Cultural and morphological characters of fifteen isolates of Sclerotium oryzae Catt. collected from different rice growing areas in Telangana and Andhra Pradesh states were studied. Significant differences in growth, mycelial dry weights and sclerotial characters were observed among the fifteen isolates grown on PDA and PDB. All the 15 isolates were divided into two groups based on the growth pattern on PDA. Group 1 consists of ten isolates SO2, SO3, SO5, SO6, SO7, SO10, SO11, SO12, SO14 and SO15 which exhibited fast growth rate in terms of colony diameter with a range of 80 mm to 83 mm. Group II consists of the isolates SO1, SO4, SO8, SO9 and SO13 which recorded moderate growth rate with the colony diameter ranged from 70 to 79 mm. In all the isolates the initiation of sclerotial formation was noticed after 4 to 6 days and the mycelium aggregated into a fullfledged round brown to black sclerotium after 6 to 8 days after inoculation on PDA. Significant differences were observed in sclerotial size in fifteen isolates of S. oryzae with a range of 308 µm to 1012 µm in diameter. In all the isolates the sclerotial formation was initiated from centre towards periphery whereas in the isolate SO1, sclerotia were scattered uniformily. The sclerotia of all the isolates were intermixed in the mycelium except in the isolate SO4 in which sclerotia were formed in circular pattern on the PDA medium. | Cultural and morphological variation in Sclerotium oryzae catt. isolates collected from major rice growing areas of Telangana and Andhra Pradhesh states, India
