Sementes de soja infectadas por Cercospora kikuchii, sob déficit hídrico

Abstract

The soybean seeds performance and the plants establishment in the field may be affected negatively by the contamination of the seeds with phytopatogens, especially under unfavorable conditions for seeds germination. The objective was to evaluate the soybean seeds performance with different stain purple levels and the fungicide treatment efficiency when the seeds are submitted to hydric deficit stress conditions. The seeds were selected and classified by staining intensity in: seeds without stains (zero), 1 to 25% and 26 to 50% of the seed surface with purple stain. The seeds were incubated in medium with hydric restriction using mannitol and treated or nottreated with thiabendazol + thiram and carbendazin + thiram fungicides mixtures. In the laboratory the physiologic conditions of the seeds were evaluated by germination, cold and sanity tests. Both chemical treatments did not eradicate the pathogen when the seeds presented high contamination level but they increased physiological performance of the soybean seeds under hydric stress. During germination under water stress conditions, the incidence of Cercospora kikuchii in soybeans increases the abnormal seedlings infected percentage.