Wheat is an important staple food crop for human consumption. Developing minerals-enriched cereals is the most promising and cost-effective approach for diminishing malnutrition. Wild emmer wheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell.], the progenitor of domesticated wheats, offers a valuable allelic repertoire for economically important traits, including grain mineral concentrations. Twenty two wild emmer wheat accessions, representing a wide range of drought resistance capacity, as well as two durum wheat cultivars, were examined under two contrasting irrigation regimes (well-watered control and water-limited) for grain yield, total biomass production and grain Zn, Fe and protein concentrations. The obtained results demonstrated the presence of a large genetic diversity for grain protein and mineral nutrient concentrations in wild emmer germplasm and about two-fold greater values as compared with domesticated wheat. A strong positive association between GPC, Zn and Fe, and no association between any of these three variables and yield was noted. The genetic basis of grain mineral concentrations was further dissected using a population of 152 recombinant inbred lines, derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc. G18-16). A total of 82 QTLs were mapped for 10 minerals. There was significant positive correlation between GPC, Zn and Fe, which was supported by a significant overlap between QTLs, suggesting a common physiological-genetic control of these compounds. The identified genetic resources and QTLs may facilitate the use of wild alleles for improvement of grain protein and mineral concentrations in elite wheat cultivars.

Localization of iron (Fe), zinc (Zn), and protein was studied in a set of spelt (Triticum aestivum ssp. spelta) genotypes selected for low (i.e. ~12 %) or high (i.e. ~25 %) grain protein concentration. Following instrumental analysis for Fe, Zn and protein, spelt seeds were longitudinally excised and stained with specific dyes for assessment of Fe, Zn, and protein localization. For Fe and Zn staining, pre-defined methods with Perls’ Prussian blue and dithizone were applied whereas protein staining was performed by a modified Bradford reagent. Following staining, seed surfaces were examined by light reflectance microscopy and photographed to (i) examine the localization of Fe, Zn and protein and (ii) visually compare the variations in color intensity with the concentration data obtained by instrumental analysis of seeds with contrasting protein concentration. The applied staining method revealed that Fe localization was limited to scutellum and aleuron; however Zn and protein was localized in the whole germ and the aleuron as well. It was concluded that the staining methods applied for protein and Fe localization can also be used for mass screening of spelt genotypes for high seed protein and Fe concentration. The role of seed proteins as a sink for Fe and Zn in the spelt seed is discussed.