Search

Genomic Selection (GS) in tree breeding optimizes genetic gains by leveraging genomic data to enable early selection of seedlings without phenotypic data reducing breeding cycle and increasing selection intensity. Traditional assessments of the potential of GS in forest trees have typically focused on model performance using cross-validation within the same generation but evaluating effectively realized predictive ability (RPA) across generations is crucial. This study estimated RPAs for volume growth (VOL), wood density (WD), and pulp yield (PY) across four generations breeding of Eucalyptus grandis. The training set spanned three generations, including 34,461 trees with three-year growth data, 6,014 trees with wood quality trait data, and 1,918 trees with 12,695 SNPs (single nucleotide polymorphisms) data. Employing single-step genomic BLUP, we compared the genomic predictions of breeding values (GEBVs) for 1,153 fourth-generation full-sib seedlings in the greenhouse with their later-collected phenotypic estimated breeding values (EBVs) at age three years. RPAs were estimated using three GS targets (individual trees, trees within families, and families), two selection criteria (single- and multiple-trait), and training populations of either all 1,918 genotyped trees or the 67 direct ancestors of the selection candidates. RPAs were higher for wood quality traits (0.33 to 0.59) compared to VOL (0.14 to 0.19) and improved for wood traits (0.42 to 0.75) but not for VOL when trained only with direct ancestors, highlighting the challenges in accurately predicting growth traits. GS was more effective at excluding bottom-ranked candidates than selecting top-ranked ones. The between-family GS approach outperformed individual-tree selection for VOL (0.11 to 0.16) and PY (0.72 to 0.75), but not for WD (0.43 vs. 0.42). Furthermore, higher levels of relatedness and lower genotype by environment (G × E) interaction between training and testing populations enhanced RPAs for VOL (0.39). In summary, despite limited effectiveness in ranking top VOL individuals, GS effectively identified low-performing individuals and families. These multi-generational findings underscore GS's potential in tree breeding, stressing the importance of considering relatedness and G × E interaction for optimal performance. [ABSTRACT FROM AUTHOR]

Cultivated cotton plants are the world's largest source of natural fibre, where yield and quality are key traits for this renewable and biodegradable commodity. The Gossypium hirsutum cotton genome contains ~80K protein-coding genes, making precision breeding of complex traits a challenge. This study tested approaches to improving the genomic prediction (GP) accuracy of valuable cotton fibre traits to help accelerate precision breeding. With a biology-informed basis, a novel approach was tested for improving GP for key cotton fibre traits with transcriptomics of key time points during fibre development, namely, fibre cells undergoing primary, transition, and secondary wall development. Three test approaches included weighting of SNPs in DE genes overall, in target DE gene lists informed by gene annotation, and in a novel approach of gene co-expression network (GCN) clusters created with partial correlation and information theory (PCIT) as the prior information in GP models. The GCN clusters were nucleated with known genes for fibre biomechanics, i.e., fasciclin-like arabinogalactan proteins, and cluster size effects were evaluated. The most promising improvements in GP accuracy were achieved by using GCN clusters for cotton fibre elongation by 4.6%, and strength by 4.7%, where cluster sizes of two and three neighbours proved most effective. Furthermore, the improvements in GP were due to only a small number of SNPs, in the order of 30 per trait using the GCN cluster approach. Non-trait-specific biological time points, and genes, were found to have neutral effects, or even reduced GP accuracy for certain traits. As the GCN clusters were generated based on known genes for fibre biomechanics, additional candidate genes were identified for fibre elongation and strength. These results demonstrate that GCN clusters make a specific and unique contribution in improving the GP of cotton fibre traits. The findings also indicate that there is room for incorporating biology-based GCNs into GP models of genomic selection pipelines for cotton breeding to help improve precision breeding of target traits. The PCIT-GCN cluster approach may also hold potential application in other crops and trees for enhancing breeding of complex traits. [ABSTRACT FROM AUTHOR]

Forests worldwide are under increasing pressure from climate change and emerging diseases, threatening their vital ecological and economic roles. Traditional breeding approaches, while valuable, are inherently slow and limited by the long generation times and existing genetic variation of trees. CRISPR technologies offer a transformative solution, enabling precise and efficient genome editing to accelerate the development of climate-resilient and productive forests. This review provides a comprehensive overview of CRISPR applications in forestry, exploring its potential for enhancing disease resistance, improving abiotic stress tolerance, modifying wood properties, and accelerating growth. We discuss the mechanisms and applications of various CRISPR systems, including base editing, prime editing, and multiplexing strategies. Additionally, we highlight recent advances in overcoming key challenges such as reagent delivery and plant regeneration, which are crucial for successful implementation of CRISPR in trees. We also delve into the potential and ethical considerations of using CRISPR gene drive for population-level genetic alterations, as well as the importance of genetic containment strategies for mitigating risks. This review emphasizes the need for continued research, technological advancements, extensive long-term field trials, public engagement, and responsible innovation to fully harness the power of CRISPR for shaping a sustainable future for forests. [ABSTRACT FROM AUTHOR]

Hevea brasiliensis is an evergreen woody tree widely used in industrial production in tropical rain forest. However, rubber trees are extremely vulnerable to low temperature stress, which seriously limits the cultivation and use of rubber trees in low temperature areas. NAC transcription factor gene family is common to many plant species, and can participate in a variety of behaviors that are crucial for plants to cope with the challenges from the environment. However, little is known about the evolution history, function and expression patterns of NAC family in rubber trees. Here, 51 HbNAC genes were identified in rubber tree by genome search, and they were divided into 11 subclasses according to phylogenetic relationship. The members of a subfamily share a similar number of introns and exons. We conducted transcriptome analyses to obtain cold-responsive HbNACs, and the transcriptome data showed the expression of HbNAC26 and HbNAC11 was significantly induced by cold stress, suggesting a potential role of these genes in cold stress. The expression pattern of HbNACs in different tissues and different developmental stages was studied by real-time PCR. In addition, the complementary effect of defective yeast mutants indicated that the HbNAC11 gene could be a positive regulator of cold stress in rubber trees. The results of this study can lay a foundation for studying the biological function of NAC and improving cold resistance breeding of rubber trees. [ABSTRACT FROM AUTHOR]

The study investigates the long-term impact of Lophodermium needle cast on open-pollinated Scots pine progenies in Latvia. A significant impact of cumulative needle cast damage on growth and survival was found. Notably, 51% of trees experienced severe damage after the 4th growing season. Genetic factors played a role in survival at 12 years. Height growth was significantly affected, with height at age 3 and cumulative needle cast damage as key predictors for heights at ages 12 and 16. Genetics demonstrated a substantial impact, with heritability coefficients of 0.25 for cumulative needle cast damage and 0.24 for height, and negative genotypic correlations (rG ≥ -0.71) between the traits. Selecting the top 10% families based on height at 12 years yielded a 14.2% improvement in height and a simultaneous 8.4% reduction in cumulative needle cast damage, enhancing survival by 9.8%. Thinning somewhat mitigated the negative effect of needle cast. The findings highlight the need for adaptive forestry strategies in the Baltic Sea region. [ABSTRACT FROM AUTHOR]

