Early selection for resistance to <Emphasis Type="Italic">Heterobasidion parviporum</Emphasis> in Norway spruce is not likely to adversely affect growth and wood quality traits in late-age performance

Infections with Heterobasidion parviporum devalue the Norway spruce timber as the decayed wood does not meet the necessary quality requirements for sawing. To evaluate the incorporation of disease resistance in the Norway spruce breeding strategy, an inoculation experiment with H. parviporum on 2-year-old progenies of 466 open-pollinated families was conducted under greenhouse (nursery) conditions. Lesion length in the phloem (LL), fungal growth in sapwood (FG) and growth (D) were measured on an average of 10 seedlings for each family. The genetic variation and genetic correlations between both LL, FG and growth in the nursery trial and wood quality traits measured previously from 21-year old trees in two progeny trials, including solid-wood quality traits (wood density, and modulus of elasticity) and fiber properties traits (radial fiber width, tangential fiber width, fiber wall thickness, fiber coarseness, microfibril angle and fiber length). For both LL and FG, large coefficients of phenotypic variation (>?26%) and genetic variation (>?46%) were detected. Heritabilities of LL and FG were 0.33 and 0.42, respectively. We found no significant correlations between wood quality traits and growth in the field progeny trials with neither LL nor FG in the nursery trial. Our data suggest that the genetic gains may reach 41 and 52% from mass selection by LL and FG, respectively. Early selection for resistance to H. parviporum based on assessments of fungal spread in the sapwood in nursery material, FG, will not adversely affect growth and wood quality traits in late-age performance.     

Comparison of wood,fibre and vessel properties of drought-tolerant eucalypts in South Africa§

Three drought-tolerant eucalypt genotypes have been investigated for a broad spectrum of properties to provide a basis for comparison on their suitability for various end-uses. The genotypes included were a Eucalyptus grandis × E. camaldulensis hybrid, E. gomphocephala and E. cladocalyx, selected based on previous studies that indicated good potential to tolerate arid conditions, reasonably good volume growth and straightness of stems. In this study, information was added on differences between species and parts of stems in growth (volume and biomass) and properties of wood (density and stiffness), fibres (dimensions and microfibril angle) and vessels (size and numbers). We found high wood densities and stiffness values for E. cladocalyx and E. gomphcephala, making them suitable for construction wood. Logs from the mid-part of the stem had the best timber properties, as the butt logs showed the highest microfibril angle and lowest wood stiffness due to longitudinal juvenility. Such juvenility was also to some degree observed for wood density and fibre length. The information gained will be especially helpful for selecting species and processing options for small farm and community plantations for producing higher-value products that may be sold to generate much-needed income as well as for local uses, such as fuelwood and charcoal.     

Differences in xylem response to drought provide hints to future species selection

New Forests - The long-term impacts of summer drought and high temperatures on xylem traits of conifers are scarcely investigated, even though such traits can play an important role in determining...     

Herschel detects a massive dust reservoir in supernova 1987A

We report far-infrared and submillimeter observations of supernova 1987A, the star whose explosion was observed on 23 February 1987 in the Large Magellanic Cloud, a galaxy located 160,000 light years away. The observations reveal the presence of a population of cold dust grains radiating with a temperature of about 17 to 23 kelvin at a rate of about 220 times the luminosity of the Sun. The intensity and spectral energy distribution of the emission suggest a dust mass of about 0.4 to 0.7 times the mass of the Sun. The radiation must originate from the supernova ejecta and requires the efficient precipitation of all refractory material into dust. Our observations imply that supernovae can produce the large dust masses detected in young galaxies at very high redshifts.     

Seasonal variation in ethylene concentration in the wood of Pinus sylvestris L

Ethylene concentrations were determined in gas samples extracted from sealed holes made in the sapwood and heartwood of stems of 70-100-year-old Scots pine (Pinus sylvestris L). Gas could be collected from the heartwood holes by lowering the pressure by means of a large syringe. However, attempts to extract gas from air spaces in the sapwood with the same technique failed, presumably because of lack of an interconnected system of gas-filled canals. High ethylene concentrations, usually in excess of 1 ppm, accumulated in the sapwood holes within one day after sealing. Ethylene concentrations in the sapwood rose to 3-7 ppm during the growing season, and decreased to 0.1-0.3 ppm during the winter. In response to extreme drought, sapwood ethylene concentration increased to 30 ppm, followed by a rapid decrease after the onset of rain. Ethylene concentrations in gas samples from the heartwood were consistently lower than 1 ppm. The lowest values, about 0.1 ppm, were found during the autumn and early winter, whereas values around 0.5 ppm were typical from February to August.     

