Reaction of winter wheat cultivars to eyespot assessed visually and by real-time PCR

The reaction of twelve winter wheat cultivars frequently grown in the Czech Republic and twenty-five new breeding lines to inoculation with Oculimacula yallundae and Oculimacula acuformis was evaluated in small plot trials from 2017–2018. The assessment was carried out visually by symptoms and by a quantitative real-time polymerase chain reaction (qPCR). The aims of the study were to compare the results of both methods, to evaluate the effect of the resistance gene Pch1 to eyespot, and to select new breeding lines resistant to eyespot. The relationship between the eyespot symptoms and the pathogen DNA content in plant tissues followed a moderate linear regression. Low levels of eyespot were observed in the cultivars/lines possessing the resistance gene Pch1 (Annie, Hermann, Rebell, SG-S1215-14, SG-S1825-14, SG-S791-13) and also in the line SG-SU630-15. The qPCR method was able to detect low levels of the pathogens in the plant tissue and to distinguish two eyespot pathogens. O. acuformis was detected in very low concentrations in the inoculated plants compared with O. yallundae. The eyespot infection rate was significantly higher in 2017 than in the next agricultural season due to extremely dry and warm spring weather in 2018.