Summary: Forests face many threats. While traditional breeding may be too slow to deliver well‐adapted trees, genomic selection (GS) can accelerate the process. We describe a comprehensive study of GS from proof of concept to operational application in western redcedar (WRC, Thuja plicata).Using genomic data, we developed models on a training population (TrP) of trees to predict breeding values (BVs) in a target seedling population (TaP) for growth, heartwood chemistry, and foliar chemistry traits. We used cross‐validation to assess prediction accuracy (PACC) in the TrP; we also validated models for early‐expressed foliar traits in the TaP.Prediction accuracy was high across generations, environments, and ages. PACC was not reduced to zero among unrelated individuals in TrP and was only slightly reduced in the TaP, confirming strong linkage disequilibrium and the ability of the model to generate accurate predictions across breeding generations. Genomic BV predictions were correlated with those from pedigree but displayed a wider range of within‐family variation due to the ability of GS to capture the Mendelian sampling term.Using predicted TaP BVs in multi‐trait selection, we functionally implemented and integrated GS into an operational tree‐breeding program. [ABSTRACT FROM AUTHOR]

ABSTRACT Salt stress is the main factor limiting the large‐scale cultivation of Shanxin poplar; therefore, improving its salt tolerance is crucial. In this study, we identified and characterized a CRF gene (PdbCRF5) in Shanxin poplar. Compared with the wild‐type poplar, the Shanxin poplar overexpressing PdbCRF5 were more sensitive to salt stress. The PdbCRF5‐silenced plants exhibited improved salt tolerance. ChIP‒PCR, EMSA, and Y1H confirmed that PdbCRF5 can regulate the expression of the PdbbZIP61 by binding to ABRE element. Further analysis revealed that the overexpression of PdbbZIP61 can reduce cell damage by increasing ROS scavenging, and on the other hand, overexpression of PdbbZIP61 can improve the salt tolerance of Shanxin poplar by regulating the expression of the PdbNCED genes to increase the ABA content. In addition, we also demonstrated that PdbCRF5 can inhibit the expression of the PdbbZIP61 in combination with PdbCRF6. The overexpression of PdbCRF6 also reduced the salt tolerance of Shanxin poplar. Therefore, we found that PdbCRF5 negatively regulates the salt tolerance of Shanxin poplar by inhibiting the PdbbZIP61, indicating that PdbCRF5 plays an important role in the tolerance of Shanxin poplar to salt stress and is an important candidate gene for gene editing and breeding in forest trees. [ABSTRACT FROM AUTHOR]

To evaluate the inheritance of natural durability of Acacia mangium Willd., wood-color parameters (Y [lightness], x [red to green], and y [yellow to blue]), mass loss by a white-rot fungus (Trametes versicolor) and brown-rot fungus (Fomitopsis palustris), and three different extracts (methanol extract, total phenol, and total flavanol content) were measured using the inner and outer heartwood of 10-year-old trees from 20 half-sib families in the third-generation A. mangium in Indonesia. The broad-sense heritability (H2) values were moderate to high for the wood-color parameters and mass loss by white- and brown-rot fungi (H2 = 0.210–0.851) and low to moderate for three different extracts (H2 = 0.000–0.576). Significant negative phenotypic correlations were found between the three different extracts and mass loss by T. versicolor and F. palustris. In addition, negative correlations were found between the wood-color parameters and three different extracts. Similar results were found between the total phenol content and y and between the total flavanol content and Y in genetic correlations. Therefore, A. mangium families with lower Y and y in heartwood could produce progenies with higher total phenol and total flavanol content, leading to higher natural decay resistance. [ABSTRACT FROM AUTHOR]

ABSTRACT Breeding tree genotypes that are both productive and drought‐resistant is a primary goal in forestry. However, the relationships between plant hydraulics and yield at the genotype level, and their temporal stabilities, remain unclear. We selected six poplar genotypes from I‐101 (Populus alba) × 84 K (P. alba × Popolus tremula var. glandulosa) for experiments in the first and fourth years after planting in a common garden. Measurements included stem embolism resistance, shoot hydraulic resistance and its partitioning between stems and leaves, vessel‐ and pit‐level anatomy, leaf carbon acquisition capacity, carbon allocation to leaves, and aboveground biomass (yield proxy). Significant genetic variations in hydraulic properties and yield were found among genotypes in both years. Productive genotypes had wide vessels, large thin pit membranes, small pit apertures, and shallow pit chambers. Hydraulic resistance was negatively correlated with yield, enabling high stomatal conductance and assimilation rates. Productive genotypes allocated less aboveground carbon and hydraulic resistance to leaves. Temporally stable trade‐offs between stem embolism resistance and yield, and between hydraulic segmentation and yield, were identified. These findings highlight the tight link between hydraulic function and yield and suggest that stable trade‐offs may challenge breeding poplar genotypes that are both productive and drought‐resistant. [ABSTRACT FROM AUTHOR]

Heterobasidion parviporum is a fungal pathogen that is drastically damaging Norway spruce (Picea abies) in Europe. The infections will result in root and stem rot, causing significant economic losses for forest owners. Previous studies have shown that the PaLAR3 gene, which encodes the leucoanthocyanidin reductase enzyme, can increase resistance to H. parviporum in Norway spruce. The presence of the B allele at the PaLAR3 locus has been associated with higher (+)‐catechin concentrations and increased enzyme production in inoculation experiments, resulting in inhibited pathogen growth. The control of H. parviporum involves a multifaceted approach, including silvicultural and sustainable forestry practices, genetic resistance and chemical/biological control. In this study, we determined the PaLAR3 genotypes in a representative sample of Norway spruce breeding materials from southern Finland and examined their effect on necrosis caused by H. parviporum in spruce stems. The results showed that the homozygous PaLAR3BB genotype was present in only 9% of the trees. However, the necrotic area interacted with homozygous PaLAR3BB under low‐water treatment. These findings support the idea that the PaLAR3 locus may be a valuable marker for identifying P. abies resistance to different strains of Heterobasidion parviporum. [ABSTRACT FROM AUTHOR]

The ascomycete Hymenoscyphus fraxineus causes the devastating ash dieback disease of European ash (Fraxinus excelsior L.). Spore traps are often used to measure the amount of ascospores in the environment, but the pathogen-load of the soil in ash stands has not been recorded so far. This is of particular interest with regard to the occurrence of ash stem necrosis, a decisive factor for the severe course of the disease. In order to gain a more differentiated insight into the pathogen-load in ash stands, we analysed soil samples from four ash tree sites in southern Germany, covering a clone plantation, two seed orchards and a forest. The pathogen-load was determined using a quantitative TaqMan real-time PCR assay for ten to twenty plots per stand. Results obtained by the species-specific assay highlighted that the pathogen-load is heterogeneously distributed in the ash stands. H. fraxineus DNA targets were detected in 17% of the soil samples. The pathogen-load differed according to soil depth, with the highest pathogen abundance in the top 5 cm, followed by 5–10 cm and finally 10–15 cm. Pathogen-load and thereby infection pressure were found to be highly variable for the individual trees in one stand. Overall, the study discovered detectable levels of H. fraxineus in the soil of all four study sites, which supports the hypothesis that H. fraxineus can be found in the soil of ash stands. The qPCR approach was found to be an effective method for monitoring the load of H. fraxineus in soil and for demonstrating the successful application of the method on the sample type of custom-made spore traps. Results suggest the implication of site-specific pathogen-load determination in future H. fraxineus-monitoring and selection of less susceptible ash trees for breeding and seed production. [ABSTRACT FROM AUTHOR]

