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Grube M.,University of Graz | Furnkranz M.,University of Graz | Zitzenbacher S.,University of Graz | Huss H.,Agricultural Research and Education Center Raumberg Gumpenstein | Berg G.,University of Graz
European Journal of Plant Pathology | Year: 2011

The Styrian oil pumpkin, Cucurbita pepo L. subsp. pepo var. styriaca Greb. is a crop of cultural, commercial, and medical importance. In the last decade, yield losses of pumpkins increased dramatically. The ascomycetous fungus Didymella bryoniae (Fuckel) Rehm was identified as main causal agent provoking gummy stem blight as well as black rot of pumpkins. We observed a remarkable phenotypic diversity of the fungal pathogen, which contrasted with a high genotypic similarity. Evidence of pathogenictiy of D. bryoniae on Styrian oil pumpkin was demonstrated in a newly developed greenhouse assay. Isolates representing the five observed phenotypic groups fulfilled the Koch's postulates. In the field, the fungal disease was often associated with bacterial colonization by Pectobacterium carotovorum, Pseudomonas viridiflava, Pseudomonas syringae and Xanthomonas cucurbitae. The pathogenic behaviour of bacterial isolates on pumpkin was confirmed in the greenhouse assay. The high co-incidence of fungal and bacterial disease suggests mutualistic effects in pathogenesis. With a new assay, we found that bacteria can use the mycelium of D. bryoniae for translocation. We argue that the rapid rise of the multi-pathogen disease of pumpkins results from combined action of versatile pathogenic bacteria and the rapid translocation on a structurally versatile mycelium of the fungal pathogen. © 2011 KNPV. Source


Schrabauer J.,University of Natural Resources and Life Sciences, Vienna | Buchgraber K.,Agricultural Research and Education Center Raumberg Gumpenstein | Moder K.,University of Natural Resources and Life Sciences, Vienna | Liebhard P.,University of Natural Resources and Life Sciences, Vienna
Journal fur Kulturpflanzen | Year: 2014

Perennial grasslands play an important role as an extensive CO2 sink. Fodder and biofuels can be produced in an ecologically acceptable manner on such sites. Projected future climate-change scenarios suggest that Central Europe's grasslands will be increasingly affected by drought. In order to determine whether there is potential for some alternative drought-adapted grass species to contribute to herbage production for either forage or biomass, we tested the agronomic performance of ten grass species (Agropyron elongatum, Agropyron intermedium, Agropyron desertorum, Agropyron trachycaulum, Elymus hoffmannii, Elymus junceus, Bromus inermis, Bromus marginatus, Festuca arundinacea and Panicum virgatum) in comparison to four reference grasses (Dactylis glomerata, Arrhen-atherum elatius, Agrostis gigantea and Agropyron repens). Experiments were conducted in small-plot cutting trials at two sites across two growing seasons with either one or multiple cuts per season. In the one-cut system, P. virgatum provided the highest average annual dry matter (DM) yield (14 258 kg ha-1), followed by A. elongatum (13 086 kg ha-1). The multi-annual persistence of these two species under the experimental conditions was given only when P. virgatum was not harvested before freezing off and A. elongatum was harvested only once per year. Moreover, both species are susceptible to lodging. In the multiple-cut system, F. a run-dinacea showed a high yield (12 533 kg DM ha-1 average annual yield) and a low presence of associated weeds (only 0.1% surface area). Cultivating this grass species requires considering its only moderate competitiveness during the establishment phase. Based on the rapid establishment of A. trachycaulum, this species is expected to be best suited as a cover crop in seed mixtures. The yields of A. desertorum, A. trachycaulum, A. repens, E. junceus and B. marginatus were below the experimental average (9255 kg DM ha-1 at multiple cuttings). Source


Furnkranz M.,University of Graz | Lukesch B.,University of Graz | Muller H.,University of Graz | Huss H.,Agricultural Research and Education Center Raumberg Gumpenstein | And 2 more authors.
Microbial Ecology | Year: 2012

Recent and substantial yield losses of Styrian oil pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) are primarily caused by the ascomycetous fungus Didymella bryoniae but bacterial pathogens are frequently involved as well. The diversity of endophytic microbial communities from seeds (spermosphere), roots (endorhiza), flowers (anthosphere), and fruits (carposphere) of three different pumpkin cultivars was studied to develop a biocontrol strategy. A multiphasic approach combining molecular, microscopic, and cultivation techniques was applied to select a consortium of endophytes for biocontrol. Specific community structures for Pseudomonas and Bacillus, two important plant-associated genera, were found for each microenvironment by fingerprinting of 16S ribosomal RNA genes. All microenvironments were dominated by bacteria; fungi were less abundant. Of the 2,320 microbial isolates analyzed in dual culture assays, 165 (7%) were tested positively for in vitro antagonism against D. bryoniae. Out of these, 43 isolates inhibited the growth of bacterial pumpkin pathogens (Pectobacterium carotovorum, Pseudomonas viridiflava, Xanthomonas cucurbitae); here only bacteria were selected. Microenvironment-specific antagonists were found, and the spermosphere and anthosphere were revealed as underexplored reservoirs for antagonists. In the latter, a potential role of pollen grains as bacterial vectors between flowers was recognized. Six broad spectrum antagonists selected according to their activity, genotypic diversity, and occurrence were evaluated under greenhouse conditions. Disease severity on pumpkins of D. bryoniae was significantly reduced by Pseudomonas chlororaphis treatment and by a combined treatment of strains (Lysobacter gummosus, P. chlororaphis, Paenibacillus polymyxa, and Serratia plymuthica). This result provides a promising prospect to biologically control pumpkin diseases. © 2011 Springer Science+Business Media, LLC. Source


