A high protein gene (Gpc-B1) from wild emmer wheat is available to wheat breeders. High protein lines often have weaker gluten characteristics. As part of a recent project with hard white wheat we demonstrated that stacking a high molecular glutenin subunit (Bx7Oe) associated with strong gluten properties with Gpc-B1, we were able overcome the weak gluten properties of the latter. We hypothesized that using this stack we would be able to develop higher yielding lines with acceptable grain protein levels in the CWRS wheat class. We grew a series of replicated trials of Near Isogenic Lines in a CDC Landmark background in 2022 – 2024. In all years the tandem inclusion of the high protein allele (Gpc-B1) and OE (overexpression) allele of HMW glutenin subunit Bx7 resulted in lines with stronger dough properties (approaching those of the upper dough strength check cultivar “Glenn”). The Gpc-B1 allele resulted in 3-5% grain yield penalty which was associated with the around 0.8% unit increase in grain protein content (equivalent to a 5% increase). The yield penalty was associated with a slight reduction in grain-filling period, test weight and kernel weight. The Glu-1Ay allele status of 150 emmer and einkorn wheat accessions was determined using the SDS-PAGE technique. Domesticated Emmer lines exhibited lower frequencies of expressed Glu-1Ay subunits than wild emmer and einkorn lines. In line with previous studies, a total of five different electrophoretic mobilities for expressed Glu-1Ay subunits were identified. Carriers of the Glu-1Ay subunit were initially used in crosses with bread wheat lines Crocus, BW1085 and CDC Landmark to initiate the incorporation of the active allele into a CWRS wheat background. The F1 plants were grown in growth chambers in 2022. In the fall of 2022, we were able to identify interspecific F2 seed carrying the HMW Glu-1Ay subunit. Using the half-seed method, we planted the F2 embryos and used the resulting plants as females for another round of crossing with CWRS wheat. A second round of introgression was completed in 2023. Progeny derived from crosses with a CDC Einkorn breeding line crossed with bread wheat now have been crossed back to CWRS parentage four times and have a desirable plant type. Finally, populations involving high yielding CWRS experimental lines and a Glu-B1 Bx7 and Gpc-B1 allele donor have been developed. These populations were advanced to homozygosity in 2023. The most advanced lines (n=314) were evaluated for grain yield and leaf and stem rust reaction in 2023. A small percentage of these lines (n=29) were re-evaluated in 2024. In conclusion, the yield penalty associated with Gpc-B1 may be a barrier to its wider adoption in the development of higher-yielding CWRS wheat germplasm.

Extension Messages

• We found that the high protein gene we used reduced grain yield in a CWRS wheat genetic background (undesirable outcome).
• We found that stacking the high protein gene with a strong gluten gene allowed us to develop lines with strong gluten characteristics while increasing the protein content (desirable outcome).
• We were able to transfer a protein subunit associated with improved baking quality from einkorn wheat to spring wheat (desirable outcome)