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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #409461
Research Project: Resilience of Integrated Weed Management Systems to Climate Variability in Midwest Crop Production Systems

Location: Global Change and Photosynthesis Research

Title: First report of severe tolpyralate sensitivity in corn (Zea mays) discovers a novel genetic factor conferring crop response to a herbicide

Author
item Williams, Martin
item Hausman, Nicholas
item SABALLOS, ANA - Oak Ridge Institute For Science And Education (ORISE)
item Landau, Christopher
item Brooks, Matthew
item FLANNERY, PAT - University Of Wisconsin
item TRACY, WILLIAM - University Of Wisconsin
item THOMPSON, CHARLIE - Illinois Foundation Seeds

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2023
Publication Date: 3/1/2024
Citation: Williams II, M.M., Hausman, N.E., Saballos, A., Landau, C.A., Brooks, M.D., Flannery, P., Tracy, W., Thompson, C. 2024. First report of severe tolpyralate sensitivity in corn (Zea mays) discovers a novel genetic factor conferring crop response to a herbicide. Pest Management Science. 80(3):1645-1653. https://doi.org/10.1002/ps.7896.
DOI: https://doi.org/10.1002/ps.7896

Interpretive Summary: Herbicides registered for use on crops are expected to selectively kill weeds and not harm to the crop. This research investigated a report of severe corn injury from tolpyralate, an herbicide registered on corn. We confirmed severe injury to a specific line of corn from tolpyralate, observed severe injury in other diverse corn lines, and determined the genetic basis of corn sensitivity to the herbicide. The impact of this research is that it sheds light on severe injury in specific corn lines to a herbicide labeled on the crop; a phenomenon that hasn't happened since the early 1990s. Caution should be exercised in using tolpyralate in corn. Specifically, the herbicide manufacturer needs to revise the pesticide label to mitigate crop injury and seed companies should identify sensitive germplasm and improve tolpyralate tolerance.

Technical Abstract: BACKGROUND: Tolpyralate is a relatively new inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD), is registered for postemergence use in all types of corn (Zea mays L.) and has a record of excellent crop tolerance. A report of severe crop injury to sweet corn inbred (XSEN187) led to the following objectives: 1) determine if sensitivity to tolpyralate in XSEN187 exists, and if confirmed, 2) determine the genetic basis of tolpyralate sensitivity, and 3) screen other corn germplasm for sensitivity to tolpyralate. RESULTS: Inbred XSEN187 was confirmed sensitive to tolpyralate. Inclusion of methylated seed oil or nonionic surfactant in the spray volume facilitated severe crop injury. Tolpyralate sensitivity in XSEN187 is not conditioned by alleles at Nsf1, a cytochrome P450-encoding gene (CYP81A9) conditioning tolerance to many corn herbicides. Evidence suggests tolpyralate sensitivity in XSEN187 is conditioned by a single recessive gene which was subsequently mapped to the Chr05: 283,240 - 1,222,909 bp interval. Moreover, tolpyralate sensitivity was observed in 48 other sweet corn and field corn inbreds. CONCLUSIONS: Severe sensitivity to tolpyralate exists in sweet corn and field corn germplasm when the herbicide is applied according to label directions. While corn response to several other herbicides, including HPPD-inhibitors, is conditioned by the Nsf1 locus, corn sensitivity to tolpyralate is the result of a different locus. This first report of severe corn injury from tolpyralate shows the problem exists in diverse corn germplasm and identifies a genetic basis for sensitivity.