Re-evolution of durum wheat by introducing the Hardness and Glu-D1 loci

Authors: Morris, Craig; Kiszonas, Alecia; MURRAY, JESSICA - Washington State University; BOEHM, JEFFREY - Washington State University; IBBA, MARIA ITRIA - Washington State University; ZHANG, M - North Dakota State University; CAI, X - North Dakota State University

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/23/2019
Publication Date: 11/20/2019
Citation: Morris, C.F., Kiszonas, A., Murray, J., Boehm, J., Ibba, M., Zhang, M., Cai, X. 2019. Re-evolution of durum wheat by introducing the Hardness and Glu-D1 loci. Symposium Proceedings. 3:103. https://doi.org/10.3389/fsufs.2019.00103.
DOI: https://doi.org/10.3389/fsufs.2019.00103

Interpretive Summary: Durum wheat is an important but underutilized crop. High kernel hardness and weak gluten hinder its culinary uses and hence broader utilization. Here we demonstrate how translocations from ‘bread’ wheat can soften the kernel texture and improve dough strength and bread baking quality. Milling and flour properties of soft durum wheat are nearly the same as for soft white ‘bread’ wheat. These changes should expand durum wheat utilization and production. The soft kernel trait in durum affects nearly every aspect of milling and baking quality. SKCS hardness, break flour yield and flour yield were similar to commercial soft white wheat cultivars. With the exception of dough water absorption, dough strength was essentially unchanged and reflected the inherent gluten properties of the durum background. That said, the introgression of Glu-D1 alleles dramatically changed dough strength and bread volume, with Dx2+Dy12 showing superiority over Dx5+Dy10.

Technical Abstract: Durum wheat is an important crop worldwide. In many areas, durum wheat appears to have competitive yield and biotic and abiotic advantages over bread wheat. What limits durum production? In one respect, the comparatively more limited processing and food functionality. Two traits directly relate to these limitations: kernel texture (hardness) and gluten strength. We have addressed both using ph1b-mediated translocations from bread wheat. For kernel texture, ca. 28 Mbp of chromosome 5DS replaced about 20 Mbp of 5BS. SKCS hardness was reduced from ca. 80 to 20 as the puroindolines were expressed and softened the endosperm. Break flour yields increased from 17% to >40%. Straight-grade flour had low starch damage (2%), and a mean particle size of 75 µm. Crosses with CIMMYT durum lines all produced soft kernel progeny and a high degree of genetic variance for milling and baking quality. Solvent Retention Capacities (SRC) and cookie diameters were similar to soft white hexaploid wheat, showing that soft durum can be considered a “tetraploid soft white spring wheat”. Regarding gluten strength, CIMMYT durums contributed a high genetic variance, with the “best” progeny exhibiting SDS sedimentation volume, SRC Lactic Acid and Mixograph characteristics that were similar to medium-gluten strength U.S. hard red winter. The best loaf volume among these progeny was 846 cm3 at ca. 12.8% flour protein. To further address the issue of gluten strength, Soft Svevo was crossed with durum lines possessing Dx2+Dy12 and Dx5+Dy10. Bread baking showed that Dx5+Dy10 was overly strong, whereas Dx2+Dy12 significantly improved bread loaf volume. The best progeny produced a loaf volume of 1010 cm3 at 12.1% protein. As a comparison, the long-term in-house regression for loaf volume-flour protein for hard red ‘bread’ wheats is 926 cm3 at 12.1% protein. Obviously, from these results, excellent bread making potential has been achieved.