Expression of catalase, alcohol dehydrogenase, and malate dehydrogenase in rot grains upon fungicide use on maize hybrids grown at different spacings

Abstract

ABSTRACT. In this study, we evaluated the fungicide effect on the incidence of rot grains and expression of catalase (CAT), alcohol dehydrogenase (ADH), and malate dehydrogenase (MDH) enzymes in commercial maize hybrids grown with conventional and reduced spacing in Guarapuava, PR, Brazil. The experiment was designed in random blocks with a 3 × 8-factorial scheme, totaling 24 treatments. The first factor constituted three levels, the first with foliar fungicide application [150.0 g/L trifloxystrobin (15.0%, w/v) + 175.0 g/L prothioconazole (17.5%, w/v)] at a dose of 0.4 L/ha at V8-stage eight expanded leaves and the second with an application of 0.5 L/ha at VTtasseling and check (no fungicide application) stage. The second factor comprised eight maize hybrids that were divided into two groups, 2 E.R. Kluge et al.Genetics and Molecular Research 16 (2): gmr16029634 complex (AG 9045PRO, AG 8041PRO, DKB245PRO2, and 2B707PW) and susceptible (P 32R48H, DKB390PRO, P 30F53H, and P 30R50H), according to their reaction to the causative fungus, totaling 72 plots at each site in the crop of 2013/2014. The percentage of rot grains and the expression of CAT, ADH, and MDH were evaluated for each hybrid. The percentage of rot grains was influenced by the hybrid and fungicide used. The (trifloxystrobin + prothioconazole) reduced the incidence of rot grains, with relatively higher reduction in the hybrids considered susceptible. The higher expression of CAT enzyme was related to the higher incidence of rot grains because of grain deterioration, depending on the hybrids evaluated. A higher expression of ADH and MDH enzymes was observed in the maize hybrids belonging to the group considered tolerant.

EFEITO RESIDUAL DE FONTES FOSFATADAS, CALCÁRIO E SILICATO E NO DESENVOLVIMENTO DE Avena strigosa

“…A incidência de grãos ardidos em milho também apresenta dificuldade de controle, e resultados de pesquisa são controversos, não abordando aspectos relacionados a tecnologia de aplicação. Na literatura existem resultados indicando a não redução de grãos ardidos com aplicação foliar de fungicidas (estrobilurinas e triazóis), independentemente do número e época da aplicação (SMALL et al, 2012;LANZA et al, 2016), assim como da percentagem de grãos ardidos ser influenciada pelo híbrido e fungicida utilizado (BRITO et al, 2012;KLUGE et al, 2017).…”