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This study combined phytosanitary surveys, laboratory analyses, and mathematical modeling to show how hail-induced wounds can foster the infections of the blight pathogen Cryphonectria parasitica, locally associated with extensive dieback of chestnut (Castanea sativa). Orchards and coppices located within and outside the assessed dieback area in a single location in the North West of Italy were inspected to appraise the abundance of hail-induced wounds and C. parasitica infections. The incidence of C. parasitica was significantly higher within the dieback area compared with outside (92% versus 60%; P < 0.05). Hail-induced wounds were observed on small branches and shoots of all trees sampled within the dieback area, whereas they were less abundant outside (20% of trees), suggesting either that the dieback was directly associated with the injuries caused by the hailstorms or that those injuries may have facilitated infections of C. parasitica. Isolations conducted on 359 branches and shoots showed that hail-induced wounds served as infection courts for C. parasitica and that infections depended on the size rather than on the number of hail wounds. We fitted a logistic model showing that hail-induced wounds whose perimeter was larger than 66 mm were at particular risk of C. parasitica infection. A newly designed geometrical-based model is proposed to relate hailstones size, hail wound perimeter, and the risk of infection. We established that hail-induced wounds are entry points for virulent and hypovirulent strains of C. parasitica, since 6.5% of isolates were infected by Cryphonectria hypovirus-1.

Chestnuts are multipurpose trees significant for the economy and wildlife. These trees are currently found around the globe, demonstrating their genetic adaptation to different environmental conditions. Several biotic and abiotic stresses have challenged these species, contributing to the decline of European chestnut production and the functional extinction of the American chestnut. Several efforts started over the last century to understand the cellular, molecular, and genetic interactions behind all chestnut biotic and abiotic interactions. Most efforts have been toward breeding for the primary diseases, chestnut blight and ink disease caused by the pathogens, Cryphonectria parasitica and Phytophthora cinnamomi, respectively. In Europe and North America, researchers have been using the Asian chestnut species, which co-evolved with the pathogens, to introgress resistance genes into the susceptible species. Breeding woody trees has several limitations which can be mostly related to the long life cycles of these species and the big genome landscapes. Consequently, it takes decades to improve traits of interest, such as resistance to pathogens. Currently, the availability of genome sequences and next-generation sequencing techniques may provide new tools to help overcome most of the problems tree breeding is still facing. This review summarizes European and American chestnut’s main biotic stresses and discusses breeding and biotechnological efforts developed over the last decades, having ink disease and chestnut blight as the main focus. Climate change is a rising concern, and in this context, the adaptation of chestnuts to adverse environmental conditions is of extreme importance for chestnut production. Therefore, we also discuss the abiotic challenges on European chestnuts, where the response to abiotic stress at the genetic and molecular level has been explored.

To understand the genetic relationships of Castanea species, 16 phenotypic traits were measured, simple sequence repeat (SSR) markers were analyzed, and molecular identity cards (IDs) were constructed for 118 Castanea materials using fluorescent capillary electrophoresis. The coefficient of variation values of the 16 morphological traits of the test materials ranged from 11.11% to 60.38%. A total of 58 alleles were detected using six pairs of SSR core primers, with an average number of 9.7 alleles per locus. The average number of valid alleles per locus was 3.9419 and the proportion of valid alleles was 40.78%. A total of 105 genotypes were detected, and the number of genotypic species that could be amplified per primer pair ranged from 8 to 26. The mean value of the observed heterozygosity was 0.4986. The variation in the He, H, and PIC values was similar; the size of I value was approximately 2.21 times larger, and its mean number of variations was 0.7390, 0.7359, 0.6985, and 1.6015, respectively. The classification of 118 Castanea species was performed using three analytical methods: structure analysis, neighbor-joining (NJ) cluster analysis, and principal coordinate analysis (PCoA), and the results of the three methods were in high agreement. Six pairs of SSR core primers with high polymorphism and strong discriminatory properties were used to identify 118 Castanea plants, and a unique molecular ID card was constructed for each material. These results provide insight into the genetic diversity and population structure of Castanea plants and a theoretical basis for improving the phenomenon of mixed varieties and substandard plants in the Castanea plant market.

