Published online by Cambridge University Press: 20 January 2017
The tomato mutant line HRT was obtained by ethyl methanesulfonate seedmutagenesis of the commercial tomato line M82. Greenhouse studies wereconducted to determine whole-plant response to the imidazolinone herbicidesimazamox, imazapic, and imazapyr; pyrithiobac-sodium (a herbicide from thepyrimidinylthiobenzoic acid group); and propoxycarbazone sodium(sulfonylaminocarbonyltriazolinone group). The mutant was highly resistantto imazamox, imazapic, and imazapyr, but did not differ from M82 in itsresponse to the sulfonylurea herbicides Envoke (trifloxysulfuron), Monitor(sulfosulfuron), and Glean (chlorsulfuron). Equip (foramsulfuron), asulfonylurea herbicide, was toxic to M82 but less so to HRT plants. Underfield conditions, HRT showed high resistance to imazapic and imazapyr. Theherbicides at a rate of 144 g ai ha−1 did not cause any reductionin HRT plant vigor, development, or yield. Results of greenhouse and fieldexperiments demonstrated high Egyptian broomrape–control efficacy with theimidazolinone herbicides imazapic and imazapyr. Two imazapic applications of9.6 or 14.4 g ai ha−1 and three applications of 4.8 g ai ha−1 in pot experiments completely prevented appearance ofbroomrape shoots aboveground. Three and four applications of the sameherbicides in the field at a rate of 12 or 24 g ai ha−1completely prevented shoot appearance without any yield losses. Singleimazapic application as high as 144 g ai ha−1 did not damage theplants or reduce HRT yield.
Associate Editor for this paper: William Vencill, University of Georgia.