Eine hohe Resistenz gegen Bodenpathogene, gute Standortanpassung und Veredlungsaffinität sind die entscheidenden Merkmale von Unterlagen. Bei der Pathogenresistenz ist bei Reben die Widerstandsfähigkeit gegen die Reblaus Daktulosphaira vitifoiae essentiell, da die europäische Kulturrebe Vitis vinifera L über keinerlei Resistenzen verfügt und nur an wenigen Standorten ein wurzelechter Anbau möglich ist. Amerikanische Wildformen mit solchen Reblausresistenzen sind daher in der Unterlagenzüchtung von großer Bedeutung. Die langfristige Sicherung solcher Genotypen ist daher eine Voraussetzung für spätere Züchtungsarbeiten zur Erstellung neuer besserer Unterlagen. Daneben spielt auch die Standortanpassung eine wichtige Rolle. Vitis berlandieri ist hier am wichtigsten, da sie als einzige Art über eine hohe Kalkverträglichkeit verfügt und die Mehrheit der deutschen und europäischen Weinbaustandorte durch hohe Kalkgehalte im Boden charakterisiert sind. Kalkempfindliche Arten leiden unter Kalkchlorose mit stark vermindertem Wuchs. Aufgrund begrenzter Verfügbarkeit wurden jedoch nur wenige Pflanzen der Art in der Unterlagenzüchtung verwendet und damit nur ein Teil des Potentials der Art genutzt. In einem gemeinsamen Projekt mit dem United States Department for Agriculture wurden daher im September 2005 im ursprünglichen Verbreitungsgebiet der Art in Zentraltexas Samen von Wildformen gesammelt und die Hälfte davon in Geisenheim zur Keimung gebracht und ausgepflanzt. Derzeit werden mehr als 5000 Pflanzen in der in vivo Erhaltung. In den kommenden Jahren werden diese hinsichtlich ihrer relevanten Eigenschaften phänotypisch charakterisiert und in einem späteren Stadium auch genotypisiert, um für weitere Kreuzungs- und Selektionsarbeiten nutzbares material zu identifizieren.
Barley (Hordeum vulgare) is an important cereal grain which serves as major animal fodder crop as well as basis for malt beverages or staple food. Currently barley is ranked fourth in terms of quantity of cereal crops produced worldwide. In times of a constantly growing world population in conjunction with an unforeseeable climate change and groundwater depletion, the accumulation of knowledge concerning cereal growth and rate of yield gain is important. The Nordic Genetic Resource Center holds a major collection of barley mutants produced by irradiation or chemical treatment. One phenotypic group of barley varieties are dwarf mutants (erectoides, brachytic, semidwarf, uzu). They are characterized by a compact spike and high rate of yield while the straw is short and stiff, enhancing the lodging resistance of the plant. Obviously they are of applied interest, but they are also of scientific interest as virtually nothing is known about the genes behind the development of plant dwarfism. The aim of this project is to identify and isolate the genes carrying the mutations by using state of the art techniques for gene cloning at the Carlsberg Laboratory. The identified genes will be connected with the mutant phenotype to reveal the gene function in general. One or two genes will be overexpressed and the resulting recombinant proteins will be biochemically and structurally characterized. The insights how the mutation effects the protein will display the protein function in particular. Identified genes and their mutant alleles will be tested in the barley breeding program of the Carlsberg brewery.
Eine hohe Resistenz gegen Bodenpathogene, gute Standortanpassung und Veredlungsaffinität sind die entscheidenden Merkmale von Unterlagen. Bei der Pathogenresistenz ist bei Reben die Widerstandsfähigkeit gegen die Reblaus Daktulosphaira vitifoiae essentiell, da die europäische Kulturrebe Vitis vinifera L über keinerlei Resistenzen verfügt und nur an wenigen Standorten ein wurzelechter Anbau möglich ist. Klimaveränderungen erfordern neue Unterlagen mit hoher Reblausfestigkeit und besserer Standortanpassung. Aufgrund der derzeitigen Szenarien werden sowohl Trockenresistenz als auch Toleranz gegen hohe Kalkgehalte insbesondere in Verbindung mit hohem Bodenwassergehalte zukünftig von Bedeutung sein. Hierfür werden entsprechende Kreuzungen vorgenommen, die Sämlinge aufgezogen, auf ihre Reblausfestigkeit getestet und anschießend Prüfungen der Wurzelungs- und Veredlungsfähigkeit vorgenommen. Anschließend wird die Witterungs- und Bodenanpassung der Zuchtstämme insbesondere auf Trocken- und Kalkstandorten untersucht. Ziel ist die Entwicklung verschiedener Unteralgen, die eine vollständige Reblausresistenz mit hohen Trockenheits- und/oder Kalktoleranz kombinieren.