Chestnut cultivation for nut production is increasing in the eastern half of the United States. Chinese chestnuts (Castanea mollissima Blume), or Chinese hybrids with European (C. sativa Mill.) and Japanese chestnuts (C. crenata Sieb. & Zucc.), are cultivated due to their high kernel quality, climatic adaptation, and disease resistance. Several hundred thousand pounds of high-quality fresh nuts are taken to market every fall, and several hundred additional orchards are entering bearing years. Grower-led on-farm improvement has largely facilitated this growth. A lack of significant investments in chestnut breeding in the region, paired with issues of graft incompatibility, has led many growers to cultivate seedlings of cultivars rather than grafted cultivars. After decades of evaluation, selection, and sharing of plant materials, growers have reached a threshold of improvement where commercial seedling orchards can be reliably established by planting offspring from elite selected parents. Growers recognize that if cooperation persists and university expertise and resources are enlisted, improvement can continue and accelerate. To this end, the University of Missouri Center for Agroforestry (UMCA) and chestnut growers throughout the eastern United States are partnering to formalize a participatory breeding program – the Chestnut Improvement Network. This partnership entails the UMCA providing an organizational structure and leadership to coordinate on-farm improvement, implement strategic crossing schemes, and integrate genetic tools. Chestnut growers offer structural capacity by cultivating seedling production orchards that provide financial support for the grower but also house segregating populations with improved individuals, in situ repositories, and selection trials, creating great value for the industry.

Castanea henryi is a monoecious plant with a low female-to-male ratio, which limits its yield. The phytohormone cytokinin (CK) plays a crucial role in flower development, especially gynoecium development. Here, the feminizing effect of CK on the development of C. henryi was confirmed by the exogenous spraying of N-(2-chloro-4-pyridyl)-N’-phenylurea (CPPU). Spraying CPPU at 125 mg·L−1 thrice changed the male catkin into a pure female catkin, whereas at 5 mg·L−1 and 25 mg·L−1, only a part of the male catkin was transformed into a female catkin. A comparative transcriptome analysis of male catkins subjected to CPPU was performed to study the mechanism of the role of CKs in sex differentiation. Using Pearson’s correlation analysis between hormone content and hormone synthesis gene expression, four key genes, LOG1, LOG3, LOG7 and KO, were identified in the CK and GA synthesis pathways. Moreover, a hub gene in the crosstalk between JA and the other hormone signaling pathways, MYC2, was identified, and 15 flowering-related genes were significantly differentially expressed after CPPU treatment. These results suggest that CK interacts with other phytohormones to determine the sex of C. henryi, and CK may directly target floral organ recognition genes to control flower sex.

Pollination is essential for efficient reproduction in pollinator-dependent crops that rely on the attraction of pollinators to flowers. Especially, floral nectar is considered to be an important factor attracting pollinator like honey bees, but differences among major chestnut species (Castanea crenata, C. mollissima, C. dentata, and C. sativa) are still little explored. This study aims to evaluate the value of honey source by analyzing floral nectar characteristics and comparing the composition of volatile organic compounds (VOCs) that mediate plant-pollinator interaction. In this study, we analyzed nectar samples obtained from male flowers using HPLC and HS-SPME/GC–MS. The five chestnuts showed significant differences between the volume of secreted nectar, free sugar composition, amino acid content and VOCs composition. Furthermore, C. crenata (Japanese cultivar ‘Ungi’) was revealed to emit the highest total amounts of VOCs and high levels of benzenoid compounds that are generally associated with flower-visiting insects. The sugar content per catkin, which is used to determine the honey yield, was the highest in C. crenata, suggesting that C. crenata ‘Ungi’ can be highly valued as a honey tree. Therefore, a better understanding of the relationship between pollinator and nectar characteristics of C. crenara could contribute to a prospective honey plant.

The chestnut drying process was optimized by Response Surface Methodology (RSM). A central composite design with two numerical factors was selected for modelling the drying process. The numerical factors were air temperature from 40 to 60°C and air velocity from 0.75 to 1.75 m s-1. The investigated responses were color values, including lightness (L*), redness (a*), yellowness (b*), total color changes (?E) and browning index (BI). The study revealed that the drying temperature was significantly effective on lightness, redness, total color changes and browning index. However, none of the independent variables were significant on yellowness. The L*, a*, ?E and BI of chestnuts during drying process were adequately described by RSM models. According to desirability function, the optimum drying conditions of chestnuts were 40°C and 0.75 m s-1 air. At optimum conditions, predicted L*, a*, ?E and BI values were 76.34, -0.20, 7.45 and 17.00, respectively. Under optimized conditions the experimental values of L* (77.46), a* (-0.36), ?E (6.31) and BI (16.88) agreed with the predicted values. RSM was not successful to develop a satisfactory model for b* values of chestnuts during drying process. © 2018 International Society for Horticultural Science. All Rights Reserved.

