The aim in this was to evaluate the effect off the spray temming and time (hour of the day) of fungicide aplication, during the flowering period on the physiological seed quality, seed health, sterility, weight of thousand seeds and yield of irrigated rice. The experiment was conducted in Pelotas, RS, during the 2005/06 growing season when the "Combat" cultivar was sprayed with Folicur 200 CE (tebuconazol 200 g/L), at the rate of 0.5 L commercial product/ha. The experimental design was a factorial combination (3 x 3 + 1) of fungicide application at three flowering stages (5%, 50% and 80%) and three timings (9 am, 1 pm and 5 pm). After harvesting, the seed physiological quality was evaluated by the germination and vigor tests (1st count, cold test and seedling emergence in the soil). Sterility, weight of a thousand seeds, seed yield and seed health, by the blotter test, were also evaluated. The results showed that fungicidal application in irrigated rice improved yield and seed quality, regardless of the spray timing and hour of the day. A fungicide application at 1 pm resulted in the lowest yield compare to the other application times. At high daylight temperatures and in more advanced stages of flowering, fungicide applications result in a lower seed quality.
Oryza sativa; seed health; sterility; vigor
