Performing Department
(N/A)
Non Technical Summary
Soybean is the world's largest source of animal protein feed and the second largest source of vegetable oil. This is due largely to its high protein concentration, complete amino acid profile, and high proportion of unsaturated fatty acids. Soybean seed typically contains 38-42% protein on a dry matter basis, which is primarily used to feed livestock, and 20% oil, which is refined for food and industrial purposes. Soybean meal--the byproduct of oil extraction--typically contains 44 to 48% crude protein. Advantages of soybean meal in livestock feed include high levels of amino acids, a good source of energy, vitamins and minerals, digestibility of amino acids, high availability, and reliability in a consistent product with fairly predictable prices for use in production. In recent years, the protein content of U.S. soybeans, a major component of soy meal, has been decreasing. Farmers must produce high quality soybeans without sacrificing yield to meet the needs of the current livestock industry. Breeding initiatives have focused on increasing the intrinsic value of soybean by increasing protein and improving oil quality. Our previous research discovered a major quantitative trait locus for increased protein with a favorable allele from 'Danbaekong', which increases 3-4% in seed protein. The allele was introgressed into an elite cultivar to create 'Benning HP,' which yields comparably to the recurrent parent.The uses of soybean oil continue to expand because of the versatility of this valuable vegetable oil. High-oleic soybeans offer benefits of increased oxidative stability under high heat use. Increasing oleic acid and decreasing linolenic acid in soybean oil has been achieved by combining four null alleles for fatty acid desaturase genes. Using marker-assisted selection, we have successfully developed and released high oleic and low linolenic soybean cultivars. To keep the demand for soybean products high, breeders must combine the high protein, high oleic, and low linolenic acid traits so that the oil and protein are both optimal when they are separated during processing. By identifying recombinants for high oleic and high protein genes, we have developed breeding lines with a five-gene stack.The objective of this project is to test experimental lines in the Southeast region and release 1-2 soybean varieties in maturity groups VI, VII or VIII with high protein (>44%), high oleic (>75%), and low linolenic (<3%) acid traits. The development of cultivars with this trait stack will increase the value of soybeans for producers and end consumers. The outcome addresses USDA's program area priority "The Conventional Plant Breeding for Cultivar Development program (A1143) will support public breeding efforts that provide farmers with greater access to locally and regionally adapted cultivars".
Animal Health Component
0%
Research Effort Categories
Basic
0%
Applied
30%
Developmental
70%
Goals / Objectives
The overall goal for this project is to develop high yielding and value-added soybean cultivars for the growers in the Southeast region of the United States. The specific objective of this project is to test experimental lines in the Southeast region and release 1-2 soybean varieties in maturity groups VI, VII or VIII with high protein (>44%), high oleic (>75%), and low linolenic (<3%) acid traits. The development of cultivars with this trait stack will increase the value of soybeans for producers and end consumers.
Project Methods
Previously, we have developed >300 lines with high protein (>44%), high oleic (>75%), and low linolenic (<3%) acid traits from multiple pedigrees, which were grown in plant rows in 2021. Based on the agronomic traits and seed composition, 124 lines were selected for preliminary yield trials at four locations: Athens and Plains, GA, Auburn, AL, and Bossier City, LA in 2022. Two replicates per location were planted with 0.76 m row spacing and 4.9 m row length. Data collected will include maturity, plant height, lodging, yield, seed size, and seed quality. Maturity will be recorded as the number of days after August 31 for 95% of a plot to reach physiological maturity (R8). Flower, pubescence, and hilum colors will also be recorded during the season for quality control.Harvested seed will be evaluated via NIR to determine seed composition. High yielding lines with good agronomic performance as well as high protein, high oleic acid, and low linolenic acid traits across locations will be advanced to the second-year yield testing in 2023.2023:Based on the yield trials in 2022, 34 lines will be advanced to the UGA Advanced Yield Trials (AYT) at six locations, including three locations in GA, two locations in AL and one location in LA. Two current commercial checks with similar maturity will be included in each test set. Four-row plots with three replicates per location will be planted with a row length of 4.8 m and a row spacing of 76 cm using an Almaco cone planter fitted with Almaco SkyTrip GPS tripping. During the late growing season, the plots will be end-trimmed to a length of 3.6 m to limit the edge effect of plots by removing equal portions of each side of the plots.Throughout the growing season, multiple applications of