Sheath rot resistant breeding has been difficult due to a lack of knowledge about the pathogen's genetic variability and virulence pattern. Therefore, better understanding the disease's development, prediction of future disease outbreaks, the current inquiry will be carried out with the following specific aims in mind, limited work done on pathogen diversity. Fourteen isolates were collected from seven districts of Bihar (Zone I) for the study of cultural variability like radial growth, colour of mycelium and type of growth on PDA and morphological variability like length of Conidiophore, length of conidia and conidiation on PDA media. All the fourteen isolates grow fluffy irregular on PDA, Mycelium colour of eight isolates (Sob-1, Sob-2, Sob-4, Sob-5, Sob-6, Sob-8, Sob-9 and Sob-13) were whitish with pale orange colour, two isolates (Sob-3 and Sob-12) were whitish with deep orange and remaining four isolates (Sob-7, Sob-10, Sob-11 and Sob-14) were whitish with orange ochre. Highest ra

Isolates, variability, Conidia, Conidiophore.

Among the isolates, significant differences were observed in the length of conidiophores of different isolates tested on PDA media. Over all the isolates tested isolate Sob-8 (0.85cm) and Sob-11 (0.95cm) had least growth while isolate Sob-7 (3.20cm) had maximum radial growth on PDA, maximum length of Conidiophore was recorded in isolate Sob-4 (57.9µm) while the least length of Conidiophore was recorded in isolate Sob-8 (46.7µm). Longest length of conidia was observed in isolate Sob-10 (5.95µm) while the least conidial length was observed in Sob-5 (4.65µm).

Nithin Kumar J.N. and Rai, B. (2021). Variability among the isolates of Sarocladium oryzae isolated from Bihar (Zone I). Biological Forum – An International Journal, 13(2): 269-272.