Inheritance of nonhost resistance of barley to the powdery mildew fungi of cereals and grasses

The durability and effectiveness of nonhost resistance suggests promising practical applications for crop breeding, relying upon elucidation of key aspects of this type of resistance. Inheritance and mapping studies are valuable for identifying genes that are determinants of specificity of the host or nonhost status. To overcome the problems associated with inheritance studies involving two different plant species, it is possible to study the genetics of resistance in plants that display natural variation in the degree of resistance to a non-adapted pathogen, the so-called “near-nonhosts”. Barley can be considered a near nonhost to non-adapted powdery mildews of cereals and grasses (Blumeria graminis ff. spp.), because a few accessions are somewhat susceptible at seedling stage. In the present thesis, the main goal was to investigate the genetic factors responsible for the specificity of the (non)host status in barley to B. graminis ff. spp. We also investigated the causes of an unknown condition affecting the grain quality in three mapping populations having the barley line SusPtrit as a parent.