Bird species depending on seeds from masting trees face large temporal and spatial variation in food availability and perform nomadic or irruptive movements to locate food. In northern Europe, the Common Crossbill (Loxia curvirostra) is specialized on seeds from Norway Spruce (Picea abies) which usually has peak years followed by crop failure. Common Crossbills breed in mast years and emigrate when spruce seeds are no longer available. On the other hand, the Parrot Crossbill (L. pytyopsittacus) is specialized on seeds from Scots Pine (Pinus sylvestris) in which seed production is more stable from year to year. The Parrot Crossbill is therefore thought to be more sedentary. However, both species may switch food if there is low abundance of their 'own' seed type, but little is known about the relative importance of crop size of the two tree species on breeding population size and migration of the two crossbill species. Here, we analyse time series (up to 36 years) of crossbills and crop size of spruce and pine in Norway and Sweden to investigate this. We found that breeding population sizes of both species were positively related to spruce crop size. Surprisingly, pine crop size had no positive influence, not even on the Parrot Crossbill. Emigration of both crossbill species (based on autumn migration counts in southern Sweden) increased when there were small seed crops of spruce, but pine crop size had no influence, not even on the Parrot Crossbill. There was no influence of population size on emigration. These results suggest that alternative food resources had an asymmetric effect, only influencing the Parrot Crossbill. This asymmetry explains why the two crossbill species often have synchronous eruptions despite being specialized on different tree species with different seed crop size dynamics. [ABSTRACT FROM AUTHOR]

Efficient post‐drought recovery of growth and assimilation enables a plant to return to its undisturbed state and functioning. Unlike annual plants, trees suffer not only from the current drought, but also from cumulative impacts of consecutive water stresses which cause adverse legacy effects on survival and performance. This review provides an integrated assessment of ecological, physiological and molecular evidence on the recovery of growth and photosynthesis in trees, with a view to informing the breeding of trees with a better ability to recover from water stress. Suppression of recovery processes can result not only from stress damage but also from a controlled downshift of recovery as part of tree acclimation to water‐limited conditions. In the latter case, recovery processes could potentially be activated by turning off the controlling mechanisms, but several obstacles make this unlikely. Tree phenology, and specifically photoperiodic constraints, can limit post‐drought recovery of growth and photosynthesis, and targeting these constraints may represent a promising way to breed trees with an enhanced ability to recover post‐drought. The mechanisms of photoperiod‐dependent regulation of shoot, secondary and root growth and of assimilation processes are reviewed. Finally, the limitations and trade‐offs of altering the photoperiodic regulation of growth and assimilation processes are discussed. [ABSTRACT FROM AUTHOR]

Progeny trials in tree breeding are often laid out using blocked experimental designs, in which families are randomly assigned to plots and several trees are planted per plot. Such designs are optimized for the assessment of family effects. However, tree breeders are primarily interested in assessing breeding values of individual trees. This paper considers the assessment of heritability at both the family and tree levels. We assess heritability based on pairwise comparisons among individual trees. The approach shows that there is considerable heterogeneity in pairwise heritabilities, primarily due to the differences in both genetic as well as error variances among within- and between-family comparisons. Our results further show that efficient blocking positively affects all types of comparison except those among trees within the same plot. [ABSTRACT FROM AUTHOR]

Planting of resistant clones is the main control strategy for rust caused by Austropuccinia psidii on eucalypts in Brazil. Phenotyping for resistance to rust is performed at the last stage of the breeding programme on genetic material preselected for growth and industrial traits, which therefore may include susceptible genotypes. An alternative way to increase the frequency of resistant individuals in the breeding population is to perform resistance phenotyping during the initial stages of the programme. However, the impact of this approach on other characteristics considered as priority in the selection of genetic material should be assessed. In this study, we evaluated whether early selection for resistance to rust influenced total diameter at breast height (DBH), height (TH), average annual increment (IMA) and basic wood density (BWD), which are important selection criteria in eucalypt breeding. For this, a total of 6 703 plants from 70 full-sib progenies of Eucalyptus grandis, E. urophylla and hybrids of these species were phenotyped for rust resistance before transplanting, under controlled conditions, and again at seven months after transplanting, under field conditions and natural infection. Subsequently, the breeding population was evaluated for BWD indirectly through pilodyn penetration at 24 months after planting, and for DBH, TH and MAI at 37 months. Considering the final phenotype, 25.3% individuals were classified as resistant and 74.7% were susceptible to rust. Comparative genetic analyses between resistant and susceptible individuals showed that selection for resistance, performed early, did not influence DBH, TH, MAI or BWD traits. Thus, the early selection of resistant genotypes speeds up the exclusion of susceptible genotypes, saving time and resources in the development of new commercial clones without interfering with other important traits for tree breeding. [ABSTRACT FROM AUTHOR]

Acacia mearnsii De Wild (black wattle) is one of the most important forestry crops in South Africa. The bark of this species contains high-quality tannins, while its wood is used for wood chips, charcoal and mining timber. One of the main problems faced by black wattle farmers is frost damage, thus there is an urgent need to develop frost-tolerant black wattle varieties. A quick method for the screening of frost tolerance variation would be beneficial for black wattle breeders and would result in the need for fewer families to undergo field trials. Frost tolerance in plants is directly related to their ability to undergo cold acclimation in response to changing weather conditions. During the cold acclimation process, many physiological changes occur, including modifications in protein expression. In this study, two-dimensional gel electrophoresis was used to investigate changes in protein expression among 40 black wattle families with varying levels of frost tolerance before and after a cold-stress treatment. The proteomic data generated from this was analysed using multivariate analysis. Six proteins were observed to be upregulated in frosttolerant black wattle families. The proteins were identified and have been previously shown to contribute to the protection of cellular membranes, maintenance of photosynthetic processes and the prevention of protein misfolding and aggregation. [ABSTRACT FROM AUTHOR]

Forestry companies SAFCOL and Sappi conducted a study in South Africa to examine genetic variation and select improved material in full-sib hybrid families of Pinus patula × Pinus tecunumanii. The results from the study on clonal and seedling hybrid populations of P. patula × P. tecunumanii low-elevation subpopulations (TECL) revealed a significantly larger impact of TECL compared to P. patula. The TECL parents exhibited higher general hybridising ability (GHA) variance for volume gain and modulus of elasticity (MOE). Consequently, future hybrid crosses should focus on increasing the number of TECL parents in the breeding programme to improve these traits. In the hybrid seedling population of P. patula × P. tecunumanii high-elevation subpopulation (TECH), P. patula exerted a substantial influence on volume gain and MOE. However, the TECH parents displayed zero estimates of GHA variance for volume and a low GHA variance for MOE, relative to GHA variance among P. patula parents for MOE. Thus, this study recommends testing more P. patula parents in new intercrosses of this variety to enhance volume and MOE gain. [ABSTRACT FROM AUTHOR]

