Combined selection of Gpc-B1 and Glu-B1 locus encoding the Bx7OE subunit for improving end-use quality of hard white wheat

Wheat in Canada is classified into nine different market classes based on attributes that impact end-use functionality. The Canada Western Hard White Spring (CWHWS) class was created in 2001 to diversify wheat production. The quality requirements of the CWHWS class demand strong gluten properties but lower grain protein (GP) content levels compared to the premium CWRS class. Generally, GP and grain yield are negatively correlated, so a reduction in GP would allow CWHWS cultivars to express greater yield potential. However, lowering GP can result in weaker gluten strength. This study investigated the combined use of Gpc-B1 and Bx7OE to increase GP while maintaining the dough strength in hard white wheat lines. Additionally, the effects of these introgressions on agronomic traits (grain yield, days to heading, days to maturity, plant height, test weight, and thousand kernel weight) were evaluated. Seven populations (each comprising 40 RILs, all varying for presence of Bx7OE, and five populations carrying all possible combinations of Gpc-B1 and Bx7OE) were developed using marker-assisted selection and elite cultivars or advanced breeding lines as parents and tested in three field environments in Saskatchewan, Canada. End-use quality was measured on grain (protein content, kernel hardness), and flour (protein, ash, protein loss, color, and farinograph). Results from our study showed a 0.8-1.1% increase in GP content relative to CWHWS cultivars (used as checks in the study) and dough strength properties similar to CWRS cultivar 'CDC Teal' (representing uppermost limit of dough strength in CWRS class at the time). Except for a slight increase in plant height (still comparable to elite cultivars), no deleterious effects on agronomic or other quality traits were observed. We conclude that combined selection of Gpc-B1 DIC with Bx7OE is effective in developing CWHWS lines with a desirable end-use quality.

Automated summary

The study revealed that the combined selection of Gpc-B1 and Bx7OE is effective in increasing GP content while maintaining dough strength in CWHWS wheat lines. No deleterious effects on agronomic or other quality traits were observed, indicating the potential for developing CWHWS lines with desirable end-use quality.