Soybean (Glycine max (L.) Merr.) cultivar tolerance to sulfentrazone

Sulfentrazone has excellent soil activity on many small-seeded broadleaf weeds, however, soybean injury in "eld experiments has been noted under certain environmental conditions. Injury levels in these "eld experiments have appeared to di!er in severity among soybean cultivars. Growth chamber studies were initiated with the objective of examining the suspected di!erences in tolerance among soybean cultivars. Over 40 soybean cultivars, selected from the USDA Soybean Germplasm Collection, were tested for tolerance to sulfentrazone. The soybean cultivars were grown under constant conditions in a growth chamber in a soil mix treated with sulfentrazone at 0.28 kg ai ha preemergence. Ratings of plant injury and measurement of height and biomass reduction were made 14 days after treatment and compared to the respective untreated check plants of each cultivar. Notable di!erences in tolerance to sulfentrazone across the cultivars were observed. The cultivars were divided into three groups based on plant response and classi"ed as having either high, medium, or low tolerance to sulfentrazone. Results of this study suggest that cultivar selection may lower the risk of early season injury to soybean and potential yield reductions. 2001 Elsevier Science Ltd. All rights reserved.