RESPONSE OF BROCCOLI (BRASSICA-OLERACEA) CULTIVARS TO POSTTRANSPLANT OXYFLUORFEN

Broccoli cultivars were evaluated for differential response to oxyfluo rfen applied postemergence (0.1 to 1.6 kg ai/ha) in the greenhouse and post-transplant (0.125 to 1.0 kg/ha) in a spring and a fall field stu dy. One cultivar, 'Green Goliath,' was injured more by oxyfluorfen tha n other cultivars in all environments. 'Pinnacle,' was consistently le ss injured than others. 'Early Dawn' and 'Emerald City' were intermedi ate in response to oxyfluorfen. At application rates of 0.25 kg/ha or less, all cultivars recovered sufficiently from injury to produce broc coli heads of equal weight and quality as controls. Cultivars differed in their tolerance of oxyfluorfen at rates above 0.25 kg/ha. Late-mat uring cultivars (i.e., Pinnacle) usually recovered from injury to yiel d similarly to hand-weeded plots while early-maturing cultivars were m ore likely to show yield losses. Broccoli cultivars possess sufficient tolerance to oxyfluorfen applied post-transplant for weed control. Ap propriate choice of cultivar will enhance its utility.