Using electrolyte leakage to detect soybean (Glycine max) cultivars sensitive to sulfentrazone

Laboratory studies were conducted to determine if electrolyte leakage from either leaf tissue, germinating seeds, or excised roots correlated with pre viously established soil-applied field response of soybean cultivars and ta rget weeds to sulfentrazone. Sulfentrazone-induced electrolyte leakage from leaf tissue of coffee senna (sensitive), sicklepod (tolerant), and soybean cultivars 'Asgrow 6785' and 'Carver' (sensitive) and 'Stonewall' and 'DPL 3606' (tolerant) was monitored over time. Electrolyte leakage from leaf tis sues, caused by 25 ppm (65 muM) sulfentrazone, agreed directly with the kno wn response of these weeds, but response of the four soybean cultivars was equivalent. Furthermore, sulfentrazone-induced electrolyte leakage from lea f tissue of Asgrow 6785 and Stonewall was not affected by sulfentrazone con centration as high as 100 ppm (258 muM) nor by light intensity (4 and 120 m u mol/m(2)/s photosynthetically active radiation). For germinating seeds, s ulfentrazone-induced electrolyte leakage was also independent of soybean cu ltivar. In contrast, electrolyte leakage from excised roots of germinal soy bean seedlings did concur directly with the previously established cultivar sensitivity to soil-applied sulfentrazone. Results indicate that electroly te leakage from excised roots of soybean germinal seedlings can be used to assess cultivar sensitivity to soil-applied sulfentrazone.