Tarhana is a traditional fermented Turkish food. It’s produced by mixing yoghurt, wheat flour, yeast, salt, and some raw and cooked vegetables such as onions, tomatoes, green and red peppers and spices such as mint, paprika, basil, dill followed by lactic and alcoholic fermentation. The fermentation may occur in a period from one to seven days. In this study, instead of wheat flour, gluten-free corn flour and chestnut flour were used to produce tarhana for celiac patients, and the acceptability of the tarhana was evaluated. Tarhana production was carried out by using the mixtures of corn flour and chestnut flour in five rates (0, 25, 50, 75 and 100%). Tarhana samples were fermented for 48 h. The color, pH, titratable acidity values of tarhana samples were analyzed at the beginning (0 h) and the end (48 h) of the fermentation. The tarhana samples were dried to

This paper asks whether we can identify a recurrent domestication syndrome for tree crops (fruits, nuts) and track archaeologically the evolution of domestication of fruits from woody perennials. While archaeobotany has made major contributions to documenting the domestication process in cereals and other annual grains, long-lived perennials have received less comparative attention. Drawing on examples from across Eurasia, comparisons suggest a tendency for the larger domesticated fruits to contain seeds that are proportionally longer, thinner and with more pointed (acute to attenuated) apices. Therefore, although changes in flavour, such as increased sweetness, are not recoverable, seed metrics and shape provide an archaeological basis for tracking domestication episodes in fruits from woody perennials. Where available, metrical data suggest length increases, as well as size diversification over time, with examples drawn from the Jomon of Japan (Castanea crenata), Neolithic China (Prunus persica) and the later Neolithic of the Near East (Olea europaea, Phoenix dactylifera) to estimate rates of change. More limited data allow us to also compare Mesoamerica avocado (Persea americana) and western Pacific Canarium sp. nuts and Spondias sp. fruits. Data from modern Indian jujube (Ziziphus mauritiana) are also considered in relation to seed length:width trends in relation to fruit contents (flesh proportion, sugar content). Despite the long generation time in tree fruits, rates of change in their seeds are generally comparable to rates of phenotypic evolution in annual grain crops, suggesting that gradual evolution via unconscious selection played a key role in initial processes of tree domestication, and that this had begun in the later Neolithic once annual crops had been domesticated, in both west and east Asia. Electronic supplementary material The online version of this article (10.1007/s00334-017-0659-2) contains supplementary material, which is available to authorized users.

The genus Castanea includes several tree species that are relevant because of their geographical extension and their multipurpose character, that includes nut and timber production. However, commercial exploitation of the trees is hindered by several factors, particularly by their limited regeneration ability. Regardless of recent advances, there exists a serious limitation for the propagation of elite genotypes of chestnut due to decline of rooting ability as the tree ages. In the present review, we summarize the research developed in this genus during the last three decades concerning the formation of adventitious roots (ARs). Focusing on cuttings and in vitro microshoots, we gather the information available on several species, particularly C. sativa, C. dentata and the hybrid C. sativa x C. crenata, and analyze the influence of several factors on the achievements of the applied protocols, including genotype, auxin treatment, light regime and rooting media. We also pay attention to the acclimation phase, as well as compile the information available about biochemical and molecular related aspects. Furthermore, we considerate promising biotechnological approaches that might enable the improvement of the current protocols. This research was funded by the Xunta de Galicia of grant number IN607 2017/6 and the APC was partially funded by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

Dendrostoma was recently proposed in Erythrogloeaceae (Diaporthales, Sordariomycetes), with all known members recorded as being plant pathogenic on economically important tree hosts. During our collections of Dendrostoma species in China, mild to severe canker symptoms were observed on sweet chestnut (Castaneamollissima) and oak (Quercus spp.) trees. Dead and dying plant tissues exhibiting Dendrostoma canker symptoms were sampled for fungal isolation. A total of 37 Dendrostoma isolates were obtained and analysed using morphological characteristics and molecular data (ITS, LSU, RPB2, TEF1-α). Based on these data, 10 novel clades could be distinguished, which also proved to represent morphologically distinct species described here as Dendrostomaaurorae, D.castaneae, D.castaneicola, D.chinense, D.dispersum, D. parasiticum, D.qinlingense, D.quercus, D.shaanxiense and D.shandongense spp. nov. A key to species of the genus is also provided.

Chloroplast (cp) DNA genomes are traditional workhorses for studying the evolution of species and reconstructing phylogenetic relationships in plants. Species of the genus Castanea (chestnuts and chinquapins) are valued as a source of nuts and timber wherever they grow, and chestnut species hybrids are common. We compared the cp genomes of C. mollissima, C. seguinii, C. henryi, and C. pumila. These cp genomes ranged from 160,805 bp to 161,010 bp in length, comprising a pair of inverted repeat (IR) regions (25,685 to 25,701 bp) separated by a large single-copy (LSC) region (90,440 to 90,560 bp) and a small single-copy (SSC) region (18,970 to 19,049 bp). Each cp genome encoded the same 113 genes, 82–83 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes. There were 18 duplicated genes in the IRs. Comparative analysis of cp genomes revealed that rpl22 was absent in all analyzed species, and the gene ycf1 has been pseudo-genized in all Chinese chestnuts except C. pumlia. We analyzed the repeats and nucleotide substitutions in these plastomes and detected several highly variable regions. The phylogenetic analyses based on plastomes confirmed the monophyly of Castanea species.

