Study of endophytic and rhizobacteria against root rot pathogen Macrophomina phaseolina in sesame

Macrophomina phaseolina is one of destructive soil borne pathogens causing significant yield losses in oilseed crops such as groundnut, soybean and sesame. Bacterial endophytes isolated from sesame wild species were tested for their antagonistic against Macrophomina phaseolina and Plant Growth-Promoting Rhizobacteria (PGPR) activities in sesame. Totally twenty isolates were isolated from wild species and released varieties. Out of twenty entophytes isolated, three strains were showed maximum inhibition of M. phaseolina mycelial growth ranged from 44.31 to 46.59 %. The three isolates were identified as Stenotrophomonas maltophila (PP716377.1), Bacillus stercoris (PQ578246.1) and Bacillus subtilis (PQ57832.1) and submitted in National Center for Biotechnology Information (NCBI). Under pot culture experiment, Bacillus stercoris showed increased sesame seed germination (95.20 %), shoot (16.18 cm) and root length (4.0 cm) and vigour index (1921) compared to control. Further, the isolates were tested under field condition along with other biocontrol agents and chemicals during two consecutive season (rabi/summer 2023-2024 and Kharif 2024-2025) at Regional Research station, Vriddhachalam, Tamil Nadu Agricultural University, Tamil Nadu. Among the studied treatments during two seasons, the T4 - seed treatment (4 g/kg) and soil application Trichoderma asperellum + soil application B. stercoris (2.5 kg/ha) + soil drenching with carbendazim (1 g/L) on 30 and 45 days after sowing (DAS) recorded less disease incidence of 6.8 % and 7.2 % which accounted 70.18 and 74.91 % reduction of root rot over control respectively and also increasing yield 700 kg/ha and 678 kg/ha.