Schmidt J.,University of Natural Resources and Life Sciences, Vienna | Schonhart M.,University of Natural Resources and Life Sciences, Vienna | Biberacher M.,Research Studios Austria Forschungsgesellschaft mbH Studio iSPACE | Guggenberger T.,Agricultural Research and Education Center Raumberg Gumpenstein | And 5 more authors.
Energy Policy | Year: 2012

Local actors at community level often thrive for energy autarky to decrease the dependence on imported energy resources. We assess the potentials and trade-offs between benefits and costs of increasing levels of energy autarky for a small rural region of around 21,000 inhabitants in Austria. We use a novel modeling approach which couples a regional energy system model with a regional land use optimization model. We have collected and processed data on the spatial distribution of energy demand and potentials of biomass, photovoltaics and solar thermal resources. The impacts of increasing biomass production on the agricultural sector are assessed with a land-use optimization model that allows deriving regional biomass supply curves. An energy system model is subsequently applied to find the least cost solution for supplying the region with energy resources. Model results indicate that fossil fuel use for heating can be replaced at low costs by increasing forestry and agricultural biomass production. However, autarky in the electricity and the heating sector would significantly increase biomass production and require a full use of the potentials of photovoltaics on roof tops. Attaining energy autarky implies high costs to consumers and a decline in the local production of food and feed. © 2012 Elsevier Ltd. Source


Pichler M.,University of Veterinary Medicine Vienna | Damberger A.,University of Veterinary Medicine Vienna | Arnholdt T.,University of Veterinary Medicine Vienna | Schwendenwein I.,University of Veterinary Medicine Vienna | And 3 more authors.
Journal of Dairy Science | Year: 2014

The objective of this study was to evaluate the suitability of the electronic handheld devices FreeStyle Precision (FSP; Abbott Germany, Wiesbaden, Germany) and GlucoMen LX Plus (GML; A. Menarini GmbH, Vienna, Austria) for the measurement of β-hydroxybutyrate (BHBA) in whole blood in dairy goats. Additionally, glucose concentration was analyzed with the FSP device. For method comparison, the samples were also analyzed in the laboratory by standard methods, which served as the gold standard in our study. A further objective was to evaluate the agreement between samples obtained by minimal invasive venipuncture of an ear vein and measurements of whole blood samples from the jugular vein (vena jugularis). In total, 173 blood sample pairs collected from 28 goats were obtained from an ear vein and from the jugular vein. The Spearman correlation coefficients (rsp) for BHBA concentrations determined with the FSP or GML and the gold standard were 0.95 and 0.85 for the ear vein and 0.98 and 0.88 for the jugular vein, respectively. Bland-Altman plots of differences showed a positive bias of 0.12 (ear vein) and 0.21 (jugular vein) when determination was performed with the FSP and a negative bias of 0.21 (ear vein) and 0.24 (jugular vein) when using the GML. For the FSP, applying the adjusted thresholds determined by ROC analysis of 0.9 (ear vein) and 1.0mmol/L (jugular vein) allowed to distinguish between healthy goats and animals with hyperketonemia with sensitivities (Se) and specificities (Sp) for samples from the ear vein of 0.98 and 0.85, and from the jugular vein of 0.99 and 0.94, respectively. For the GML, adjusted thresholds were 0.5mmol/L for the ear vein (Se=0.94, Sp=0.75) and 0.6mmol/L for the jugular vein (Se=0.88, Sp=0.91). Repeated analyses of defined whole blood samples showed average inter- and intraassay coefficients of variation of 6.6 and 7.3% for FSP, and of 35.6 and 35.4% for GML, respectively. Test characteristics for determining glucose concentration with the FSP compared with the gold standard were poor (ear vein: rsp=0.41; jugular vein: rsp=0.51), with low validity to distinguish between hypo- and normoglycemia (Se=0.71, Sp=0.66). The present study showed good test characteristics for the FSP and moderate for the GML device for determining BHBA concentrations in whole blood. Additionally the results demonstrate the suitability of testing BHBA concentration in a blood drop obtained from an ear vein. Based on the results of this study, the FSP device is not suitable to differentiate normo- from hypoglycemia in goats. © 2014 American Dairy Science Association. Source

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