The sweet chestnut (Castanea sativa Mill.) is the only native species of this genus in Europe, where it faces various threats that are causing a severe decrease in populations, with the resulting loss of genetic diversity. In the Iberian Peninsula, it is of high economic and ecological importance, being well represented, especially in northern areas, whilst it is limited to isolated populations in medium-range mountains in southern Spain (Andalusia region). Taking advantage of this fragmented distribution, this study analyzes the dynamics of atmospheric transport of Castanea pollen through Andalusia region in order to obtain a better understanding of the pollination pathways as a key aspect of the floral biology of this partially anemophilous species. The aerobiological characteristics of this species are also of special interest since its pollen has been recognized as allergenic. Pollen transport pathways were studied by applying back-trajectories analysis together with aerobiological, phenological, land cover, and meteorological data. The results reveal that airborne Castanea pollen concentrations recorded in the city of Cordoba, in the center of Andalusia region, reach medium- and even long-range distances. The backward-trajectory analysis indicates that most of the pollen data detected outside the Castanea flowering season were related to westerly slow and easterly airflows. Furthermore, some of the case studies analyzed indicate the presence of southerly airflow patterns, which could influence medium- and long-range transport events from chestnut populations further south, even from those located in north African mountains. The integrated analysis of the results offers us better knowledge of the cross-pollination pathways of this endangered species, which help us to understand its genetic flows, as a basis for designing conservation strategies for this highly fragmented species in southern Spain.

Following the abandonment of dual nomenclature and the implementation of single-name nomenclature for pleomorphic fungi, Coryneum was considered to have priority over Pseudovalsa and was recommended for use. Currently, Coryneum is the only genus in the family Coryneaceae (Diaporthales). However, DNA sequence data are lacking for most Coryneum species, and no detailed phylogenetic analyses of the genus are yet available. In the present study, fresh Coryneum samples were collected from chestnut (Castanea) and oak (Quercus) trees in China and morphologically compared with accepted Coryneum species. Based on morphological characteristics, they were identified as one known species, Coryneum castaneicola, and three novel species described here as C. gigasporum, C. sinense, and C. suttonii. Conidial dimensions and host association were considered major characters for species distinction. The previously unknown sexual morph of C. castaneicola is reported and described. A phylogenetic analysis of nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and large subunit (28S) sequence data of a representative matrix of Diaporthales confirmed Coryneaceae to represent a monophyletic clade. A phylogenetic analysis of a combined sequence matrix containing the ITS-28S rDNA, the translation elongation factor 1-α (TEF1α), and the second largest subunit of the RNA polymerase II (RPB2) of the four Chinese and four additional European Coryneum species was performed, confirming the distinctness of these novel species.

Dendrostoma was recently proposed in Erythrogloeaceae (Diaporthales, Sordariomycetes), with all known members recorded as being plant pathogenic on economically important tree hosts. During our collections of Dendrostoma species in China, mild to severe canker symptoms were observed on sweet chestnut (Castaneamollissima) and oak (Quercus spp.) trees. Dead and dying plant tissues exhibiting Dendrostoma canker symptoms were sampled for fungal isolation. A total of 37 Dendrostoma isolates were obtained and analysed using morphological characteristics and molecular data (ITS, LSU, RPB2, TEF1-α). Based on these data, 10 novel clades could be distinguished, which also proved to represent morphologically distinct species described here as Dendrostomaaurorae, D.castaneae, D.castaneicola, D.chinense, D.dispersum, D. parasiticum, D.qinlingense, D.quercus, D.shaanxiense and D.shandongense spp. nov. A key to species of the genus is also provided.

Dryocosmus kuriphilus is the most impactful alien pest of chestnut currently reported in almost the whole Europe after its accidental introduction in Piemonte (North-west Italy) where it was found for the first time in 2002. The Piemonte Region Administration funded a project aimed to find control solutions based on both the biological control of gall-wasp and the study of plant response. This work was carried out from 2004 to 2013 and reports studies on assessment of production loss (2006–2012), cultivar susceptibility (2004–2013) and amount of nutrients subtraction caused by the insect (2012). The assessment of yield loss showed that infestation values (G/B = No. galls/bud) lower than 0.3 G/B caused no significant losses; values between 0.3–0.6 G/B originated a moderate decrease in productivity. A drastic decrease of productivity was observed for values above 0.6 G/B. A second objective was to assess varietal susceptibility in 62 cultivars. The susceptibility trait showed a wide range of variation from total resistance (7 cultivars: two Castanea sativa , one Castanea crenata and 4 Euro-Japanese hybrids) to high susceptibility (>0.6 G/B; 14 cultivars). Finally, size and proximate differences in leaves with gall and healthy leaves were studied to assess the changes due to infestation. Significant differences for leaf area, moisture, dry matter, ash, sugars, starch, and total carbohydrates were observed between the two types of leaves indicating a deep influence of the infestation on leaf functionality and on its photosynthetic capacity.

