Plant Growth-Promoting Microbial Consortia for Effective Biocontrol of Groundnut Collar Rot and Chickpea Wilt

Abstract

Fungal seed- and soilborne diseases are economically devastating threats to global agriculture. The pathogenic fungi infiltrate seeds during production, storage, or planting and persist within the soil, posing a significant challenge to crop health and yield. The use of microbial consortia has become a promising alternative for their management. In this study, 15 isolates (six fungal and nine bacterial) were evaluated for their broad-spectrum antagonistic activities against eight major seed- and soilborne pathogens, namely, Rhizoctonia solani (rice), Fusarium verticillioides (maize), Macrophomina phaseolina (maize), F. udum (redgram), F. oxysporum f. sp. ciceris (chickpea), Sclerotium rolfsii (groundnut), Aspergillus niger (groundnut), and Alternaria sesami (sesame) under in vitro conditions. All isolates showed significant variations in their inhibitory capabilities against all eight pathogens. Evaluation of their plant growth-promoting traits identified isolates Trichoderma asperellum (Tricho1 and Tricho2) and Bacillus subtilis (B3, S4KB5 and S8KB2) as the most effective broad-spectrum biocontrol isolates. All three microbial consortia (MC1, MC2, and MC3) developed using compatible potential isolates were promising in reducing disease incidence and promoting plant growth in groundnut and chickpea. The microbial consortium MC1 comprising Tricho1 + S4KB5 + S8KB2 was the most effective in both groundnut and chickpea, which recorded the lowest collar rot and wilt incidence of 9.33% and 8.33%, respectively. The study identified effective broad-spectrum plant growth-promoting microbial consortia. These consortia can be evaluated under field conditions and exploited both as biopesticides and biofertilisers in sustainable agriculture.