Identification of a SNP Marker Associated with WB242 Nematode Resistance in Sugar Beet

The beet-cyst nematode (Heterodera schachtii Schmidt) is one of the major diseases of sugar beet. The identification of molecular markers associated to the nematode resistance would be helpful for developing resistant varieties. The aim of this study was the identification of SNP (Single Nucleotide Polymorphism) markers for the nematode resistant source WB242. A WB242-F₂ population was phenotyped for nematode resistance. DNA of the ten most resistant and ten most susceptible individuals was pooled and subjected to Restriction-site Associated DNA Sequencing (RAD-Seq) which generated 7,241 single nucleotide polymorphisms (SNPs). Then, a subset of 384 SNPs were genotyped on 192 F₂ individuals to identify SNPs associated with nematode resistance. SNP_192, localized on chromosome 5, resulted as the most significantly associated SNP (P = 4.6 × 10⁻¹³). This association was further validated on a set of resistant and susceptible varieties. We conclude that SNP_192 is a valuable marker for improvement of nematode resistance through marker-assisted selection.