In this study, results of photomixotropic and photoautotrophic chestnut micropropagation are compared. The aim is to increase the quality of micropropagated plants as well as to reduce costs due to plant loss during acclimatization. A successful protocol has been developed for the proliferation phase without exogenous sucrose added to the medium that has been tested with 4 genotypes. For this, shoots were exposed to decreasing sugar levels for several months to ensure their viability in sucrose-free medium. In vitro rooting in photoautotrophic conditions was applied to 15 chestnut genotypes. Every genotype formed vigorous plants which were easy to acclimatize. More than 6000 shoots were rooted with a rooting and acclimatization average value of 71% for the best treatment. This result was better than the one obtained in conventional micropropagation.

The most dangerous pathogen affecting the production of chestnuts is Phytophthora cinnamomi a hemibiotrophic that causes root rot, also known as ink disease. Little information has been acquired in chestnut on the molecular defense strategies against this pathogen. The expression of eight candidate genes potentially involved in the defense to P. cinnamomi was quantified by digital PCR in Castanea genotypes showing different susceptibility to the pathogen. Seven of the eight candidate genes displayed differentially expressed levels depending on genotype and time-point after inoculation. Cast_Gnk2-like revealed to be the most expressed gene across all experiments and the one that best discriminates between susceptible and resistant genotypes. Our data suggest that the pre-formed defenses are crucial for the resistance of C. crenata to P. cinnamomi. A lower and delayed expression of the eight studied genes was found in the susceptible Castanea sativa, which may be related with the establishment and spread of the disease in this species. A working model integrating the obtained results is presented info:eu-repo/semantics/publishedVersion

Summary Honeys were studied in order to know the relationships between their botanical origin, the total content of phenols and flavonoids, and the 2.2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The principal floral resources for honeybees in the studied area were Castanea sativa, Rubus, Eucalyptus, Erica, and Cytisus. Results showed the influence of Erica and Castanea in the phenol content, flavonoids content, and the antioxidant activity of honeys. The presence of Erica in honeys was related to the highest phenol content; so heather honeys had a mean content of 178.9 mg/100g. Honeys with high Castanea pollen content had the highest value of flavonoids (7.7 mg/100g) and a minor value of half maximal inhibitory concentration (IC50) (9.4 mg/ml). Eucalyptus and blackberry were the honeys with minor contents of these compounds. A stepwise linear regression was used to estimate the phenol content of honeys. The contribution of Erica and Castanea was highlighted in the obtained model (R2 = 0.61), with significant p-value (< 0.01).

7º Congreso Forestal Español.- 26-30 junio 2017.- Plasencia, Cáceres, En este trabajo se presentan los resultados de aplicar por primera vez las condiciones fotoautotróficas al cultivo in vitro de castaño, a fin de incrementar la calidad de la planta durante las etapas de multiplicación, enraizamiento y aclimatación, y favorecer su propagación a gran escala. Para la etapa de multiplicación, los experimentos realizados han permitido diseñar un protocolo eficaz de cultivo sin aporte de azúcares exógenos, que se utilizó con 4 genotipos de castaño resistentes a la tinta. Este protocolo consiste en disponer segmentos apicales y basales en biorreactores de 10 L, usando medio líquido y dados de lana de roca como soporte, y someterlos a alta intensidad lumínica y ventilación forzada con aire enriquecido en CO2. Para el enraizamiento se utilizaron 15 genotipos que fueron tratados con inmersión basal en ácido indol- 3-butírico, seguido de cultivo en biorreactores de 16 L sobre bloques de lana de roca en medio sin azúcar y con altos niveles de CO2. Los porcentajes de enraizamiento y aclimatación fueron elevados y permitieron aplicar este sistema con eficiencia a todos los genotipos estudiados.

Se presentan los resultados de la medición en 228 ejemplares de castaños híbridos de 20 clones distintos en vivero, de edades comprendidas entre 4 y 7 años. Se realizaron muestreos destructivos para caracterizar las principales potencialidades de los clones en lo que se refiere a crecimiento y distribución de la biomasa aérea (fuste y ramas). Así, se elaboró una tarifa de biomasa total (peso seco), conjunta para todos los clones, en cuyo ajuste las mejores variables fueron el diámetro en la base y el diámetro normal, con R2 = 0,87 y REMC = 0,61 kg árbol-1. Además, se establecieron unos rankings de clones según su capacidad para obtener: — Una mayor capacidad de ramificación (medida mediante la biomasa de ramas), por su influencia en la aptitud para producción de fruto. — Una mayor producción de biomasa del fuste y del crecimiento en diámetro y altura, por su influencia en la aptitud para uso forestal maderable BOIBEL FORESTAL S.L.(proyectos “SOUTONOVO: cooperación para o desenvolvemento dun novo proceso integrado de talladía do castiñeiro”, “INTEGRACASTANEA: Proxecto de integración vertical do castiñeiro: da mellora xenética ás producións finais”)

