Bioassay to Screen Tomato Seedlings for Tolerance to Metribuzin

Abstract

Studies were carried out to develop a nutrient culture technique to select tomato (Lycopersicon esculentum Mill.) genotypes for tolerance to metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one], The bioassay consisted of growing tomato seedlings from seed in styrofoam cups modified with cheesecloth bases. The cups were floated on half-strength Hoagland’s solution with metribuzin and placed in controlled environment cabinets maintained at 25 °C, with a light intensity of 24.2 klx for 14 h/day and 80% RH. The nutrient–herbicide solution was changed every 5 days, Metribuzin at 0.25 ppm was the optimum concentration for selection between tolerant and susceptible cultivars, under the environmental conditions described. The seedlings were harvested 15 days after sowing and scored for phytotoxic symptoms; seedling height to the terminal bud was measured. It was possible to screen a large number of seedlings in a confined space, using this technique. Significant differences were noted between tolerant Fireball and Vision cultivars and susceptible Heinz 1706 and Trimson cultivars.

Differential Tolerance of Sweet Potato (Ipomoea batatas) Clones to Metribuzin

“…Differential genotypic tolerance to metribuzin has been reported for soybean (11,20), tomato (5,21,22), Irish potato (4,6,9), barley (Hordeum vulgare L.) (8), and, winter wheat (Triticum aestivum L.) (10,18). The basis of differential cultivar tolerance was reportedly due to differential rates of metribuzin metabolism in soybean (2,20), tomato (19), barley (8), and potato (7).…”

Development of High Levels of Metribuzin Tolerance in Lentil

“…These include soybean [ Glycine max (L.) Merr.] (Hardcastle 1974; Mangeot et al 1979; Barrentine et al 1982), tomato ( Solanum lycopersicum L.) (Souza Machado et al 1978; Gawronski 1983), potato ( Solanum tuberosum L.) (Ivany 1979; Gawronski et al 1985), sweetpotato [ Ipomoea batatas (L.) Lam.] (Harrison et al 1985; Motsenbocker and Monaco 1993), cowpea [ Vigna unguiculata (L.) Walp.]…”

Tolerance of Tomato (Lycopersicon esculentum) Cultivars to Metribuzin

“…Semi -susceptible cultivars, including Venture and Fireball, had chlorotic petioles and veins. The Fireball cultivar was less tolerant than noted by Souza Machado (13) and Stevenson (16). Our Fireball tomatoes were produced for many yr in Poland on soils not treated with herbicides.…”

“…Differences in varietal tolerance to this herbicide have also been recorded in soybean [Glycine max (L.) Merr.] (8), tomatoes (9,13,16), and potatoes (Solanum tuberosum L.) (6,7). Other studies have addressed genetic inheritance of resistance (2,15), and differences in mode of action of the herbicide (4,12,14).…”