Morphological and molecular diversity of Nordic oat through one hundred years of breeding

Summary Genetic diversity in microsatellites and development of agronomical characters in Nordic oat cultivars (Avena sativa) from the 20th century, ranging from landraces to new cultivars, were studied. A clear development in agronomical characters has taken place in this period: Straw length has been reduced, harvest index has increased and heading date has declined. The persistent oat breeding effort in the northern part of the region was indicated by the data, since cultivars from this region showed higher harvest index. Also adaptation to shorter summers was apparent in cultivars from the most northern part of the area. When comparing cultivars released after 1940 to the landraces, the loss of diversity revealed for the agronomical characters was also indicated by the molecular data. This indicates that a more general loss of diversity has taken place in the period, possibly due to random factors during the breeding process (bottleneck effect). The reduction in diversity revealed by recent cultivars at an agronomical as well as a molecular level emphasises the importance of implementing a conservation strategy for older material in order to secure genetic diversity for future oat breeding efforts.     

Two-dimensional simulation of airflow and carbon dioxide transport over a forested mountain: Part I: Interactions between thermally-forced circulations

Local-scale wind regimes over an idealized two-dimensional (2D) mountain having similar horizontal and vertical scales as Vancouver Island were investigated using a high-resolution mesoscale model. The model-generated flow outputs were then used as ersatz data to assess the impact of limiting assumptions in the eddy-covariance (EC) method as well as the effectiveness of tower flux data time-filtering for the main tower site of the Fluxnet-Canada British Columbia flux station. In this paper, we describe the simulated mesoscale and local-scale flow regimes, and in Part II we describe their use in assessing tower-data analyses of CO₂ fluxes.The numerical model was enhanced to include parameterizations for: tree drag, radiation effects of forest canopies on the surface energy budget, and soil heat conduction. Simulations were performed both over an idealized bare hill and over a forested hill. The simulated flow involved interactions between the land/sea breeze, convective thermals, and mountain circulations under fair-weather conditions.The resulting simulated winds over the forested slope were much weaker than those over a bare slope. The nocturnal drainage flow over the forested slope was separated into sub-canopy and above-canopy regimes due to the temperature inversion at treetop. The strongest downslope flows occurred above the canopy with a minimum velocity occurring in the upper canopy where canopy drag is the strongest. The overturning of large convective eddies during daytime resulted in intermittent downslope flows under the canopy during the day. Wind regimes had a rapid shift from upslope to downslope flow above the canopy just after sunset. Further testing will be made using 3D simulations with higher resolution.     

Changes in contents of carotenoids and vitamin E during tomato processing

The aim of this study was to investigate the effect of different types of tomato processing on contents of lycopene, beta-carotene, and alpha-tocopherol. Samples of tomato sauce, tomato soup, baked tomato slices, and tomato juice were taken at different times of heating, respectively, after each step of production. HPLC was used to analyze contents of carotenoids and vitamin E. Due to the loss of water during thermal processing, contents of lycopene, beta-carotene, and alpha-tocopherol on a wet weight basis increased. On a dry weight basis, contents of lycopene increased or decreased depending on the origin of the tomatoes used, whereas the beta-carotene contents decreased or were quite stable. In contrast to lycopene, beta-carotene isomerized due to thermal processing. The alpha-tocopherol contents significantly rose during short-term heating. The increase was not caused by release of alpha-tocopherol from the seeds containing predominantly gamma-tocopherol and accounting for 2% of total alpha-tocopherol content only.     

Optimierte Strategien zur Krankheitsbekämpfung in der Gerste unter Berücksichtigung neuer Erkenntnisse zur Epidemiologie des Blattfleckenkomplexes

The leaf spot complex constitutes an increasing challenge for integrated pest control in barley. The complex consists of biotic and abiotic factors causing early ripening after a rapid loss of green leaf area, in particular in upper, exposed leaves. Severe symptoms appear late in the growing season after heading. The experience from recent years shows that the control of the leaf spot complex improves yield. Best control is achieved by new, effective fungicides. Efficiency is improved by late fungicide application and is dose-dependent. In contrast, late treatments provide poor control of early appearing diseases. For a successful disease control in barley good efficiency in the control of the leaf spot complex appears based on a sufficient control of the other diseases. For optimization of disease control, we require improved knowledge of the epidemics of the leaf spot complex and of the contribution of individual biotic and abiotic factors. Besides the weather, the fungal pathogen Ramularia collo-cygni and its photodynamic toxins play a mayor role in symptom development. By combination of conventional and molecular diagnostics we aim at a better understanding of the complex as a basis for early and reliable prediction of epidemics. Because non fungicidal factors like the physiological plant age play a significant role in the occurrence of the leaf spot complex, they should be taken into account for integrated control.     

Genetic diversity in European accessions of the Barley Core Collection as detected by isozyme electrophoresis

Genetic diversity in 79 European accessions of the Barley Core Collections was surveyed using isozyme electrophoresis. A total of 26 alleles were observed at the ten isozyme loci. All loci were polymorphic except Pgd-1 which was monomorphic. The comparison of the results with those of previous studies indicates that most of the alleles occurring in the European Barley are also observed in this set of the European Barley Core Collections. Only five alleles (Est-1 Al; Est-5 Ag, Te; Pgi-1 C and Ndh-2 B) were absent. Nine of 26 alleles were rare alleles, which were detected only in one or two accessions. Moreover, most of rare alleles were detected in 6-rowed winter barley. It is very important to include rare alleles for maximising the genetic variations in core collections. In the set of European Barley Core Collection, 6-rowed barley contained larger diversity than 2-rowed barley; winter type contained larger diversity than spring type. The cluster analysis separated 79 accessions into three major groups. Group I is more complex and comprised 2-rowed spring, 2-rowed winter and 6-rowed winter barley. In this group, 18 accessions in the cluster A and 14 accessions in the cluster B possessed identical genotypes as judged from the ten isozyme data. Principal coordinate analysis could not clearly separate the spring cultivars from the winter barley lines, as well as not separate 2-rowed from 6-rowed barley.     

Dynamics of slow-moving landslides from permanent scatterer analysis

High-resolution interferometric synthetic aperture radar (InSAR) permanent scatterer data allow us to resolve the rates and variations in the rates of slow-moving landslides. Satellite-to-ground distances (range changes) on landslides increase at rates of 5 to 7 millimeters per year, indicating average downslope sliding velocities from 27 to 38 millimeters per year. Time-series analysis shows that displacement occurs mainly during the high-precipitation season; during the 1997-1998 El Ni?o event, rates of range change increased to as much as 11 millimeters per year. The observed nonlinear relationship of creep and precipitation rates suggests that increased pore fluid pressures within the shallow subsurface may initiate and accelerate these features. Changes in the slope of a hill resulting from increases in the pore pressure and lithostatic stress gradients may then lead to landslides.     

Policy. OPV cessation--the final step to a "polio-free" world

The 20-year, U.S. $4 billion-dollar international effort to eradicate wild polioviruses now includes monovalent oral poliovirus type 1 vaccine (mOPV1), which was first given to 40 million children in India in April 2005. As this vaccine is being introduced to eliminate some of the last poliovirus reservoirs, the Global Polio Eradication Initiative is planning for the eventual synchronized worldwide cessation of the routine use of all oral poliovirus vaccines (OPVs) because of their capacity to cause, rarely, outbreaks of paralytic poliomyelitis. This Policy Forum reviews the feasibility and implications of eventually stopping the use of live polio vaccines.