Two experiments were carried out under field conditions at Embrapa Soja, Londrina, Paraná to evaluate the response of soybean genotypes to trifluralin and imazaquin, during the agricultural season of 2000/2001. The treatments were arranged in a split-plot design in a randomized complete block experiment with four replicates. Genotypes (BR 16, BRS 183, BRS 184, BRS 155, BRS 156, BRS 132, BRS 133, BRS 136, BRS 134, BRS 135, Embrapa 58, Embrapa 59, Embrapa 48, BRS 212, BR96-25619, BR96-12086 and BR95-8400) were sowed in the whole plots. In the subplots, trifluralin rates of 0.0 (check), 1.8 kg a.i. ha-1 (recommended rate) and 3.6 kg a.i. ha-1 (double rate - experiment 1) and imazaquin rates of 0.0 (check), 0.14 kg a.i. ha¹ (recommended rate) and 0.28 kg a.i. ha-1 (double rate - experiment 2) were applied. All genotypes were tolerant to the recommended rates of both herbicides, with light symptoms of phytotoxicity without yield losses. However, cultivars BRS 183, BRS 156, Embrapa 59 and Embrapa 58 showed lower yields when submitted to double the recommended rate of trifluralin. Only BR9625619 showed significant yield reduction due to the double rate of imazaquin.
Glycine max; phytotoxicity; selectivity
