Effect of different temperature levels and time intervals on germination of uredospores of Puccinia sorghi

In plant disease development, temperature is a critical factor. To determine how specific environmental variables affect corn rust, we determined temperature effects on urediniospore germination. Spore germination was maximum within 24 h of incubation, in the temperature range of 20-30°C. The mean maximum spore germination was recorded at 25°C (66.16% germination) which is statistically on par at 30°C (optimum range). The germination percentage declined gradually at temperatures above and below 25°C. The maximum reduction in germination was recorded at 30°C and 2 h time interval. Thus, the cardinal temperatures for uredospore germination on water agar are 5, 25 and 35°C for 24 h of incubation, respectively. At the maximum and minimum temperature levels, the minimum incubation period extended beyond two hours.  Key words: Effect, temperature, time intervals, Puccinia sorghi, maize, common rust.