Response of selected soybean cultivars to metribuzin

The purpose of this study was to determine the tolerance of several commercially grown soybean [Glycine max (L.) Merr.] cultivars to metribuzin under the same edaphic, climatic and cultural conditions. Twenty cultivars from maturity groups V and VI were studied in 1981 and 1982 at the University of Tennessee Plant Sciences Field Laboratory, Knoxville, Tennessee. Six cultivars were different in 1982. The soil type was a Statler loam. The oxidizable organic matter in the A-horizon was 1.2%. The pH of this Statler loam was 5.8. Approximately 2.3 cm of rain fell within 3 days of planting and preemergence application of metribuzin in 1981. In 1982, 3.9 cm of rain fell within 2 days after planting and preemergence application of metribuzin. A split-plot arrangement of treatments was used. The mainplots were metribuzin at rates of 0.56 and 1.12 kg/ha and an untreated check. The split-plots were the soybean cultivars. Data collected were plant stand, plant vigor and seed yield. In general, of the 26 soybean cultivars studied, 'Coker 156', 'GS 737', 'Terra-vig 505' and 'Terra-vig 606' were most susceptible to metribuzin applied preemergence. The cultivars 'Agripro AP55', 'FFR 560', 'Peterson X5683' and 'Ringaround 502' had a lesser degree of susceptibility to metribuzin. Cultivars which had moderate tolerance to metribuzin were: 'Asgrow A5474', 'Bedford', 'Centennial', 'Coker 80-931', 'Deltapine 246', 'Deltapine 416', 'Deltapine 506', 'Essex', 'Forrest', 'McNairSOO', 'Nathan', 'Pioneer 9561', 'Ringaround 481', 'Ringaround 604', 'Ringaround 680' and 'Walker'. Of the cultivars studied, 'Jeff' and 'Tracy-M' had the greatest degree of tolerance to metribuzin applied preemergence.