A research project was initiated in 1995 to develop Liberty-tolerant cotton using genetic engineering techniques. A plant chimeric bar gene was introduced into Coker 312 using Agrobacterium infection of hypocotyls. PCR analysis and direct screening with Liberty were conducted on plantlets to determine if the bar gene was being expressed. Seeds were collected from tolerant plants. Field experiments were conducted in 1997 at the Texas Agricultural Experiment Station near Lubbock to evaluate the performance of Liberty-tolerant cotton. Tolerance was evaluated at various cotton growth stages, to various Liberty rates, and to repeated Liberty applications. Liberty treatments were applied using a tractor-mounted compressed-air sprayer or a CO2 backpack sprayer that delivered 10 GPA. Plots were hand-weeded throughout the growing season.