Registration of 12 soft red winter partial waxy wheat germplasms carrying one or two null alleles at the Wx loci

Authors: MA, FENGYUN - The Ohio State University; STURBAUM, ANNE - Retired ARS Employee; Baik, Byung-Kee

Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2023
Publication Date: 7/7/2023
Citation: Ma, F., Sturbaum-Abud, A.K., Baik, B.V. 2023. Registration of 12 soft red winter partial waxy wheat germplasms carrying one or two null alleles at the Wx loci. Journal of Plant Registrations. 17:593-598. https://doi.org/10.1002/plr2.20307.
DOI: https://doi.org/10.1002/plr2.20307

Interpretive Summary: Starch constitutes 70-80% of wheat flour and thus its properties considerably influence the 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 one or two out of three GBSS genes carry null alleles, wheat starch of reduced amylose proportion is produced and is called “partial waxy.” With a reduced amylose proportion and thus an increased amylopectin proportion, partial waxy wheat starch takes up more water at a faster rate and produces a more viscous cooked paste than regular wheat starch. Partial waxy wheat has been reported to be desirable for making Asian noodles with desirable cooking and textural properties and extending bread shelf life. Several partial waxy wheat varieties and germplasms of soft white, hard white and hard red wheat backgrounds that are adapted to the Great Plains and the Pacific Northwest have been released in the United States. However, no partial waxy wheat variety or germplasm adapted to the eastern region of the United States has been developed and released. To promote the production capacity of partial waxy wheat in the eastern U.S. region and satisfy the potential demands of wheat millers and food manufacturers, the USDA-ARS developed and released twelve soft red winter (SRW) partial waxy wheat germplasms lacking one or two GBSS genes by the introduction of one or two null alleles to two SRW wheat varieties adapted to the eastern region of the United States. Amylose contents of isolated starches ranged from 23.9 to 25.8% in single-null, and from 18.4 to 24.3% in double-null, partial waxy wheat germplasms, while they ranged from 26.8 to 27.1% in the parent varieties. These partial waxy wheat germplasms present an important genetic resource to wheat breeding programs for the development of wheat varieties with unique starch properties that are adapted to the eastern region of the United States, thus extending the use of SRW wheat in products which require a reduced starch amylose content.

Technical Abstract: Partial waxy wheat carries one or two null alleles at the Wx loci encoding the granule bound starch synthase I and produces flours with reduced starch amylose content, which are potentially desirable for maintaining moistness and extending shelf life of bread and improving textural properties and sensory acceptance of white salted and instant fried noodles. The USDA-ARS developed and released twelve soft red winter (SRW) partial waxy wheat germplasms, SWQL-K-A-1, SWQL-K-B-1, SWQL-K-D-1, SWQL-K-AB-1, SWQL-K-AD-1, SWQL-K-BD-2, SWQL-W-A-5, SWQL-W-B-1, SWQL-W-D-2, SWQL-W-AB-4, SWQL-W-AD-2 and SWQL-W-BD-1, by the introgression of one or two null alleles at the Wx loci from a soft spring waxy wheat germplasm to two SRW wheat varieties. Twelve waxy wheat germplasms were selected from backcross-four (BC4) or -five (BC5) derivatives of the SRW wheat varieties ‘Kristy’ and ‘Wilson’ (99ID490/5*Kristy and 99ID490/6*Wilson, respectively) by marker assisted selection. The kernel hardness of partial waxy wheat germplasms in Kristy and Wilson backgrounds ranged from 62.7 to 64.3 and 28.4-31.7, respectively, while that of the corresponding wild type was 58.6 and 30.3, respectively. Amylose contents of isolated starches ranged from 23.9% to 25.8% in single-null partial waxy wheat germplasms, 18.4-24.3% in double-null partial waxy wheat germplasms and 26.8-27.1% in parents and wild types. These partial waxy wheat germplasms would be useful for the development of SRW partial waxy wheat varieties adapted to the eastern region of the United States and extending the use of SRW wheat in products which require a reduced starch amylose content.