Dynamics of distribution of the cause agent of powdery mildew Blumeria graminis tritici on wheat during 2005-2009

Anahtar Kelimeler:

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Dynamics of distribution of the cause agent of powdery mildew Blumeria graminis tritici on wheat during 2005-2009

Powdery mildew is one of the most important diseases on wheat in regions with cool and moderate climate. Depending on the climatic conditions, yield losses may vary from 5 % to 45 %. The harmfulness of the pathogen is dependent both on the climatic factors and on the resistance of the cultivars. The dynamics of development and distribution of Blumeria graminis tritici in the region of Dobrudzha Agricultural Institute was followed during 2005 – 2009. Twenty lines and varieties of wheat were involved in the investigation. The dynamics of propagation of the pathogen’s population in the wheat crop was highly variable over years according to the climatic conditions and the presence of virulence in the distributing population of the pathogen. Significant propagation was observed in the individual years when the maximum temperatures were over 10 °С. When temperatures exceed 25 °С, the formation of conidiospores ceased gradually. Regardless of the variable conditions over the investigated years, the observation is that there is predominance of certain virulence, which is an indication that there is effect of the genetic potential for resistance of the cultivars as well. Highest attacking rate was registered in the populations of the pathogen with virulence V-1, V-2+, V3c, V-4a, V-4b, V-6, V-7, V-8, V-2+8 and V-Mil. The virulent populations V-2+6, V-2+4+6, V-5+6 and V- Mld had low rate of propagation

Keywords:

powdery mildew, Blumeria graminis tritici, virulence pathogen,

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