Location: Soybean and Nitrogen Fixation Research
Project Number: 6070-21220-070-000-D
Project Type: In-House Appropriated
Start Date: Apr 11, 2023
End Date: Apr 10, 2028
Objective:
1. Conduct research to improve yield potential of soybean by identifying novel variation of economically important traits in the USDA Soybean Germplasm Collection using genomic-assisted methods and use the information to develop new soybean germplasm/varieties adapted to the Southeastern region of the United States.
1.A. Develop and evaluate genetically diverse populations derived from crosses between Northern and Southern germplasm/varieties for improved seed yield, genetic diversity, protein content, and test weight.
1.B. Develop MG V-VIII high-protein germplasm with >80% yields of check cultivars and 12-50% G. soja genomes from G. max x G. soja crosses.
2. Conduct research to improve soybean oil and meal protein concentrations and quality profiles by identifying and characterizing genetic variation of unique soybean parental sources and develop new germplasm/varieties for use as parents in developing new varieties or commercial production.
2.A. Identify alleles for improved seed-protein concentrations and composition from G. soja using Recombinant Inbred Lines (RILs).
2.B. Develop MG V-VI high yielding germplasm with 24% or higher oil content on zero moisture basis.
2.C. Develop and release MG V-VII germplasm with >48% meal protein without reducing yield compared to commercial checks.
2.D. Determine if variation in a small RNA (Gm_mir395) reported to regulate S uptake in Arabidopsis plays a similar role in soybean, characterize its mechanism of action and the affect that mismatch between the RNA and its target sequence has in regulating S metabolism.
2.E. Combine unrestricted high oleic, low linolenic, and low RFO (raffinose family of oligo saccharides) alleles into MG V-VII high (>48%) meal protein high yielding lines.
2.F. Develop and release germplasm that meet the needs of the soybean food market.
3. Conduct research to improve drought, heat, and flood tolerance of soybean; determine molecular and physiological mechanisms that preserve yield and seed composition under abiotic stress conditions; and transfer these traits into adapted germplasm for release to various users.
3.A. Develop high-yielding germplasm with improved drought or flood tolerance.
3.B. Elucidate the molecular or physiological roles of key regulatory genes in the nitrogen fixation response to drought.
3.C. Identify physiological traits related to stable or improved seed quality under abiotic stress.
3.D. Screen diverse soybean accessions in irrigated and water-limited conditions and identify genetic markers associated with more stable yield and seed composition under drought.
3.E. Screen high (>46%) seed protein breeding lines for potential drought tolerance.
Approach:
Commercially grown soybean cultivars are among the least diverse crops in the U.S. Such narrow genetic base renders the crop vulnerable to diseases, weather extremes and changes in market demand. The lack of diversity also reduces the rate of yield gain, and any yield gain usually leads to reduction in seed protein, making soybean a less valuable crop. The soybean crop is primarily valued for its protein and oil. Soybean meal is the largest source of plant protein worldwide and 60-70% of the value of soybean is derived from the meal and the rest from its oil. Fortunately, vast genetic resources (20,000 soybean accessions) are available in the USDA soybean germplasm collection to remedy the problem related to genetic diversity. Genetic markers and DNA sequences supporting these genetic resources are also readily available but so far have not been utilized extensively. This project will i) identify untapped genetic resources in the soybean collection to improve key economic traits, ii) determine the genetic location and mechanisms of loci governing these traits, iii) investigate the physiology underlying economically important traits, and iv) transfer desirable alleles from unadapted accessions to adapted genetic backgrounds and release them to the soybean industry. The key traits to be addressed are seed yield (Objective 1), seed composition (Objective 2), and tolerance to drought, heat, and flood (Objective 3). The research will be accomplished by combining conventional breeding technology with modern genomics and plant physiology methods. Attainment of these goals will result in novel and improved breeding stocks, new genomic and physiological insights to improve the efficacy of breeding and ensure profitability of the U.S. soybean crop.
