Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2010
Publication Date: 12/21/2010
Publication URL: hdl.handle.net/10113/48717
Citation: Morris, C.F., Simeone, M.C., King, G.E., Lafiandra, D. 2010. Transfer of soft kernel texture from Triticum aestivum to durum wheat, Triticum turgidum ssp. durum. Crop Science. 51:114-122. Interpretive Summary: In the present report we describe in detail the development of soft kernel durum wheat through homoeologous translocation of the puroindoline genes and the Hardness locus from T. aestivum (bread wheat). This "repair of an accident of nature" has the potential to alter the future relationship that humankind has with durum wheat, hopefully to the improvement of both. Nature restored the soft kernel trait to hexaploid wheat via the hybridization of T. turgidum with Ae. tauschii. Ironically, hexaploid wheat is apparently unable to live without the assistance of humans, as no wild forms are found in nature. And like its 'sister' species, the cultural and culinary relationships that formed between hexaploid wheat and humankind are intimately intertwined with its kernel texture.
Technical Abstract: Durum wheat (Triticum turgidum ssp. durum) is a leading cereal grain whose primary use is the production of semolina and then pasta. Its rich culinary relationship to humans is related, in part, to its very hard kernel texture. This very hard texture is due to the loss of the Puroindoline genes which were eliminated during the allopolyploid formation of T. turgidum ca. 0.5 million years ago. In the present report, we describe the restoration of the Puroindoline genes through ph1b-mediated homoeologous translocation. Puroindoline a and puroindoline b were successfully translocated from chromosome 5D of the soft wheat (T. aestivum) variety Chinese Spring into cv. Langdon durum using a Langdon 5D(5B) disomic substitution line. Although initial translocation lines were highly unstable, recurrent back-crossing into Svevo durum variety produced stable lines that segregated in a normal 1:2:1 soft (+translocation), heterozygous, and very hard (-translocation) pattern. The final back-cross (BC3) Svevo line was grown in Arizona under common cultural practices where it produced uniformly soft grain with a Single Kernel Characterization Hardness Index of 24±14. The restoration of this fundamental property of durum wheat grain will undoubtedly have an expansive and profound effect on the way that durum grain is milled and the products that are therefrom prepared. As such, our interaction with this important food species will continue to evolve.