Differential Tolerance of Hawaiian Sugarcane Cultivars to Diuron

Abstract

Hawaiian sugarcane cultivars(SaccharumL. hybrids) differed considerably in their tolerance to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). There was a greater concentration of diuron in the younger leaves of a sensitive cultivar, ‘H 53–263,’ compared with a tolerant cultivar, ‘H 50–7209′; degradation of diuron was more extensive in ‘H 50–7209′. The metabolites identified after applications of carbonyl-labeled diuron to the root system were 1-(3,4-dichlorophenyl)-3-methylurea (monomethyl-diuron) and 1-(3,4-dichlorophenyl)urea (demethylated diuron). Differences in diuron phytotoxicity to cultivars ‘H 53–263’ and ‘H 50–7209’ are at least partially explained by differences in the distribution and degradation of diuron.