Abstract:Sunflower crops (Helianthus annuus L.) are a source of pathogens that can be transmitted by means of the seeds. An alternative for the treatment of seeds can be the application of an ozone compound, which has been used in various segments to eliminate microorganisms. Three lots of the Embrapa 122 variety have been used to assess the efficacy of ozone to control pathogens in sunflowers seeds. To typify the profile of the lots we have determined the moisture content, the first germination counting, the germination, the germination speed index, emergence, initial stand, emergence speed index and health. The lots have been stored in an ozone-rich environment for periods of 20, 60 and 120 minutes and without ozone (control). After the treatments, the seeds were tested to assess their health and physiological quality through the said tests as well as a test for accelerating aging, tetrazolium and incidence and severity of fungi. It has been concluded that the treatment for H. annuus seeds, Embrapa 122 variety, with ozone concentration of 1741 ppmv (0.24 g/h), for 60 minutes, reduces the fungal presence of Alternaria sp., Fusarium sp., Aspergillus sp. and Penicillium sp. without affecting their physiological potential.

The seed sector is increasingly dynamic and therefore demands rapid decision-making. The tetrazolium test is a rapid test that determines the viability of seeds, especially from species that show slow germination or dormancy. The methodology described in the Rules for Seed Testing for Stylosanthes sp. is not applied effectively to the Stylosanthes capitata Vogel species. Three seed lots of S. capitata seeds with different quality levels were used to fit the tetrazolium test methodology. In order to determine the physiological quality of seeds, the tests of germination, first count germination, emergence speed index, initial and final seedling emergence percentage, electrical conductivity, respiratory activity and seed moisture content were performed, besides the imbibition curve for the establishment of pre-imbibition periods of the seeds to perform the tetrazolium test. The pre-imbibition and staining periods of 6, 12 and 18 h, and 3, 6, 12 and 24 h at concentrations of 0.075%, 0.1% and 0.5% tetrazolium solution were tested. It was concluded that the 12-h pre-imbibition period and 6-h staining at the 0.1% tetrazolium solution is ideal for evaluating the viability of S. capitata seeds.Index terms: forage seeds, viability, vigor.Adequação da metodologia do teste de tetrazólio em sementes de Stylosanthes capitata Vogel RESUMO -O setor sementeiro está cada vez mais dinâmico e por isso demanda rápidas tomadas de decisões. O teste de tetrazólio é um teste rápido que determina a viabilidade das sementes, principalmente de espécies que apresentam germinação lenta ou dormência. A metodologia contida nas Regras para Análise de Sementes para a espécie Stylosanthes sp. não se aplica efetivamente para a espécie Stylosanthes capitata Vogel. Para adequar a metodologia de condução do teste de tetrazólio, foram utilizados três lotes de sementes de S. capitata com níveis de qualidade distintos. Na determinação da qualidade fisiológica das sementes, foram realizados os testes de germinação, primeira contagem da germinação, índice de velocidade de emergência, estandes inicial e final, condutividade elétrica, atividade respiratória e grau de umidade, além da curva de embebição para estabelecimento dos períodos de pré-embebição das sementes para a condução do teste de tetrazólio. Foram testados os períodos de pré-embebição e coloração, de 6, 12 e 18 h e, 3, 6, 12 e 24 h, nas concentrações de 0,075%, 0,1% e 0,5% da solução de tetrazólio. Concluiu-se que o período de 12 h de pré-embebição e 6 h de coloração na solução de tetrazólio a 0,1% é o ideal para a avalição da viabilidade de sementes de S. capitata.Termos para indexação: sementes forrageiras, viabilidade, vigor. 1The 12 h period of pre-imbibition and 6 h staining at 0.1% concentration of the tetrazolium solution is ideal to evaluate the viability of Stylosanthes capitata seeds. Tetrazolium test on Stylosanthes seeds

