and distinguish between the two sections represented in the study area. Using the nuclear microsatellites, we described patterns of genetic diversity across species with the endemic <italic>Q. alnifolia</italic> exhibiting reduced genetic diversity. Additionally, we employed a multivariate analysis, which could clearly differentiate among the three species. The two intermediate individuals clustered within the point cloud of <italic>Q. infectoria</italic> ssp. <italic>veneris</italic> and also possessed a chloroplast haplotype typical for this species. Therefore, we rejected the hypothesis of intersectional hybridization and interpreted their phenotypic appearance as the result of high phenotypic plasticity within <italic>Q. infectoria</italic> ssp. <italic>veneris</italic>.</p> </abstract>ARTICLEtrue or non-conservative strategy to advance breeding generation? A case study in using spatial variation and competition model<abstract> <title style='display:none'>Abstract</title> <p>The greatest challenge faced when breeding populations of forest species is to achieve the right equilibrium among genetic gain and no loss of the effective population size. Thus this study aims to define the best thinning strategy to compose a seed orchard of <italic>Eucalyptus benthamii</italic> to obtain genetic gain maintaining the effective population size. The population of <italic>E. benthamii</italic> studied consisted of 28 open-pollinated progenies. The diameter at breast height (DBH) and height (H) parameters were determined three years after planting. Measurement data were analyzed and compared using four different mathematical models (with and without competition effect and spatial variation). Strategies considering genetic gain and effective population size were simulated considering the number of families, the number of individuals between families, and the total number of individuals. The mathematical model accounting for the competition effect had the best fit for DBH whereas the model accounting for the environmental variation effect presented the best fit for H. The ranking of BLUPs grouped the families into three clusters (best, intermediate/average, worst/poor families). The strategy that maintains 40 % of the individuals, generates a genetic gain of 13 % in DBH and 8 % in total height while maintaining an effective population size greater than 92 for booth traits.</p> </abstract>ARTICLEtrue structure and diversity in wild and breeding populations of<abstract> <title style='display:none'>Abstract</title> <p><italic>Eucalyptus urophylla</italic> S.T. Blake is a species of great commercial importance, especially in tropical regions, and it is the main eucalypts species cultivated in Brazil. This study evaluated the genetic diversity among and within seven populations of <italic>E. urophylla</italic> and estimated the genetic distance between individuals to draw inferences about the genetic structure between and within the sampled populations. For that, 19 microsatellite markers were genotyped in 254 individuals originating from four wild populations, introduced in Brazil, two breeding populations, and one population consisting of commercial clones. The wild populations of <italic>E. urophylla</italic> introduced in Brazil have high genetic similarity and the few generations of breeding have already generated significant differences in population structure between improved and wild populations. As expected, breeding populations are closer to commercial clones than wild populations. However, compared to wild populations, breeding populations exhibit greater genetic diversity as they originated from a mixture of provenances. The population formed by clones was the only one that showed a negative Wright fixation index, that is, heterozygosity was higher than expected for a population in Hardy-Weinberg equilibrium.</p> </abstract>ARTICLEtrue of the phenotypic diversity of wild cherry ( L.) populations and halfsib lines by multivariate statistical analyses<abstract> <title style='display:none'>Abstract</title> <p>Wild cherry (<italic>Prunus avium</italic> L.) is a multi-purpose tree species with great ecological and economic importance for European forestry. Evaluating this species phenotypic diversity and quantitative traits characterization is of great importance to define its genetic resources conservation and breeding strategies. In this work, variations of physiological, biochemical, anatomical and morphological traits of one-year-old wild cherry seedlings were evaluated within and among populations to distinguish and characterize their phenotypic portfolio. We observed significant differences at the intra- and inter-population levels considering both biochemical and physiological leaf traits, whereas differences in morphological and anatomical traits were found to be significant only among half-sib lines within populations (i.e. intra-population level). With a multivariate approach, we explored the inter-population specificity and found out that the tiered approach spanning from organ morphology, across physiological scale, to the biochemical level gave out enough power to discriminate between different populations, and their acquisition and resource-use strategies. Moreover, stepwise discriminative analysis showed that radical scavenger capacity against 2,2’-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS•+) and water-use efficiency contributed to discrimination of studied populations to the largest extend. Lastly, our study highlights the robustness of certain functional traits, such as ABTS•+, water-use efficiency, net photosynthesis, total flavonoid content, width of stomata guard cell, and stomatal aperture length, which could be considered as a proxy to discriminate between wild cherry populations and assess phenotypic diversity.