Background: Larch is an important timber tree species. The traditional methods of tree genetic breeding have been progressing slowly. It is necessary to carry out gene function analysis and genetically modified breeding research. The NAC transcription factor family is a plant-specific transcription factor family with various biological functions, as shown in recent research. However, there are few studies on the NAC gene among gymnosperm coniferous species. Results: LoNAC3 with complete cds was identified and isolated from the cDNA of Larix olgensis based on transcriptome data. The cDNA length of LoNAC3 is 1185 bp, encoding 394 amino acids, with a conserved NAM domain located at the N-terminus, and subcellular localization in the nucleus. The results of real-time quantitative PCR analysis showed that at different growth stages and in different tissues of L. olgensis, the relative expression level of LoNAC3 was highest in the needles. After drought, salt, alkali stress and hormone treatment, expression was induced to different degrees. The expression level of LoNAC3 was significantly increased under drought and salt conditions. The relative expression level changed under methyl jasmonate (MeJA) and abscisic acid (ABA) treatment. By observing the phenotype of overexpressed LoNAC3 tobacco, it was found that overexpressed tobacco is shorter and blooms earlier than wild-type tobacco. Under abiotic stress, LoNAC3 overexpressed tobacco has lower germination rates and poorer growth status. Transgenic tobacco under stress treatment has a higher malondialdehyde (MDA) content than wild-type tobacco, while peroxidase (POD) activity is lower than wild-type tobacco. Conclusions: Through the analysis of LoNAC3 sequence and promoter expression, it can be concluded that LoNAC3 is involved in the drought and salt stress response processes of L. olgensis, and is induced by ABA and MeJA expression. Overexpression of LoNAC3 leads to stunted tobacco growth and negatively regulates its tolerance to drought and salt stress through the reactive oxygen species pathway. The preliminary analysis of the expression pattern and function of the LoNAC3 can provide a theoretical basis and high-quality materials for genetic improvement of larch in later stages. [ABSTRACT FROM AUTHOR]

Acacia crassicarpa is a fast-growing leguminous tree that is widely cultivated in tropical areas such as Indonesia, Malaysia, Australia, and southern China. This tree has versatile utility in timber, furniture, and pulp production. Illumina sequencing of A. crassicarpa was conducted, and the raw data of 124,410,892 reads were filtered and assembled de novo into 93,317 unigenes, with a total of 84,411,793 bases. Blast2GO annotation, Benchmark Universal Single-Copy Ortholog evaluation, and GO-term classification produced a catalogue of unigenes for studying primary metabolism, phytohormone signaling, and transcription factors. Massive transcriptomic analysis has identified microsatellites composed of simple sequence repeat (SSR) loci representing di-, tri-, and tetranucleotide repeat units in the predicted open reading frames. Polymorphism was induced by PCR amplification of microsatellite loci located in several genes encoding auxin response factors and other transcription factors, which successfully distinguished 16 local trees of A. crassicarpa tested, representing potentially exploitable molecular markers for efficient tree breeding for plantation and biomass exploitation. [ABSTRACT FROM AUTHOR]

The Belgian Salpingidae are small elongated or long-oval beetles measuring 1,5 to 5,2 mm. They are usually glossy black or brown, sometimes with a reddish-brown head and pronotum. Larvae, as well as imagos, live behind the bark of dead deciduous and coniferous trees and in the galleries of bark beetles. This small beetle family counts about 350 species worldwide. In Europe, 19 species are known. In this article, the 11 Belgian species are discussed with attention to their breeding trees and their distribution. Not much is known about their way of life. [ABSTRACT FROM AUTHOR]

Western redcedar has high economic value and has been traditionally used for cultural purposes by Indigenous communities. Second-growth redcedar is potentially growing faster due to lower planting densities, fertilization, and tree breeding. Little quantitative information is available about the impact of management practices on wood quality, particularly heartwood extractives. This study evaluated the effects of growth rate and site on heartwood extractives at two locations aged 70–90 years in British Columbia, Canada. A three-parameter sigmoid model was fit to the data using nonlinear mixed effects to analyze the relationship between heartwood extractives relative to cambial age, growth rate, and sampling site. The southern site had significantly higher cumulative extractive concentrations, while all extractive concentrations increased faster. This study shows that smaller trees will reach their peak concentrations earlier than larger trees. Results show that faster growth through active management of western redcedar may lead to increased and more uniformly distributed content of heartwood extractives. [ABSTRACT FROM AUTHOR]

In the Andean-Patagonian region of Argentina, Pinus ponderosa Douglas ex C. Lawson is the most widely cultivated forest tree species. Its breeding program, started in 1998, is now progressing towards the establishment of 1.5 generation clonal seed orchards. Considering recent advances in the phylogeny and taxonomy of the species, it is necessary to delve deeper into the genetic variation of the breeding population. Here, we first aim to address a previously unresolved question concerning the putative genetic lineages (varieties) of P. ponderosa that were introduced from the USA. We assessed this question through the molecular characterization of the nad1 second intron minisatellite of the mitochondrial genome of 61 plus trees planted in 1.0 clonal seed orchards, followed by Sanger sequencing to determine mtDNA haplotypes. Then, we conducted a nursery common garden trial to determine the relative contribution of the genetic factors (lineages and clones) to the variation in early growth traits, which may reflect adaptation across native geographic ranges and are also important for nursery stock production. We found three mtDNA variants, which correspond to haplotypes H1, H5 and H8, form the North-West native range of the species. In general, the variation in early seedling growth traits was not attributable to the haplotypic groups; instead, variation among clones was high and heritable. Considering the initial performance of the breeding population, it appears feasible to manage 1.0 and 1.5 clonal seed orchards by maintaining sub-specific taxa mixed together, while assessing the potential impact of intra-specific hybridization and field performance of progeny for timber production and resilience to climate change. [ABSTRACT FROM AUTHOR]

The European beech (Fagus sylvatica L.) is one of the most important tree species in Europe. In order to understand the breeding and biological aspects of the species, the Institute of Forest Genetics and Forest Tree Breeding (Großhansdorf, Germany) has carried out several series of provenance trials in collaboration with researchers throughout Europe. The most extensive series was the International Beech Provenance Trial 1993/95 (established in 1995). One of the provenance trials, Bu19_19 (Roztochja), involving 70 provenances from 10 European countries, was established in Ukraine at the north-eastern edge of the species' natural range. We investigated survival and DBH at this site in May 2023. The average survival rate was 38% (57 trees per provenance), while the number of surviving trees per provenance ranged from 37 to 76. The average DBH was 11.2 centimeters, with the DBH of some individual trees exceeding 30 centimeters. The Bu19_19 provenance trial remains a valuable resource for studying the performance of European beech populations and can provide important insights into their resilience and adaptation. [ABSTRACT FROM AUTHOR]

