Morphological, Molecular Identification and Pathogenicity of Rhizoctonia solani Kuhn: A Seed and Soil Borne Pathogen Infecting French Bean

Abstract

French bean (Phaseolus vulgaris L.), holds significant importance as a both vegetable and pulse crop in India. Root rot disease has become threat for successful french bean cultivation.  Fusarium spp., Sclerotium rolfsii, Rhizoctonia sp., Macrophomina, Pythium spp.  and Thielaviopsis sp. may incite root rot disease in french bean. The root rot caused by Rhizoctonia soalni Kuhn is one among the root rot causing pathogens, is a major devasticating disease in this crop. The objective of this investigation was to perform the morphological, molecular identification and pathogenicity of R. solani Kuhn infecting french bean root rot. The pathogen was isolated from the naturally infected french bean field with characteristic symptoms like yellowing, drying at the soil level, stunting, poor seedling establishment, uneven growth, chlorosis, and premature defoliation in severely affected cases. It was isolated using standard tissue isolation technique and identified based on morphological traits. The fungus was molecular identified by sequencing ITS region of rDNA by using ITS1 and ITS4 primers. Further, pathogenicity of R. solani was proved according to Koch’s postulates.