Since iron (Fe) and zinc (Zn) are essential micronutrients for human immunity and metabolic activities, it is important to biofortify major food crops such as wheat and improve the bioavailability of Fe and Zn. In this review, we focused on analyzing studies conducted to identify and evaluate QTLs, genes, and associated molecular markers related to Fe and Zn content in wheat, their absorption mechanisms, and bioavailability in terms of genetics and breeding. Because bread wheat has a limited Fe and Zn content in its grains, many studies have used wild, synthetic, or mutant wheat resources with high Fe and Zn contents. Many studies have been conducted to characterize related genes, of which Gpc-B1 is the major gene that increases the final content of Fe, Zn, and protein in association with an Gpc-B1 increase in Fe uptake and regulate Zip and YSL expression. Research determining the appropriate phytic acid content and increasing phytase activity to improve bioavailability was also highlighted.

An advanced F₈ population was derived from a cross between the hard wheat cultivar “Keumkang” carrying Pinb-D1b and the soft wheat cultivar “Olgeuru” carrying Pinb-D1a. A breeding line named “Hetero”, which exhibited the heterozygous-like Pinb-D1a/Pinb-D1b genotype, was selected by sequence analysis and KASP (Kompetitive Allele Specific PCR) assay. Physicochemical and processing characteristics of flour were tested in the Hetero line and compared with the two parental cultivars for two years. Hetero display a Glu-1 composition similar to Keumkang and a Glu-3 composition intermediate between Keumkang and Olgeuru. Contrary to the expectation that Hetero carrying the Pinb-D1a/Pinb-D1b genotype would exhibit an intermediate phenotype between the two parents, its overall flour physicochemical characteristics were more similar to Keumkang than to Olgeuru. The flour yield of Hetero (71.6%) was lower than that of Keumkang (74.5%). However, the flour particle size (73.3 μm) and damaged starch content (4.6%) of Hetero were similar to those of Keumkang (71.9 μm and 4.5%). The protein content (16.5%) and sodium dodecyl sulfate-sedimentation volume (72.8 mL) of Hetero were higher than those of Keumkang (14.0% and 57.5 mL) and Olgeuru (11.4% and 45.5 mL). The mixograph water absorption (68.7%) and mixing tolerance (17.7 mm) values of Hetero were higher than those of Keumkang (65.6% and 15.9 mm) with the same mixing time of 3.9 min. The bread loaf volume of Hetero was lower than that of Keumkang (866.7 vs. 894.7 mL). The cooked noodles hardness of Hetero was higher than that of Keumkang (5.9 vs. 4.7 N).

Starch properties of 32 Korean barley cultivars (Hordeum vulgare L.) were evaluated to improve the Korean barley breeding program. The average amylose content of non-waxy barley cultivars was approximately 3.5 times higher than that of waxy barley cultivars. Furthermore, non-waxy barley cultivars showed lower damaged starch content, water retention capacity, swelling volume, swelling power, and peak viscosity than waxy barley cultivars, while they showed bigger average starch granule size and higher final viscosity. Among Korean barley cultivars, the amylose content showed a positive correlation with damaged starch content, water retention capacity, swelling volume and power, and peak viscosity, while showing a negative correlation with pasting temperature and final viscosity. Among non-waxy barley cultivars, the amylose content showed a positive correlation with damaged starch content, but correlation with swelling power, peak viscosity, pasting temperature, and final viscosity was negative. Among waxy barley cultivars, the amylose content showed negative correlation with peak viscosity. There were positive correlations between swelling volume and peak viscosity among Korean barley and waxy barley cultivars. Also, there were positive correlations between swelling power and peak viscosity among Korean barley and non-waxy barley cultivars. Principal Components Analysis revealed that amylose content and peak viscosity are the main factors affecting starch properties of Korean non-waxy barley cultivars, and Korean non-waxy barley cultivars can be classified into two groups with these two factors. Water retention capacity and peak viscosity are the main factors affecting starch properties of waxy barley cultivars and classify them into two groups. The starch properties of Korean barley cultivars demonstrated in this study are useful to improve end-use quality for processed foods using barley. In addition, the continuous qualitative evaluation of barley is very important for the Korean barley breeding program.

The flour physiochemical properties and end-use quality of wheat were evaluated to identify the effect of high temperature (HT) during grain maturation. HT caused a decrease in the width and thickness of grains. However, HT did not affect the grain weight, volume, length, test weight and 1,000-kernel weight in Korean wheat cultivars. Although HT marginally affected the general flour physiochemical properties and gluten composition, the effects were not significant. Based on the results of the evaluation of end-use quality, the effect of HT on the end-use quality was not significant. Nevertheless, the allelic composition was related to the quantity and quality of grain under HT conditions. In Korean wheat cultivars containing Glu-D1d and -D1f alleles, the 1,000-kernel weight was decreased by HT. In addition, Glu-D1f was more sensitive to HT than was Glu-D1d. The proportion of the y-type high-molecular-weight glutenin subunits (HMW-GSs) was decreased by HT in Korean wheat cultivars containing the Glu-A1ab allele, and was increased in cultivars containing the Glu-B3d allele. Furthermore, the proportions of gliadin and low-molecular-weight glutenin subunits (LMW-GSs) were decreased by HT in Korean wheat cultivars containing Glu-A1ab or Glu-B3ahi alleles.