Monogenic Semidominant Sulfonylurea Resistance in a Line of White Chicory

This paper reports on a chlorsulfuron-resistant line of white chicory (Cichorium intybus cv. ‘Witloof’) regenerated from non-mutagenized cell cultures. The resistance was inherited as a monogenic semi-dominant trait. Homozygous resistant individuals withstood doses of herbicide 1500 to 2000-fold higher than the susceptible ones, whereas this ratio was around 300 for the heterozygotes. Cross-resistances to seven other sulfonylureas and to one imidazolinone were revealed, leading to the conclusion that this resistance could be due to mutation of the target enzyme.