Genetic Variation of High Molecular Weight Glutenin Subunits in Wheat Accessions in China

The high molecular weight glutenin subunits (HMW-GS) are essential in determining bread-making quality, and knowing their composition can help in making appropriate decisions to improve wheat (Triticum aestivum L.) quality. The HMW-GS compositions of 189 Chinese wheat landraces (CWLs), 61 introduced lines (ILs), and 840 Chinese improved varieties (CIVs) were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in this study. The aim was to identify novel HMW-GS alleles and to compare the genetic diversity among the three groups. A total of 31 HMW-GS alleles and 86 allele combinations were found in all accessions. For CWL and CIV, the predominant pattern was (null, 7+8, 2+12), with a frequency of 71.6 and 26.0%, respectively. The predominant pattern in the IL was (null, 7+9, 2+12) with a frequency of 13.6%. The IL had the largest variation and the average index of genetic variation (H). The H was 0.6117, whereas CWL and CIV had H values of 0.2275 and 0.5161, respectively. In addition, the present study showed that an increase of 7+9 and 5+10 in the CIV came from the use of foreign parents. The results revealed that the IL was an important reservoir for improving Chinese wheat-quality characteristics such as grain protein content, hardness, and sodium dodecyl sulfate (SDS) sedimentation. Although the genetic variation in the CWL was low, it contained novel alleles (1Bx7.1* and 1By8.1*), which indicated that this group was also a potential resource for wheat-quality improvement.