</p> </abstract>ARTICLEtrue variation in height, diameter and second flushing in four-year old maritime pine progeny tests in Türkiye<abstract> <title style='display:none'>Abstract</title> <p>A maritime pine (<italic>Pinus pinaster</italic> Ait.) breeding program was initiated in Türkiye by selecting plus trees from plantations across the country. Quantifying genetic variation in growth traits is essential for this program. Four-year old trees from 140 open-pollinated maritime pine families were assessed for height (HT), root collar diameter (D) and number of shoots in the fourth growing season (S) in three progeny test plantations (Kefken, Gebze and Çatalca) in northwest Türkiye. Growth was greater in Kefken, followed by Gebze and Çatalca. Both individual tree (h<italic><sub>i</sub></italic><sup>2</sup>) and family mean (h<italic><sub>f</sub></italic><sup>2</sup>) heritability estimates were greatest for HT (h<italic><sub>i</sub></italic><sup>2</sup>=0.22 and h<italic><sub>f</sub></italic><sup>2</sup> =0.77) followed by D (0.16 and 0.59) and S (0.08 and 0.45). While genetic correlation between HT and D was strong (r<italic><sub>A</sub></italic>=0.72), S was correlated moderately with HT (0.56) and weakly with D (0.11). Genotype × environment interaction was significant only for D. While modest genetic gains (up to 15.20 % over the average of family means) from selections at age four seem possible for growth, changes in patterns of genetic variation and interrelationships among the traits as the trees age remains to be explored in the future.</p> </abstract>ARTICLEtrue amphidiploid induction of a distant hybrid × cv. ‘Xiaohuyang-2’ and its effect on plant morphology and anatomy<abstract> <title style='display:none'>Abstract</title> <p>Highly gametic sterility of a distant hybrid <italic>Populus simonii</italic> × <italic>P. euphratica</italic> cv. ‘Xiaohuyang-2’ restricts its utilization in breeding programs of <italic>Populus</italic>. Amphidiploid induction by somatic chromosome doubling is expected to restore its gametic fertility. In this study, nodal-segment and leaf explants of ‘Xiaohuyang-2’ were used to induce chromosome doubling with colchicine <italic>in vitro</italic>. Although chromosome doubling of the nodal-segment explants only produced mixoploids, the treatments of leaf explants on adventitious bud regeneration medium successfully produced 4 amphidiploids, which might be attributed to the direct organogenesis of the adventitious buds on the leaf explants. This is the first report of amphidiploid induction in a distant hybrid between <italic>Populus</italic> section Tacamahaca and sect. Turanga. The highest amphidiploid induction frequency was 16.7 %. Both the explant survival rate and polyploidization frequency were significantly affected by colchicine concentration and exposure time. The amphidiploid plants significantly differed from the diploid and mixoploid plants in morphological and anatomical characteristics. They had larger, thicker, and greener leaves than the diploids and mixoploids. The increase in ploidy level also resulted in changes in stomatal features. The induced amphidiploid plants of the distant hybrid ‘Xiaohuyang-2’ are expected to play important roles in breeding programs of <italic>Populus</italic> in the future, which can be used as a bridge parent with the ability of unreduced gamete formation to cross with fast-growth germplasms to produce triploids pyramiding desirable traits of fast growth, easy cutting propagation, and salt and drought tolerances.</p> </abstract>ARTICLEtrue studies for trait improvement in four important tree species: Current status and future prospects<abstract> <title style='display:none'>Abstract</title> <p>Trees hold the lifeline of the earth’s biodiversity and serve as a commercial entity delivering broad applications to human-kind. In addition to being used as wood and timber, trees are a source of secondary metabolites, medicinal compounds, and other derivatives with high commercial value. Thus, the scope for improvement of these traits and quality traits (insect/pest resistance, wood quality, etc.) has always been demanding; however, limited progress has been made compared to other crop species. Trait improvement has always been challenging in trees owing to several practical difficulties, but genomics has enabled the precise identification