Variations in the quality parameters and gluten proteins in synthetic hexaploid wheats solely expressing the Glu-D1 locus

This study evaluated the quality potential of seven synthetic hexaploid wheats (2n=6x=42, AABBDD) expressing only allelic variation at Glu-D1 of Aegilops tauschii (SHWSD). Major quality parameters related to dough strength, gluten proteins (including high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS), gliadins), and their ratios between SHWSD and the weak gluten wheat control Chuannong 16 (CN16) were measured in at least three environments (except STD7). The zeleny sedimentation value (ZSV), dough development time (DDT), dough stability time (DST), and farinograph quality number (FQN) of SHWSD were considered stable under different environments, with their respective ranges being 8.00–17.67 mL, 0.57–1.50 min, 0.73–1.80 min, and 9.50–27.00. The ZSV, DDT, DST, and FQN of SHWSD were smaller than those of CN16, suggesting that SHWSD had a weaker dough strength than CN16. Although SHWSD had a lower gluten index than CN16, its wet and dry gluten contents were similar to or even higher than those of CN16 in all environments tested. The protein content of grains (12.81–18.21%) and flours (14.20–20.31%) in SHWSD was higher than that in CN16. The amount of HMW-GS in SHWSD sharply decreased under the expression of fewer HMW-GS genes, and the LMW-GS, gliadins, and total glutenins were simultaneously increased in SHWSD in comparison with CN16. Moreover, SHWSD had higher ratios of LMW-GS/glutenin and gliadin/glutenin but a lower ratio of HMW-GS/glutenin than CN16. These results provide necessary information for the utilization of SHWSD in weak-gluten wheat breeding.