herbicide, fungicide, and insecticide will be applied as needed by following recommendations from the Georgia Soybean Production Guide (Bryant, 2021). Agronomic traits including plant height, lodging, maturity, and seed size will be collected on yield plots in the growing season. Plots are harvested using research plot combines with weight systems to record plot seed weight and moisture at the time of harvest. Plot yields are converted into lb/ac at 13% moisture for further analysis. Harvested seed will be evaluated via Near-infrared Spectrometry (NIR) to determine seed composition and gas chromatography (GC) to determine the fatty acid profile. During the growing season, lines will be evaluated for nematode (soybean cyst nematode and root-knot nematode) and disease (frogeye leaf spot and stem canker) resistance by our collaborators, Drs. Melissa Mitchum and James Buck in the UGA greenhouse facility. High yielding lines with good agronomic performance and high protein, high oleic acid, and low linolenic acid traits across locations will be advanced to the USDA Uniform Tests in 2024 following the same methods.2024:By analyzing the results of yield trials and seed composition in 2023, 12 top yielding lines with expected seed composition will be advanced to the USDA Uniform Yield Tests at 16 locations in NC, SC, GA, AL, and LA. Field management will be similar to 2023. During the growing season, lines will be evaluated again for nematode (soybean cyst nematode and root-knot nematodes) and disease (frogeye leaf spot and stem canker) resistance by our collaborators, Drs. Melissa Mitchum and James Buck in the UGA greenhouse facility.A four-row seed increase plot with a length of 60 ft for each line will be planted at the UGA Iron Horse Plant Science Farm in Watkinsville, GA. During the fall, 100 plants per line will be selected from the seed increase plot. Each plant will be individually threshed and genotyped with HOLL, protein, nematode resistance, and disease resistance trait markers to select homozygous plants for these traits to create breeder seed.2025:Based on the yield trials in 2024, 6 top yielding lines with expected seed composition will be yield-tested in the USDA Uniform Yield Tests at 16 locations in NC, SC, GA, AL, and LA and also entered into the State Variety Tests in NC, SC, GA, and AL. Field management will be similar to previous years. During the growing season, lines will be evaluated again for nematode (soybean cyst nematode and root-knot nematodes) and disease (frogeye leaf spot and stem canker) resistance by our collaborators, Drs. Melissa Mitchum and James Buck in the UGA greenhouse facility.According to the genotyping results, individual plants for each line will be selected and grown as breeder plant rows at the UGA Iron Horse Plant Science Farm. By evaluating the agronomic traits, breeder plant rows will be selected in the field for harvest. Harvested seed will be analyzed via NIR to determine seed composition and GC to determine the fatty acid profile and phenotyped for seed size, seed coat, and hilum colors. To determine the purity of traits in these rows and detect adventitious presence, DNA will be extracted from a ground sample of each row and genotyped using seed composition, nematode and disease resistance, and transgenic DNA marker assays to select desirable lines. Seed from selected rows will be combined to create breeders seed for further foundation seed increase. The data collected across four years will be combined to develop an application for approval of release by the UGA Cultivars and Germplasm Release Committee.Statistical analysesData of yield trials across multiple locations and years will be analyzed in SAS version 9.4. A PROC MIXED procedure will be utilized, in which genotype will be treated as a fixed effect and environment, genotype by environment interaction, and rep within environment will be treated as random effects. Tukey's honestly significant difference (Tukey's HSD, α=0.05) will be used to determine significant differences for traits including yield, protein, oleic acid, linolenic acid, maturity, height, lodging, and seed weight in the lines relative to the commercial checks in the similar maturity.Seed composition analysisSeed samples of lines collected in the yield trials from 2023 through 2025 from each environment will be analyzed for protein and oil contents using the Perten DA 7250 analyzer (PerkinElmer Inc., Stockholm, Sweden). The NIR spectroscopy has been calibrated by the manufacturer using thousands of samples with known seed composition values for whole seed and ground seed samples. Seed composition measured using NIR spectroscopy will be reported as a percent on a dry matter basis for all reps and locations.Thirty seed randomly selected from each plot at all locations will be used for fatty acid analysis using gas chromatography (GC). The GC analyses will be conducted at the USDA-ARS/University of Missouri, Columbia, MO following the protocols reported by Bilyeu et al., (2006) and Bilyeu et al., (2005).Release and market soybean cultivarsThe University of Georgia has a well-established system, called "Georgia Integrated Cultivar Release System (GICRS)". The release and marketing of the resulting cultivars will be supported by GICRS.