of genetic determinants of these traits and provided tools and approaches to tweak them for enhancing the traits of interest. Next-generation sequencing (NGS) has expedited genomics and transcriptomics research by facilitating the sequencing of genomes and transcriptomes, identifying genes, profiling the regulation of their expression, and constructing gene regulatory networks. Also, NGS has enabled the development of large-scale genome-wide molecular markers for high-throughput genotyping applications, which are useful in breeding for desirable traits. As it allows improved understanding of the gene function and its network at different developmental stages of trees with reference to an environmental stimulus can further help the breeder to enhance the knowledge on spanning genotype and phenotype. Thus, the potential of genomics in expediting trait improvement has been well realized; however, its application in tree species, particularly in commercially important ones including <italic>Tectona grandis</italic>, <italic>Azadirachta indica</italic>, <italic>Casuarina</italic> spp., and <italic>Salix</italic> spp, requires further research. Given this, the present review enumerates the progress made in genomics research on these four species and provides the roadmap for their trait improvement toward enhancing productivity and ecosystem services.</p> </abstract>ARTICLEtrue performance of wild cherry ( L.) clones in planted forests under different managements in Galicia, NW Spain<abstract> <title style='display:none'>Abstract</title> <p>Wild cherry (<italic>Prunus avium</italic> L.) is one of the main valuable temperate broadleaved species from Europe considering the market appreciation of their timber. In the present study we analyzed the growth performance of different wild cherry clones under different management treatments. A field trial was settled in Bosques Naturales S.A. “Sendelle” forests (Arzúa, Galicia, NW Spain) with a multifactorial design to analyze the effect of clones (4 clones), pruning intensity (33 % and 50 % of total height) and fertilization (3 treatments). It was monitored for 8 years. Clone was found out to be the most important variable in this study while tree growth was neither significantly affected by the pruning intensity nor the fertilization treatments. Clone selection is highlighted as a key issue in wild cherry commercial planted forests for timber production and the selected C-15 clone shows an excellent field performance compared to other clones based on the trial and the literature, reaching a DBH of 14 cm after eight years.</p> </abstract>ARTICLEtrue of nuclear microsatellite markers for L. and their transferability to six related species<abstract> <title style='display:none'>Abstract</title> <p>Common ash (<italic>Fraxinus excelsior</italic> L.) is an economically and ecologically important tree species in Europe acutely threatened by ash dieback. Here, we present a new set of Simple Sequence Repeat markers for <italic>F. excelsior</italic> and six related ash species based on published <italic>in silico</italic> designed primers. Forty SSR markers, mainly from genic regions, were tested for amplification and polymorphism and characterized in two ash populations in Germany. Transferability of polymorphic markers to six related <italic>Fraxinus</italic> species (<italic>F. angustifolia</italic>, <italic>F. ornus</italic>, <italic>F. quadrangulata</italic>, <italic>F. pennsylvanica</italic>, <italic>F. americana</italic> and <italic>F. biltmoreana</italic>) was also assessed. Eighteen markers, predominantly from genic regions including three markers closely linked to candidate genes for ash dieback, were successfully amplified and polymorphic in <italic>F. excelsior</italic>, of which between 10 to 17 were transferable to one of the six related species. High genetic diversity was found in the two ash populations (<italic>N<sub>a</sub></italic> = 7.8 and 6.9, <italic>H<sub>e</sub></italic> = 0.71 and 0.68), while low genetic differentiation between populations (<italic>F<sub>ST</sub></italic> = 0.025) was observed. The newly characterised SSR markers extend the set of genetic markers available for <italic>F. excelsior</italic> and six other ash species for future studies on the genetic diversity and structure of ash populations.</p> </abstract>ARTICLEtrue, adaptability, and stability in progeny tests across three environments in the Aguaytia River Basin, Ucayali, Perú<abstract> <title style='display:none'>Abstract</title> <p><italic>Guazuma crinita</italic> is a fast-growing tree with potential for use in agroforestry systems, due to its rapid wood production, which can contribute significantly to the livelihoods of small-scale farmers in the Peruvian Amazon. However, indiscriminate logging due to high demand is leading to the disappearance of natural forests. As such, the International Council for Research in Agroforestry (ICRAF) began a domestication program to reduce pressure on natural populations of the species. The objective of the present study was to use analyses of genetic