Bread-baking quality and the effects of Glu-D1 gene introgressions in durum wheat (Triticum turgidum ssp. durum)

Authors: Morris, Craig

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2021
Publication Date: 11/9/2021
Citation: Morris, C.F. 2021. Bread-baking quality and the effects of Glu-D1 gene introgressions in durum wheat (Triticum turgidum ssp. durum). Cereal Chemistry. 98(6):1151-1158. https://doi.org/10.1002/cche.10473.
DOI: https://doi.org/10.1002/cche.10473

Interpretive Summary: Durum wheat (Triticum turgidum subsp. durum) is an important crop globally but its production runs far secondary to that of ‘common’ or ‘bread’ wheat, T. aestivum. In the Mediterranean Basin, durum wheat was historically better adapted of the two, and was used in pasta, couscous and local breads. In the last century or so, durum wheat has established itself as the preferred ingredient for pasta and the globalization of Italian cuisine. This review discusses the dough strength and bread making quality of durum wheat, and effects of Glu-D1 gene introgressions. Durum wheat can be considered a major but underutilized crop globally. Although durum possesses some advantages over bread wheat in terms of pest resistance, abiotic stress resistance, and agronomic performance, the widely held view is that it is inferior for bread baking. The reason for this inferiority is described in terms of either weak and/or inextensible gluten. One strategy to overcome this limitation is through the introduction of the Glu-D1 alleles from bread wheat. Several methods have been employed to introduce or transfer Glu-D1 into durum wheat. These have included whole chromosome additions of 1D, substitutions of 1D for 1A or 1B, spontaneous and Ph1b-induced homoeologous recombination of bread wheat chromosome 1D with the 1A or 1B of durum, and genetic transformation using Glu-D1 Dx and Dy genes singly or together.

Technical Abstract: Background and objectives: Durum wheat (Triticum turgidim ssp. durum) (2n = 28, AABB) utilization is somewhat hampered by its weak and/or inextensible gluten. One strategy to overcome this limitation is through the introduction of the Glu-D1 alleles from bread wheat (Triticum aestivum) (2n = 42, AABBDD). Findings: Several methods have been employed to introduce or transfer Glu-D1 into durum wheat. These have included whole chromosome additions of 1D, substitutions of 1D for 1A or 1B, spontaneous and Ph1b-induced homoeologous recombination of bread wheat chromosome 1D with the 1A or 1B of durum, and genetic transformation using Glu-D1 Dx and Dy genes singly or together. Conclusions: The introduction of whole 1D chromosomes has two main drawbacks, 1) instability of the n = 30 chromosome addition lines, and 2) agronomic inferiority of 1D substitutions. Genetic transformation has shown limited utility as gene insertion and inheritance are not predictable, and consumer acceptance of genetically modified organisms is not wide-spread. Consequently, homoeologous recombination appears to be the most promising approach. Key considerations include 1) size of the 1D translocation, 2) substituted (loss, replacement) of a portion of 1A or 1B, and 3) utilization of Dx2+Dy12 vs. Dx5+Dy10, or other possible Glu-D1 alleles. In general, introduction of Glu-D1 increased dough strength and bread baking baking quality. Glu-D1 Dx2+Dy12 seemed superior to Dx5+Dy10, as the latter produced excessively strong, inelastic doughs.