The global climate change reported over recent years may prompt changes in the atmospheric pollen season (APS). The aim of this study is to evaluate the possible impact provoked by meteorological conditions variations at different seasons of the year or different geographical areas on APS. Alnus, Betula and Castanea atmospheric pollen seasons and trends during the last 17 years at Ourense and Vigo (Galicia—NW Spain) and Perugia (Italy) were analysed. Possible incidence of the meteorological trends observed in the different cities on the atmospheric pollen seasons and the chill and heat requirements were evaluated. Pollen data from Ourense, Vigo and Perugia (1995–2011) were used. Pollen sampling was performed using LANZONI VPPS 2000 volumetric traps (Hirst in Ann Appl Biol 36:257–265, 1952), placed on top of different buildings at a similar height from the ground. Several methods, dates and threshold temperatures for determining the chill and heat requirements needed to trigger flowering were tested. Different temporary order in the pollination sequence was observed between the three pollen types studied in the three sites. Alnus flowers few days in advance in Ourense respecting to Vigo and 1 month earlier than Perugia. The Betula flowering start date in Ourense and Vigo is almost simultaneous, taking place only 5 days in advance with respect to Perugia. Finally, scarce differences in the APS onset of Castanea were detected between the three cities. The variations observed among the two areas (Umbria, Italy and Galicia, Spain) in the onset of pollen season in the winter or spring flowering trees could be explained by differences in the thermal requirements needed for flowering as consequence of the climatic conditions recorded during the previous period to flowering. The length of the chilling and heat period as well as the thermal requirements obtained showed differences between geographical areas. The chill requirements accumulated were higher in Perugia than Ourense and Vigo. By contrary, the lowest heat accumulation was achieved in Perugia. The observed trends in the APS characteristics and the weather-related parameters were not homogeneous both in the pollen types and sites. The pollen index of Betula and Castanea pollen in Ourense shows a significant trend to increase.

Centuries of co-evolution between Castanea spp. biodiversity and human populations has resulted in the spread of rich and varied chestnut genetic diversity throughout most of the world, especially in mountainous and forested regions. Its plasticity and adaptability to different pedoclimates and the wide genetic variability of the species determined the spread of many different ecotypes and varieties in the wild. Throughout the centuries, man has used, selected and preserved these different genotypes, vegetatively propagating them by grafting, for many applications: fresh consumption, production of flour, animal nutrition, timber production, thereby actively contributing to the maintenance of the natural biodiversity of the species, and providing an excellent example of conservation horticulture. Nonetheless, currently the genetic variability of the species is critically endangered and hundreds of ecotypes and varieties are at risk of being lost due to a number of phytosanitary problems (canker blight, Chryphonectria parasitica; ink disease, Phytophthora spp.; gall wasp, Dryocosmus kuriphilus), and because of the many years of decline and abandonment of chestnut cultivation, which resulted in the loss of the binomial male chestnut. Recently, several research and experimentation programmes have attempted to develop strategies for the conservation of chestnut biodiversity. The purpose of this paper is to give an overview of the status of biodiversity conservation of the species and to present the results of a 7 year project aimed at the individuation and study of genetic diversity and conservation of Castanea spp. germplasm.

In order to face environmental constraints, trees are able to re-orient their axes by controlling the stress level in the newly formed wood layers. Angiosperms and gymnosperms evolved into two distinct mechanisms: the former produce a wood with large tension pre-stress on the upper side of the tilted axis, while the latter produce a wood with large compression pre-stress on the lower side. In both cases, the difference between this stress level and that of the opposite side, in light tension, generates the bending of the axis. However, light values of compression were sometimes measured in the opposite side of angiosperms. By analysing old data on chestnut and mani and new data on poplar, this study shows that these values were not measurement artefacts. This reveals that generating light compression stress in opposite wood contributes to improve the performance of the re-orientation mechanism., Pour s'adapter à l'environnement, les arbres sont capables de contrôler l'état de contraintes des nouvelles couches de bois formé pour réorienter leurs axes. Angiospermes et gymnospermes ont évolué vers deux stratégies différentes : les premiers produisent un bois à forte précontrainte de tension sur la face supérieure de l'axe incliné alors que les derniers mettent en place un bois en précontrainte de compression sur la face inférieure. La différence de contrainte avec la face opposée constituée de bois en légère tension produit un même résultat, la flexion de l'axe. Pourtant, au hasard des expérimentations, des valeurs de compression ont plusieurs fois été observées dans le bois opposé des angiospermes. Cette étude reprend des donnés anciennes sur le châtaignier et le manil et les complète avec des données sur peuplier pour mettre en évidence qu'il ne s'agit par d'erreurs de mesure mais réellement d'une stratégie de ces arbres consistant à produire du bois en légère précontrainte de compression pour une meilleure efficacité du redressement.