The current planting of economically important timber species, such as Douglas-fir, mainly relies on genetically improved seeds from seed orchards. However, published research on the effects of climate change has largely focused on natural populations. To bridge this gap, data from 80 cooperative second-cycle coastal Douglas-fir progeny tests across eight breeding zones in western Washington and Oregon were analyzed. Climate transfer functions for age-12 growth were derived, showing significant results for the US Pacific Northwest. Region-specific transfer functions (Coast, Inland, and Cascade) displayed stronger correlations. Mean annual temperature and mean coldest month temperature were the most important climatic variables explaining growth. The study found that populations from slightly warmer areas tended to grow better but moving populations from colder to warmer areas by 2 °C (analogous to projected global warming) would result in an 8% genetic loss in age-12 height and a 25% genetic loss in age-12 volume. However, substantial diversity in climatic response was found among full-sib families within large breeding zones, suggesting that breeding and selecting suitable families for future climatic conditions within breeding zones is feasible. The study discusses potential strategies to adapt current breeding programs to address the impacts of future climate change while maintaining high population growth rates in Douglas-fir breeding programs. [ABSTRACT FROM AUTHOR]

The growth characteristics (stem diameter at 1.3 m above the ground and tree height) and stress-wave velocity of the stem were determined for three species from natural stands in four provenances in Mongolia (Populus laurifolia from Arkhangai, Populus suaveolens from Bulgan and Ulaanbaatar, and Populus × sibirica from Ulaanbaatar) to compare the characteristics among species and to clarify the correlations between the characteristics. The mean stem diameter and tree height values were 25.5 cm and 11.8 m, 20.4 cm and 10.1 m, and 21.8 cm and 9.9 m in P. laurifolia, P. suaveolens, and Populus × sibirica, respectively. The stress-wave velocity of the stems in P. laurifolia (3.30 km s−1) showed a significantly lower value than that of the stems in the other two species, suggesting that the Young’s modulus in P. laurifolia might be low. Although the growth characteristics of P. suaveolens in the Bulgan and Ulaanbaatar were similar, a lower p-value in the t-test was found in the stress-wave velocity of the stems. Furthermore, there were no significant or lower correlation coefficients between the growth characteristics and the stress-wave velocity of the stems in P. laurifolia and P. suaveolens. Based on the results, it is concluded that tree breeding for wood quality can be established for three Populus species in Mongolia.

Abstract Understanding the genotype-by-environment interaction (GEI) and considering it in the selection process is a sine qua non condition for the expansion of Brazilian eucalyptus silviculture. This study’s objective is to select high-performance and stable eucalyptus clones based on a novel selection index that considers the Factor Analytic Selection Tools (FAST) and the clone’s reliability. The investigation explores the nuances interplay of GEI and extends its insights by scrutinizing the relationship between latent factors and real environmental features. The analysis, conducted across seven trials in five Brazilian states involving 78 clones, employs FAST. The clonal selection was performed using an extended FAST index weighted by the clone’s reliability. Further insights about GEI emerge from the integration of factor loadings with 25 environmental features through a principal component analysis. Ten clones, distinguished by high performance, stability, and reliability, have been selected across the target population of environments. The environmental features most closely associated with factor loadings, encompassing air temperature, radiation, and soil characteristics, emerge as pivotal drivers of GEI within this dataset. This study contributes insights to eucalyptus breeders, equipping them to enhance decision-making by harnessing a holistic understanding-from the genotypes under evaluation to the diverse environments anticipated in commercial plantations.

Understanding the genotype-by-environment interaction (GEI) and considering it in the selection process is a sine qua non condition for the expansion of Brazilian eucalyptus silviculture. This study's objective is to select high-performance and stable eucalyptus clones based on a novel selection index that considers the Factor Analytic Selection Tools (FAST) and the clone's reliability. The investigation explores the nuances interplay of GEI and extends its insights by scrutinizing the relationship between latent factors and real environmental features. The analysis, conducted across seven trials in five Brazilian states involving 78 clones, employs FAST. The clonal selection was performed using an extended FAST index weighted by the clone's reliability. Further insights about GEI emerge from the integration of factor loadings with 25 environmental features through a principal component analysis. Ten clones, distinguished by high performance, stability, and reliability, have been selected across the target population of environments. The environmental features most closely associated with factor loadings, encompassing air temperature, radiation, and soil characteristics, emerge as pivotal drivers of GEI within this dataset. This study contributes insights to eucalyptus breeders, equipping them to enhance decision-making by harnessing a holistic understanding-from the genotypes under evaluation to the diverse environments anticipated in commercial plantations. [ABSTRACT FROM AUTHOR]

• Pollination is essential for both fruit production as well as genetic variations. • Dichogamous nature of walnut is hindering pollination, fruit set and breeding. • Inter-specific hybrids offer considerable variations and genetic diversity. • Better understanding of pollination mechanisms can reduce PFA in walnuts. Pollination promotes both fruit production as well as genetic variations in fruit crops. Walnut belongs to the deciduous, monoecious, anemophilous and self-compatible fruit tree. Regardless of self-compatibility, due to dichogamous nature of crop it is hindering pollination, fruit set and breeding in walnut. Pollination mechanisms in walnut are not completely understood, and this unusually complex pollination behavior necessitates that we improve our mechanistic understanding of cytology, flower and pollen morphology, pollen collection, storage and germination and pollination process in walnut. A deeper understanding of pollination mechanisms is vital for fruit production as well as to reduce pistillate flower abortion (PFA) and to speed up future walnut breeding and varietal improvement by enhancing genetic diversity and developing hybrid verities targeted for having desirable traits like lateral bearing, precocity, batter fruit quality, high productivity, earlier harvest and resistance to late-spring frost, cherry leaf roll virus (CLRV), blight and pistillate flower abortion. A comprehensive grasp of walnut pollination mechanisms enables experts to offer more effective technical guidance to walnut growers. This article presents recent advancements in our understanding, consolidating pertinent and up-to-date information on walnut pollination mechanisms into a single resource for the first time. It serves as a valuable reference for researchers engaged in horticultural research, particularly in the domains of pollination, fruit production, and walnut tree breeding. [ABSTRACT FROM AUTHOR]

Summary: Forests make immense contributions to societies in the form of ecological services and sustainable industrial products. However, they face major challenges to their viability and economic use due to climate change and growing biotic and economic threats, for which recombinant DNA (rDNA) technology can sometimes provide solutions. But the application of rDNA technologies to forest trees faces major social and biological obstacles that make its societal acceptance a 'wicked' problem without straightforward solutions. We discuss the nature of these problems, and the social and biological innovations that we consider essential for progress. As case studies of biological challenges, we focus on studies of modifications in wood chemistry and transformation efficiency. We call for major innovations in regulations, and the dissolution of method‐based market barriers, that together could lead to greater research investments, enable wide use of field studies, and facilitate the integration of rDNA‐modified trees into conventional breeding programs. Without near‐term adoption of such innovations, rDNA‐based solutions will be largely unavailable to help forests adapt to the growing stresses from climate change and the proliferation of forest pests, nor will they be available to provide economic and environmental benefits from expanded use of wood and related bioproducts as part of an expanding bioeconomy. [ABSTRACT FROM AUTHOR]

