Roggenschwarzrost, Puccinia graminis f. sp. secalis, mit resistenten Sorten kontrollieren

Stem rust in rye (Puccinia graminis f. sp. secalis) is favored by hot spring and pre-summer temperatures and a lack of resistant cultivars in Germany. Our study aimed in analyzing the virulence situation of the pathogen and resistance situation of the host. Forty-one single-pustule isolates were tested with a preliminary differential set of 11 inbred lines selected out of a greater set of 48 lines. In addition, six lines reacted fully resistant in a detachedleaf test in seedling stage. Isolates showed a mean complexity of five virulences and were classified into 32 pathotypes. Only seven pathotypes could be found more than once. A Simpson index of 0.99 reveals a high level of diversity of German stem rust populations. In 2012, 30 rye populations were cultivated under organic conditions at five field sites, and further 40 populations at three sites, to determine the level of adult-plant resistance. The most commonly grown cultivars were highly susceptible to stem rust under artificial infection with disease severities of about 50%. Twelve foreign rye populations contained 16-62% fully resistant plants. These data are a promising starting point for developing more resistant rye cultivars.