The species of the Stigmella ruficapitella group occurring in the Western Palaearctic and feeding on Quercus are reviewed. We recognise 19 species, five of which are described as new: Stigmella fasciata sp. n. on Quercus pubescens from Slovenia, Croatia, Greece and Turkey, S. cocciferae sp. n. on Q. coccifera from Greece, Turkey and Israel, S. kasyi sp.n. from Afghanistan, possibly feeding on Quercus baloot, S. bicuspidata sp. n. from Turkey (host unknown) and S. karsholti sp. n. on Q. canariensis from Tunisia. Stigmella ilicifoliella (Mendes, 1918) comb. n., stat. rev. is removed from synonymy with S. suberivora (Stainton, 1869), it occurs in France, Spain and Portugal, partly sympatric with S. suberivora on Quercus rotundifolia, Q. ilex and Q. suber. Stigmella nigra Dufrane, 1955 is synonymised with S. ilicifoliella. S. suberivora, S. ilicifoliella, S. szoecsiella (Borkowski, 1972), S. macrolepidella (Klimesch, 1978), S. zangherii (Klimesch, 1951), S. dorsiguttella (Johansson, 1971), S. trojana Z. & A. Lastuvka, 1998 and S. eberhardi (Johansson, 1971) are redescribed. A new diagnostic character on the forewing underside is described for male S. svenssoni (Johansson, 1971). Data on distribution and biology are given for all species, keys are given for males and for male and female genitalia. All known hostplants are listed, including several new records. The fauna on evergreen oaks, counting three species, is poor compared to that on deciduous oaks and compared to the genus Ectoedemia. The Eastern Mediterranean region, with about five endemic species, has a more diverse fauna than the Western part, were only three endemic species occur.

Chestnuts, members of the genus Castanea , family Fagaceae, are valuable worldwide, and all species have noteworthy ecological, economic, and cultural importance in their native ranges. Historically, American chestnut (Castanea dentata (Marshall) Borkh.) was an abundant tree species in eastern North America until its decimation in the early 20 th century by chestnut blight, caused by the fungus Cryphonectria parasitica . To regain the benefits of this prized species in North America, efforts are ongoing to produce and introduce blight-resistant hybrids of C. dentata and the blight-resistant Chinese chestnut ( C. mollissima Blume). It is important that the C. mollissimaportion of hybrids be well adapted to the C. dentata native range and growing conditions, but very little is known about the ecology of C. mollissima . To improve the quality and success of hybrid breeding programs, this knowledge gap is addressed. In Dayville, CT, there exists a 50-yr-old naturalized stand of C. mollissima co-mingled with native forest species adjacent to an 85-year-old C. mollissima orchard. We addressed questions of forest composition, spatial distributions of woody stems, horizontal and vertical distributions of woody roots, past stand dynamics of C. mollissima , health and ecophysiology of C. mollissima , and genetic relationships of C. mollissimain the forest and orchard. On this site the exotic species is adapted and competitive and has assumed an ecological position similar to its extirpated relative, C. dentata . From a competition point of view, the introduced species has been neither overly aggressive nor suppressed relative to sympatric native forest tree species. Genetic composition of the naturalized population compared to its adjacent planted parents indicated little effect of natural selection or inbreeding depression. The seeming ease and persistence with which this exotic species introduced itself begs for an explanation as to why such naturalized stands of C. mollissima scarcely exist elsewhere in eastern North America. Likely explanations are that a rare time window of low seed and seedling depredation allowed seedlings to establish, and the shallow soil depth at this particular site has limited the native forest canopy height to a height that is attainable by the characteristically short-statured C. mollissima . The existence and success of this naturalized stand of C. mollissima supports the notion that hybrids between C. mollissima and C. dentata may be equally successful in future natural and anthropogenic forests in North America. However, the issue of seed/seedling depredation by wildlife needs to be considered as well as the possibility that hybrids may need the genetic potential to grow taller on more productive sites.

