Effects of the SSSF were comparable to that found at 100 ppm of GA3. Considerable decrease
of OGR was noted at 1000 ppm GA3. Therefore, instead of 5.0×1010 conidia/ml spore suspension,100 ppm GA3 might be suitable for the test of rice varieties against bakanae disease. Effects of
GA3 have to be ensured clearly by using a control set side by side.
The effect of temperature (ºC) on rice seedlings height (cm) untreated and treated in vitro with
SS and 100 ppm GA3 presented in the Fig. 2. The figure shows that seedling heights of untreated
control sets increased with the increase of temperature but, acceleration of the average heights
with the increase of temperature in SS and GA3 treated sets were much higher than that of the
control set. Therefore, temperature had an influence on OGR of diseased plants. The Fig. 2 also
shows that acceleration in SS treated sets was slightly higher than that of GA3 treated sets. It is
well known that pathogen produce gibberellins including GA3 and this might be owing to the
combined action of gibberellins produced by the pathogen present in the suspension.