Fitopatologia Brasileira (2007) 32, 458-464

Wirton M. Coutinho, Renata Silva-Mann, Maria das Graças G.C. Vieira, Cibele F. Machado and José C. Machado (2007)
Qualidade sanitária e fisiológica de sementes de milho submetidas a termoterapia e condicionamento fisiológico
[Health and physiological quality of maize seeds submitted to thermotherapy and physiological preconditioning]
Fitopatologia Brasileira 32 (6), 458-464
Abstract: Thermotherapy has been used for eliminating fungi on seeds. However, physiological and biochemical alterations, which may occur on seeds following this treatment, have not been thoroughly investigated. In this work, the efficacy of heat treatment (hot water) followed by osmopriming, in the control of fungi associated with maize seeds and its effects on physiological seed quality, was evaluated. The fungi associated with the seeds were detected by the deep-freezing blotter method, and physiological quality was determined by germination, first-germination counting and electric conductivity tests in addition to determination of eletrophoretic patterns of the enzymes: esterase (EST), malate dehidrogenase (MDH) and alcohol dehidrogenase (ADH). The heat treatment used was hot water at 60°C for 5, 10 and 20 minutes. After treatment, a fraction of the seeds was submitted to osmopriming on roll paper soaked in PEG 6000 solution at -1.2 MPa. All heat treatments reduced or eliminated Acremonium strictum on maize seeds. Heat treatments for 10 and 20 minutes reduced significantly the percentage of Fusarium verticillioides. Increasing period of heat treatment raised the values of conductivity and reduced significantly seed germination rate and first-germination counting. Heat treatment for 20 minutes altered the eletrophoretic pattern of esterase and malate dehidrogenase enzymes. Osmopriming did not reverse damage caused by the heat treatments.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sarocladium strictum	Maize/corn (Zea mays)
	Fusarium verticillioides	Maize/corn (Zea mays)