S1-2: Leptosphaeria species causing blackleg disease in oilseed rape and frequencies of L. maculans races in the Czech Republic

Abstract: This project aimed to monitor frequencies of effector (Avr) genes in populations of
Leptosphaeria maculans in the Czech Republic. Isolates of L. maculans were collected from
17 cropping areas during 2017-2020. Presence of different Avr genes was tested using a set of
differential cultivars with 485 L. maculans isolates collected. The results indicate that AvrLm7 was the most abundant Avr gene in these L. maculans populations (92.6 % of isolates). Other Avr genes were less frequent. In total, 17 different races of L. maculans were identified.