Vol. 10, Issue 5 (2021)

Author(s):
N Chiranjeevi, M Reddi Kumar, B Padmodaya, NC Venkateswarlu, P Sudhakar and R Sarada Jayalakshmi Devi

Abstract:
A total of 22 chickpea dry root rot causing pathogen Rhizoctonia bataticola isolates and 40 antagonistic endophytic bacteria were isolated from chickpea roots which are collected from different chickpea growing districts of Andhra Pradesh. Cultural and morphological variability among the pathogen isolates were studied by growing on PDA and observed variation in colony growth rate, colour, texture, time taken to grow full plate, Sclerotial initiation, Sclerotial density, Sclerotial size and shape. Among the 14 potential endophytic bacterial isolates, Gram negative (7) and Gram positive (7) were recorded in equal proportion and all were rod shaped bacteria. Out of the 14 isolates, a total of 9, 7, 2, 1, 2, 3, 3, 13, 6, 3 and 0 showed positive for amylolytic activity (starch hydrolysis), proteolytic activity (Gelatin hydrolysis), lactose utilization, indole production, methyl red test, Voges-Proskeur test, citrate utilization, presence of catalase activity, ammonia production, HCN production and siderophore production respectively. 16S r DNA sequence analysis was used to identify the potential bacterial isolates such as CREB 9, CREB 21 and CREB 37 and which were exhibited close similarity of 97.75, 98.48 and 93.28 percent with Enterobacter cloacae, Pseudomonas aeruginosa and Bacillus subtilis respectively. Under glasshouse conditions, among the treatments T7 (seed treatment with potential bacterial antagonist (talc formulation) @10 g kg^-1 + soil application with talc based formulation of potential bacterial antagonist @100 g pot^-1) was found to be superior as it recorded maximum germination percent, plant height, root length, dry weight and least percent disease incidence compared to other treatments.