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Chromosomes of Korean hexaploid wheat were investigated to compare the chromosomal karyotype for cytogenetic diversity. Chromosomal karyotyping was done with in situ hybridization using two types of simple sequence repeats (SSR)s, (AAG)5 and (AAC)5 labeled with tetramethyl-rhodamine-5-dUTP and fluorescein-12-dUPT as a fluorescence, respectively. The two SSRs as cytogenetic markers revealed that the cytogenetic characteristics of the wheat chromosomes were remarkably a B genome. In this study, the chromosomal karyotype of Keumkang, a Korean hexaploid wheat cultivar, was the A, B, and D genomes used as a cytogenetic reference. The expressed signals from the two SSRs showed a difference in the chromosomal karyotype of chromosome 1B among the Korean hexaploid wheat. The distribution pattern and the degree of condensation for the (AAG)5 and (AAC)5 signals on the short arm of chromosome 1B were different in the Korean hexaploid wheat shown in descending order: Keumkang > Joeun > Johan > Olgeuru. Olgeuru had a lower level of distribution and condensation for the two SSRs signals compared to the other Korean hexaploid wheat. In the A genome, chromosome 7A showed an unbalanced expression of the (AAG)5 signal on the distal region of the short and long arms in several Korean hexaploid wheat while Joeun, a Korean hexaploid wheat, showed a definite (AAG)5 signal on the distal region of each arm of chromosome 7A. Among the Korean hexaploid wheat, Shinmichal1, a Korean hexaploid waxy wheat, had a chromosome with a unique expression pattern for (AAG)5 and (AAC)5 compared the other Korean hexaploid wheat. Those cytogenetic differences identified in this study are useful as an indicator to improve the cytogenetic diversity in the Korean wheat breeding program.

This study was performed to identify how the different levels of nitrogen application affected the variances of gluten properties and end-use qualities and the differences of variances among Korean wheat cultivars. Protein and dry gluten content, SDS sedimentation volume and water absorption of Mixolab increased as nitrogen application increased. This ratio of the increase was higher in Korean wheat cultivars for bread than in Korean wheat cultivars for noodles and cookies. The proportion of (α+β)-gliadin measured by reversed-phase high-performance liquid chromatography (RP-HPLC) increased, but the proportion of ω- and γ-gliadin decreased as the protein content increased. The Korean wheat cultivars for bread showed a high proportion of (α+β)-gliadin increase, the Korean cultivars for noodles had a high proportion of γ-gliadin decrease and the Korean wheat cultivars for cookies had a high proportion of ω-gliadin decrease. However, there was no variation of the component in the proportion of glutenin component measured by RP-HPLC, even though the protein content was increased, but all of the protein fractions measured by size exclusion (SE)-HPLC were increased. The soluble monomeric protein showed a high proportion of Korean wheat cultivars for bread by the increase of protein content. Bread loaf volume increased by the increase of protein content but there were no variances in the ratio of increase among Korean wheat cultivars. The cookie diameter decreased with the increase of protein content, and this ratio of decrease was the highest in Korean wheat cultivars for cookies. The hardness of cooked noodles also increased by the increase of protein content but there were no variations in springiness and cohesiveness. The decrease proportion of ω-gliadin affected the increase of bread loaf volume, the hardness of cooked noodles, and the decrease of cookie diameter.