Inheritance and efficiency of crown rust resistance in the line Pc 50-4 (Avena sterilis L.).

Pc 50-4, gene of resistance to oat crown rust, is a member of the set of genes transferred to cultivated Avena sativa L. from wild Avena sterilis L. In our study, a high level of the efficiency of Pc 50-4 in the control of a number of pathotypes originating from different regions of Europe and Middle East, collected in 2000–2004, is demonstrated. Only 5 pathotypes from different geographical areas were virulent to Pc 50-4 out of the total of 71 tested isolates. The efficiency of the gene Pc 50-4 is 0.9296. This value is well comparable with the very high efficiency of the set of genes which are commonly used as differentials in the Research Institute of Crop Production in Prague as well as with genes successfully used in breeding resistance programmes in North America. Hybridological F2 and F3 analyses performed in field and glasshouse conditions show that in the Pc 50-4 line the resistance to two recently identified pathotypes of oat crown rust is conditioned by one major gene as well.