Association Mapping of Cadmium Uptake Locus in Durum Wheat Advanced Breeding Lines.

Cadmium (Cd) is a toxic heavy metal that can retard the plant development and can cause serious effects on humans. The amount of Cd in grains depends on multiple factors including the uptake of Cd from Soil and translocation through xylem and phloem to the grains. Association mapping was used to analyze two durum wheat collections consisting of advanced breeding lines from the North Dakota State University durum wheat (Triticum turgidum L var. durum Desf.) breeding program to discover markers associated with the amount of Cd accumulated in the grains. The samples were sent to the USDA-ARS Cereal Crops Genotyping Laboratory (Fargo, ND) for genotyping with high density single nucleotide polymorphism (SNP) markers using a custom designed Illumina iSelect BeadChip platform containing 9,000 SNPs using the Illumina Infinium Assay protocol. For the 2009 collection, one QTL that explains 3 % of phenotypic variation was identified on 2B at 7.25 cM which could cosegregate with a height locus identified earlier. For the 2010 collection, one marker that explains 34 % of phenotypic variation was identified on 5B at 165.7cM and one other at 178.3cM that explains 27% of phenotypic variation and could be linked to the gene Cdu1 identified previously. Since the complexity of steps involved in the Cd accumulation in grains, identification of additional QTL using better coverage of markers and a large collection of genotypes would help MAS for Cd accumulation.