a b s t r a c tFumonisins and zearalenone are mycotoxins produced by Fusarium spp. that commonly contaminate maize and its derivative products. Recent reports have shown that fumonisin B2 and B4 might also be produced by Aspergillus niger and Tolypocladum species, although their prevalence in maize is for sure connected to Fusarium species. The aim of this study was to evaluate the occurrence of fumonisins and zearalenone in maize, stored in 10 family farms located in the State of Minas Gerais, Brazil. Samples were collected in four periods, at intervals of two months, totalling 40 samples. Mycotoxins were isolated using commercial immunoaffinity columns and its concentrations were evaluated by fluorometric technique. Fumonisins were detected in all 40 samples, with values ranging from 230 to 6450 mg kg À1 , and zearalenone was detected in 38 maize samples, with levels from 1.8 to 99 mg kg À1 . Zearalenone levels were below the acceptable limit for human consumption but the fumonisins levels were above this limit in most samples, implying in risks to consumers' health.

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Resumo -O objetivo deste trabalho foi avaliar a eficiência da aplicação foliar de fungicidas na redução da incidência de patógenos fúngicos, de grãos ardidos e de fumonisinas totais em grãos de milho (Zea mays). Foram conduzidos três ensaios: um no município de Luís Eduardo Magalhães, na Bahia, e dois em Sete Lagoas, em Minas Gerais, nas safras 2010/2011 e 2011/2012, com cultivo de diferentes híbridos comerciais. Os seguintes fungicidas foram aplicados zero, uma e duas vezes: picoxistrobina + ciproconazol, piraclostrobina + epoxiconazole, trifloxistrobina + tebuconazole, azoxistrobina + ciproconazol e tiofanato metílico. Em todos os ensaios, foram realizados a quantificação da incidência de grãos ardidos, o teste de patologia de sementes e a quantificação dos teores de fumonisinas totais. Não foi observada diferença significativa para os fatores fungicida e número de aplicações, exceto para rendimento de grãos, em todos os ensaios. Esses resultados são indicativos da ineficiência da aplicação de fungicidas na redução da incidência de patógenos fúngicos, de grãos ardidos e dos teores de fumonisinas totais em grãos de milho.Termos para indexação: Fusarium, Zea mays, controle químico, micotoxinas, patógenos fúngicos. Fungicide leaf application and incidence of kernel rot and total fumonisins in cornAbstract -The objective of this work was to evaluate fungicide leaf application on the reduction of fungal pathogen incidence, kernel rot, and total fumonisins in corn (Zea mays) kernels. Three experiments were performed: one in the municipality of Luís Eduardo Magalhães, in the state of Bahia, and two in the municipality of Sete Lagoas, in the state of Minas Gerais, Brazil, during the 2010/2011 and 2011/2012 crop seasons, with planting of different commercial hybrids. The following fungicides were applied zero, one, and two times: picoxystrobin + cyproconazole, pyraclostrobin + epoxiconazole, trifloxystrobin + tebuconazole, azoxystrobin + cyproconazole, and thiophanate-methyl. For all trials, the quantification of kernel rot incidence, the grain pathology test, and the quantification of total fumonisins were performed. No significant difference was observed for the factors fungicide and number of applications, except for grain yield, in all trials. These results show the ineffectiveness of fungicide applications in reducing fungi incidence, kernel rot, and levels of total fumonisins in corn kernels.Index terms: Fusarium, Zea mays, chemical control, mycotoxins, pathogenic fungi. IntroduçãoNa safra 2014/2015, o Brasil produziu cerca de 84 milhões de toneladas de milho (Zea mays L.), o que o tornou, além de autossuficiente para o consumo interno, um dos principais países exportadores desse cereal. Classificado como o terceiro maior exportador mundial, o Brasil comercializa quantidades superiores a 27 milhões de toneladas para países como o Irã, a Colômbia e a Coreia do Sul (Agrianual..., 2015).Contudo, as exigências comerciais relacionadas à qualidade dos grãos, destinados tanto à exportação quanto ao consumo interno, têm ...

A study was carried out to investigate the inheritance of resistance to anthracnose, caused by Colletotrichum sublineolum, in sorghum. Crosses between resistant and susceptible parents and backcrosses between F 1 plants and the susceptible parents were carried out under field conditions. The F 1 generations and the segregant populations were evaluated under artificial inoculation conditions in the greenhouse. In the F 1 generation of all crosses with the respective isolates, all of the plants presented a resistance reaction except for the F 1 plants resulting from the BR009 · SC283 cross. In the F 2 generation, the frequencies of resistant and susceptible plants conformed to the hypothesis that one gene with two alleles controls host resistance, except in one cross. Out of the eight backcrosses, six presented segregation that corresponded to the hypothesis formulated. For most crosses, resistance was dominant, and the proportions of resistant and susceptible plants in the segregant populations conformed to the frequencies expected under the hypothesis of gene-for-gene resistance and dominant gene action.

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