EFFECT OF POST-EMERGENT HERBICIDES APPLICATION ON CAROTENOID CONCENTRATION IN GREEN CORN

ABSTRACT - Considering the influence of herbicides in the metabolism of the carotenoids in corn, the objective of the present study was to evaluate the effect of herbicides and genotype on carotenoids concentration. The green corn hybrids BRS 1030 and P30F53 were subjected to a post-emergent herbicides application at 20 and 30 days after emergence. Carotenoids were extracted from corn grains and analyzed to quantify α- and β-carotene, lutein, zeaxanthin, β-cryptoxanthin, total carotenoids (TC), and total of vitamin A carotenoids precursors (proVA). The application of foramsulfuron + iodosulfuron-methyl-sodium (40 + 2.6 g ha-1), nicosulfuron (20 g ha-1), mesotrione (120 g ha-1) and tembotrione (80 g ha-1 and 100 g ha-1) promoted higher concentration of carotenoids in fresh green corn. Lutein, zeaxanthin, β-cryptoxanthin, β-carotene, α-carotene, proVA carotenoids, and TC concentration increased after foramsulfuron + iodosulfuron-methyl-sodium in late application (V5 to V6), nicosulfuron in both applications, mesotrione applied post-initial (V3 to V4), tembotrione (100 g ha-1) in both applications and tembotrione (80 g ha-1) in late post-application, at least for one hybrid. The content of carotenoids in the green corn kernels differed between ‘BRS 1030’ and ‘P30F53’. Our results suggest a possibility of significant increase of carotenoids in green corn kernels through the handling of corn production with post-emergent herbicides. Key words: Zea mays, carotenoid biosynthesis, carotenes, vitamin A, herbicide. A APLICACAO DE HERBICIDAS POS-EMERGENTES INFLUENCIA A CONCENTRACAO DE CAROTENOIDES EM MILHO VERDE RESUMO - Considerando a influencia dos herbicidas no metabolismo de carotenoides em milho, o objetivo foi avaliar o efeito dos herbicidas e do genotipo na concentracao de carotenoides. Os hibridos de milho verde BRS 1030 e P30F53 foram submetidos a aplicacao de herbicidas aos 20 e aos 30 dias apos a emergencia. Os carotenoides foram extraidos dos graos e analisados para quantificar α-caroteno, β-caroteno, luteina, zeaxanthina, β-cryptoxanthina, carotenoides totais (CT) e total de carotenoides precursores de vitamina A (proVA). As aplicacoes dos herbicidas foramsulfuron + iodosulfuron-methyl-sodium (40 + 2.6 g ha-1), nicosulfuron (20 g ha-1), mesotrione (120 g ha-1) e tembotrione (80 g ha-1 and 100 g ha-1), aplicados em mistura com atrazine (1.000 g ha-1), promoveram aumento da concentracao de carotenoi-des em graos de milho verde. Luteina, zeaxantina, β-cryptoxantina, β-caroteno, α-caroteno, proVA carotenoides e CT em graos de milho verde aumentaram apos foramsulfuron + iodosulfuron-methyl-sodium na aplicacao tardia (estagios V5 a V6), nicosulfuron em ambas as aplicacoes, mesotrione aplicado pos-inicial (V3 a V4), tembotrione (100 g ha-1) em ambas as aplicacoes e tembotrione (80 g ha-1) na aplicacao tardia, pelo menos em um dos hibridos avaliados. O teor de carotenoides nos graos de milho verde diferiu entre ‘BRS 1030’ e ‘P30F53’, indicando o efeito do genotipo na biossintese destes compostos. Os resultados sugerem a possibilidade de aumento significativo de carotenoides em graos de milho verde por meio do manejo da producao de milho com os herbicidas pos-emergentes. Palavras-chave: Zea mays, biossintese de carotenoides, carotenos, vitamina A, herbicidas.