Identification and validation of a major cadmium accumulation locus and closely associated SNP markers in North Dakota durum wheat cultivars

Durum wheat has the tendency of accumulating more cadmium (Cd), a biotoxic heavy metal, in seeds than other commonly grown cereals, thus posing a serious food safety/public health concern. This could have serious negative impact on the national pasta industry and the international export market of durum wheat. The phenotyping for selecting low Cd lines is expensive and time consuming. The use of markers could be a more sustainable approach for selecting lines with low Cd levels. Here, a RIL population developed from a cross between Grenora (high Cd) 9 Haurani (low Cd) and two association mapping panels consisting of advanced breeding lines from the North Dakota durum wheat breeding program were used to identify QTL and associated markers for Cd. A major QTL, with Haurani contributing low Cd uptake allele and explaining 54.3 % phenotypic variation, was detected on chromosome 5BL. Association mapping using 2010 collection validated the results of linkage mapping and identified major QTL on 5BL. The 2009 collection, showed the presence of a major QTL on chromosome 2B. The SNP marker associated with major QTL on 5BL was converted to user friendly KASPar assay. The major QTL and associated KASPar marker were further validated using another RIL population developed from a cross of Strongfield (low Cd) and Alkabo (high Cd). The development of suitable marker assay, associated with major Cd uptake QTL, would help the selection for low Cd accumulating lines, minimizing the costly phenotypic evaluation for this important trait.