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Dissertation
Changes of traditional farming systems and their effects on land degradation and socio-economic conditions in the Inle Lake region, Myanmar
(2016-04-22)
At many locations in Myanmar, ongoing changes in land use have negative environmental impacts and threaten natural ecosystems at local, regional and national scales. In particular, the watershed area of Inle Lake in eastern Myanmar is strongly affected by the environmental effects of deforestation and soil erosion caused by agricultural intensification and expansion of agricultural land, which are exacerbated by the increasing population pressure and the growing number of tourists. This thesis, therefore, focuses on ...
Dissertation
Isolation and characterisation of novel nematophagous fungi from eggs of the cereal cyst nematode Heterodera filipjevi and identifying their secondary metabolites with nematicidal activity
(2018-06-11)
Parasitism caused by cereal cyst nematodes (CCNs) is a major limiting biotic factor in cereal cropping systems. CCNs attack cereal crops and can lead to significant yield reductions. Field observations in experimental wheat fields of the International Maize and Wheat Improvement Centre (CIMMYT) in Turkey had revealed a sharp decline in nematode populations of the cereal cyst nematode Heterodera filipjevi. Microscopic studies of the cyst samples obtained from these fields regularly demonstrated the presence of fungi ...
Dissertation
Einfluss der Flächenwahl, Anbaudichte und Landschaftsstruktur auf den Befallsstatus und die Ausbreitung der Möhrenfliege Psila rosae F. (Diptera: Psilidae) im ökologischen Möhrenanbau
(2012-07-23)
Durch die vermehrte Nachfrage von Biomöhren im Lebensmitteleinzelhandel ist die Anbaufläche ökologisch erzeugter Möhren in den letzten zehn Jahren deutlich angestiegen. Der Anbau konzentriert sich auf bestimmte Regionen und erfolgte damit zunehmend auf großen Schlägen in enger räumlicher und zeitlicher Abfolge. Mit der steigenden Wirtspflanzenpräsenz steigt auch der Befallsdruck durch die Möhrenfliege. Während der Schädling im konventionellen Anbau mit Insektiziden kontrolliert wird, stehen dem Ökologischen Landbau ...
Dissertation
Conservation agriculture in organic farming: Impacts on weeds and plant-parasitic nematodes during the transition
(2017-10-12)
Der Bodenschutz ist eine der wichtigsten Anforderungen an die Landwirtschaft im 21. Jahrhundert. Daher sind nicht-wendende Bodenbearbeitungssysteme, basierend auf dem Anbau von Untersaaten und Zwischenfrüchten, verstärkt in den Fokus der europäischen Agrarwirtschaft geraten. Allerdings können diese neuartigen Systeme das Spektrum und die Abundanz gewisser Krankheiten, Schädlinge und Unkräuter grundlegend verändern. Ein Beispiel ist die Zunahme von Unkräutern und ihren Samenbanken während der Übergangsphase von ...
Dissertation
Genetic variation of and environmental effects on inducibility of resistance in tomatoes (Solanum lycopersicum L.) to Phytophthora infestans (Mont) de Bary
(2010-12-02)
Many plant strengtheners are promoted for their supposed effects on nutrient uptake and/or resistance induction (IR). In addition, many organic fertilizers are supposed to enhance plant health and several studies have shown that tomatoes grown organically are more resistant to late blight, caused by Phytophthora infestans to tomatoes grown conventionally. Much is known about the mechanisms underlying IR. In contrast, there is no systematic knowledge about genetic variation for IR. Therefore, the following questions ...
Dissertation
Development and Integration of Biocontrol Products in Branched Broomrape (Phelipanche ramosa) management in Tomato
(2012-10-19)
Parasitic weeds of the genera Striga, Orobanche, and Phelipanche pose a severe problem for agriculture because they are difficult to control and are highly destructive to several crops. The present work was carried out during the period October, 2009 to February, 2012 to evaluate the potential of arbuscular mycorrhizal fungi (AMF) to suppress P. ramosa on tomatoes and to investigate the effects of air-dried powder and aqueous extracts from Euphorbia hirta on germination and haustorium initiation in Phelipanche ramosa. ...
Dissertation
Pathogens occuring in the winter pea-maize-winter wheat rotation, their host specificity and the potential of compost in suppressing foot and root disease of peas
(2015-09-17)
The overall aim of the work presented was to evaluate soil health management with a specific focus on soil borne diseases of peas. For that purpose field experiments were carried out from 2009 until 2013 to assess crop performance and pathogen occurrence in the rotation winter pea-maize-winter wheat and if the application of composts can improve system performance. The winter peas were left untreated or inoculated with Phoma medicaginis, in the presence or absence of yard waste compost at rate of 5 t dry matter ha-1. ...
Dissertation
Etiology of Maize Root rot in Oman: Causal agents and effects of a compost based organic growing system
(2018-08-16)
Summary:
In Oman, the main cereal crop Maize is facing serious problems due to high salinity, alkaline soils with low organic matter, high temperatures, and root rot diseases. Production peaked at 40,000 t in 2011 but dropped to less than 15,000 t in 2014.
A survey on maize root rot in eight maize growing governorates in Oman yielded nine fungal and oomycetes species of which Pythium arrhenomanes and Fusarium fujikuroi were first reports on maize in Oman. Both are able to attack multiple hosts. Under controlled ...
Dissertation
Studies on the diversity of the main necrotrophic pathogens on wheat and barley Pyrenophora tritici-repentis and Cochliobolus sativus
(2017-10-30)
Leaf blights such as tan spot of wheat (Pyrenophora tritici-repentis) and spot blotch of barley (Cochliobolus sativus) are among the main constraints in achieving high and stable yields and are the main concerns among the several intrinsic drawbacks of narrow cropping sequencesas both are residue borne. The development of useful and durable resistance against prevalent races requires detailed information on the virulence diversity of the pathogen and the type of resistances available in the host. Thus, the focus of ...