Variability in Phytophthora drechsleri f. sp. cajani and Effect of Temperature

The present experiment was undertaken to study the cultural, morphological and pathological variation in six isolates of Phytophthora cajani. The isolates were collected from pigeonpea growing areas of eastern Uttar Pradesh. Isolates exhibited considerable variations in cultural characters and growth on potato dextrose agar medium. The universal ITS1 and ITS4 primers showed the difference among P. cajani isolates. There was significance influence of temperature on the growth of isolates, however isolates could not be differentiated based on the temperature. The average growth (1.69 cm2) at 30°C temperature was recorded with all the isolates followed by average growth (1.25 cm2) at 35°C temperature. The maximum radial growth (3.6 cm2) was observed at 96 h in isolate PDC015-1. The isolate PDC013-1 and PDC0143 showed highest 47.0% plant mortality on ICP 7119 genotype. Among the isolates PDC014-3 killed 28.6% plants after 4th day of inoculation.