Parental choice and seed size impact the uprightness of progeny from interspecific Glycine hybridizations

Authors: Taliercio, Earl; EICKHOLT, DAVID - North Carolina State University; Read, Quentin; Carter Jr, Thomas; WALDECK, NATHAN - Northwestern University; Fallen, Benjamin

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2023
Publication Date: 5/19/2023
Citation: Taliercio, E.W., Eickholt, D., Read, Q.D., Carter Jr, T.E., Waldeck, N., Fallen, B.D. 2023. Parental choice and seed size impact the uprightness of progeny from interspecific Glycine hybridizations. Crop Science. 63(4):2184-2195. https://doi.org/10.1002/csc2.21015.
DOI: https://doi.org/10.1002/csc2.21015

Interpretive Summary: The lack of genetic diversity of soybean threatens food security in the United States because the crop lacks the genetic resources to deal with emerging pests, changing climate, and evolving market demands. To meet demands for genetic resources to deal with these urgent needs we are breeding with wild soybean (Glycine soja) which is an excellent source of genetic diversity but produces agronomically poor offspring. We are optimizing breeding with wild soybean by identifying factors that can improve the recovery of agronomically valuable progeny from crosses between wild and domesticated soybean. We have determined that the domesticated variety, NC Dunphy, is a superior choice as a parent that produces substantially more valuable progeny than another North Carolina variety, NC Raleigh. Unexpectedly, we also found that larger seeds can produce more agronomically valuable progeny than relatively smaller seeds. Taken together this novel information will be useful to improve the recovery of valuable genetic resources form wild soybean.

Technical Abstract: The narrow genetic base of the US soybean crop makes it vulnerable to emerging abiotic and biotic stress challenges. Additionally, the narrow genetic base limits the ability of the soybean crop to meet changes in consumer and market demand including improved seed composition, specifically increased protein content and functionality. The USDA Glycine germplasm collection provides a valuable genetic resource to meet these challenges. Glycine soja accounts for over 800 unique entries in the collections and is more genetically diverse than domesticated soybean. Even though wild soybean hybridizes freely with G. max, breeding efforts with wild soybean have not been widely employed because, the interspecific progeny inherit undesirable traits from the wild parent. Particularly the interspecific progeny inherits a vine-like architecture that prevents them from being easily machine harvested. We assessed the impact of parental choice and subsequent selection of larger seeds on selection within F3 populations on the recovery of desirable machine harvestable progeny from interspecific hybridization. We found that choice of both domesticated and wild soybean parents influenced the frequency of desirable progeny. Selection for large seed size improved the recovery of desirable upright plants in 7 of 11 populations. Marker analysis of parents and progeny indicated that there was little selection against the genome of the wild parent in progeny with larger seeds. We concluded that selecting an optimal G. max parent and planting larger seeds selected from within segregating bulk populations can significantly improve efforts to utilize wild soybean in improving the US soybean crop.