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Feeding of cabbage flea beetles on various Brassica species can reduce crop productivity. While progressing towards the goal of reducing the use of synthetic pesticides and promotion of environmental protection, we wish to exploit plants' natural resilience. The results of our study carried out in 2009-2010 show that glucosinolate contents vary with plant species and plant organs. Among the indole glucosinolates, all Brassica species (cabbage, oil radish, oil seed rape and white mustard) displayed the presence of glucobrassicin, whose influence on cabbage flea beetles varied according to the plant species. We established that gluconasturtiin content in oil seed rape negatively (r = -0.99) influenced the feeding of flea beetles, while the progoitrin (r = 0.51), sinalbin (r = 0.61) and gluconapin (r = 0.67) stimulated the feeding of flea beetles in this crop. No significant influence of glucobrassicin on flea beetles was detected in oilseed rape, while this glucosinolate negatively influenced the intensity of flea beetles feeding in oil radish and white mustard (r = - 0.32, r = - 0.64). Oil radish thus proved to be the most suitable species as a trap crop for flea beetles. We conclude that protection of the Brassicas against flea beetles can depend on glucosinolate content, but additional tests to confirm practical meaning of this study in environmentally acceptable cabbage production are required.

Pavlovic M.,International Hop Growers Convention IHGC Secretary General | Pavlovic M.,Slovenian Institute of Hop Research and Brewing | Pavlovic V.,University of Maribor
Agrociencia | Year: 2011

Hops (Humulus lupulus L.) are vital for the brewing industry, as they contribute significantly to the organoleptic qualities of beer, including taste and flavor. Experimental hop breeding data from the Slovenian Institute of Hop Research and Brewing (IHPS) were used to create a model based on the multi-attribute decision modeling methodology. The model has 18 attributes hierarchically grouped within four main attributes: Biology, Chemistry, Morphology and Brewing value. Furthermore, utility functions in the model were defined by sets of elementary decision rules throughout the entire hierarchy for all aggregated attributes. The central part of the model contains 144 decision rules, which were specified according to the model users' previous breeding experiences. Four prospective hop hybrids and a reference hop variety with the target characteristics of plant resistance and brewing value were evaluated. Based on the breeding experiences and model results attributes' assessments were carried out. Decisions based on the model evaluation offered an additional tool for experts' final decisions in selecting appropriate materials for further breeding or the commercial use of hop plants.

Rojht H.,University of Ljubljana | Kosir I.J.,Slovenian Institute of Hop Research and Brewing | Trdan S.,University of Ljubljana
Journal of Plant Diseases and Protection | Year: 2012

Ethanol extracts of Rosmarinus officinalis, Lavandula angustifolia and Ruta graveolens were tested against adults of Acanthoscelides obtectus and Leptinotarsa decemlineata. Using a newly developed computer tracking system, a choice test revealed that all of the extracts have a repellent action. The highest repellent activity against the bean weevils adults was the ethanol extract of rue, whereas the highest repellent activity against the Colorado potato beetle adults was the lavender extract. We suggest that a cocktail of volatile components in the ethanol extracts was responsible for the observed repellent action. All three of the extracts have insecticidal effects on bean weevils, reducing F1 adult emergence, with no side effects on the germination of the bean plants. In contrast, the extracts did not demonstrate an insecticidal effect on Colorado potato beetles. © Eugen Ulmer KG, Stuttgart.

Hrastar R.,Slovenian Institute of Hop Research and Brewing | Abramovic H.,University of Ljubljana | Kosir I.J.,Slovenian Institute of Hop Research and Brewing
European Journal of Lipid Science and Technology | Year: 2012

Camelina sativa is an alternative, low input oilseed crop with oil of high nutritional value. In Slovenia, C. sativa landrace has been grown by local farmers in the Koroška region since the middle of the 20th century. In our study, we determined oil and glucosinolate content (GLS) of camelina seed and free fatty acid (FFA), peroxide value (PV), iodine value (IV), tocopherol contents (T), and fatty acid profile of camelina oil from ten locations over three consecutive growing seasons. The oil content ranged from 28.78 to 40.21%, while IV, PV, and FFA fell into a range that makes this oil useful in various nutritional applications. Camelina was remarkably rich in essential n-3 α-linolenic acid (33.32-37.65%) and γ-T (532-798mg/kg) in oil, and GLS (16.39-41.43μmol/g) in seed. Due to observed variability, it seems that the seed and oil characteristics of C. sativa landrace are affected by the local environmental conditions at a specific farm location and by variable genotypes between farms as a result of a more than half a century of environmental selection. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dezelak M.,Slovenian Institute of Hop Research and Brewing | Zarnkow M.,TU Munich | Becker T.,TU Munich | Kosir I.J.,Slovenian Institute of Hop Research and Brewing
Journal of the Institute of Brewing | Year: 2014

Typical beer contains significant amount of gluten, and being the third most popular beverage worldwide, the commercial production of its gluten-free form is of rising interest. This research aimed to prepare bottom-fermented beverages from buckwheat and quinoa and to explore their physical, chemical and sensory properties. Compared with barley, the analysis of brewing attributes of buckwheat and quinoa showed a lower malt extracts, longer saccharification times, higher total protein and fermentable amino nitrogen content and higher values of the iodine test and colour. Fermentability values, the wort pH and the soluble protein content were similar for barley and buckwheat, but different for quinoa, whereas only values of viscosity and beverage pH were similar between barley and quinoa. Both beverages, especially the quinoa beverage, contained a superior level of metal cations. The fermentable carbohydrate content in the buckwheat wort was comparable to barley but lower in quinoa; however, worts derived from both pseudocereals contained predominantly glucose. The amino acid content of the buckwheat wort was similar to barley, whereas the content in the quinoa beverage was almost twice as high. The content of volatile compounds commonly associated with beer aroma was comparable between the barley and buckwheat beverage but significantly lower in the quinoa; however, the latter contained some distinctive volatile substances not found in the other beverages. The organoleptic perception of the buckwheat beverage was better than that of the quinoa, although both showed a good general acceptance. In general, buckwheat appears quite similar to barley, whereas quinoa shows many unique properties. © 2014 The Institute of Brewing & Distilling.

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