AFLP similarities among historic Danish cultivars of fodder beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L. subsp. <Emphasis Type="Italic">vulgaris</Emphasis>var. <Emphasis Type="Italic">rapacea</Emphasis> Koch)

Dead seeds of a fodder beet cultivar ‘Elvetham’ stored under ambient conditions since 1880 were compared to a homonymous sample preserved in an on-farm situation in Denmark. DNA was isolated from single seeds and successfully applied to Amplified Fragment Length Polymorphism (AFLP) analysis of the accessions. Six primer pairs were used to determine the similarity between the two accessions based on 112 polymorphic bands. Furthermore, similarity among seven cultivars of fodder beets representing the main types used in Scandinavia at the end of the 19th century was determined. This analysis was based on 152 polymorphic bands. Differentiation among the seven cultivars was determined to a mean G _ST value of 0.438, while G _ST between the two ‘Elvetham’ accessions was 0.266. A principal coordinate analysis based on jaccards similarity index illustrates that the two ‘Elvetham’ accessions are different from each other. The differentiation is higher than the value found between two separate ‘Eckerndorfer’ accessions. The results indicate that the cultivated accession has changed. Additionally, the value of applying old dead seed material for documentation in gene banks is demonstrated. During the analysis it was found that DNA isolated from seeds and leaves behaved differently in the AFLP process, however, the two fractions assigned to their common accession.     

Using natural 13C abundances to differentiate between three CO2 sources during incubation of a grassland soil amended with slurry and sugar

This study describes a novel approach to separate three soil carbon (C) sources by one tracer method (here ¹³C natural abundance). The approach uses the temporal dynamics of the CO₂ efflux from a C₃ grassland soil amended with added C₃ or C₄ slurry and/or C₃ or C₄ sugar to estimate contributions of three separate C sources (native soil, slurry, and sugar) to CO₂ efflux. Soil with slurry and/or sugar was incubated under controlled conditions, and concentration and δ¹³C values of evolved CO₂ were measured over a 2‐week period. The main assumption needed for separation of three C sources in CO₂ efflux, i.e., identical decomposition of applied C₃ and C₄ sugars in soil, was investigated and proven. The relative contribution to the CO₂ efflux was higher, but shorter with an increased (microbial) availability of the C source, i.e., sugar > slurry > SOM. The shortcomings and limitations as well as possible future applications of the suggested method are discussed.     

Surveys in Private and Communal Forests: Data Collection Methods in Bavaria

More than half of the forest land in Bavaria belongs to private forest owners, who contribute a large amount of the industrial timber supply. The level of information about private forests is in comparison to the communal forests inadequate. The increasing demand for data about the forest sector in Bavaria can be partially covered by regular inventories but requires supplementary monitoring activities. Regular surveys based on voluntary participation deliver data, but often do not fulfil statistical requirements due to low response rates of 15–20% to postal surveys. The Bavarian annual postal cutting survey has been built up over 5 years using a roster of voluntary participants. This pragmatic and cost-effective approach provides reliable data for statistical purposes and gives insight in the forest management activities of small-scale forest owners. Recent technical developments, in particular the availability of grids and digital land-use maps, facilitate the random sampling of forest owners. This approach has been applied in a climate change project, but the results did not meet the expectations because of low response rates. The rather labour- and cost-intensive census of forest owners as applied in the project in Eastern Bavaria cannot be recommended except in exceptional circumstances. In the described project a qualitative approach with four distinct questionnaires has been adopted in order to identify ways to reach forest owners that are either not interested in their forests or do not respond to requests. Due to low response rates the objectives of the study could only be partially achieved.     

Volatile composition analysis by solid-phase microextraction applied to oak wood used in cooperage (Quercus pyrenaica and Quercus petraea): effect of botanical species and toasting process

The purpose of this study was to investigate the sorption of selected volatile substances from oak wood-chip samples (Quercus pyrenaica Willd. and Quercus petraea L.) subjected to different toasting levels, namely, without toasting, with medium toasting, and with strong toasting, through the use of solid-phase microextraction (SPME). The main volatile compounds identified as a function of the toasting level and botanical species were furfural, hexanal, α-pinene, d-limonene, decanal, vitispirane, ethyl hexanoate, cis-3-methyl-γ-octalactone (“oak lactone” or “whisky lactone”), α-terpineol, p-xylene, and nonanal. Considering the data obtained from the toasted woods (medium and strong intensity) in comparison with those of nontoasted woods, it can be pointed out that the average peak area and the number of compounds identified in the gas chromatogram decreased during the toasting process. In general, regarding the compounds analyzed, quantitative differences were found between the two oak wood species under study. High values of volatile compounds were found in Quercus pyrenaica oak wood chips. In addition, for the number of compounds identified in oak wood extracts and directly extracted from solid oak wood chips by SPME, it is concluded that the best extraction process for volatile compounds from oak wood is the use of oak wood-chip liquid extracts.     