Salinity occurs often simultaneously with drought stress. Therefore, breeding for tolerance to combined both stresses can contribute significantly to crop yield. However, classical selection in salinity has generally been unsuccessful, partly due to high variability of salt stress resulting from the different salinity and drought status. Unfortunately, the use of unrealistic stress protocols for mimicking salinity and drought stress is the norm rather than the exception in biotechnological studies. Therefore, the great challenge is to gain knowledge required to develop plants with enhanced tolerance to field conditions. Our overall hypothesis is that a realistic stress protocol simulating a field environment with combined salt and drought stress as a platform for precision phenotyping of plant tolerance to salinity may solve this problem. This study will demonstrate that highly managed stress environments can be created and key traits of plants can be characterised by using advanced non-destructive sensors that are able to identify relevant traits of plants.
Abiotic environmental stresses are among the major factors limiting agricultural productivity in many developing countries. A common feature of various environmental stresses is the excessive accumulation of reactive oxygen species (ROS) in the leaf tissue leading to 'oxidative stress' and in turn visible leaf lesions, reduced growth, and in severe cases plant death. This project aims at identifying molecular mechanisms associated with oxidative stress tolerance in rice (Oryza sativa L.) under three different environmental conditions: (i) high tropospheric ozone concentration, (ii) zinc deficiency, and (iii) iron toxicity. This is achieved by dissecting naturally occurring genotypic variability in oxidative stress tolerance into distinct quantitative trait loci (QTL). Physiological mechanisms and genes underlying such tolerance QTL are identified by adopting an interdisciplinary approach including biochemical characterization of the antioxidant systems, transcriptome profiling, and experiments with gene knock-out mutants for candidate genes. Theoretical understanding of stress tolerance mechanisms obtained from laboratory experiments would be validated in field experiments together with international research institutions and partners in developing countries. At a later stage, the project strives to adopt emerging techniques in gene discovery such as single nucleotide polymorphism (SNP) based association mapping, and apply lessons learned from studying the 'model cereal crop' rice to other species such as barley (Hordeum vulgare L.). The project is expected to contribute to world-wide efforts in adapting crop production to stress environments by specifically advancing the understanding of oxidative stress tolerance.
Transgenes inserted into crop plants could migrate into the genetic material of closely related wild types and cause undesirable effects - such as the development of resistance to herbicides. Background Goatgrasses (Aegilops) are genetically closely related to wheat and are often found in wheat fields, where they can be very aggressive weeds. If genetically modified wheat - for example a variety resistant to a certain herbicide - was brought onto the market on a large scale, there would be a danger of the modified genes migrating by means of wheat pollen into the genetic material (genome) of goatgrasses, making these weeds resistant to herbicides too. This risk has been demonstrated on many occasions. However, little is known about the actual probability of this gene migration occurring. Objectives The project aims to quantify to which extent the genes of genetically unmodified wheat have already mingled naturally with the genome of goatgrasses growing in the vicinity. The project also aims to assess the extent to which modified genes from transgenic wheat could spread into other, related wild types if they were to cross. Methods Various goat grasses from the Mediterranean region and North America will be investigated using genetic markers to establish how many genes have already migrated from unmodified wheat into the genome of these grasses through foreign pollination. The way these migrated genes are passed on to other related wild species will be investigated by cross-breeding various goatgrasses under both natural and experimental conditions. Significance The frequency with which wheat genes are transferred to closely related wild types and an understanding of the mechanisms by which the transferred genes spread among the wild types are important in assessing the risk associated with the development of marketable transgenic wheat varieties. In addition, the goatgrasses that will be studied are currently native predominantly around the Mediterranean and in North America but are likely to become more common in our country in the future, not least because of their migratory potential and the effects of global warming.
Do genetically modified strawberries pose a threat to wild varieties? Do genetically modified strawberries pose a threat to wild varieties? Strawberries are an important niche product in Switzerland. Breeders are experimenting with genetic engineering methods to enhance the marketability of this product. There are risks inherent in this approach since the transfer of modified genes to wild strawberries could endanger the continued existence of the wild varieties. Background Transgenic varieties of strawberry with higher yields and enhanced root development already exist. The first release trials have already begun in Italy. However, if transgenic varieties of strawberry cross-breed with wild ones, there may be negative effects. The hybrids produced in this way are often sterile, yet by back-crossing with wild types or by producing prolific numbers of offshoots they can penetrate the native flora and displace it. Objectives This project has two basic goals. First, it seeks to assess the extent to which transgenic strawberries are capable of cross-breeding with their wild relatives. Second, it seeks to investigate the possible ecological impact of such crossbreeding under various environmental conditions in order to assess the risks associated with cultivating transgenic strawberries in the open. Methods Greenhouse experiments with honey bees, the most important pollinators of strawberries, will be carried out to show whether and how efficiently natural pollination occurs between transgenic and wild strawberries. Genetic methods will be used to determine how frequently foreign pollination between cultivated and wild strawberries has already occurred in the open in the past. The possible ecological implications of this will be quantified using life history data such as growth and competitive pressure. In these experiments, transgenic and artificially cross-bred strawberries from the laboratory will be planted in various soils. Significance The cultivation of transgenic plants is associated with potential risks for their wild relatives. Scientists have warned that the latter could become extinct as a result of undesirable cross-breeding. However, to date the true extent of these risks has barely been investigated. This project aims to close this gap by generating basic data with transgenic and wild strawberries as model organisms. These data could ultimately be relevant for other related crop plants such as apple trees or cherry trees.
