Location: Plant Genetics Research
Project Number: 5070-21000-040-41-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2020
End Date: Sep 30, 2021
The research leverages the discoveries from our previous efforts by confirming the benefits of our targeted traits for improving drought tolerance and providing a genomic selection roadmap for utilizing the alleles for these four traits (Canopy Temperature, Canopy Wilting, Water Use Efficiency, and Nitrogen Derived From the Atmosphere) to enhance drought tolerance in improved germplasm. Our specific objectives are: Objective 1: Introgress all four drought tolerance traits into a single genetic background using genomic selection using the lines from the germplasm collection with the most favorable alleles. Objective 2: Advance agronomically sound breeding lines from crosses between accessions with the four drought-tolerance traits and an elite, hub parent. Objective 3: Evaluation and identification of breeding lines with increased WUE for possible future release. Objective 4: Identify and confirm genetic markers for physiological traits relevant for soybean response to drought stress.
Soybean lines will be developed combining alleles for four distinct drought-tolerant traits in a single, novel genetic background. Using molecular marker data we will select lines with the predicted greatest drought tolerance, which will be leverage for genetic mapping population development and eventual future germplasm releases which we anticipate will have unprecedented drought tolerance (Objective 1). We have produced >200,000 F2 soybean seed from crosses between an elite, adapted parent crossed to one of 20 different drought-tolerant accessions. Each of these 20 accessions were specifically chosen from the USDA germplasm collection based off genetic mapping results that identified them as bearing the best possible alleles for one or more drought-tolerance traits. We will begin screening this extremely large F2 resource in 2020; selections made in 2020 will be advanced in 2021 based on agronomic characteristics and genomic selection. These selections will be fast-tracked for future germplasm releases (Objective 2). We have also developed four advanced breeding lines that have been selected for high water use efficiency and seed heat tolerance/germination. Depending upon results of irrigated and rainfed experiments in 2020, the most promising lines will be entered into regional yield trials in 2021 (Objective 3). In previous and ongoing work, we performed Genome Wide Association Studies aimed at understanding the genetic architecture for four drought tolerance traits in soybean. A series of experiments we performed in previous years identified a large number of potentially valuable genetic loci. We are now confirming and extending these results using biparental QTL mapping populations. We will also attempt to characterize overall drought tolerance trait stability/plasticity using our uniquely rich genome wide association study phenotypic data. We will attempt to identify genetic loci responsible for drought-trait stability/plasticity across multiple environments. We anticipate this will provide tremendous insights into the genetic mechanisms responsible for how genotypes respond to different drought treatments across environments (Objective 4).