MESOTRIONE HERBICIDE TOXICITY IN MAIZE PLANTS ORIGINATING FROM SEEDS WITH DIFFERENT SIZES AND SHAPES

Abstract

The objective of this experiment was to evaluate the fitotoxicity of theherbicide mesotrione in corn plants that originated from seeds with different morphologiccharacteristics. It was conducted in a greenhouse, located in the municipal district ofCapão do Leão, RS. The treatments were composed by the combinations of three groupsof seed sizes, classified in sieves of oblong openings [seeds retained in the sieve of width14/64" (sieve 14), in the sieve 18/64" (sieve 18) and in the sieve 21/64" (sieve 21)], oftwo formats of seeds (crushed and round) and of five doses of the herbicide mesotrione(0.0; 60.0; 120.0; 180.0; and 240.0 g ha-1), on a total of 30 treatments. The experimentaldesign was the one with randomized blocks in outline factorial (3x2x5) with fourrepetitions. After the separation and classification of the seeds, they were sowed in vasesfilled out with homogenized soil. In each vase eight corn seeds were sowed, in the depthof 3.0 cm, and mesotrione was administered 24 hours after the pre-emergence. Thefollowing evaluations were carried out: speed of emergency of the seedlings; total numberof emerged seedlings; visual injury and height of plants to the 7, 14 and 21 days after theemergence (DAE); and dry biomass of the roots and of the aerial part to 21 DAE. Theformat and the size of the seeds were not shown as important factors in the tolerance ofthe plants to the fitotoxicity herbicide mesotrione. The increase of the applied doses ofmesotrione did not cause reductions in the acquisition of dry biomass as much of theaerial part as of the roots of corn plants.

Keywords

• Zea mays
• carotenoid synthesis inhibitors: selectivity: seeds management