We estimated genetic parameters of two Pinus caribaea var. caribaea progeny tests based on growth traits aiming at the identification of the best selection strategy. This study was conducted in two progeny tests located in Selvíria (MS), Brazil. Tests were set up in block design, one with 76 progenies (area 1) and the other with 99 progenies (area 2). Genetic parameters were estimated using the SELEGEN software through REML/BLUP method. To estimate the genetic gain through selection, four selection methods and ten selection intensities were tested. The intensity of selection that maximizes genetic gain and genetic diversity was calculated by the optimization point. Significant variation was observed between and with progeny for all traits in area 2 and only within plots for height in area 1. Higher values of heritability were observed in area 1. Considering the optimization of selection, the best selection method for both areas was the individual. [ABSTRACT FROM AUTHOR]

The expansion of forest plantations to supply the wood market requires selection of genotypes that can provide high gains, which may compromise long-term tree breeding programs. With the final purpose of producing quality sawn wood, the aims of this study were to: (a) estimate genetic parameters for a progeny/provenance test of Plathymenia foliolosa Benth; (b) carry out optimized selection based on an inbreeding rate (F) from 0 to 7% in progeny/provenance tests evaluated at 35 months for P. foliolosa and Cordia trichotoma (Vell.) Arrab. ex Steud, and at 42 months for Zeyheria tuberculosa (Vell.) Bureau ex Verl.; (c) develop a practical index for balancing gains and F; d) and indicate the most appropriate genetic base structure based on effective population size ( N e ) to subsidize conservation strategies, breeding programs, and clonal orchard with those species native from Brazil. Diameters at breast height (DBH) were obtained in progeny/provenance tests conducted in the south of Bahia–Brazil. For P. foliolosa, the moderated heritability (h2a) value of 0.55 demonstrated favorable conditions for selection based on DBH. For this trait, there is better possibility of achieving progressive gains by exploiting genetic variability into the families (CVgi). Simulation of scenarios without optimization for P. foliolosa, C. trichotoma and Z. tuberculosa showed a high possibility of gains for breeding programs, ranging between 95.6 and 311.05%. However, in those scenarios, high rates of F were also observed. For the three species, selection based on the selection optimization index (SOI) was proposed in order to balance ideal increments in genetic gains and maintenance of genetic diversity. With the use of SOI, it was possible to simulate selection of scenarios with good prospects of gain balanced with N e in a practical and direct manner for germplasm conservation strategies, production of improved seeds in clonal orchards, and tracking recombination cycles within breeding populations. [ABSTRACT FROM AUTHOR]

Trees in breeding programmes are often selected at 1/4–1/3 of rotation, called 'early selection', which is typically between 8 and 10 years in radiata pine. However, differences between populations and genotypes selected for either basic density or wood stiffness are already apparent at age 2. We report the application of very early screening techniques for wood properties in the New Zealand Radiata Pine Breeding Programme deployment populations. Approximately 3000 trees representing three populations with 92 families and 10 clones were grown in a common garden trial, leaning for 21 months to separate compression and opposite wood. The trees were harvested and analysis carried out separately by wood type. The trial showed the existence of large variability in wood properties at early age, in some cases similar to variability near rotation age, and moderate to high degree of genetic control ( 0.35 ≤ h 2 ≤ 0.71 ). The genetic association between traits was strong, particularly between wood stiffness and longitudinal shrinkage ( - 0.69 ) and between longitudinal and volumetric shrinkage (0.83), suggesting that improving stiffness would also have a strong effect on improving dimensional stability. Basic density was also associated with stiffness and shrinkage, but with lower predictive capacity. These results can be used for roguing deployment populations-which already contain superior growing trees-and quickly upgrade the wood quality of seeds and clones currently available to New Zealand forest growers. We discuss necessary modifications to turn this research work into operation to screen any new material before commercial release. [ABSTRACT FROM AUTHOR]

The Rawa Kidang Restoration is an area designated to plant tree species that rhinos like. Food is planted at the Rawa Kidang Restoration to maintain the rhino population. Knowledge of the importance of tree health is necessary because this can be a guide for rejuvenating or breeding trees attacked by disease or pests. To know the quality of rhino food, you need information about the health of rhino food trees. This research aims to investigate the health of rhino food trees in the Rawa Kidang Restoration. This research uses the Cluster Plot Level Index (CLI) formula to observe and examine canopy conditions and tree damage. The canopy condition parameters consist of five parameters: live crown ratio, density, transparency, diameter, and dieback. The parameters for the tree damage condition are the damage's location, the type I feel, and the level of tree damage. The research results show that the tree health value in cluster plot 1 is 2.35; in plot cluster 2, 2.50; in plot cluster 3, 3.70; and in plot cluster 4, 2.92. So, it can be concluded that the average tree health value in the four plot clusters is in the medium category. The severity of canopy conditions and tree damage can be influenced by surrounding conditions such as sunshine, growing conditions, water, and growing space. [ABSTRACT FROM AUTHOR]

The breeding of forest tree species in the Baltic region has notably contributed to wood production for the bioeconomy. Growth modelling is used for long-term estimates of forest development. However, usually based on data from unimproved stands, they may underestimate the growth of improved trees. Accordingly, it is important to identify and integrate the altered stand dynamics associated with improved planting stock into existing growth models to accurately capture the resulting gains or, alternatively, develop new functions specifically designed for improved trees. We used the generalized algebraic difference approach to model and analyze height growth patterns of Scots pine and silver birch with different genetic improvement levels (improved forest reproductive material categories 'qualified' and 'tested'). Modelling was based on 14 260 and 55 926 height–age series from open-pollinated progeny trials in Latvia and Lithuania with an age range of 3–46 and 5–22 years for pine and birch, respectively. Dynamic generalized algebraic difference approach forms of commonly applied height growth functions with forest reproductive material-category-specific sets of coefficients were tested. The dynamic form of the Chapman–Richards and King–Prodan equations had the best fit for Scots pine and silver birch, respectively. The expected height growth of the category 'tested' was slightly better than the one for 'qualified', with more distinct differences in silver birch. The model with forest reproductive material-category-specific coefficients reflected the actual growth of improved trees; however, such application is limited to sites with medium and high site indices, where improved planting stock is typically used. We recommend the model for young stands up to the age of 20 and 40 years for pine and birch, respectively, considering the empirical data cover on which the functions are based. A unified dynamic height model with the same functional form but category-specific parameterization for different improvement levels allows a practical applicability and effective communication amongst diverse users, thereby promoting the utilization of the model amongst forest owners and managers who possess information regarding the origin of planting stock. [ABSTRACT FROM AUTHOR]