parameters, adaptability (PRVG), productivity (MHPRVG), and stability (MHVG), to select <italic>G. crinita</italic> genotypes from a three-year-old progeny test established in the Aguaytía River Basin, in Ucayali, Peru. The test was established in three different sites, with three blocks, 200 progeny per block, and two individuals per plot. The measured traits were diameter at breast height (DBH), total height (H), and total aerial biomass (B). Significant differences in traits between progenies were detected, but with no genotype x environment interaction (GxE). However, the genotypic correlation among sites was important (&gt; 0.702), suggesting that genetic improvement is possible by selecting the same progeny across sites. The mean heritability among progenies was moderate for all traits (0.34–0.369) and selective precision through combined site analysis was relatively high (0.583–0.608). Based on selection for DBH through combined analysis, MHVG, PRVG, and MHPRVG, 50 superior progenies (25.9 %) were identified for all environments. These should be prioritized in breeding programs as they can offer stable genetic variability for future selection cycles.</p> </abstract>ARTICLEtrue and genetic nature of polyploidy in paleoendemic coast redwood ( (D. Don) Endl.)<abstract> <title style='display:none'>Abstract</title> <p>It is not known when the polyploid coast redwood (<italic>Sequoia sempervirens</italic>) evolved from its diploid ancestors, and what is its type of polyploidy. Whether close relatives of <italic>Sequoia</italic>, giant sequoia (<italic>Sequoiadendron giganteum</italic>) and dawn redwood (<italic>Metasequoia glyptostroboides</italic>), have possibly contributed to the ancestry of hexaploid of <italic>Sequoia</italic> remains an open question. The nature of hexaploidy in <italic>Sequoia</italic> has baffled biologists for more than a century. Based on the chromosome configurations in <italic>Sequoia</italic>, G. Ledyard Stebbins was the first geneticists who postulated in 1948 that <italic>Sequoia</italic> is an autoallohexaploid (AAAABB), and an ancient species of <italic>Metasequoia</italic> might have been one of the putative ancestors of <italic>Sequoia</italic>. After its chromosome number (2n=6x=66) was confirmed in hexaploid <italic>Sequoia</italic>, the type of polyploidy in <italic>Sequoia</italic> has been further investigated for the past 70 years by a number of investigators, using cytogenetic and genetic data. Although an autoallohexaploid (AAAABB) origin of <italic>Sequoia</italic> has remained one of the dominant hypotheses until recently, an alternative hypothesis, amongst other possible origins, was also put forth by Ahuja and Neale (2002), that <italic>Sequoia</italic> may be partially diploidized autohexaploid (AAAAAA), derived from some ancestral species of <italic>Sequoia</italic>, thus carrying a single ancestral genome. Cytogenetic, molecular genetics, and genome sequence data now support the hypothesis that <italic>Sequoia</italic> originated as an autohexaploid.</p> </abstract>ARTICLEtrue survey sequencing of and identification of simple sequence repeat (SSR) markers<abstract> <title style='display:none'>Abstract</title> <p><italic>Ailanthus altissima</italic> is a deciduous tree native to China and introduced to other parts of the world as an ornamental plant. It exhibits resistance to both abiotic and biotic stress factors and has various pharmacological effects and strong allelopathy, generating significant research interests. However, the genome sequence of this species has not been reported, limiting its research development. The purpose of the study was to determine the genome size and characteristics of <italic>A. altissima</italic> to conduct its genomic survey. Next-generation sequencing and K-mer analysis were employed to measure the genome size of <italic>A. altissima</italic>. Overall, a total of 61.93 Gb high-quality clean data were acquired, representing approximately 64.09× coverage of the <italic>A. altissima</italic> genome. The genomic characteristics of <italic>A. altissima</italic> include a genome size of 966.38 Mbp, a heterozygosis rate of 0.78 %, and a repeat rate of 41.22 %. A total of 735,179 genomic SSRs markers were identified based on genome survey sequences. Alignment analysis showed that <italic>A. altissima</italic> was closely related to <italic>Citrus sinensis</italic> and <italic>Leitneria florida-na</italic>. This study provides basic information for future whole-genomic sequencing of <italic>A. altissima</italic>. This will facilitate a knowledge of the population structure, genetic diversity, long distance-gene transfer, and pollen-based gene flow analyses of <italic>A. altissima</italic> populations from its known distribution ranges in China, focusing on planted and natural forest stands.