Improving wheat grain composition for human health: an atlas of QTLs for essential minerals

Abstract Wheat is an important source of mineral micronutrients for humans and livestock. We therefore grew three biparental populations developed from crosses between the spring cultivar Paragon and landraces originating from about 100 years ago under multiple environments and analysed the grain for minerals including six minerals which are often deficient in diets for humans (calcium, iron, magnesium, potassium, zinc) and livestock (copper). A total of 774 QTLs for minerals in grain, straw and calculated biomass were identified which were reduced to 23 strong robust QTLs for essential nutrients in grain by selecting for QTLs that were mapped in at least two sample sets with LOD scores above 5 in at least one set. The increasing alleles for sixteen of the QTLs were present in the Watkins lines and seven in Paragon. The number of QTLs for each mineral varied between three (for K and Zn) and five (for Cu) and they were located on 14 of the 21 chromosomes with clustering on chromosomes 5A (4 QTLs), 6A (3 QTLs) and 7A (3 QTLs). Several strong QTL were selected to determine the gene content within a distance of five megabases of DNA either side of the marker for the QTL with the highest LOD score. In addition, induced mutagenesis was used to identify the gene responsible for the strongest QTL (for Ca on chromosome 5AL) as the ATPase transporter gene TraesCS5A02G543300. The identification of these QTLs with associated SNP markers and candidate genes will facilitate the improvement of grain nutritional quality.