The risk of predation directly affects the physiology, behavior, and fitness of wild birds. Strong social connections with conspecifics could help individuals recover from a stressful experience such as a predation event; however, competitive interactions also have the potential to exacerbate stress. Few studies have investigated the interaction between environmental stressors and the social landscape in wild bird populations. In 2 years of field studies, we experimentally simulated predation attempts on breeding female tree swallows (Tachicyneta bicolor). At the same time, we manipulated female breast plumage color, a key social signal. Simulated predation events on tree swallows early in the nestling period reduced young nestlings' mass by approximately 20% and shortened telomere lengths. Ultimately, only 31% of nestlings in the predation group fledged compared with 70% of control nestlings. However, the effects of experimental manipulations were timing dependent: the following year when we swapped the order of the experimental manipulations and simulated predation during incubation, there were no significant effects of predation on nestling condition or fledging success. Contrary to our expectations, manipulation of the social environment did not affect the response of tree swallows to simulated predation. However, manipulating female plumage during the nestling period did reduce nestling skeletal size and mass, although the effects depended on original plumage brightness. Our data demonstrate that transient stressors on female birds can have carry‐over effects on their nestlings if they occur during critical periods in the breeding season. [ABSTRACT FROM AUTHOR]

[Objective] The synthesis pattern of tea tree chlorophyll by synergistic effect of soil pH and magnesium ions was explored to pro- vide theoretical basis for the cultivation of tea tree and breeding of new variety. (Method) Taking Fuding Dabaicha as the study object, the plant tissue enzyme activity kits were used to determine the synergistic effects of the soil with different pH pH 4 (P1) and pH 5 (P2)] and different magnesium ion concentrations [0 mg/L (To, CK), 50 mg/L (T1), 100 mg/L (T2) and 150 mg/L (T3)] on the key enzymes of chlorophyll synthesis in tea tree, including magnesium chelatase, uroporphyrinogen III synthase and 5-amino ketoglutarate dehydratase. The high-throughput technology was used for transcriptomic sequencing of the leaf slices tissue of Fuding Dabaicha with different treatments, and then the synergistic effect of soil pH and magnesium ion on the synthesis of chlorophyll in tea tree were studied. (Result) The soil pH and magnesium ions had different synergistic effects on the key enzymes of chlorophyll synthesis in tea tree (magnesium chelatase, uroporphyrinogen III synthase and 5-amino ketoglutarate dehydratase). The activities of magnesium chelatase, uroporphyrinogen III synthase and 5-amino ketoglutarate dehydratase treated with P2T, were the highest with 492.41, 336.28 and 132.24 U/L, respectively. The analysis of GO and KEGG functional enrichment showed that the key regulatory genes in the development of Fuding Dabaicha leaves were mainly involved in the processes of carbohydrate metabolism and polysaccharide metabolism. The differentially expressed genes were mainly enriched in starch and sucrose metabolism, stilbenes and other pathways. The analysis of KEGG metabolic pathway of photosynthesis of carbon fixation pathway showed that P2T, treatment significantly improved the carbon fixation pathway of tea tree, and had a promotional effect on both photosynthesis and sugar accumulation. [Conclusion] P2 T1 treatment (the synergistic effects of pH 5 and 50 mg/L magnesium ion) of tea tree has the best effect on chlorophyll synthesis, which is beneficial to the synthesis and accumulation of materials, and is advantageous to the quality and yield of tea tree. [ABSTRACT FROM AUTHOR]

Genetically improved forest reproductive materials are now widely accessible in many European countries due to decades of continuous breeding efforts. Tree breeding does not only contribute to higher-value end products but allows an increase in the rate of carbon capture and sequestration, helping to mitigate the effects of climate change. The usefulness of breeding programmes depends on (i) the relevance of the set of selected traits and their relative weights (growth, drought tolerance, phenology, etc.); (ii) the explicit management of targeted and “neutral” diversity; (iii) the genetic gain achieved; and (iv) the efficiency of transferring diversity and gain to the plantation. Several biological factors limit both operational breeding and mass reproduction. To fully realise the potential of tree breeding, the introduction of new technologies and concepts is pivotal for overcoming these constraints. We reviewed several European breeding programmes, examining their current status and factors that are likely to influence tree breeding in the coming decades. The synthesis was based on case studies developed for the European Union-funded B4EST project, which focused on eight economically important tree species with breeding histories and intensities ranging from low-input breeding (stone pine, Douglas-fir and ash) to more complex programmes (eucalyptus, maritime pine, Norway spruce, poplar, and Scots pine). Tree breeding for these species is managed in a variety of ways due to differences in species’ biology, breeding objectives, and economic value. Most programmes are managed by governmental institutes with full or partial public support because of the relatively late return on investment. Eucalyptus is the only tree species whose breeding is entirely sponsored and managed by a private company. Several new technologies have emerged for both phenotyping and genotyping. They have the potential to speed up breeding processes and make genetic evaluations more accurate, thereby reducing costs and increasing genetic gains per unit of time. In addition, genotyping has allowed the explicit control of genetic diversity in selected populations with great precision. The continuing advances in tree genomics are expected to revolutionise tree breeding by moving it towards genomic-based selection, a perspective that requires new types of skills that are not always available in the institutions hosting the programmes. We therefore recognise the importance of promoting coordination and collaboration between the many groups involved in breeding. Climate change is expected to bring in new pests and diseases and increase the frequency of extreme weather events such as late frosts and prolonged droughts. Such stresses will cause slow growth and mortality, reducing forest productivity and resilience. Most of these threats are difficult to predict, and the time-consuming nature of conventional breeding does not allow for an adequate and timely reaction. We anticipate that most breeding programmes will need to revise their selection criteria and objectives to place greater emphasis on adaptive performance, tolerance to multiple environmental stresses, stability in different environments, and conservation of genetic diversity. Testing breeding materials in a variety of environments, including potentially contrasting climates, will become increasingly important. Climate change may also force the incorporation of new genetic resources that provide new useful adaptations, which may involve the use of new, previously unexplored gene pools or hybridisation, with the enormous challenge of incorporating useful alleles without adding along an unfavourable genetic background. Decision-support tools to help landowners and foresters select the best-performing forest reproductive material in each specific environment could also help reduce the impact of climate change.

