A total of twelve University yield trials were conducted in six Mid-South and Southeast states during 1993 and 1994, to better determine the agronomic characteristics of two strains of transgenic BXN(TM) cotton (Gossypium spp.). The transgenic BXN^® strains had been transformed to be resistant to bromoxynil, the active ingredient in Buctril^® herbicide. Recent studies have demonstrated this resistance and the usefulness of Buctril^® in a cotton weed control program (Wilcut, et al., 1993, Patterson and Norris, 1993). The combination of BXN^® cotton and Buctril^® herbicide has been defined as the BXN^® system. Ultimate grower acceptance of this new technology may largely depend on how well the BXN cotton strains perform compared to standard varieties in yield and other agronomic characteristics.

Studies were conducted in Alabama, Arkansas, Louisiana, Mississippi, North Carolina and Tennessee in 1993 and 1994. Most studies were conducted as small plot, replicated trials, however, the Louisiana studies were replicated on-farm strip trials both years. The Mississippi study in 1994 was also an on-farm strip trial. In the 1993 studies, a BXN^® cotton strain was compared to check varieties of either DPL 50, DPL 51, DPL 5415 or DES 119. The variety Stoneville 453 was also used as a check variety at all locations in 1993. The performance of the BXN^® strain was evaluated in various weed control programs including: 1) standard preplant and preemergence herbicides with Buctril^® substituted for post-directed herbicides, 2) standard preplant herbicide with Buctril^® replacing preemergence and post-directed herbicides, 3) standard herbicide program without Buctril(^®) applications. Check cotton varieties received the standard weed control program for the area. In 1994 a sister strain of the 1993 BXN^® variety was used in all studies. Also Stoneville LA887 replaced Stoneville 453 as a check variety at all locations because the maturity range of ST LA887 is similar to the BXN^® variety.