Location: Plant Physiology and Genetics Research
Project Number: 2020-21410-008-002-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2022
End Date: Nov 30, 2023
Drought is the single greatest cause of soybean yield loss, and the incidence and severity of drought is expected to increase in coming decades. Only a small proportion of soybean acreage in the United States is irrigated (<9%) and simply irrigating more is not a sustainable solution. Crop insurance can partially redress crop losses due to drought, but a more sustainable solution is meeded to identify and deploy adapted soybean cultivars that are more tolerant of water limitation. Breeding efforts generally focus on repeated crossing between elite lines – essentially failing to take advantage of the vast genetic diversity in the soybean USDA-GRIN germplasm collection. We have taken key steps to leverage this diversity, via multi-location and drought stress genetic experiments that identified maturity group (MG) 4 Plant Introductions (PIs) with positive drought–associated traits: lower Canopy Wilting (CW), higher Water Use Efficiency (WUE), higher Nitrogen Derived From the Atmosphere (NDFA, as a measure of nitrogen fixation), and lower Canopy Temperatures (CT). Our experiments leveraged prior investment by the USB in obtaining marker data for >19,000 accessions in the USDA germplasm collection. These efforts have paid off, and we have already reported several hundred genetic marker associations with our drought tolerance traits. We are actively applying genomic selection and have crossed PIs with these favorable traits with an elite public parental line and are developing multiple breeding populations containing the best possible alleles for multiple drought-associated traits. Our efforts will reach fruition during the lifetime of this grant; germplasm releases will serve to broaden the genetic base and deploy drought alleles in improved soybean genotypes that will provide valuable tools to commercial and public breeders and producers to meet the substantial challenges of increased incidence and severity of drought stress.
Our previous research with Plant Introduction lines with favorable drought associated traits crossed to an elite public parental line resulted in the creation of multiple breeding populations containing the best possible alleles for multiple drought-associated traits. We also intercrossed among our populations to generate uniquely valuable Multi-parent Advanced Generation InterCross (MAGIC) populations specific for drought traits. We have both basic scientific and applied objectives for this proposal. Our germplasm development effort will reach fruition during the lifetime of this proposed three year grant (this proposal is for year one of three). We intend to identify and release soybean germplasm which will serve to broaden the genetic base and deploy drought alleles in improved soybean genotypes. These efforts will provide valuable tools to commercial and public breeders and producers to meet the substantial challenges of increased incidence and severity of drought stress. We have four interconnected objectives/deliverables for this project: 1. Multi-location testing for yield/drought tolerance using G1F4:5 derived materials, created by repeated agronomic and genomic selection experiments. 2. Ongoing agronomic/genomic selection of MAGIC G4F4 populations towards future germplasm releases. 3. Genotype a single MAGIC G4F4:5 population, which combines multiple drought tolerance traits, for use in genetic mapping efforts. 4. Evaluate the potential utility and predictive ability of seed isotopic data in comparison to whole plant isotopic data, as an indrect measurement of water use efficiency and/or drought tolerance potential.