Sweet Corn Cultivars Respond Differentially to the Herbicide Nicosulfuron

Abstract

Twelve sweet corn (Zea mays L. var. rugosa Bonaf.) cultivars were tested for response to nicosulfuron at rates of 0, 18, 36, and 72 g a.i./ha. Weight of marketable ears indicated that five cultivars were intolerant to the herbicide. Three of the cultivars that were intolerant contained the shrunken-2 endosperm mutant (sh) and two contained the sugary enhancer endosperm mutant (se). Cultivars that were most tolerant of nicosulfuron contained the sh, gene. Incorporation of terbufos insecticide before planting led to decreased marketable yield when nicosulfuron was applied at 36 g·ha in all cultivars tested. Chlorpyrifos insecticide incorporated before planting did not affect tolerance to nicosulfuron. Neither soil-applied insecticide affected yield when nicosulfuron was not applied. Chemical names used: 2-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony]-N,N-dimethyl-3-pyridinecarboxamide (nicosulfuron); S-[[(1,1-dimethylethyl)thio]methyl] O,O-diethylphosphorodithioate (terbufos); O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)phosphorothioate (chlorpyrifos).