Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Plant, Soil and Environmental Sciences

Major Professor

Larry S. Jeffery

Committee Members

Charles R. Graves, Fred L. Allen


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.

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