CLOMAZONE SELECTIVITY IN CORN (ZEA MAYS) OBTAINNED WITH THE USE OF DIETHOLATE
2002
DÉCIO KARAM | ANDREA ALMEIDA CARNEIRO | LÚCIA H. ALBERT | MICHELLE BARBEIRO DA CRUZ | GRACIELLE T. COSTA | PAULO CÉSAR MAGALHÃES
The objective of this work was to evaluate the clomazone selectivity of corn plants treated previously with dietholate. For this purpose, two experiments were set up in green house and laboratory at Embrapa Milho e Sorgo, Sete Lagoas, MG. Corn seeds BRS 2223 were treated with dietholate at 500 g to 100 Kg of corn seeds. Herbicide treatments consisted of 8 different rates of clomazone (0.0; 62.5; 125.0; 250.0; 500.0; 1000.0; 2000.0; 4000.0 g.ha-1) plus a control treatment. Corn plants originated from untreated seeds showed in the case of plants originated from treated seeds, presented the same 50% index only at 1921 g ha-1clomazone rate. The shoot dry weight difference between corn plants from treated and untreated seeds was observed only after 2000 g.ha-1 of clomazone rate. Shoot dry weight reductions of 80% and 90% for plants treated and untreated seeds, respectively, were obtained at 4000 g.ha-1 of clomazone rate. The chlorophyll content had a 50% decrease at 784 g.ha-1 and 1740 g.ha-1 clomazone rate for plants from treated and untreated seeds respectively. In an in vitro experiment, seeds treated at the same dietholate rate, were grown in culture medium added with clomazone (4, 8, 16, 32 and 64 ppm). The estimated reductions in the chlorophyll contend for the in vitro plants were respectively 83,9% and 31,1% for plants grown from treated and untreated seeds. These results showed that dietholate safener increases the selectivity of corn plants to clomazone.
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