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Accumulation of carbohydrates and pungent principles in characteristic seed and set grown onion varieties (Allium cepa L.)
Get PDFThe profile of carbohydrates of onions (Allium cepa L.), mainly consisting of fructooligosaccharides (FOS), has a strong impact on digestibility, processability and storability. This study focused on the accumulation of FOS and pungent principles in onions during bulb maturation. Different onion varieties were grown from both, seedsand sets. Total FOS concentrations in onions of cv. ‘Sturon’ were higher when grown from sets than from seeds throughout the entire maturation period, reaching final levels of 75.7 ± 2.2 and 61.8 ± 11.8 g/L FOS, respectively. Higher levels in set grown onions might be due to their earlier emergence, thus resulting in an extended photosynthetically active period (+12% total sunshine hours). However, seed grown, so-called dehydrator onions (cv. ‘Stardust’) had significantly higher FOS contents than set grown cv. ‘Sturon’ onions at all sampling points (final FOS level: 129.3 ± 16.6 g/L), indicating cultivar-dependant accumulation. Furthermore, dehydrator onions accumulated FOS with highest molecular weight and a unique FOS distribution, allowing clear discrimination of such dehydrator cultivars. Besides carbohydrates, pungency as indicated by pyruvic acid levels was shown to be determined by sulphurous fertilization and its timing
Modern aspects of wheat grain proteins
Get PDFThe unique baking properties of wheat have contributed to the large variety of food products made of wheat. Wheat products are immensely popular, which is reflected in their ubiquitous consumption. Concerning wheat quality, a main challenge for intense growing strategies is to adapt wheat plants of unaltered yield and baking quality to decreased nitrogen input, which will limit unwanted nitrogen leaching into drinking water and safe resources. A probably more important challenge for wheat adaptation will be caused by global climate change. For a relative small percentage of the human population wheat grain proteins can cause a number of serious diseases including coeliac disease. Susceptible persons often have to completely avoid wheat, as well as rye and barley products. Methods for detection of gluten protein are well advanced, increasing safety for patients. Wheat breeding using traditional breeding and modern genome editing approaches are seen to be necessary to develop new wheat cultivars for adaptation to new environmental conditions caused by climate change, reduced nitrogen input and increased production efficiency, as well as reduction of disease potential. Wheat grain protein analytical methods are important, e.g. for determination of quality parameters and for decision making in breeding programmes. Aspects of protein extraction, proteomic analysis and database coverage of wheat protein sequences are discussed
Breeding progress in wheat: Simultaneous improvement of disease resistance, yield and product quality
Get PDFDie Weizenzüchtung in Deutschland hat in den letzten Jahrzehnten beeindruckende Erfolge erzielt. Zukünftig steht sie jedoch vor erheblichen Herausforderungen, die Erzeugung hochwertiger Nahrungsmittel unter nachhaltigen Produktionsbedingungen zu ermöglichen. Die züchterische Verbesserung des genetischen Ertragspotentials über Jahrzehnte hat einen erheblichen Beitrag zur Steigerung der Weizenerträge geleistet. Eine weitere Steigerung erscheint möglich, der Fokus sollte künftig jedoch noch mehr in der Stabilisierung der landwirtschaftlichen Erträge liegen. Die Verbesserung der Krankheitsresistenz gegen pilzliche Pathogene, Virosen und verstärkt auch Insekten bleibt dabei eine dauernde Aufgabe, die durch die eingeschränkte Verfügbarkeit pestizider Wirkstoffe zentrale Bedeutung gewinnen wird. Ein sehr hoher Forschungsaufwand wird nötig sein, die Ertragsstabilität gegen abiotische Stressoren, v.a. Trockenheit und Hitze, zu verbessern. Eine Erhöhung der Nährstoffeffizienz ist Voraussetzung für einen geringeren, umweltschonenden Ressourcenverbrauch, während die hohe Kornqualität zu erhalten ist. Die Studie betont das Potential, welches durch neue Züchtungstechniken für die Integration der zahlreichen Ansprüche besteht und regt an, eine Balance zwischen Risikovorsorge und Innovation zu suchen.Wheat breeding has achieved impressive successes in Germany in recent decades. In the future, it will however face considerable challenges in enabling the production of high-quality food under conditions of sustainable production. The improvement of genetic yield potential has made a significant contribution to the increase in grain yields. Further increase seems possible, but the future focus should be to enhance yield stability. Improving disease resistance to fungal pathogens, viruses, and increasingly to insect pests remains a permanent task that will gain central importance due to reduced release of pesticide substances. A significant increase in research efforts will be necessary to improve yield stability against abiotic stresses, mainly drought and heat. Moreover, an increase in nutrient efficiency will be a prerequisite for an environment-friendly resource consumption, while high grain quality has to be maintained. The study stresses the potential of the new breeding techniques, such as genome editing, to integrate all these demands through breeding and suggests searching for a balance between risk prevention and innovation
