Proposed work to evaluate, characterize and develop breeding lines and cultivars with some natural resistance to dicamba (and 2,4-D) to prevent losses due to drift and volatilization.

1) characterize the differential response to Dicamba drift damage, 2) identify regions of the soybean genome regulating tolerance to Dicamba through genome wide association studies; 3) select and develop soybean lines adapted to mid-south United States with enhanced natural tolerance to Dicamba; and 4) design and implement haplotypes tolerant to Dicamba to fasten the development of tolerant soybean cultivars.

1) well characterized differential response in soybean to dicamba drift injuries, 2) high-yielding soybean lines adapted to Mid-south US with enhanced tolerance to Dicamba; 3) identified genomic regions responsible for enhanced Dicamba tolerance and respective haplotypes; and 4) a journal publication reporting the impact of Dicamba injury on soybean yield, and 5) a poster presentation for graduate students at professional conference to share the research findings with the scientific community.

Updated April 27, 2021:
The Mid-South Soybean Board was organized to promote soybeans, soybean products, soybean research and development. Originally formed in 2009, other members include the soybean checkoff organizations of Arkansas, Louisiana, Mississippi, and Texas. The Missouri Soybean Merchandising Council joined the MSSB in 2012. The goals are to eliminate duplicate research spending and to develop and fund research of importance to our producers. District 7 MSMC Director Baughn Merideth serves as the MSSB Director for Missouri.

MSMC has partnered on a dicamba research. Testing is being conducted to compare non-Xtend soybean varieties for natural tolerance to dicamba. This could be used to identify genetic natural tolerance to dicamba to develop lines that would not experience as much damage if subjected to off-target movement. Observation and yield testing show strong and consistent negative correlation between off- target dicamba damage and yield performance in 2019 and 2020. Results were obtained across 4,841 yield plots in two years.

Many advanced breeding lines with superior tolerance to off-target dicamba damage have been identified, of which several will be entered in the 2021 USDA uniform trials for more extensive testing.

The selection and development of natural tolerant soybean varieties to Dicamba could potentially benefit Mid-south US growers that are either growing conventional or alternative herbicide-tolerant varieties. Additionally, public breeding programs do not have the access to the Xtend technology for breeding purposes. Therefore, the identification and design of haplotypes with natural enhanced Dicamba tolerance represents a powerful tool to public breeding programs to maintain the flux of their cultivar development pipeline.