Morphological variability and mycelial compatibility of Sclerotium rolfsii

Abstract

Sclerotium rolfsii is one of the most important plant pathogenic fungi causing severe economic losses round the globe. S. rolfsii is a soil inhabitant, polyphagous facultative parasite, its distribution is ubiquitous in nature encompassing almost all the agro climatic zones of the world. Survey indicated that there was prevalence of S. rolfsii infection in Manipur. After 72 hours of incubation on PDA among the radial growth in different colonies ranged from 41.41 to 31.08 mm, colour ranged from dull white to cottony white, with sparse and fluffy growth, with or without concentric rings, while on PDB isolates had shown a range of 11.03-8.17g and 0.59-0.31g for fresh weight and dry weight respectively. The size, weight and number of sclerotia were in the range of 2.48-1.00mm, 61.21-13.75mg and 489.2-91.00 respectively. Colour of sclerotia ranged from light brown to dark choclate brown with spherical to irregular shape. Among the different media tested, PDA had shown best for radial growth and sclerotial formation. Mycelial compatibility studies conducted in all possible combinations revealed that presence of compatible and in-compatible isolates of S. rolfsii with different degrees of aversion in Manipur.