Submitted to: National Sweetpotato Collaborators Group Progress Report
Publication Type: Abstract Only
Publication Acceptance Date: December 18, 2007
Publication Date: January 19, 2008
Citation: Harrison Jr, H.F., Jackson, D.M. 2008. Differential Clomazone, Herbicide Tolerance among Sweetpotato Genotypes. National Sweetpotato Collaborators Group Progress Report. Page 7. Technical Abstract: Clomazone (Command 3ME) is a broad spectrum preemergence herbicide that is registered for use in sweetpotato [Ipomoea batatas L. (Lam.)]. It controls several important annual weeds that are not controlled by the other sweetpotato herbicides. Following clomazone application for weed control in the plant beds of the U.S. Vegetable Laboratory breeding program, we observed genotypic differences in response to the herbicide. The most susceptible clones exhibited extensive foliar bleaching; whereas, bleaching was not observed on the most tolerant genotypes. All clones were rated for bleaching, and 12 with differential response to the herbicide were selected for further evaluation. Most of the highly susceptible clones that we identified originated from the USVL program. In a greenhouse concentration-response experiment, the most tolerant clones (Beauregard and SC 1149-19) were injured less by 16 mg clomazone/kg potting soil than the most susceptible clones were by 1 mg/kg. This indicates that there are substantial differences in clomazone tolerance among sweetpotato clones. Similar differences in foliar bleaching were observed in a field study; however, clomazone injury did not appear to greatly reduce yields of even the most susceptible clones. Susceptibility to clomazone is undesirable, and clones exhibiting the trait should be removed from sweetpotato breeding programs.