Slow-moving vehicles in Swedish traffic

The objective of this study was to reach a better understanding of accidents on Swedish roads involving slow-moving vehicles and to suggest ways of preventing such accidents. We analyzed accident data from a 5-year period (1992-1996) involving all types of farm vehicles as well as horses and horse-drawn vehicles. During each year of the period under investigation, slow-moving vehicles were involved in more than 250 traffic accidents on Swedish roads, and an average of 10 people were killed, 66 sustained serious injuries, and 192 sustained slight injuries. This was about 1.3% of all persons injured in traffic accidents in Sweden. The deaths and injuries mostly involved car drivers and passengers. Tractor drivers and unprotected road users (people walking or traveling by motorcycle, moped, or bicycle) also sustained serious injuries and deaths. Vehicles overtaking slow-moving vehicles from behind were the most common type of accident (30%), followed by turning accidents (27%), accidents at crossroads (26%), and with oncoming vehicles (17%). To strengthen the suggestions for improvement, a questionnaire was sent out to driving school teachers in Sweden. Subjects were asked about their experiences with farm vehicles on the roads and their suggestions for ways to increase traffic safety. Based on the accident data and the questionnaire responses, we developed several suggestions for reducing road accidents, including measures for making farm vehicles more visible, improvement of the training provided at driving schools, and information campaigns directed at drivers of farm vehicles and other road users. Further in-depth research is needed to analyze road accidents involving slow-moving vehicles and to test different intervention measures.     

Genetic mapping of the barley lodging resistance locus Erectoides‐k

The barley (Hordeum vulgare L.) mutant erectoides‐k.32 (ert‐k.32) was isolated in 1947 from an X‐ray‐mutant population of cultivar ‘Bonus’. The mutant was released as a cultivar in 1958 with the name ‘Pallas’ – one of the first cereal crop cultivars developed from induced mutants. ‘Pallas’ is a semi‐dwarf barley cultivar known for its culm stability and resistance to lodging. In total, eight allelic ert‐k mutants are known that show different phenotypic strength concerning culm length and spike architecture. They represent alternatives to the widely used, but pleiotropic ‘Green Revolution’ alleles of the Sdw1 (semidwarf1/denso) and Uzu1 (semi‐brachytic1) genes in breeding of robust elite barley cultivars. In the present study, we locate Ert‐k to a 15.7‐cM region in the centromeric region of chromosome 6H. Although the interval is estimated to contain approximately 700 genes, the work provides a solid foundation for the identification of the underlying mutations causing the ert‐k lodging‐resistant phenotype. In addition, the linked markers could be used to follow the ert‐k mutant genotype in marker‐assisted selection of new lodging‐resistant barley cultivars.     

Age and weather effects on between and within ring variations of number,width and coarseness of tracheids and radial growth of young Norway spruce

Annual growth, fibre and wood properties of Norway spruce are all under strong influence from genetics, age and weather. They change dynamically, particularly at young ages. Most genetic research and tree improvement programs are based on data from this most dynamic phase of the life of trees, affected by differences in weather among sites and years. In the work presented, influences of age and weather were investigated and modelled at the detail of annual rings and at the sub-tree ring level of earlywood, transitionwood and latewood. The data used were analysed from increment cores sampled at age 21 years from almost 6000 Norway spruce trees of known genetic origin, grown on two sites in southern Sweden. The traits under investigation were radial growth, cell widths, cell numbers, cell wall thickness and coarseness as a measure of biomass allocation at cell level. General additive mixed models (GAMMs) were fitted to model the influences of age, local temperature and precipitation. The best models were obtained for number of tracheids formed per year, ring width, average radial tracheid width in earlywood, and ring averages for tangential tracheid width and coarseness. Considering the many sources behind the huge variation, the explained part of the variability was high. For all traits, models were developed using both total tree age and cambial age (ring number) to express age. Comparisons indicate that the number of cell divisions and ring width are under stronger control of tree age, but the other traits under stronger control of cambial age. The models provide a basis to refine data prior to genetic evaluations by compensating for estimated differences between sites and years related to age and weather rather than genetics. Other expected applications are to predict performance of genotypes in relation to site or climate and simulation of climate change scenarios.