Perceived importance of precision farming technologies in improving phosphorus and potassium efficiency in cotton production

Site-specific information technologies (IT) provide knowledge about the spatial variability within a field to improve the efficiency of inputs through variable-rate (VR) applications. Identifying factors that influence farmers’ perceptions of the importance of precision farming (PF) technologies in improving the efficiency of phosphorus (P) and potassium (K) fertilizer applications can help to determine why different groups of farmers adopt PF. Knowing these factors can be useful in targeting specific groups of farmers to adopt PF and increase fertilizer efficiency to meet crop needs and reduce P and K losses to the environment. Data were obtained from a 2001 mail survey of cotton (Gossypium hirsutum L.) farmers in six southeastern states in the United States of America. Ordered logit analysis was used to evaluate the level of importance to those who had adopted PF technologies placed on such technologies they had used to improve the efficiency of P and K applications. Results showed that such farmers found soil sampling by management zone or on a grid, and on-the-go sensing most important. Precision farmers who used mapping and remote sensing found PF technologies least important. Older precision farmers who rented larger proportions of their land and used computers for farm management were more likely than other precision farmers to place greater importance on PF technologies in improving the efficiency of P and K applications.     

Realizing all-spin-based logic operations atom by atom

An ultimate goal of spintronic research is the realization of concepts for atomic-scale all-spin-based devices. We combined bottom-up atomic fabrication with spin-resolved scanning tunneling microscopy to construct and read out atomic-scale model systems performing logic operations. Our concept uses substrate-mediated indirect exchange coupling to achieve logical interconnection between individual atomic spins. Combined with spin frustration, this concept enables various logical operations between inputs, such as NOT and OR.     

Age and timing of the Permian mass extinctions: U/Pb dating of closed-system zircons

The age and timing of the Permian-Triassic mass extinction have been difficult to determine because zircon populations from the type sections are typically affected by pervasive lead loss and contamination by indistinguishable older xenocrysts. Zircons from nine ash beds within the Shangsi and Meishan sections (China), pretreated by annealing followed by partial attack with hydrofluoric acid, result in suites of consistent and concordant uranium/lead (U/Pb) ages, eliminating the effects of lead loss. The U/Pb age of the main pulse of the extinction is 252.6 +/- 0.2 million years, synchronous with the Siberian flood volcanism, and it occurred within the quoted uncertainty.     

Resistance to late blight and soft rot in six potato progenies and glycoalkaloid contents in the tubers

Glycoalkaloids are anti-nutritional compounds commonly found in wildSolanum species used as resistance sources to major potato pathogens. It is therefore important for breeding purposes to know whether selecting for resistance using such species necessarily selects also for high glycoalkaloid contents in the tubers. To test this hypothesis, we used six partial progenies from crosses betweenSolanum tuberosum and accessions ofS. andigena, S. berthaultii, S. phureja, andS. vernei to investigate the possible correlation between resistance toPhytophthora infestans and/or toErwinia carotovora subsp.atroseptica and the concentration of glycoalkaloids in tubers. Concentrations of α-solanine and α-chaconine in the tubers segregated in each progeny, as did resistance to each pathogen. Some, but not all, clones from each progeny showed hypersensitive reactions to the isolate ofP. infestans used. Furthermore, clones within each progeny also differed for components of partial resistance toP. infestans, suggesting that all four wild species could be used as sources of both race-specific and partial resistance to late blight. With the exception of low, but statistically significant, correlations between concentration of α-solanine and two late blight resistance components (incubation period and spore production per unit lesion area) in progenies derived fromS. vernei, and despite a trend towards higher glycoalkaloid concentrations in the tubers of the clones most resistant to soft rot within progenies derived fromS. berthaultii andS. vernei, no consistent relationship between resistance to either disease and concentrations of α-solanine and/or α-chaconine was observed. These results indicate that neither race-specific nor partial resistance to late blight and soft rot in the accessions used as progenitors of resistance depend on high solanine or chaconine concentrations. These resistance sources could thus prove useful in breeding programs for improved behaviour againstP. infestans and/orE. carotovora.