Selective control of jointed goatgrass (Aegilops cylindrica) with imazamoxin herbicide-resistant wheat

Jointed goatgrass (Aegilops cylindrical is a serious problem for winter whe at producers throughout the western U.S. Interference from this weed can se verely reduce grain yield and contaminate harvested grain, resulting in doc kage losses. There are currently no selective herbicides registered for con trolling jointed goatgrass in wheat. Imazamox, an imidazolinone herbicide, was applied to an imidazolinone herbicide-resistant (IMI) wheat mutant of t he winter wheat cultivar 'Fidel.' Jointed goatgrass control from spring pos temergence application of imazamox ranged from 61 to 97% when applied at 36 g/ha. Negligible crop injury from imazamox treatment was observed at 36 g/ ha at several locations under dryland environments in the U.S. Pacific Nort hwest. Wheat yield was increased 19 to 41% by imazamox treatment in three o f four experiments. Percent dockage resulting from jointed goatgrass spikel et contamination of harvested wheat grain was eliminated by imazamox treatm ent. Introduction of the IMI trait into commercial wheat cultivars could pr ovide an effective method for selective control of jointed goatgrass in win ter wheat.