Variability Management of Collar Rot Sclerotium rolfsii Sacc and Tripartite Interaction Between Host Pathogen and hizobacteria in Soybean

Abstract

The present investigation comprises of understanding the plant-pathogen-rhizobacteria newlineinteractions to help in developing sustainable biocontrol measures for management of newlinesclerotium wilt (Sclerotium rolfsii Sacc.) of soybean. newlineThe pathogen isolates collected from sixteen different geographical regions showed newlinevariation for colony morphology, sclerotial characters and oxalic acid production. The DNA newlinesequences of all the 16 isolates were compared using bioinformatics tool NCBI (National Centre newlinefor Bioinformatics) BLAST programme. Based on sequence comparison, the identification of newlineSclerotium rolfsii isolates were confirmed and recorded the maximum of 97 per cent similarity newlinewith already known Athelia rolfsii strains. The dendrogram constructed based on the ITS newline(Internal Transcried Spacer) sequences formed two clusters A and B, the isolates collected from newlinesame geographical location formed the same cluster. newlineAmong ten rhizobacteria evaluated against Sclerotium rolfsii, the highest mycelial newlineinhibition was observed from the isolate AUUB 209 (Streptomyces enissocaesilis) (76.79 %) in newlinedual culture method, 36.47 per cent in paired plate technique and 76.99 per cent from the newlinesupernatant of this rhizobacteria. These top ten rhizobacteria were found positive for different newlineplant growth promoting traits like Indole acetic acid, siderophore, ammonia, HCN, chitinase newlineproduction and phosphate solubilisation. The rhizobacterial supernatant influenced growth newlinepromotional activities like increase in germination percentage, shoot, root length, seedling newlinevigour index, fresh weight and dry weight under paper towel method. newlineField experiments were carried out at the experimental plot, Main Agricultural Research newlineStation, Dharwad during kharif 2021 and Research and Development centre, Ugar Sugar Works newlineLtd., Ugar Khurd (Belagavi district) during summer 2021 for the management of collar rot by newlineusing effective rhizobacteria AUUB 209 (Streptomyces enissocaesilis) and AUDT 626 newline(Streptomyces racemochromogenes). The results indicated that the seeds treat