Inheritance of resistance to Rhynchosporium secalis in spring barley (Hordeum vulgare L.)

The inheritance of durable resistance of selected spring barley varieties to Rhynchosporium secalis was investigated. Data from the F₂ generation of a 4 × 4 diallel, without reciprocals and the F₄ generation of three crosses selected out of this diallel, suggest that resistance in this sample of varieties tested is complex in inheritance. Significant additive effects were detected indicating that the resistance level of barley cultivars may be improved by the hybridisation of suitable varieties. However, the genes conferring resistance seem to be concealed by the expression of one completely dominant resistance gene in our set of varieties. These results are partly in conflict with previous results on the inheritance of resistance to R. secalis in the breeder's line ‘11258/2286₁₃A’ indicating that the effectiveness of this resistance gene may be greatly influenced by the genetic background of the current population of R. secalis.