Summary:
Overcoming the devastation of drought is a cornerstone of sustainable soybean production. Several recent major droughts across the US stress the need for building better long-term drought resilience. Farmers are facing different levels of drought vulnerability, reflecting both variation in local drought risk and differences in farm operations. Drought is no longer considered a localized problem to certain regions of the US, but a significant problem that is worsening and can affect farmers anywhere in the US. The main goal of this project is to ensure drought does not significantly impact US soybean production by developing drought-resilient soybean varieties. As drought stress becomes more prevalent the protection offered by drought-resiliency could have an even greater impact on soybean yield in the future. The bottom line is that every bushel saved from drought stress by using tolerant varieties would directly translate into net income for US soybean farmers.
Accomplishments:
1) Over 10,000 genotypes (maturity groups (MG) II-VIII) were evaluated in field trials across multiple states, moderate to severe drought stress were recorded and phenotypic response was measured. 2) Six soybean varieties were released, which demonstrated consistent drought tolerance and perform better under drought than previous releases. 3) Soil moisture sensor and cloud technology provided by Meter Group Inc. USA were used to evaluate drought tolerance. The soil moisture data is now being analyzed to identify the best time/day to take canopy wilting notes to improve efficiency and accuracy in collecting canopy wilting scores and evaluating drought tolerance. 4) Two Genome-Wide Association Study (GWAS) panels, multiple mapping populations, and Recombinant Inbred Lines (RILs) were evaluated to identify new genes associated with drought tolerance. 5) Analysis of ground based RGB, hyperspectral, and visual wilt score data, as well as drone based multispectral, thermal, and RGB imagery were collected to develop a high-throughput phenotyping platform. 6) Development is currently in progress to identify new methods including supervised/unsupervised machine-learning algorithms to cluster genotypes based on UAV imagery and deep-learning algorithms. 7) Over two years, two breeding lines consistently exhibited the greatest intrinsic leaf water use efficiency (WUE) among the tested lines, suggesting that both lines are good sources of this leaf trait that contributes to drought tolerance. 8) A set of diverse lines (500 lines) was characterized for root system architecture (RSA) traits to identify genes associated with root traits that can contribute drought tolerance in soybean. Image analysis is ongoing. GWAS will be performed in 2024 to identify genes controlling the root traits for marker-assisted selection. 9) Two slow wilting genes were identified to improve canopy wilting under drought conditions. Lines with these two genes show almost no canopy wilting. 10) Field trials designed to test effects of the TXVA inoculant, a drought-tolerant N-fixing rhizobium, on root nodulation and soybean yield, and its ability to solubilize phosphorus under non-irrigated conditions were conducted. 11) Field days were held in multiple states and multiple presentations were given at scientific meetings to show our work to local farmers, researchers and industry personnel. 12) A gene was identified that controls root initiation and elongation, which can increase yield under drought stress. A patent application has been submitted for the use of this gene.