</p> </abstract>ARTICLEtrue of optimal timing of early selection based on time trends of genetic parameters in<abstract> <title style='display:none'>Abstract</title> <p>Early selection is an imperative in ongoing forest tree breeding. This study estimated the optimal timing of early selection in <italic>Abies sachalinensis</italic> (F. Schmidt) Mast. based on time trends of genetic parameters obtained from two test sites. Tree height (<italic>H<sub>t</sub></italic>) at 5, 10 (11), 15, 20, 30, and 40 years of age and diameter at breast height (DBH) at 20, 30, and 40 years of age were analyzed. The efficiency of early selection per year (<italic>E</italic>) for performing early indirect selection relative to performing direct selection at the earliest rotation age (40 years of age) was estimated based on narrow-sense heritability (<italic>h</italic><sup>2</sup>) and age–age genetic correlation (<italic>r</italic>). The <italic>h</italic><sup>2</sup> of <italic>H<sub>t</sub></italic> peaked at 10 or 15 years of age (0.52–0.71), and that of DBH was the highest at 20 years of age (0.19 or 0.22). The age–age genetic correlation between tree heights or between tree height and DBH at different ages decreased with increasing differences between ages (regression coefficients were −0.011 and −0.007, respectively). The <italic>E</italic> values were highest at 10 or 15 years of age (0.84-1.74 and 1.42-2.24 for <italic>H<sub>t</sub></italic> and <italic>H<sub>t</sub></italic>-DBH, respectively), indicating the optimum selection timing. In Japapnese forestry, the initial growth rate is considered important for reducing weeding costs. Selection at 10 or 15 years of age had more than in &gt;65 % indirect genetic gain relative to the direct genetic gain at 5 years of age; thus, selection at 10-15 years of age is appropriate considering the initial and mature phases of tree growth.</p> </abstract>ARTICLEtrue of Additive, Dominance, and Epistatic Genetic Variance in Eucalypt Hybrid Population<abstract> <title style='display:none'>Abstract</title> <p>Additive, dominance and epistasis genetic variances were estimated from analysis of a clonally replicated full-sib progeny test grown in the Republic of Congo. Phenotypic variance components were estimated for ages 4 through 25 months for growth and at ages 8 and 18 months for ecophysiological traits. The estimation of genetics effects was derived from the individual mixed model. Genetic structure was incorporated into variances and covariance’s effects based on markers information. The detected genetic effects of epistasis are significant in some traits. This study shows that epistasis variance can be non-zero and contribute significantly to the genetic variability of growth and ecophysiological traits. We conclude that the epistatic effect for quantitative traits may exist, but estimates may not be obtained, either because the models used are inappropriate or because the epistasis variance is too small relative to other components of the genetic variance to be estimated.</p> </abstract>ARTICLEtrue DNA isolation procedure for different tree species as a convenient lab routine<abstract> <title style='display:none'>Abstract</title> <p>DNA isolation is a fundamental technique for all molecular biology laboratories. Depending on the plant species, DNA isolation can be challenging. In particular, adapted protocols rarely exist for tree species which are not used as standard model organisms. Here, we describe a flexible DNA isolation protocol that works for 59 tree species in a modular system. It is based on an ATMAB-containing extraction buffer to which proteinase K and/or boric acid are added, depending on the plant species. Subsequent purification steps include one or two precipitations with dichloromethane and, depending on the tree species, an optional sodium acetate precipitation. Using leaf material of a hybrid poplar clone from <italic>in vitro</italic> culture, it was determined that higher amounts of DNA could be isolated with this material than from field leaves. Starting from leaf material, DNA isolation for difficult cases was achieved with cambium or root tissue. This protocol was used to extract DNA for subsequent PCR amplification. Markers for cpDNA, mtDNA, and genomic DNA were used for standardized testing.</p> </abstract>ARTICLEtrue ducts size varies genetically and is positively associated to resin yield of open-pollinated progenies<abstract> <title style='display:none'>Abstract</title> <p>Mexico ranks 5<sup>th</sup> in worldwide resin production. <italic>Pinus oocarpa</italic> is the most widely tapped pine tree in Mexico. Michoacán (central-western Mexico) is the first nationwide state producer of resin. Despite the <italic>P. oocarpa</italic> relevance, there is no genetic improvement program in the country for resin production. We evaluated the degree of genetic control for growth, anatomical traits, resin yield, and the correlation among them at an early age (five-years-old for growth, six for resin, and anatomical traits) in a <italic>P. oocarpa</italic> half-sib progeny trial. Families were originated from selected mother trees, based on their resin yield. We found significant genetic variation among families for stem volume (<italic>h</italic><italic><sup>2</sup></italic><italic><sub>i</sub></italic>= 