Identifying Molecular Markers for Ozone Tolerance in Soybean

Tropospheric ozone (O₃) is a damaging air pollutant that is currently costing U.S. farmers hundreds of millions of dollars in yield losses each year.  The detrimental effect of O₃ on soybean production has been recognized over the past 30 to 40 years, yet there has been little effort to improve soybean response to O₃ through breeding or biotechnology.  Free Air Concentration Enrichment (FACE) allows the growth of soybeans under elevated O₃ concentrations in the production environment, and can provide a platform for conducting genetic screening and elucidation of the mechanisms that underpin genetic variation in productivity at elevated O₃ concentrations.  Over 40 genotypes of soybean have been screened for O₃ tolerance from 2002-2008 at the soybean FACE experiment in Champaign, IL, and two cultivars (Pana and Dwight) with different responses to O₃ were used as parent lines for a recombinant inbred line (RIL) population.  In 2011, 208 F6 RILs were grown at ambient (~40 ppb) and elevated O₃ (~100 ppb) in the field.  The population will be genotyped using the 1536 Universal Soy Linkage Panel 1.0, and a genome-wide genetic linkage map will be generated.  Phenotypic traits including plant growth and development, leaf optical properties and yield were scored in 2011.  These data will be used to detect QTLs for O₃ tolerance in soybean that can be used to develop germplasm better adapted to currently damaging levels of O₃.