Characterization of the Resistance to Powdery Mildew and Leaf Rust Carried by the Bread Wheat Cultivar Victo.

Leaf rust and powdery mildew are two important foliar diseases in wheat. A recombinant inbred line (RIL) population, obtained by crossing two bread wheat cultivars ('Victo' and 'Spada'), was evaluated for resistance to the two pathogens at seedling stage. Upon developing a genetic map of 8726 SNP loci, linkage analysis identified three resistance Quantitative Trait Loci (QTLs), with 'Victo' contributing the resistant alleles to all loci. One major QTL (Qgb-7A) was detected in response to on chromosome 7A, which explained 90% of phenotypic variation (PV). The co-positional relationship with known powdery mildew () resistance loci suggested that a new source of resistance was identified in . Two QTLs were detected in response to : a major gene on chromosome 5D (Q.gb-5D), explaining a total PV of about 59%, and a minor QTL on chromosome 2B (Q.gb-2B). A positional relationship was observed between the Q.gb-5D with the known 1 gene, but polymorphisms were found between the cloned 1 and the corresponding 'Victo' allele, suggesting that Q.gb-5D could represent a new functional 1 allele. Lastly, upon anchoring the QTL on the reference genome, candidate genes were hypothesized on the basis of gene annotation and in silico gene expression analysis.