With previous USB support, we developed screening protocols, identified flood-tolerance genes, and developed flood-tolerant germplasm. Three flood-tolerant lines with a 12-15 bu/a yield advantage under flooding stress were transferred to seed companies for commercial variety development. Current efforts are focusing on identifying new genetic resources and gene-editing for flood tolerance to develop varieties with a higher level of tolerance for greater yield protection (~20 bu/ac). In the past year, we successfully finished 2024 planting season. A patent for the method of use of the major flood tolerance gene in Nguyen lab was issued in February 2024 (Patent Number 11905518). Three flooding-tolerant/high-yielding germplasm lines were released in 2024. Two other high-yielding and flood-tolerant lines (S17-1146 and S12-1362) are being released as conventional germplasm with flood tolerance. These 2 lines have been transferred to GDM seeds for crossing under a Material Transfer Agreement (MTA). We got licenses from Bayer and Corteva to introgress the herbicide resistance traits (Enlist-E3 and XtendFlex) into our advanced breeding lines with strong flood tolerance for variety development. New genetic resources and gene discovery for flood tolerance in the early season and wild soybean are progressing as expected. Gene-editing lines for the major flood tolerance gene WLT1 in the elite background, were developed and confirmed to improve root plasticity and flood tolerance in the greenhouse. Meanwhile, about 130 advanced breeding lines were genotyped for two major flood tolerance genes. About half of them carry flood tolerance genes, which will help breeders make selection decision.

The Team will continue to engage private breeders in collaborative activities to utilize the new materials and molecular breeding strategies. We published and will continue to publish findings, report activities at stakeholder meetings/workshops, host field days to communicate findings. The developed flood-tolerant and high-yielding variety/germplasm lines were or are being released as cultivars to benefit soybean growers and will be informed to farmers and breeders through field days and stakeholder extension meetings for soybean production and breeding. The data from flood screening of commercial varieties will be shared with companies and farmers to enhance awareness of flood susceptibility. Currently, seed companies are aware of our flooding-tolerant lines, and we started to transfer these materials to them. Meanwhile, Bayer and Corteva have licensed herbicide resistance traits (Enlist-E3 and XtendFlex) to our soybean breeding programs, which allow us to introgress herbicide resistance traits into our advanced breeding lines with strong flood tolerance for variety development. Although flood-tolerance trait can substantially protect yield under flooding stress, the trait is still experiencing yield loss as opposed to, for instance, disease resistance. Thus, efforts in the long-term are needed to identify more genetic resources (including wild genetic resources) and stack them into the current elite germplasm pool to develop stronger tolerance. Once the project is completed, soybean varieties with strong flood tolerance and additional value-added traits will be available to soybean farmers in the flooding-prone areas.