Comparative analysis of different biotic and abiotic agents for growth promotion in rice (Oryza sativa L.) and their effect on induction of resistance against Rhizoctonia solani: A soil borne pathogen

Abstract

Sheath blight is caused by soil borne fungal pathogen Rhizoctonia solani, resulting in up to 50% reduction of rice grain yield. Several broad-spectrum fungicides have been used to control this disease, however, these methods are costly to implement practically and have led to fungicide resistance. A sustainable approach like the use of biocontrol agents, is needed for the management of this disease. In the present experiment, we have compared three Bacillus spp. with the Trichoderma erinaceum, we identified earlier, to evaluate their role in growth promotion and biocontrol of rice diseases. Significantly, higher shoot and root length, fresh and dry biomasses were observed in Trichoderma erinaceum and Bacillus subtilis treated plants, as compared to control plants. Same four microbial isolates along with salicylic acid were used, separately, to study their role in induction of defence against Rhizoctonia solani, in a susceptible variety of rice, by studying various physiological, biochemical and pathological and yield parameters. T. erinaceum followed by B. subtilis treated plants had decreased disease progression (2.6–2.9 folds) and higher chlorophyll content and defence enzyme activities in comparison to diseased plants. Field trial with T. erinaceum and B. subtilis, suggested that T. erinaceum treated plants had decreased sheath blight disease severity (54% disease protection) and increased fresh (2.06 folds) and dry biomass (1.8 folds), total plant height (1.2 times), grain yield per/m2 (2.1 folds) as compared to diseased plants, thereby making it a potential biocontrol agent which can be used by farmers community.