The genus Castanea, chestnuts and chinkapins, belongs to the family Fagaceae, which includes other important timber producing genera such as Quercus and Fagus. The genus Castanea is divided into three geographically delimited sections with at least seven consistently recognized interfertile species: 4 species in Asia (C. mollissima, C. henryi, C. seguinii, and C. crenata), two or more species in North America (C. dentata, C. ozarkensis, and C. pumila) and one in Europe and Turkey (C. sativa). The two most important diseases of chestnut are ink disease (Phytophthora) and chestnut blight (Cryphonectria). Resistance to these is the major objective for rootstock breeding in Europe and scion breeding in North America. In both cases, the source of resistance was Asian species. European breeding programs developed resistant hybrid rootstocks, which are propagated by stooling, cuttings, or in vitro culture. A major pest of chestnut is the gall wasp Dryocosmus kuriphilus whose control is based on the spread of parasitoids but also on the selection of resistant cultivars. For nut production, the most important breeding objectives include the following: good horticultural traits, product quality, suitability to storage and processing, and ease of peeling. For timber, important characters include wood quality, rapid growth, and nonchecking of wood (ring-shake). Molecular maps have been developed, which has expanded the genetic knowledge of the chestnut. An efficient genetic transformation protocol for C. sativa through the coculture of somatic embryos with different strains of Agrobacterium tumefaciens has been described.

Fagus castanea Linnaeus, Species Plantarum 2: 997. 1753. "Habitat in Italiae & australioris Europae montibus." RCN: 7228. Type not designated. Original material: Herb. Clifford: 447, Fagus 2 α (BM). Current name: Castanea sativa Mill. (Fagaceae)., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part F), pp. 516-528 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 516, DOI: 10.5281/zenodo.291971

Fagus pumila Linnaeus, Species Plantarum 2: 998. 1753. "Habitat in America septentrionali." RCN: 7229. Lectotype (Johnson in J. Arnold Arbor. 69: 41. 1988): Clayton 927 (BM-000098026). Current name: Castanea pumila (L.) Mill. (Fagaceae)., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part F), pp. 516-528 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 516, DOI: 10.5281/zenodo.291971

Since 1987 some hybrid clones resistant to the ink disease were evaluated as rootstocks with the local cultivars in different sites of Galicia where it is normal to use grafted plants. After the first results published in 1990, in this work it is presented the behaviour of four hybrid clones after 11 years of grafting. In general, compatibility can be considered excellent and a good adaptation to Galician chestnut orchards, according to: 1) a perfect join between rootstock and cultivar; 2) an harmonious development of rootstock and cultivar; 3) a right aerial growth. Percentage of death plants has been high in every orchard (over 20 %). Grafting in nursery produce more regularity in orchards, because grafting in field it is more risky, but after callus formation, the growth it is very strong. Desde el año 1987 se comenzaron a estudiar diversos clones híbridos de castaño resistentes a la tinta como patrones de los cultivares de castaño tradicionales en distintas zonas productoras de Galicia. Después de los primeros resultados publicados en 1990 sobre los patrones híbridos CHR-162(7521), CHR-151(HS), CHR-168(110) y CHR-161(100), se han actualizado los datos sobre su comportamiento en zonas de cultivo del castaño, algunos de ellos a los 11 años de injerto, y se han incluido los datos de dos nuevas parcelas. En general, la compatibilidad puede considerarse excelente y una buena adaptación a zonas de castañares injertados gallegos, debido a: 1) una perfecta unión entre patrón y variedad; 2) un desarrollo armonioso del patrón y la variedad, y 3) un desarrollo en volumen adecuado para la zona de cultivo. El porcentaje de marras ha sido elevado en todas las parcelas (superior al 20 %). El injerto en vivero garantiza una mayor regularidad en la plantación, puesto que el injerto en campo es más arriesgado, pero una vez prendido el crecimiento es muy vigoroso.

Localized etiolation of branches in the crown of a 30‐year‐old chestnut tree produced plant material that responded much better to establishment and multiplication in vitro than unetiolated material, whose cultures were very difficult to maintain (response being measured in terms of the percentage of cultures established, the mean number of shoots formed per explant, the number of 8‐mm segments per new shoot, the length of longest shoot in each culture, and the coefficient of multiplication). Only 22% of the initial explants from unetiolated material were successfully established, as against 79% for etiolated material, with similar differences between the coefficients of multiplication of the two lines in successive cultures. Accordingly, partial etiolation of branches is proposed as a suitable pretreatment for in vitro propagation of selected mature trees, when physiologically juvenile materials such as stump sprouts, epicormic shoots or root suckers are not available.

Shoot-tip necrosis occurs during the rooting of chestnut and oak cultures. In some cultures, the role of apical dominance is taken over by one of the lateral buds, generally that nearest the apex, and the plant survives. Attempts were made to prevent necrosis by adding a low concentration of 6-benzyladenine (BA) to the rooting medium and, whilst necrosis was to a large extent avoided, the rooting rates fell considerably. Excision of the shoot-tip and application to the cut end of a drop of 25 mg l−1 BA in agar induced axillary growth. The optimum time for carrying out decapitation and BA treatment was after 10 days in the rooting medium. It is suggested that the cause of shoot-tip necrosis is the absence of cytokinin from the rooting medium linked with the root-inducing auxin treatment.