Sensitivity of selected field corn inbreds (Zea mays) to nicosulfuron

A small percentage (< 5%) of dent corn inbreds was sensitive to the herbicide nicosulfuron. Segregation within a backcross to inbred Ab18 demonstrated simple inheritance as a nuclear gene for corn sensitivity to this herbicide. Greenhouse tests indicated that cytoplasmic or maternal effects were not important in conditioning sensitivity. Tolerance in some crosses began to break down at application rates approaching twice that registered. Sensitivity was controlled by a single autosomal recessive gene in the inbred Ab18. Further testing will be required to determine whether this gene is common to other sensitive inbreds. Thorough screening continues to be necessary to identify sensitive elite inbreds in public and private breeding programs.