For effective crop improvement, breeders must be able to select on relevant phenotypic traits without compromising yield. This project proposes to investigate the evolutionary consequences of flowering time modifications on a second trait of major importance for plant breeding: immunity. This will have implications both for understanding cross-talks between flowering time and defense network and for developing efficient breeding strategies. There is clear evidence that plant maturity influences levels and effectiveness of defense. Theoretical models actually predict that changes in life-history can modulate the balance between costs and benefits of immunity. Simultaneously, actors of the immune system have often been observed to alter flowering time. Two alternative and possibly complementary hypotheses can explain this link: genetic constraints due to the pleiotropic action of players in either systems, or co-evolution, if flowering-time changes modulate the cost-benefit balance of immunity. We will conduct field assays in Arabidopsis thaliana, using constructed lines as well as recombinant inbred lines and natural accessions, to differentiate the action of the two explanatory hypotheses. Using transcriptome analyses, we will identify defense genes associating with flowering time modification (f-t-a defense genes). We will quantify their expression along the assay and test whether it varies with both flowering time and fitness. We will further test whether flowering time and immunity interact to determine yield in tomato and potato.
The time of flowering is crucial for a plant's adaptation to a given environment and has a major impact on grain yield in crop species. A large number of flowering time genes have been identified in A. thaliana, and many of them are structurally conserved across species including cereals. However, the majority of these orthologs have not been functionally characterized in barley or wheat so far. Here, we propose to conduct the first comprehensive survey on variation in flowering time candidate genes and flowering time behavior under different environmental conditions in wild barley, Hordeum spontaneum Thell. We aim at identifying novel associations between candidate genes and flowering time, and to advance the functional characterization of flowering time genes in barley. To this end we will I) characterize genetic variation at 16 candidate genes in a unique collection of 480 diverse barley lines established by the applicant, II) associate genetic variation with flowering behavior under different field and controlled conditions, and III) analyze gene expression and characterize genetic diversity in putative regulatory regions of candidate genes. The characterization of natural genetic variation at flowering time candidate genes will make an important contribution to understanding developmental genetic processes underlying adaptation and thus grain yield in barley and other grasses and increase the pool of alleles available for breeding.
The Eastern Plains region of Colombia is a large tract of tropical savannah covering approximately 17Prozent of the Colombian land mass. It is an agriculturally poor region where current agricultural practices of cattle ranching have rapidly lead to poor soil fertility and low productivity. In Colombia, agriculture represents a very important part of the economy. In an attempt to economically stabilize the region the government has developed a regional plan for the Eastern Plains. This includes converting pasture land into cropping systems that provide food security for the growing Colombian population and reducing poverty.Cassava is the key crop in the regional plan for economic development and stability. However, cassava is a plant that is almost completely dependent on a symbiosis with arbuscular mycorrhizal fungi (AMF) to efficiently obtain nutrients and grow. AMF have already been shown to greatly enhance cassava yields in the field, even when added to soil that already contains AMF. They also allow farmers to reduce fertilizer inputs and use much cheaper sources of phosphate. However, to realistically use AMF to increase cassava yields and make cassava cropping more profitable, it is necessary to inoculate with native AMF in a sterile based carrier, with low transport costs. This project seeks to isolate native AMF from soils in the eastern plains and from the roots of cassava in native undisturbed populations, screen them for effectiveness in increasing cassava yields and then put some of the most effective ones into a clean sterile culture system on artificial media for mass production. These AMF isolates will be used as inocula in field trials. Because cassava is so mycorrhiza-dependent, we also propose to screen the genetic diversity of cassava for mycorrhizal responsiveness. The Swiss group will use their expertise in molecular genetics of AMF to develop a molecular marker system for quality control of AMF inoculum in cassava roots and perform a pilot AMF breeding approach to cross AMF and obtain genetically novel AMF for use in the field. The Swiss partner will train the Colombian group in these technologies. The results of the project will be disseminated within the framework of the socio-economic plan for the region developed by the National University of Colombia's Institute for Studies in Orinoquia. Researchers in that institute will use the results of this project to make economic projections of the impact of the results on small farms and cooperatives in the Eastern Plains and at the whole regional level. They will then accordingly disseminate the information to agronomists, farmers and land-owners in the region.
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