Author(s):

Bhanothu Shiva, P Srinivas and Deepa Khulbe

Abstract: Chilli (Capsicum annuum L.) belongs to the family Solanaceae is mainly cultivated for green fruits as table purpose and dry chilli as spice. Diseases of chilli act as the chief limiting factor to its economic production. Recently, the collars rot disease of chilli caused by Sclerotium rolfsii is a threatening disease in eastern coastal regions of Odisha. Due to its soil borne nature, this disease is very difficult to be managed by chemical fungicides. Rhizosphere soil of healthy chilli plants was used for isolation and screening of native bacterial antagonists for their biocontrol efficacy and seed germination potential. Among 34 bacterial strains isolated from rhizoplane and rhizosphere of chilli roots, five isolates viz. isolate-01, isolate-17, isolate-23, isolate-24 and isolate-32 were found highly inhibitory against mycelial growth of S. rolfsii in dual cultures. Highest inhibition of radial mycelial growth of pathogen in dual culture was induced by isolate-32 (73%) followed by isolate-24 (69.6%). In greenhouse experiments percent disease incidence (PDI) was lower in artificially inoculated chilli plants treated with isolate-32 (7.4%) and isolate-24 (9.9%), with percent disease reduction over control of 85.9% and 81%, respectively. These isolates also exhibited efficient seed germination characteristics as evident by significant increase in germination (%) of treated chilli seeds of 94.5 and 89 of the plants treated respectively with isolate-32 and isolate-24 as compared to inoculated control. The study concluded that the two native rhizobacteria isolated from root zone of healthy chilli plants could successfully protect the chilli plants from the lethal infection by Sclerotium sp. while enhancing the germination of the treated plants.

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