Registration of ten soft red winter waxy wheat germplasm lines

Authors: MA, FENGYUN - The Ohio State University; Sturbaum-Abud, Anne; Baik, Byung-Kee

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2021
Publication Date: 9/28/2021
Citation: Ma, F., Sturbaum-Abud, A.K., Baik, B.V. 2021. Registration of ten soft red winter waxy wheat germplasm lines. Journal of Plant Registrations. 16:147-151. https://doi.org/10.1002/plr2.20151.
DOI: https://doi.org/10.1002/plr2.20151

Interpretive Summary: Starch constitutes 70-80% of wheat flour and thus its properties considerably influence processing and product quality, as well as the shelf life of many wheat-based foods. Starch is composed of two types of molecules, amylose and amylopectin, typically at 25 and 75%, respectively. These two starch molecules differ in size, structure and physical properties and so their proportions largely determine the functional properties of starch. The production of amylose molecules in developing wheat grain is mainly controlled by three granule-bound starch synthase (GBSS) genes. When all three GBSS genes carry null alleles, wheat starch composed of typically less than 5% amylose molecules is produced and is called “waxy.” Waxy wheat starch takes up more water at a faster rate, and produces a more viscous cooked paste that hardens at a much slower rate, than regular wheat starch, making it uniquely suitable for food products requiring these properties and for their shelf-life extension. Currently, only four waxy wheat varieties have been released in the United States, including two soft white spring wheats, one hard red winter wheat and one hard white winter wheat. To expand the production capacity of waxy wheat and satisfy the potential demands of the milling and baking industries, the USDA-ARS developed and released ten soft red winter (SRW) waxy wheat germplasms by the introduction of waxy traits to two elite SRW wheat varieties adapted to the eastern region of the United States. The starch of SRW waxy wheat germplasms showed amylose contents of 2.5 to 7.2% and produced cooked pastes with higher viscosities than the regular SRW wheat starch. These waxy wheat germplasms present the important genetic resource of the waxy trait to wheat breeding programs for the development of waxy wheat varieties, and can be further selected to wheat varieties based on their agronomic and yield performances, eventually benefiting regional growers and the milling and baking industries.

Technical Abstract: Waxy wheat carries null alleles at the three Wx loci encoding the granule-bound starch synthase I (GBSSI) and produces endosperm starch composed of mostly amylopectin with less than 5% amylose. The USDA-ARS developed and released ten soft red winter (SRW) waxy wheat germplasms by the introgression of waxy traits from a soft spring waxy wheat germplasm to two SRW wheat varieties adapted to the eastern region of the United States. Ten waxy wheat germplasms were selected from backcross-four (BC4) or BC5 derivatives of the SRW wheat varieties ‘Kristy’ and ‘Wilson’ (99ID490/5*Kristy and 99ID490/6*Wilson, respectively). The kernel hardness and starch amylose content of ten SRW waxy wheat germplasms ranged from 34.1 to 63.1 and 2.5-7.2%, respectively, while those of wild types and SRW wheat parents ranged from 33.9 to 60.4 and 26.8-27.0%, respectively. The starch of waxy wheat germplasms exhibited a lower pasting temperature, higher peak viscosity and lower setback value than the corresponding wild-type wheat starch. These waxy wheat germplasms would be useful for the development of SRW wheat varieties carrying different null alleles at the Wx loci that are adapted to the eastern region of the United States.