Resistant barley varieties may facilitate control of Ramularia leaf spot

Summary

Ramularia leaf spot (RLS) is widely present in Denmark nowadays and has the potential to reach severity levels high enough to cause economic damage. The results of multi-location surveys and field trials of several years suggest that varietal resistance can be an efficient means for controlling RLS. The spring barley cultivars most affected by RLS possess mlo-resistance against powdery mildew while the least affected ones do not. Other mildew resistances as well as varietal susceptibility to other foliar diseases were not clearly related to the RLS reaction pattern of neither spring- nor winter barley cultivars. Promising RLS resistance donors may be the spring barleys Power, Helium, Isabella, Nathalie, Cruiser and Isotta and the winter barleys Lonni, followed by Chess, Lomerit, Nobilia, and Carola. However, more work is needed to develop reliable methods for efficient RLS resistance testing and to determine the nature and genetic basis of RLS resistance and its relation to varietal resistances against other diseases.