Two-row barley response to diclofop and HOE-6001

Abstract

A field experiment was conducted near Brandon, Manitoba to determine the response of seven barley cultivars to diclofop and HOE-6001 applied at two growth stages. Diclofop at 0.7 kg ha −1 resulted in minimal barley injury, regardless of growth stage, and barley injury increased as diclofop rate increased to 1.4 kg ha −1, especially at late application. However, grain yield was reduced only at growth stage 22 (two tillers). HOE-6001 had the most injurious effect on barley and reduced grain yield by the greatest amount. Reduction in test weight or kernel plumpness was not consistent with visible injury or grain yield reduction. Diclofop will not reduce barley grain yield if applied before tillering. Barley tolerance to HOE-6001 in its present form is not sufficient to allow cost-effective use of this herbicide. However, the high degree of tolerance exhibited by TR112 indicates that it may be possible to increase HOE-6001 tolerance in barley through selection.