A study was conducted in 2002 and 2003 to evaluate response of seven rice cultivars to V-10029 applied at 20 and 40 g ai/ha to two- to three- or four- to five-leaf rice. Differential response of the rice cultivars to V-10029 was observed. Medium-grain ‘Earl’ was less tolerant to V-10029, as reflected by increased injury, shorter plants, and fewer plants at 7 d after late postemergence treatment and shorter plants and lower grain yield at harvest, when compared with nontreated Earl. Growth of medium-grain ‘Bengal’ was initially inhibited by V-10029; however, plant height at harvest and rice grain yield of Bengal were not affected. All long-grain cultivars exhibited tolerance to V-10029, both initially and at harvest. The results indicate that rice cultivars vary in tolerance to V-10029.
Nomenclature: V-10029, sodium 2,6-bis[(4,6-dimethoxypyrimidin-two-yl)oxy]benzoate; rice, Oryza sativa L. ‘Bengal’, ‘Cl-141’, ‘CL-161’, ‘Cocodrie’, ‘Cypress’, ‘Earl’, ‘Wells’.
Additional index word: Herbicide tolerance.
Abbreviations: ALS, acetolactate synthase; DAT, days after late postemergence treatment.