IMPLICATIONS OF NON-SELECTIVE HERBICIDES ON FLOODED RICE PROGENY WHEN APPLIED AT MATURITY PHASE

Abstract

With the objective to evaluate the effects of non-selective herbicides, utilized for crop desiccation at its maturity phase, on flooded rice (Oryza sativa L.) progeny, there were conducted experiments at field, laboratory, and greenhouse conditions, during the growing seasons of 1997/98 and 1998/99. Treatments tested were the herbicides glyphosate, glufosinate, and paraquat, applied at two rates and at two times, the growth regulator maleic hydrazide was used as a standard, besides a check without chemical applicátion. The rice reagent cultivar was IRGA-416. The remainder management practices applied were those recommended for the crop, which developed in the presence of a red rice infestation. It was evaluated the following variables: rice seed viability and germination, and emergence, height, and dry weight of seedlings. In general, applications of the herbicides glyphosate, glufosinate, and paraquat, at physiological maturity of flooded rice, do not affect seed viability and germination, or seedling emergence. The non-selective herbicides, used for crop desiccation showed effects equivalents to those of the growth regulator maleic hydrazide in relation to the characteristics of rice progeny. High infestation of red rice affects negatively the germination of flooded rice seeds, but does not affect initial growth of the seedlings of its progeny.