Morphological and pathological variations of rice sheath blight inciting south Indian Rhizoctonia solani isolates.

摘要

Frequent assessment of pathogen diversity is one of the most important criteria in designing disease management programmes. A study on diversity of field isolates of Rhizoctonia solani from sheath blight-infected rice fields of south India has been carried out. A total of 236 R. solani isolates were obtained from 45 locations in the surveyed area. Sclerotial features such as colour, size and shape and distribution pattern were varying among isolates. However, no other morphological features found to differ among isolates. Majority of the R. solani isolates were fast growers as they attained complete mycelial growth within 2 days in a 90-mm Petri plate and the emergence of sclerotial structures was seen even in 4 days of incubation. Selected 10 R. solani isolates exhibited considerable variations in pathogenicity on three different rice cultivars. Vellai ponni was found to be the most susceptible rice cultivar to all the field isolates of R. solani.Digital Object Identifier http://dx.doi.org/10.1080/03235408.2011.587983