Northern corn leaf blight of maize (NCLB)
Population structure of the pathogen Exserohilum turcicum and spatial efficacy of race specific resistances
The project is financed by the "Fachagentur Nachwachsender Rohstoffe" (FNR) and supported by the "Gesellschaft zur Förderung der privaten deutschen Pflanzenzüchtung e.V." (GFP, Abteilung Mais).The Background of this research project is the exceptional increase of maize since 2005 by about 60% with an area of 2.5 million ha in Germany in 2011. Due to this expansion maize is grown on more than 20% of the arable land in Germany and was the 2nd most important crop after wheat (27%) in 2011. One reason for this development is the focus on maize as the most productive crop for biomass to produce bioenergy on the basis of biogas.
In some regions in Germany maize is grown with more than 70% in the crop rotation. This fact leads to several upcoming phytopathological problems in maize. The most yield relevant pathogen is the leaf infecting fungus Exserohilum turcicum (Teleomorph: Setosphaeria turcica; Syn: Helminthosporium turicum) which causes the foliar disease ´Northern Corn Leaf Blight´ (Turicum Blattdürre). Against Northern Corn Leaf Blight there are four known monogenic resistance genes (Ht1, Ht2, Ht3 and HtN) which are used in maize resistance breeding. The disadvantage of monogenic inherited resistance genes is the evolution of virulent races that may overcome the used resistance genes due to coevolutionary processes in the pathogen population. This illustrates the importance of the knowledge about the race structure in the pathogen population for targeted use of race specific resistance genes in breeding and for regional efficacy of race specific resistance genes that are already used in commercial cultivars.
The first step in this project is to develop a fast race screening method based on the “conventional” method by using a differential set of near-isogenic inbred lines each containing one of the resistance genes. After inoculation of this differential set with single spore isolates and scoring the different reactions occurring on the different lines the isolate can be assigned to a specific race of the pathogen. By using this “new” screening method the central european population of Exserohilum turcicum will be monitored for the occurrence and regional patterns of different races.
Pathogenesis and mechanisms of resistance in the pathosystem Zea mays / Exserohilum turcicum are additional objects of research.
The main objectives of this project are:
- Development of a fast race screening method for Exserohilum turicum
- Race monitoring of the Exserohilum turcicum population in central Europe
- Investigation of the pathogenesis in the pathosystem Zea mays and E. turcicum
- Development of a screening method for quantitative resistances against E. turicum in maize.
Funding Institution:
Federal Ministry of Food and Agriculture
Project Management Agency: Fachagentur für Nachwachsende Rohstoffe e.V. (FNR, Agency of Renewable Resources, Germany)
Agency of Renewable Resources, Germany
Collaborators: Gemeinschaft zur Förderung der privaten deutschen Pflanzenzüchtung e.V. (GFP) 
Gemeinschaft zur Förderung der privaten deutschen Pflanzenzüchtung e.V. (GFP)
Investigator: M. Sc. agr. Hendrik Hanekamp
Supervisors: Dr. Birger Koopmann, Prof. Andreas von Tiedemann