Respostas de cultivares de soja transgênica e controle de plantas daninhas em função de épocas de aplicação e formulações de glyphosate

Abstract

Palavras-chave: Glycine max, cultivo de soja em várzea, soja RR.ABSTRACT -This work aimed to evaluate selectivity and yield components of transgenic soybean cultivars and weed control in function of application times and glyphosate formulations. and infested ckeck were allocated in the split-split plots. The yield parameters evaluated were culture herbicide phytotoxicity, weed control, number of green beans and grains per plant, grain weight and grain yield. The herbicide glyphosate in the tested formulations was selective to the tested soybean cultivars. In general, the best weed control formulation was Roundup WG ® . At the initial development of the culture, herbicide application provided better control of purslane, redroot pigweed, alexandergrass, barnyardgrass and bermudagrass. Grain yield varied among soybean cultivars but it did not differ among the glyphosate formulations, being higher when the application was accomplished at the late stages of culture development.

Eficácia e fitotoxicidade de herbicidas aplicados para manejo de plantas daninhas infestantes do trigo

“…However, the herbicides can have direct and indirect effects in the growth and development of plants (Das et al, 2003;Rizzardi et al, 2003), provoke alterations in the physiological and metabolic processes of the plants (Rizzardi et al, 2003), besides causing an impact to the agroecosystems when used incorrectly (Scremin et al, 2010 The same way, the cultivars may present different responses in face of the application of herbicides for the control of weeds due to their different genetic characteristics such as size, leaf interception, root volume, leaf area, tillering capacity, competitive ability, and others. That fact was already described in other studies involving sugar cane (Ferreira et al, 2005;Galon et al, 2009), the wheat (Paula et al, 2011), the rice (Pinto et al, 2008) and the soy .…”

Glyphosate-resistant soybeans yield in function of glyphosate salts, doses and stadium phenological

“…result happened when isopropylamine salt application at stages V 6 and R 2 of the CD 219 RR ® cultivar did not affect yield, but spraying at stage R 2 resulted in a 14% decline in the V-TOP ® cultivar in relation to treatments applied at R 4 and R 5 (ZADINELLO et al, 2012). Applying 720 g a.e ha -1 of isopropylamine, potassium and ammonium salt at 20, 35 and 50 DAP resulted in different yields in BRS 244 RR ® and M-SOY 7979RR ® , with a 20% decrease in the former (AGOSTINETTO et al, 2009). There were no differences between the isopropylamine and ammonium salt formulations for interaction between dose and application times (Table 2).…”

Riscos Toxicológicos Do Herbicida Glyphosate

“…O glyphosate de maneira geral é considerado uma molécula pouco tóxica à humanos e animais, pois nos mamíferos não existe uma via de atuação do mesmo, sendo um dos fatores que conferem a este princípio ativo um perfil toxicológico favorável quando comparado a outros (FRANZ, 1997). Todavia as diferenças existentes na formulação do herbicida podem alterar a absorção e a translocação do ingrediente ativo nas plantas, influenciando tanto a seletividade e eficiência de controle, como a toxicidade do produto (AGOSTINETTO et al, 2009b;WERLANG et al, 2003).…”

“…Tal fato se dá devido os solventes utilizados nas formulações comerciais, pois alteram as propriedades de toxicidade da molécula. Outros componentes da formulação também variam, por exemplo, as formulações de glyphosate sal de isopropilamina e sal potássico que apresentam maior eficiência no controle de espécies, comparativamente à formulação de sal amônio (AGOSTINETTO et al, 2009b).…”