8th INTERNATIONAL WHEAT CONFERENCE

ReSISTANCe BReedINg AgAINST LeAf SPoT dISeASeS
IN Szeged, huNgARy
Mária Csősz 1 , László Purnhauser 1 , Beáta Tóth 1 , József
Bakonyi 2 , László Cseuz 1
1 Cereal Research Non-Profit Ltd. Company, 6726 Szeged, Alsó kikötősor 9., Hungary
2 Plant Protection Institute, 1525 Budapest, Herman O. u. 15., Hungary
E-mail Address of presenting author: laszlone.csosz@gk-szeged.hu
Leaf spot diseases (Pyrenophora tritici-repentis, Septoria tritici, Stagonospora nodorum
and Bipolaris sorokiniana) can cause 3-50% yield loss in wheat production worldwide.
Their importance increased due to changes in agricultural practice (e.g. increased wheat
monoculture and minimum tillage). The first serious epidemic in Hungary occurred in
1999. Up to this time little information was available on the occurrence of these diseases
and their effect on grain yield in Hungary. The aim of the study was to investigate the occurrence
and frequency of leaf spot pathogens, and also to assess the resistance and yield
reaction of cultivars developed in Szeged breeding program from 2000.
Results
Occurrence and significance of leaf spot pathogens: In leaf samples collected from different
parts in Hungary only the P. tritici-repentis, S. tritici, S. nodorum and B. sorokiniana
species were identified. Of them P. tritici-repentis and S. tritici proved to be dominant
pathogens, though S. nodorum showed a significant occurrence in some years. Using
conventional and molecular identification methods, Pyrenophora teres, a typical barley
pathogen was firstly identified on winter wheat in Hungary (1, 2).
Identification of P. tritici-repentis races in Hungary: Based on seedling tests using monospore
isolates, races 1, 2, 4, 7, and 8 were identified in the pathogenic population. The other part of the
isolates could not be classified to any known races, similarly to the results of Sárová (3, 4).
Assessment of natural infection in breeding lines: Between 2000 and 2009 four serious
leaf spot epidemics were observed. At the most serious epidemics in 2005 the infection
level was 64%. Severity of symptoms was significantly influenced by the weather, as in dry
years (e.g. in 2009) it was difficult to find any symptoms.
Resistance and yield reaction of cultivars against P. tritici-repentis in artificially inoculated
environment: In multi-year field trials, cultivars GK Holló, GK Héja and GK
Csillag showed an excellent resistance to P. tritici-repentis. In experiments using artificial
infection, the maximal grain yield loss was 25 % in the most susceptible cultivars.
Transferring resistance genes into wheat cultivars: As the general resistance of Szeged
cultivars to S. tritici was much weaker than to P. tritici-repentis, the use of new resistance
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