Molecular variability and host range of Rhizoctonia solani AG1-IA in rice-vegetable based cropping systems in West Bengal, India

Rhizoctonia solani is becoming an emerging menace in rice-based vegetable-growing areas of West Bengal, India. From the survey of 2 consecutive years (2016–17 and 2017–18), thirty-eight isolates were obtained from different hosts of rice-vegetable-based cropping systems of West Bengal. Morphological, and pathogenic variability of all the isolates were studied. Correlation studies between pathogenicity and morpho-cultural characters indicated the weight of sclerotia and growth rate to be significant characteristics related to virulence of the R. solani. Molecular variability of the thirty isolates was studied by sequencing of rDNA-ITS region. Sequence analyses of the rDNA-ITS region indicated AG1-IA (21 isolates) as predominant followed by AG1-ID (8 isolates). One isolate (Krc9) was identified as Ceratobasidium oryzae-sativae. The occurrence of subgroup AG1-IA is being reported first time from crucifers in West Bengal.