Establishment and Application of Multiplex PCR System Based on Molecular Markers for Glutenin Subunit Genes (Locus) in Wheat

Wheat strong-gluten quality is closely correlated with combinations of high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS). A multiplex PCR system was established to evaluate the loci for HMW-GS and LMW-GS in wheat (Triticum aetivum L.). The multiplex PCR system confered molecular markers for Ax1/Ax2*, Bx7^OE, Dx5, Glu-A3d, Glu-B3i genes, and Glu-B3 locus, and proved to be effective and stable to amplify specific bands on target loci in 12 wheat cultivars with known gene/locus combinaitons. Using this multiplex PCR system, 62 major cultivars from Shaanxi Province, China were evaluated. The results showed that the frequencies were 56.5% for Ax1/Ax2*, 9.6% for Dx5, 33.9% for Glu-A3d, 1.6% for Glu-B3i, and 64.4% for Glu-B3, whereas gene Bx7^OE was not detected. Most cultivars carried 2 genes (locus) with the frequency of 48.3%, followed by cultivars carrying a single gene or locus (33.9%). The frequency of cultivars carrying 3- or 4-gene (locus) combinations was 11.3%. The remaining cultivars (6.5%) were free of any elite gene (locus). Therefore, the frequency of combination of multiple strong-gluten subunit genes (locus) was low in the cultivars from Shaanxi Province, which could be improved with introduced germlasm. The multiplex PCR system developed may serve as a rapid and efficient method to select breeding materials carrying multiple genes (locus) associated with strong-gluten subunit.