Crown rust (Puccinia coronata f. sp. avenae) is the main disease in the oat crop (Avena sativa L.) and the use of resistant cultivars is the most important control method. This study had as objective to determine the genetic control of resistance to crown rust in oat and to identify different gene sources for resistance to this disease. Three resistant genotypes (UFRGS 15, UFRGS 881920 and UFRGS 86A1194-2), three susceptible genotypes (UFRGS 7, UFRGS 8 and UFRGS 14) and the F3 progenies derived from crosses between these genotypes were used. The plants were evaluated individually with regard to the presence or absence of crown rust symptoms, and the data from these evaluations were used to perform a genetic analysis in which the hypothesis of one or two resistance genes were tested by the chi-square test. Results showed one dominant resistance gene in UFRGS 881920 and two complementary resistance genes in UFRGS 15, when they were crossed with the susceptible genotypes. The genetic analysis performed did not allow to determine whether these two genotypes are or are not the same source of resistance.
Avena sativa; disease resistances; Puccinia coronata; plant diseases; genetic control
