Genome‐Wide Association Mapping and Genomic Prediction of <i>Septoria nodorum</i> Blotch Resistance in Central European Winter Wheat (<scp><i>Triticum aestivum</i></scp> L.)

ABSTRACT Septoria nodorum blotch (SNB) is a fungal disease of wheat caused by the necrotrophic fungus Parastagonospora nodorum (Berk.), considered as one of the most devastating fungal diseases affecting winter wheat ( Triticum aestivum L.). The complex inheritance of resistance to SNB poses significant challenges to breeding programmes. Improving selection precision and identifying novel resistance QTLs are crucial for enhancing SNB resistance. This study investigated strategies for crop genetic improvement, including genome‐wide association mapping (GWAS) and genomic prediction (GP), within a practical breeding programme. A population of 1500 winter wheat breeding lines was phenotyped for SNB resistance over 5 years across 19 geographical locations under natural infection conditions. Despite highly unbalanced breeder's data, medium to high heritabilities for SNB resistance were achieved. GWAS identified 11 significant marker‐trait associations for SNB resistance across Chromosomes 2A, 2B, 4B, 4D, 5D and 7B. GP fivefold cross‐validation analysis revealed a predictive ability of 0.52 for SNB resistance. The resistant wheat genotypes and SNP markers identified in this study will be valuable assets for future breeding efforts to enhance SNB resistance in wheat.