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).