Rainey:
• Soybean germplasm and advanced breeding lines with high sucrose (>7%) and low RFOs will be evaluated annually and released based on the best agronomic traits and carbohydrate profiles.
• Advanced lines entered into the USDA Soybean Uniform test in 2019, and annually thereafter.
• Germplasm for selection of breeding lines with modified soluble carbohydrates derived from diverse sources and using more than one mutation developed.
• Germplasm for selection of breeding lines with modified soluble carbohydrates plus higher protein developed.

Chen:
• New lines with improved sugar, low oligosaccharide from Chen’s breeding program will be evaluated annually and those lines with best agronomic traits and desired carbohydrate profiles will be released as germplasm lines or germplasm.
• Enter advanced lines into the USDA Soybean Uniform test in 2018.

Nguyen: (for FY19)
• Each quarter of the FY19, 1,200 to 1,500 seed samples from the project collaborators of different studies will be accurately quantified for soluble sugar composition using the well- established Agilent HPLC instrument and timely reported to the project PI and the participants.
• Producing new crosses derived from exotic germplasm of novel sugar sources to develop new materials for genetic studies and breeding purposes.
• Mapping and characterization of QTL associated with high sucrose in two new PI lines; performing fin-mapping and NIL development for further investigations.
• Coordinating whole-genome resequencing of a small set of 8 novel sources of modified carbohydrates; conducting the SNP/Indel analysis for haplotype analysis and allele mining, leading to the identification of candidate gene(s) in target genomic regions and the development of functional markers.

Lorenz:
• The advanced breeding populations and breeding lines will continue to be progressed through the breeding program until a germplasm line release decision is made.
• Move RS2 into MG 0-1 germplasm by 2019.
• Enter advanced RS2 lines into the USDA Soybean Uniform test in 2020.
Rainey:
• Annually, promote the most valuable lines in the project for quantification of metabolizable energy and the component pricing value of modified carbohydrate soybean meal.
• Produce seed for feeding studies to attempt to quantify the energy contribution of protein by conducting feeding studies with lines that have higher protein and typical soluble carbohydrate profiles.
• Brake and Rainey: By 2019, determine if modified soluble carbohydrate meal can provide 100 kcal/lb of energy above commodity.

Lorenz, Rainey, Chen: The best lines developed by breeders will be increased and promoted for pilot projects based on performance data from USDA Uniform Tests.

Objective 3 deliverables.

Rainey:
• By 2019, translate trait interactions and measures of stability in the nutritional bundle into practical economic targets for soluble carbohydrates soybean breeders.
• By 2019, make recommendations about the contribution of high sucrose to meal value.
• By 2019, interpret feeding study results in terms of achievable seed composition and quality.

Nguyen: (for FY19)
• Conducting genotyping and MAS for RS2 (W331) and KTI mutant alleles to support the project breeding programs (Chen, Rainey, Lorenz) to accelerate the NIL development and the process of the trait introgression to elite backgrounds.

• Completing the QTL analysis of two sucrose populations derived from PI 229343 ad PI 417015; QTL associated with high sucrose will be detected; Haplotype blocks and structural variations will be analyzed to identify candidate gene(s).
• Conducting fine-mapping and developing NIL sets for high sucrose QTL, which will be employed for functionality study and marker development.
• Completing GWAS of a diverse panel of over 350 PI lines; leveraging the WGS dataset available for allele mining and candidate gene identification.
• In collaboration with the project collaborators, using the imputed SNP matrix to perform association mapping of new panels of soybean germplasm in an effort to detect new QTL for sugars in different maturity groups.

Rainey, Bilyeu, Lorenz
• Two generations annually of NIL development in a range of maturity groups: Lorenz 0, I; Rainey II, III; Bilyeu III, IV; AR V.
• MG 0-V BC2S3 lines will be increased in 2019 for future studies. Rainey and Lorenz:
• By 2019, evaluate trait interactions (protein, seed size, etc.) with soluble carbohydrates in publicly available data sets and germplasm resources- SoyNAM, USDA germplasm collection, and/or USB core germplasm resequencing project.
• Lorenz:
• An association panel will be grown in 2017 and 2018. Results from this study will help understand the genetic architecture on the traits described.

Updated November 21, 2019:
Raffinose family oligosaccharides (RFOs) present in soybean meal reduce metabolizable energy for monogastric animals; therefore, development of low RFO soybean meal is of great interest to the swine and poultry industries. Modified carbohydrate composition is considered the most promising meal trait due to the potential value to the animal industry and the lack of negative agronomic impacts. Previous results from poultry feeding studies conducted by this team indicate that a statistically significant improvement in feed conversion ratio in chickens can be obtained from reducing RFOs and increasing sucrose in soybean seeds.

With a multi-institutional team with broad expertise, we have our efforts on developing and commercializing new soybean varieties with improved soluble carbohydrate composition and an improved nutritional bundle in a range of maturity groups (MG I-V).

Our Objectives are: 1) Develop of soybean varieties with >7% sucrose and lower RFO’s (1-2%) that results in an increase of ME up to of 100 kcal per pound of meal; 2) Support value-enhanced meal, value-capture, and market development using data science methods.

There are different genes and alleles involved on these traits, therefore different combinations are always valuable. In addition to the previously known alleles, our team discovered new alleles that makes it possible to have soybean with ultra-low RFOs and at least 7% seed sucrose. All the breeders working on this project are working on incorporate those valuable alleles into elite high yielding lines, so that farmers will have soybean varieties that combine high yielding and the desirable levels of sucrose and RFOs. With such soybeans in hand, we expect to increase the value of soybean meal $0.50 per bushel.

Each team focus on its environment’s factors, such as temperature, light, soil and rain conditions, but we are also focused on developing varieties that can be adopted in a range of environments, focusing on maturity groups MG0-V. For that purpose, we are working on stability and adaptability experiments, so that we can 1) understand how the sucrose and RFO’s content respond to different environments; 2) Identify germplasms that are better for these traits for a wider range of experiments.

We are also working on combining HOLL oil trait plus the ultra-low RFO trait or normal RFO and having these different sets of seeds for poultry studies. For that propose we are growing tons of each NIL set that will be used on animal feeding studies conducted by our animal nutrition partner. That will enable soybean meal performance comparisons of the normal RFO or Low RFO high oleic/low linoleic acid (HOLL) oil trait.

It’s valuable to highlight that 23 modified carbohydrate lines were selected for the USDA Uniform Trials and are being evaluated at the Uniform Test Traited Material (16 lines to Uniform Test Traited Material MG 4 and 7 Lines to Uniform Test Traited Material MG 3 ) , summer 2019. These lines were phenotyped for sucrose, raffinose and stachyose content via HPLC. The best ones might be available to farmers soon.