Association mapping of sponge cake volume in PNW elite soft white wheat (Triticum aestivum L.)

Authors: Thompson, Yvonne; CARTER, ARRON - Washington State University; WALKER, BRIAN - North Carolina State University; KISZONAS, ALECIA - Washington State University; Morris, Craig

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2020
Publication Date: 6/14/2021
Citation: Thompson, Y.A., Carter, A.H., Walker, B., Kiszonas, A., Morris, C.F. 2021. Association mapping of sponge cake volume in PNW elite soft white wheat (Triticum aestivum L.). Journal of Cereal Science. 100. Article 103250. https://doi.org/10.1016/j.jcs.2021.103250.
DOI: https://doi.org/10.1016/j.jcs.2021.103250

Interpretive Summary: In the U.S. wheat is a staple, ranking third behind corn and soybeans in planted acreage and production and is grown in 42 of the 50 states. The diverse climatic regions in the PNW are advantageous for growing different wheat classes, soft white wheat being one of the major categories with ca. 6.5 mmt produced annually. Soft white and club wheat are well suited for making baked products (cakes, cookies, pastries, etcetera). An essential quality trait of this wheat class is cake baking. While cake is a widely used term referring to an extensive range of baked goods, with distinctions made depending on the ingredients, ratios, and processing methods; here we specifically focus on sponge cakes. The key feature of sponge cakes is the absence of chemical leavening, instead relying on the entrainment of air bubbles for expansion. The Japanese sponge cake bake test is routinely used to assess the suitability of flour for high moisture cake products consumed in the Pacific-Asian market. The USDA Western Wheat Quality Laboratory (WWQL) first evaluated commercial wheat varieties and experimental breeding lines for sponge cake quality in the 1977 crop year harvest. Since then, it has been an integral evaluation of soft white and club wheat breeding programs. Here we report marker-trait associations that are positively associated with sponge cake volume of historical data that provides insights into its genetic architecture. Marker-trait associations identified had small allelic effects meaning that they influenced the wheat’s sponge cake volume minimally individually. The identified marker trait associations should be validated. Once validated, these markers would be valuable incorporations into breeder’s selection criteria pipeline for earlier detection of acceptable sponge cake volume.

Technical Abstract: Sponge cake quality is an essential end-use trait for U.S. Pacific Northwest (PNW) soft white (SW) wheat, primarily measured by the volume of a cake. The baking of each cake is relatively expensive, labor intensive, and requires a substantial amount of flour. As a result, sponge cake baking is conducted in later generations on a limited number of breeding lines. Insight into the genetic architecture of sponge cake volume would help provide an alternative to cake baking. Here we describe the analysis of 387 wheat genotypes spanning 27 crop years with a total of 706 environments for sponge cake volume. Genotyping by sequencing was used to generate molecular markers in wheat representing elite germplasm of the PNW, US. A genome wide association study was conducted to discover marker-trait associations, while accounting for population structure and kinship. A total of eight associated genomic regions were identified on chromosomes 1AB, 2A, 3BD, 4A, and 6A. Previous research has detected associations with agronomic, grain, flour, milling and baking traits on each of these chromosomes, however, none for sponge cake volume. This study serves as a foundation experiment by providing insights into the genetic architecture of sponge cake volume in an historical dataset.