Resistance of wheat varieties to common bunt

The common bunt (Tilleta caries) is widely spread and is one of the most important seed-born diseases in wheat. However, since the introduction of chemical seed dressing it can be efficiently controlled. Given that the directives of organic farming do not permit the use of synthetic chemicals for control, other means are needed in order to control the disease. In this context, the resistance of a variety is an important factor. From 2000 to 2002, nine field trials were carried out in three different locations. Twenty Swiss and other European wheat varieties were artificially infected with common bunt. They were then tested for their susceptibility to the disease. The trials showed that there was a considerable difference between the varieties. None of the checked wheat varieties was completely resistant. The best varieties (Levis, Titlis, Toronit, Arbola and Arina) had 11.4 % to 16.9 % infected heads on the average. The most susceptible variety had 50.5 % infected ears. The Swiss-bred varieties showed a good resistance to common bunt in comparison with the foreign wheat varieties. Furthermore, the trials revealed a decisive influence of the soil temperature in the first two weeks after drilling on the level of disease severity.