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Glyphosate, glufosinate, and atrazine do not affect the growth and development of glyphosate and glufosinate-tolerant (RR2/ LL) maize; however, the results are less consolidated for these herbicides applied in mixtures. The aim of the present study was to evaluate the effects of post-emergent application of glyphosate, glufosinate, and atrazine, alone and in mixtures, on the growth and development of the RR2/LL maize. The treatments consisted of the application of glyphosate (1080 g of acid equivalent [ae] ha-1), glufosinate (500 g of active ingredient [ai] ha-1), atrazine (2000 g [ai] ha-1), glyphosate + glufosinate, glyphosate + atrazine, glufosinate + atrazine, glyphosate + glufosinate + atrazine, and the control (without application). The experiment was carried out in two locations under greenhouse conditions with different maize hybrids. Crop injury and variables of the agronomic performance (height, stem diameter, chlorophyll indexes, fresh and dry weight of shoot, root dry weight, and total dry weight) were evaluated. Herbicides applied alone or in binary mixtures did not cause major damage. However, the application of the three associated herbicides in some situations might result in detrimental effects on the development of the RR2/LL maize. RESUMEN Glifosato, glufosinato y atrazina no afectan el crecimiento y desarrollo de las plantas de maíz tolerantes a glifosato y a glufosinato (RR2/LL); sin embargo, los resultados están menos consolidados para estos herbicidas aplicados en mezclas. El objetivo del presente estudio fue evaluar los efectos de la aplicación post-emergente de glifosato, glufosinato y atrazina, solos y en mezclas, sobre el crecimiento y desarrollo del maíz RR2/LL. Los tratamientos se formaron por aplicación de gli-fosato (1080 g de ácido equivalente [ae] ha-1), glufosinato (500 g de ingrediente activo [ia] ha-1), atrazina (2000 g [ai] ha-1), glifosato + glufosinato, glifosato + atrazina, glufosinato + atrazina, glifosato + glufosinato + atrazina, además del testigo (sin aplicación). El experimento se llevó a cabo en dos localidades, en condiciones de invernadero, con diferentes híbridos de maíz. Se evaluó la fitotoxicidad al cultivo y variables relacionadas con el crecimiento del mismo (altura, diámetro del tallo, índices de clorofila, masa fresca y seca de la parte aérea, masa seca de las raíces, masa seca total). Los herbicidas aplicados solos o en mezclas binarias, no causaron danos importantes. Sin embargo, la aplicación de los tres herbicidas en asociación en algunas situaciones puede resultar en efectos perjudiciales sobre el desarrollo del maíz RR2/LL.

Made available in DSpace on 2022-04-28T19:29:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 One of the first transgenic traits that has been inserted into commercial crops and being widely used is tolerance to glyphosate herbicide. This technology has provided significant benefits and conveniences to farmers due to the efficacy of glyphosate. However, for a better weed control and prevention of weed resistant biotypes the use of two or more mechanisms is recommended practice. The combination of herbicides is the subject of several studies especially evaluating weed control, aside which the selectivity of the culture is equally important. In this context, this study aimed to evaluate the responses of transgenic corn (RR2) subjected to the application of different herbicides. For this purpose, an experiment was conducted with eight treatments using glyphosate, atrazine and nicosulfuron, sole or in combination along with a control treatment (without herbicide). The experiment was performed twice (first in Piracicaba - SP then Palotina - PR) in greenhouse with different corn hybrids. Several variables related to the performance were analysed such as height measurements, stem diameter, chlorophyll index, fresh and dry shoot, root dry mass. The results showed that nicosulfuron should be positioned cautiously in new RR2 corn hybrids, as it may damage the development of the plant. Federal University of Parana, Palotina Campus, Pioneer Street, 2153 - Garden Dallas State University of the Western of Paraná University Street, 2069 - University Garden State University of São Paulo Júlio de Mesquita Filho, Dr. José Barbosa de Barros Street, 1780 University of São Paulo/ Luiz de Queiroz College of Agriculture Padua Dias Avenue, 11 - Agronomy State University of São Paulo Júlio de Mesquita Filho, Dr. José Barbosa de Barros Street, 1780