Analysis of the mechanical properties of wood attacked by Xylotrechus arvicola (Coleoptera: Cerambycidae) larvae, and its influence on the structural properties of the plant
Get PDFXylotrechus arvicola is an invasive insect on Vitis vinifera in the main wine-producing regions of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood and make galleries, which cause structural damages to the plant. The aim of this study was to investigate how grapevine wood infested by larvae affects the mechanical properties of the plant in comparation with those of uninfested wood. Samples of grapevine wood uninfested and infested by larvae were collected from vineyards. Compression and flexural strengths as well as simulated structures of grapevine wood in field, in relation to harvest weight by variety, were used to quantify the wood mechanical properties. Infested wood endured a lower strength and normal tension, and exhibited a reduction in the structural capacities in the simulation of harvest weight of \u27Cabernet-Sauvignon\u27 variety (up to 62.0 %). \u27Tempranillo\u27 (despite its high mechanical slenderness values) and \u27Cabernet-Sauvignon\u27, were the varieties that showed a higher resistance on trunks and branches, respectively. A lower bending moment was observed on the infested branches of all varieties. Changes in the mechanical properties of infested wood suggest a decrease in mechanical resistance of wood attacked by larvae that could contribute to the rupture of the infested grapevine over time. Grapevine wood attacked by X. arvicola larvae could be more sensitive to mechanical external factors in vineyards such as strong winds, harvest weight and vibration exerted by harvesting machines
Cryopreservation of grapevine (Vitis spp.) shoot tips from growth chamber-sourced plants and histological observations
Get PDFMany genebanks rely on cryopreservation as a method to preserve vulnerable field collections of vegetatively propagated crops. Effective cryopreservation procedures have been identified for Vitis; however, they usually use in vitro plantlets as the shoot tip source materials. It is costly to establish Vitis collections in vitro prior to cryopreservation. We sought to determine if growth chamber derived Vitis plants could serve as the source of shoot tips for cryopreservation. Nodal sections from growth chamber derived plants were surface-disinfected and placed in tissue culture on pre-treatment medium for 2 weeks. Uniform apical shoot tips (1 mm) were first obtained from the nodal sections and then precultured for 3 days on medium containing 0.3 M sucrose, salicylic acid, glutathione (reduced form), ascorbic acid and plant preservative mixture. Half-strength PVS2 was applied for 30 min at 22 °C, prior to full-strength PVS2 treatment at 0 °C. Cryopreserved shoot tips had the highest average regrowth of 50 and 55 % without and with cold-acclimation followed with a full-strength PVS2 exposure duration of 40 and 30 min at 0 °C, respectively. This cryopreservation protocol achieved high percentages of regrowth in V. vinifera \u27Chardonnay\u27 and \u27Riesling\u27 and V. hybrid \u27Oppenheim\u27. Histological observations revealed that shoot tips from growth chamber plants had apical as well as multiple lateral meristems that survived LN immersion. The preservation of multiple meristems in each shoot tip may increase the capacity of shoot tip regeneration in cryopreserved Vitis that originates from ex vitro sources. The high percentage of regrowth after shoot tip cryopreservation using Vitis shoot tips derived from growth chamber source plants suggest that it may be possible to cryopreserve Vitis shoot tips without first introducing each accession into tissue culture
Tannin content and antioxidant capacity of five Greek red grape varieties
Get PDFTannins are located in skins and seeds and are responsible for important sensory and quality attributes of red grapes and wines, such as astringency, bitterness and colour stability. However, little is known regarding Greek Vitis vinifera varieties. The aim of this study is to evaluate the grape phenolic content and to present data that may contribute to the development of suitable winemaking techniques for these varieties. In this study berry attributes, skin and seed content of tannins and antioxidant capacity from five Greek Vitis vinifera varieties, namely \u27Mavrotragano\u27, \u27Mandilaria\u27, \u27Kotsifali\u27, \u27Agiorgitiko\u27 and \u27Xinomavro\u27 were analyzed. Significant differences were observed in berry weight and the distribution of berry component mass in mature berries, among the different varieties. \u27Mandilaria\u27 and \u27Kotsifali\u27 had the heavier berries while the higher contribution of skins and seeds in berry was observed in \u27Agiorgitiko\u27 and \u27Mavrotragano\u27 grapes respectively. According to the results, the higher content of seed tannins in berries was determined in \u27Mandilaria\u27 and the lower in \u27Kotsifali\u27. Finally, varieties with high concentrations of tannins, \u27Mandilaria\u27 and \u27Mavrotragano\u27, also demonstrated significant high values of antioxidant capacity
