Isolation and Morphological Characteristics of Sclerotium rolfsii Inciting Collar Rot in Brinjal

Abstract

Sclerotium rolfsii, a soil-borne omnipathogenic fungus, is a major threat to crop production due to its wide host range and aggressive pathogenicity. This study aimed to isolate and characterize twenty S. rolfsii isolates from infected brinjal plants using standard tissue segment methods on PDA medium. Cultural and morphological assessments revealed significant variability among isolates in colony morphology, mycelial growth, and sclerotial traits. Radial growth ranged from 59-90 mm at 72 hours, while sclerotial formation varied from 9-34 days. The number of sclerotia per plate ranged between 75 and 1,338, with differences in color, shape, and arrangement. Microscopic and SEM examinations confirmed the presence of diagnostic features such as septate hyphae with clamp connections. Isolate identity was further verified through deposition at NFCCI with accession number NFCCI 5791. The findings highlight the morphological diversity among S. rolfsii isolates, which may influence their pathogenic behavior and epidemiology.