Trichoderma Isolates Against Abiotic Stresses and Management of Collar rot of Lentil (Lens culinaris L.) Caused by Sclerotium rolfsii

A total of 30 native Trichoderma isolates were collected from the Agricultural Research Station, Ummedganj- Kota, Rajasthan, India. Out of which 9 native isolates were evaluated for bio-efficacy against Sclerotium rolfsii. Isolate ARS K-21 exhibited maximum inhibition (89.26%), followed by ARS K-11 (83.70%) in dual culture. Subsequent evaluations revealed the compatibility of efficient isolate ARS K-21 with various bio botanicals displaying minimum inhibition with Vermiwash (1.11-3.70%) followed by Beejamarat (0.38-15.92%) and Brahmastra (7.78-19.68%), while ARS K-11 displayed compatibility only with Dasparni ark with a minimum inhibition of 1.11-3.70%. Assessment of abiotic stress tolerance of the isolates revealed that most isolates thrived at 200 mM and 400 mM NaCl salt concentrations, with ARS K-21 and ARS K-24 demonstrating moderate growth levels across higher concentrations, except at 1200 mM. Optimal growth of the isolates occurred at 25 and 30 degrees C, with deviations leading to growth inhibition. Isolates ARS K-1, ARS K-11, ARS K-12 and ARS K-21 exhibited resilience to temperature extremes. ARS K-21 has shown exceptional growth proficiency across a wide pH spectrum (pH 5 to 8.5) followed by ARS K- 24, highlighting their versatility. Mass multiplication of efficient isolate ARS K-21 enriched with vermicompost led to the standardization of a dosage (30 g/kg soil) for managing collar rot in lentil crops at 5 g inoculum per kg soil of S. rolfsii.