Comparative analysis of growth and sporulation of Phytophthora cajani on different media at varying temperatures

Abstract

Phytophthora stem blight, caused by Phytophthora cajani, is a major soilborne disease affecting pigeonpea (Cajanus cajan L. Millsp.), leading to significant yield losses. The present study evaluated the growth and sporulation of P. cajani on eleven different culture media under in vitro conditions at three temperatures (28 °C, 30 °C and 32 °C). Radial mycelial growth, colony morphology, hyphal width, sporangial size, and length-to-breadth (L: B) ratio were assessed. Results revealed that V8 agar, PBA, and PDA were the most suitable media for mycelial growth at 28 °C, while OMA, V8, and ChBA supported optimal growth at 30 °C. At 32 °C, V8 agar, ChBA, and OMA facilitated the highest growth, whereas CMA consistently exhibited the least supportive characteristics across all temperatures. The findings highlight the significance of media composition in culturing P. cajani, which is essential for further pathogenicity studies, resistance screening, and disease management strategies.