Abstract
Four near-isogenic lines of Japanese soft wheat with different compositions of high-molecular-weight glutenin subunits, which are controlled by the Glu-A1 and Glu-D1 loci were cultivated with different amounts of nitrogen fertilizer applied at flowering time and the noodle quality was analyzed. In the line that carried both the null allele controlled by the Glu-A1 locus and subunits 2.2+12 controlled by the Glu-D1 locus, tensile force of the raw noodles (RN) and breaking force of the boiled noodles (BN) were weak, and deformation of BN was small, suggesting that RN became easier to break and BN had thinner appearance and softer texture. These results may have derived from the weak dough properties. Increased flour protein content brought weaker tensile force and larger deformation of the RN and stronger breaking force and larger deformation of BN. This shows that RN had better extensibility and BN had thicker appearance and harder texture. These results reflected the dough properties with high water absorption and inferior protein quality. Increased flour protein content also gave a darker flour color as reported before. These results suggest that to adjust appropriate grain protein content and not to have both the null allele controlled by the Glu-A1 locus and subunits 2.2+12 controlled by the Glu-D1 locus would be necessary to maintain good handling performance in noodle making and make the noodles with appropriate thickness, appropriate hardness and bright color.
