Genome-Wide Association Analysis and Genomic Prediction for Adult-Plant Resistance to Septoria Tritici Blotch and Powdery Mildew in Winter Wheat

Septoria tritici blotch (STB) caused by the fungal pathogen Zymoseptoria and powdery mildew (PM) Blumeria graminis f.sp ( Bgt ) are among forefront foliar diseases of wheat that lead to a significant loss grain yield quality. Resistance breeding aimed at developing varieties with inherent resistance STB PM has been most sustainable environment-friendly approach. In this study, 175 winter landraces historical cultivars originated from Nordic region were evaluated for adult-plant (APR) in Denmark, Estonia, Lithuania, Sweden. Genome-wide association study (GWAS) genomic prediction (GP) performed based on response field conditions using 7,401 single-nucleotide polymorphism (SNP) markers generated 20K SNP chip. Genotype-by-environment interaction was both disease scores. GWAS detected stable environment-specific quantitative trait locis (QTLs) chromosomes 1A, 1B, 1D, 2B, 3B, 4A, 5A, 6A, 6B 2A, 2D, 3A, 4B, 6B, 7A, 7B resistance. GP accuracy improved when assisted QTL as fixed effect. The GWAS-assisted ranged within 0.53–0.75 0.36–0.83 PM, respectively, across tested environments. This highlights valuable source APR PM. Such germplasm could be used identify introgress novel genes modern lines.