In vitro safening of bentazon by melatonin in sweetpotato

Authors: CAPUTO, GIOVANNI - Clemson University; Wadl, Phillip; MCCARTY, LAMBERT - Clemson University; ADELBERG, JEFFERY - Clemson University; JENNINGS, KATHERINE - North Carolina State University; CUTULLE, MATTHEW - Clemson University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2020
Publication Date: 7/28/2020
Citation: Caputo, G.A., Wadl, P.A., Mccarty, L., Adelberg, J., Jennings, K.M., Cutulle, M. 2020. In vitro safening of bentazon by melatonin in sweetpotato. HortScience. 55:1406-1410. https://doi.org/10.21273/HORTSCI15128-20.
DOI: https://doi.org/10.21273/HORTSCI15128-20

Interpretive Summary: Weeds are problematic for sweetpotato production, as there are limited chemical control options (herbicides) available. This is especially true for yellow nutsedge control in sweetpotato because there are no post emergence herbicides registered for use in sweetpotato. Bentazon has been demonstrated to be effective for post emergence control of yellow nutsedge, but the tolerance of sweetpotato to bentazon is unclear. Research is needed to identify the dose response of sweetpotato to bentazon application and if additional compounds can be used to safen bentazon. The objective of this study was to assess the effect of bentazon on sweetpotato and to determine the interactive response of the cultivar Beauregard to bentazon and exogenous applications of melatonin as a safener. Tissue culture experiments were used to determine that ‘Beauregard’ was the most tolerant sweetpotato cultivars tested. Furthermore, the addition of melatonin to the herbicide showed less injury and higher plant biomass than plants treat with bentazon alone. Understanding the interactions between melatonin and bentazon herbicide in sweetpotato may lead to an improvement in weed management.

Technical Abstract: Weed competition is a main factor limiting sweetpotato production. Yellow nutsedge is a problematic weed to control due to its ability to quickly infest a field and generate high numbers of tubes and shoots. Compounding this is the lack of an herbicide registered for selective post emergence (POST) control of yellow nutsedge. Research was conducted to evaluate bentazon dose response of two sweetpotato cultivars and one advanced clone; and, the plant hormone melatonin on its ability to safen bentazon POST. Bioassays using Murashige and Skoog (MS) media supplemented with melatonin (0.232 g ai L-1 and 0.023 g ai L-1) and bentazon (0.24 g ai L-1) were conducted to evaluate the effect of bentazon on sweetpotato and to determine the interactive response of Beauregard cultivar to bentazon and exogenous applications of melatonin. Beauregard was the most tolerant cultivar, requiring dosages of bentazon 2x higher to cause the same injury compared to other cultivars. MS media containing melatonin and bentazon showed less injury and higher plant mass, than plants treated with bentazon. These results indicate that sweetpotato injury caused from bentazon may be reduced by melatonin.