Abstract:
Fungicide coated seeds are beneficial against seed or soil borne pathogens in the very initial stage to
minimize the indiscriminate use of chemicals for disease control in paddy fields. The present study
investigated the effectiveness of three levels of thiram fungicide coated-seeds having different pre-soaking
duration on inhibition of rice seed-borne fungal pathogen Curvularia sp. and the seed vigor. Treated paddy
seeds (Var. Bg-300) in four concentrations of 0 (control), 0.5,1 and 1.5 g fungicide per kg seeds and four
pre-soaking times of 5 minutes, 1, 2 and 3 days were used. Modified disk diffusion bioassay for seeds and
agar well diffusion inhibition bioassay for seed soaked water (extracts) were performed using spread
plates of Curvularia sp. Three days pre-soaked seeds were germinated in sterilized soil medium inoculated
with Curvularia sp. to screen the plant vigor. The fungicidal activity of seeds was significantly higher in 1
and 1.5 g kg*1 fungicide treatments (p<0.05). At a given pre-soak duration, a significantly high inhibition
was observed in the soaked water of seeds treated with 1 and 1.5 g kg*1 than 0.5 g kg_1of fungicide
(p<0.05). The average root height of the seeds treated with 1.5 g kg*1 fungicide concentration was
significantly higher (p<0.05) than the other treatments. However, no significant difference was observed
for the shoot lengths among treatments. Thus it can be concluded that 1.5 g kg*1 thiram treatment is
effective in inhibiting Curvularia sp. and improving seed vigor of Bg-300.
