ABSTRACT
A study was conducted to determine the fungi associated with sheath rot disease, caused by Sarocladium oryzae, in relation to health and quality of rice seed. Panicles of rice variety BR5 were collected from sheath rot infected fields and sorted according to six severity scales. The percentage of healthy seeds and seed weight decreased with increasing disease severity, measured by the scale, while the percentage of discoloured, unfilled and partially filled seeds increased with increasing severity of the disease. Among fungi associated with seed, the incidence of S. oryzae was predominant. The quantity of seed infected by S. oryzae increased with an increase in disease severity. At the highest disease severity level, more than 93% of seed was infected by S. oryzae. Incidence of C. lunata, N. oryzae and T. padwickii decreased with increased disease severity. Germination of discoloured, partially discoloured and spotted seed was reduced by 40.61%, 27.96% and 17.93%, respectively. A positive correlation was obtained between discolouration of seed and the incidence of S. oryzae and C. cladosporioides.
