SENSITIVITY OF SOYBEAN CULTIVARS TO THE MIXTURE OF SULFENTRAZONE + DIURON APPLIED IN PRE-EMERGENCE

New herbicides for soybean cultivation, mainly mixtures, have been launched on the market. However, little is known about the actual effects of these mixtures on the crop, and studies are needed to verify the sensitivity of cultivars to these herbicides. This work aimed to evaluate the sensitivity of soybean cultivars to the commercial mixture of pre-emergent herbicides sulfentrazone + diuron. The experiment was conducted in a greenhouse in a completely randomized design, with four replications, in a 20 x 3 factorial. Factor A was composed of 20 soybean cultivars. Factor B comprised two doses of sulfentrazone + diuron, being 175 + 350 g ha-1, and 350 + 700 g ha-1, equivalent to 1 and 2 L commercial product (cp) ha-1, in addition to a control treatment (zero dose). The variables evaluated were phytotoxicity, FSII activity, relative electron transport rate (rETR), shoot length, and shoot dry mass (SDM). The data were subjected to analysis of variance, and the means were grouped using the Skott-Knott test (p < 0.05). The mixture of sulfentrazone + diuron caused negative changes in the physiological and growth characteristics, especially at the highest dose evaluated. However, variability was observed in the sensitivity of the studied cultivars. HO Amambay, HO Iguaçu, HO Paraguaçu, HO Pirapó, Lança IPRO, Lótus IPRO, M6410 IPRO, TMG 2356 IPRO, TMG 2359 IPRO, and TMG 2364 IPRO cultivars were more sensitive. Therefore, it is concluded that the selectivity of the sulfentrazone + diuron mixture depends on the dose applied and the soybean cultivar.