LABORATORY SPRAY METHOD FOR DETECTINGTHE BXN~R TRAIT IN COTTON SEEDLINGS

摘要

BXN~R cotton is resistant to the herbicide bromoxynil which effectively controls many broadleaf weeds following field applicationof (BUCTRIL~R 4EC) in cotton. BXN~R seed lots must be tested prior to sale to insure that seed is indeed resistant tothe herbicide to prevent crop injury. Delinted cottonseed is planted with equidistant spacing in nursery flats and grown at7,500 lumens m-2 at 30 - 32degC with a 24-hr photoperiod. Spraying a 3,642 ppm bromoxynil solution over-the-top until runoff,to actively growing seedlings at the cotyledon to one-leaf stage, and then re-applying the herbicide two days later in the laboratoryis a valid and cost-effective means to determine percent purity of cottonseed samples. Susceptible seedlings appeardesiccated or burned at two days after herbicide application, followed by complete necrosis.