Genetic variability for resistance to fungal pathogens in bread wheat

Sustainable global wheat production requires wheat varieties, that are sufficiently resistant to the main wheat diseases. The economically important fungal pathogens worldwide include powdery mildew (PM), yellow rust (YR), leaf rust (LR) and blotch causing pathogens including Septoria nodorum blotch (SNB) and Septoria tritici blotch (STB). Here, we present the evaluation of winter wheat varieties of diverse origin against the prevalent local populations of PM, YR, LR, STB and SNB under natural infection conditions through image-based phenotyping in two consecutive years (2019 and 2020). We found several varieties to be resistant against multiple diseases. Following the association mapping, we obtained a total of 206 marker trait associations for all the parameters scored which were condensed to 79 quantitative trait loci (QTLs) (eight QTLs for PM, 25 QTLs for LR, 11 QTLs for YR, 19 QTLs for SNB and eight QTLs for STB) based on the linkage disequilibrium among the molecular markers. The known genes present at these QTLs are discussed in detail. The varieties resistant to multiple diseases, identified with the QTLs and molecular markers can be considered as elite raw material for future wheat breeding.