0.12, <italic>h</italic><italic><sup>2</sup></italic><italic><sub>f</sub></italic>= 0.35), traumatic ducts (diameter: <italic>h</italic><italic><sup>2</sup></italic><italic><sub>i</sub></italic>= 0.63, <italic>h</italic><italic><sup>2</sup></italic><italic><sub>f</sub></italic>= 0.51; area: <italic>h</italic><italic><sup>2</sup></italic><italic><sub>f</sub></italic>= 0.81), and resin yield (individual and family narrow-sense heritability: <italic>h</italic><italic><sup>2</sup></italic><italic><sub>i</sub></italic>= 0.20, <italic>h</italic><italic><sup>2</sup></italic><italic><sub>f</sub></italic>= 0.52), and a positive correlation between diameter and area of traumatic ducts with resin yield (Pearson correlation: <italic>r</italic>= 0.73, <italic>p</italic>= 0.04; <italic>r</italic>= 0.71, <italic>p</italic>= 0.0497; respectively). Results suggest that the early selection (six-years-old) of superior <italic>P. oocarpa</italic> families, based on resin yield (estimated by microchipping technique), and/or based on larger diameter and area of traumatic ducts, appears to be a feasible strategy to develop seed orchards able to provide genetically improved seeds for intensive resin tree plantations. That would be an important alternative for a state as Michoacán, Mexico, where natural <italic>P. oocarpa</italic> stands are being replaced for avocado orchards for exportation.</p> </abstract>ARTICLEtrue markers revealed a repartition depending on geographical origin and breeding status of Tunisian pistachio species<abstract> <title style='display:none'>Abstract</title> <p>Retrotransposon movements are considered to be an important factor in evolutionary processes and speciation as well as a source of genetic variation. In order to analyze genetic diversity and population structure in Tunisian pistachio species, nine inter-retrotransposon amplified polymorphism (IRAP) markers were used. As a result, eighty-six amplicons were produced among which 98.15 % were polymorphic. Mean numbers of the effective number of alleles (Ne), Shannon’s information index (I) and Nei’s genetic diversity (H) were respectively 1.529, 0.478, and 0.310. The average within-population genetic diversity (Hs) was 0.24 and the total diversity (Ht) was 0.3. The Tunisian pistachio populations exhibited high genetic differentiation (Gst =0.275) and gene flow (<italic>Nm</italic> = 1.888). The Analysis of Molecular Variance (AMOVA) indicated that variation was very high within populations (83 %). Phylogenetic tree using neighbor- joining (NJ) method and Principal Coordinates Analysis (PCoA) depicted that groupings of Tunisian varieties were made independently of the sex of the trees, but depending on their geographical origin and their breeding status. The modelbased Bayesian clustering (STRUCTURE) confirmed these observations. The inter-retrotransposons amplification polymorphism markers were significantly informative at the interspecific level. Findings reported in our study will be essential toward breeding for new pistachio genotypes with developed chemical and horticultural features.</p> </abstract>ARTICLEtrue profiles of 11 candidate genes involved in drought tolerance of pedunculate oak ( L.). Possibilities for genetic monitoring of the species.<abstract> <title style='display:none'>Abstract</title> <p>Pedunculate oak (<italic>Quercus robur</italic> L.) is one of the most significant broadleaved tree species in Europe. However, various abiotic and biotic agents have influenced pedunculate oak forests, among which drought stress has been frequently described as the main driver of this species forests decline. In this study we assessed relative expression profile of 11 candidate genes involved in many different metabolic pathways and potentially responsible for oak drought tolerance. The obtained results succeed in partially tackling drought tolerance mechanisms of targeted natural pedunculated oak population. This gene pool may represent a base for adaptation and therefore genetic diversity should be conserved. In this paper we described different expression responses of four pedunculate oak ecological groups, characterized by different physiological status (senescent vs vital) and flowering period (early (var. <italic>praecox</italic>) vs late (var. <italic>tardissima</italic>)). The most significant differences in relative gene expression levels are shown between the flowering period (<italic>tardissima</italic> (8 genes upregulated) vs <italic>praecox</italic> (3 genes upregulated)), more than a physiological status (sene-scent vs vital). Only three genes <italic>wrky</italic>53, <italic>rd</italic>22 and <italic>sag</italic>21 showed upregulated expression pattern in senescent physiological groups, indicating their possible role in the coping mechanisms of oak in stressed environment. Results showed interesting connections of relative gene expression values of identified drought-tolerance related genes with flowering period and provide further recommendations for adequate conservation and monitoring of this important oak gene pool in its southeast refugium.</p> </abstract>ARTICLEtrue