Widely used, the seeds chemical treatment can cause physiological quality loss due to phytotoxicity that the active principles may cause. In this context, the ozone gas stands out (O3) as efficient agent biocide, however its use in the pathogens control and their effects on the seeds physiological quality are still little studied. In this context, the objective was to evaluate the ozone gas efficiency as a controller agent of plant pathogens and its effect on the physiological quality of soybean seeds. For this, seeds of two soybean cultivars were treated with ozone gas in two concentrations (15 and 25 g/m³) and in five exposure times (0, 20, 40, 60 and 120 minutes). After the treatments, the seeds quality was evaluated by tests of sanity, tetrazolium, first germination count, germination percentage, initial stand, emergence percentage, emergence speed index, electrical conductivity, accelerated aging and enzymatic activity. Six pathogens were found in seeds of soybeans evaluated, namely: Phomopsis sp., Penicillium sp., Aspergillus sp., Fusarium sp., Cercospora kikuchi and Alternaria sp. It was concluded that the sanitary treatment with ozone gas reduces the incidence of these fungi and does not compromise the physiological quality of soybean seeds.

Maintaining the health of coffee seeds is especially important during storage, as soil fungi and storage fungi can considerably reduce seed quality. Thus, chemical treatments for protection of seeds in storage becomes important in agricultural production. It is necessary to evaluate the effects of these treatments on seedling development and the protection they provide against storage fungi, aiming at seed longevity and preventing rapid deterioration. The aim of this study was to evaluate the effect of chemical treatment on the physiological and sanitary quality of stored coffee seeds. Seeds of five Coffea arabica cultivars were pre-dried, treated with Vitavax®-Thiram, and placed in cold storage at 10 °C for nine months. Seed physiological quality was evaluated every three months by the germination test and by determination of root emergence percentage, seedlings with expanded cotyledonary leaves, and seedling dry matter. Seed health quality was assessed by the health test. The chemical treatment with Vitavax-Thiram does not affect the physiological quality of stored Coffea arabica seeds. Seed treatment before storage is effective in reducing the inoculum potential of Fusarium spp. and Phoma spp. in coffee seeds.

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RESUMO O gás ozônio é uma alternativa no controle de fungos em sementes e torna-se vantajoso por descartar a necessidade de armazenamento ou eliminação dos recipientes de produtos químicos. Objetivou-se testar diferentes concentrações e tempos de exposição ao gás ozônio, no controle de patógenos em sementes de pimentão, bem como seu efeito sobre a qualidade fisiológica, bioquímica. O delineamento experimental foi inteiramente casualizado, com quatro repetições, em esquema fatorial 6x2, envolvendo 6 tempos de exposição (0, 20, 40, 60, 80 e 120 minutos) e 2 concentrações do ozônio (10 e 15 g m-1). No teste de sanidade adicionou-se um tratamento químico (6x2) + 1 (fungicida Captan®-Captana). Posteriormente, as sementes foram avaliadas através dos testes de germinação, primeira contagem da germinação, tetrazólio, condutividade elétrica, índice de velocidade de emergência, emergência e sanidade. Realizou-se análise bioquímica para álcool desidrogenase (ADH), malato desidrogenase (MDH), catalase (CAT) e superóxido dismutase (SOD). O tratamento com ozônio nas concentrações e tempos testados não interfere na qualidade fisiológica e bioquímica das sementes de pimentão. O gás ozônio nas concentrações estudadas, a partir de 20 minutos aprimora a qualidade sanitária das sementes. Palavras-chave: sanidade, qualidade de sementes, O3, Capsicum annuum L. ABSTRACT zone gas is an alternative in the control of fungi in seeds and is advantageous in discarding the need for storage or disposal of chemical containers. The objective was to test different concentrations and times of exposure to ozone gas, in the control of pathogens in pepper seeds, as well as its effect on physiological, biochemical quality. The experimental design was completely randomized, with four replications, in a 6x2 factorial scheme, involving 6 exposure times (0, 20, 40, 60, 80 and 120 minutes) and 2 ozone concentrations (10 and 15 g m-1). In the health test, a chemical treatment (6x2) + 1 (fungicide Captan®-Captana) was added. Subsequently, the seeds were evaluated through germination tests, first germination count, tetrazolium, electrical conductivity, emergence speed index, emergence and health. Biochemical analysis was performed for alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), catalase (CAT) and superoxide dismutase (SOD). The ozone treatment at the tested concentrations and times does not interfere with the physiological and biochemical quality of pepper seeds. Ozone

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