Isolation, Screening and Identification of Herbicidal Actinomycetes from Rhizosphere Soils

Aim: Current study investigates the activity of rhizosphere microflora against common weeds of Coccinia grandis. Soil actinomycetes known for their potential antimicrobial and other secondary metabolites were taken for the study.

Study Design: CRD.

Place and Duration of Study: Department of Agricultural Microbiology, Tamil Nadu Agricultural University (TNAU), between November to December 2021.

Methodology: Actinomycetes were isolated from rhizosphere soils collected from the western zone of Tamil Nadu (Ooty, Western Ghats, Tirupur, Erode and Coimbatore) using different media (KKA, SCA, HV & LMSA). Their morphological characterization was done by following standard protocol. The isolates were screened based on their herbicidal activity against Trianthema portulacastrum. In vitro seed germination assay (pre-emergence) was followed to identify potential actinomycetes.

Results: Thirty actinomycetes isolates were obtained from different locations in Tamil Nadu using four different media and their morphological characterization was done. Most of them are creamy white, grey, white and some of them were producing pigments. All the isolates showed positive for Gram’s reaction.

Conclusion: Six efficient isolates were identified in the preliminary screening of weed seed germination. Further, the isolates will be studied at the field level.