Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2011
Publication Date: 7/15/2011
Citation: Harrison Jr, H.F., Jackson, D.M. 2011. Greenhouse assessment of differences in clomazone tolerance among sweetpotato cultivars. Weed Technology. 25:501-505. Interpretive Summary: Differences in tolerance of sweetpotato varieties to clomazone herbicide were observed after it was used for weed control in the sweetpotato breeding project at the US Vegetable Laboratory. A greenhouse study demonstrated that the most tolerant varieties tolerated eight to ten times the concentration of clomazone that was tolerated by the most susceptible varieties. Fifty two commercial and experimental varieties of sweetpotato were tested, and several that are susceptible to clomazone were identified. Since clomazone is a very important tool for weed management in sweetpotato in the US, it is important that new varieties are not susceptible. This report alerts breeders and other researchers that testing new sweetpotato varieties for clomazone tolerance is necessary to avoid the problem.
Technical Abstract: Differences between sweetpotato clones in response to clomazone were first observed following use of the herbicide for weed control in fields containing the sweetpotato breeding project at the US Vegetable Laboratory. Susceptible lines exhibited severe foliar bleaching and reduced growth; whereas, the most tolerant lines were not injured. Twelve clones chosen based on these observations were included in a greenhouse experiment to quantify differences in clomazone tolerance. A tolerant clone, “Beauregard’ exhibited lower injury ratings and shoot weight reduction at 8.0 mg ai clomazone/kg potting medium than the most susceptible clone, ‘04-N01’, exhibited at 1.0 mg/kg. Fifty two commercial cultivars and advanced experimental lines were evaluated for clomazone tolerance in the greenhouse, and several susceptible lines were identified. These observations indicate that some sweetpotato genotypes are highly susceptible to clomazone. Since it is important in sweetpotato weed management, developing susceptible cultivars should be avoided.