This study addresses the crucial consideration of log end splitting in breeding programmes for treated wood. There is a paucity of research focused on efficiently optimizing the phenotyping process for this particular trait. The study aimed to compare methodologies for log end splitting phenotyping and develop an image‐based crack evaluation approach. Initially, 32 eucalyptus clones underwent phenotyping using manual measurement, digital image analysis and visual evaluation. Results showed similar phenotypic values, but image analysis demonstrated better clone discrimination, reducing evaluation time to 78 h compared to manual measurement. The second part focused on testing convolutional neural network architectures (UNet, LinkNet and FPN) using real and synthetic images. U‐Net exhibited slight superiority based on higher Intersection over Union (IoU) values, exhibiting a high correlation (.89) with true values. This approach significantly reduced evaluation time to approximately 10.15 h, emphasizing its efficiency compared to traditional methods. [ABSTRACT FROM AUTHOR]

European beech is negatively affected by climate change and a further growth decline is predicted for large parts of its distribution range. Despite the importance of this species, little is known about its genetic adaptation and especially the genetic basis of its physiological traits. Here, we used genotyping by sequencing to identify SNPs in 43 German European beech populations growing under different environmental conditions. In total, 28 of these populations were located along a precipitation and temperature gradient in northern Germany, and single tree‐based hydraulic and morphological traits were available. We obtained a set of 13,493 high‐quality SNPs that were used for environmental and SNP‐trait association analysis. In total, 22 SNPs were identified that were significantly associated with environmental variables or specific leaf area (SLA). Several SNPs were located in genes related to stress response. The majority of the significant SNPs were located in non‐coding (intergenic and intronic) regions. These may be in linkage disequilibrium with the causative coding or regulatory regions. Our study gives insights into the genetic basis of abiotic adaptation in European beech, and provides genetic resources that can be used in future studies on this species. Besides clear patterns of local adaptation to environmental conditions of the investigated populations, the analyzed morphological and hydraulic traits explained most of the explainable genetic variation. Thus, they could successfully be altered in tree breeding programs, which may help to increase the adaptation of European beech to changing environmental conditions in the future. [ABSTRACT FROM AUTHOR]

The economic efficiency of conventional breeding strategies for forest trees based on biparental crosses is compared with that of alternative strategies based on pedigree reconstruction using molecular markers. Analyses of economic efficiency is based on comparisons of breeding scenarios corresponding to the same total investment. The first step is the description and cost evaluation of each basic operation, from crossing to genetic selection and clonal archive establishment. Breeding scenarios are then compared by stochastic sampling with a parametric genetic model (POPSIM), the comparison criteria in this case being genetic gain in the seed orchard for a given level of genetic diversity. Additionally, the economic gain resulting from the use of improved material is estimated for different levels of breeding investment. Our analysis shows that genotyping costs account for a much smaller proportion of total investment than phenotyping costs. We also show that, in comparisons of breeding scenarios corresponding to the same total investment, the three main breeding strategies (biparental crosses, polymix crosses, and open pollination) achieve similar genetic gains provided that sufficiently large numbers of parents are considered. These results open up promising perspectives for the wider integration of molecular markers into forest tree breeding strategies. [ABSTRACT FROM AUTHOR]

Copyright of World Food Policy is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Productive Scots pine (Pinus sylvestris L.) stands in the Baltic region ensure high-quality sawlogs for the timber market and contribute to carbon sequestration. Spike knots are serious stem defects, which reduce the proportion of valuable timber; therefore, the extent of genetic control of their occurrence and relationship with other traits must be assessed for the potential to reduce negative impact via tree breeding. We aimed to evaluate the family effect on the presence of spike knots and its relation to growth traits in open-pollinated Scots pine progenies. A higher incidence of spike knots was associated with better height growth and the presence of lammas shoots. The family had a statistically significant effect on growth and spike knots, yet a mainly weak genotypic correlation was observed between both traits (rG = − 0.25 ... 0.40). The family mean heritability of the spike knots was moderate (hf2 = 0.42 ... 0.46), opposite to very low (h2 = 0.02... 0.05) single tree heritability. Although the presence of lammas shoots was low and was not affected by genetics, it showed a strong positive genotypic relationship with the formation of spike knots in the next growing season (rG = 0.80). The potential to select fast growing families with a low probability of spike knots was indicated, but a more comprehensive analysis is necessary to determine the extent of the genetic relationship between this stem defect and lammas shoots. [ABSTRACT FROM AUTHOR]

Silver birch, a widely distributed deciduous tree native to Europe, is valued for its wood applications in construction, furniture making, and paper production. In Lithuania, silver birch ranks as the third most common forest-tree species, comprising 22% of the forested areas, and is an important species for tree breeding due to its potential and adaptability. This study was focused on assessing the mechanical properties of wood (sample and log hardness, wood density, dynamic modulus of elasticity (MOEdyn), static modulus of elasticity (MOE) and bending strength (MOR)) in silver birch (Betula pendula L. Roth.) trees from different half-sibling families. Two experimental plantations of the progenies of Lithuanian populations (half-sib families) of silver birch from different regions were analysed. From these plantations, four genetic families were selected for mechanical properties evaluation. The study findings revealed significant variability in various wood properties among different genetic families, although the static modulus of elasticity did not exhibit significant differences between the chosen genetic families. All measured wood properties decreased from the bottom to the top of the model trees. Wood hardness displayed a moderately negative correlation for wood density and weak correlations for MOE and MOR. Given the weak correlations between wood hardness and other wood mechanical properties, it is suggested that MOEdyn would be a more suitable trait for genetic studies. [ABSTRACT FROM AUTHOR]

Tamarind is important agroforestry tree species grown largely due to the multipurpose utility. Tamarind exhibits high cross-pollination and significant variability recorded in phenological, vegetative and reproductive traits. The variation in pulp color and acidity tamarind delineated into red, brown, sour, and sweet Tamarind variants. This investigation aimed to evaluate the diversity in leaf and stomatal morphometric traits among the sour, red, and sweet tamarind variants. Mature leaves from different tamarind variants were collected and subjected to SEM and fluorescent microscopy for detailed leaf morphoanatomical assessments at microscopic laboratory in the Institute of Forest Genetics and Tree Breeding, Coimbatore. The analysis revealed significant variations in rachis length, stomata count, stomatal density, stomatal length, stomatal width, and pore length on both adaxial and abaxial leaf surfaces. A comparison indicated similarities in characteristics between sour and sweet tamarind, distinguishing them from the red variant. Furthermore, the data analysis revealed a significant positive correlation between Stomatal Index, stomatal density, and stomatal count across all variants. [ABSTRACT FROM AUTHOR]

Brenneria goodwinii is a bacterial pathogen causing severe decline in Quercus brantii. We explored the effects of B. goodwinii on physiological traits of Q. brantii seedlings and assessed differences between families in the response to the pathogen. We examined 210 seedlings from 14 half-sib families. To evaluate disease resistance, foliar symptoms and several physiological traits, including chlorophyll fluorescence and electrolyte leakage were measured in pathogen-inoculated and mock-inoculated seedlings. In addition, seven EST-SSR markers associated with stress resistance were genotyped in two resistant and two susceptible families. All physiological traits were negatively affected by pathogen inoculation. There was significant genetic variation among the families, with the most susceptible ones showing a worse physiological condition. The heritability and coefficient of genotypic variation of the resistance increased during the experimental period reaching relatively high values (0.49 and 35%, respectively) five weeks after inoculation. EST-SSR analysis revealed that resistant families showed the highest heterozygosity. Two of the seven evaluated loci were associated with the measured physiological traits and showed high FST values. Our results support that resistant mother trees can be selected for disease management. The putative alleles of FIR053 locus could be useful for identifying resistant Q. brantii families to the pathogen. [ABSTRACT FROM AUTHOR]