Comparative Evaluation of Bioagents, Botanical Extracts, and Fungicides for Enhancing Seed Germination and Seedling Vigour in Brassica juncea

Abstract

Seed-borne pathogens, particularly Alternaria brassicae, cause significant losses in Brassica juncea by reducing germination, lowering seedling vigour, and increasing early-season mortality. Eco-friendly seed treatment approaches using bioagents and botanical extracts may offer viable alternatives to chemical fungicides by enhancing seed health and crop stand establishment. Seventeen treatments comprising bioagents (Trichoderma spp., Pseudomonas fluorescens, Bacillus subtilis), botanical extracts (garlic, ginger, turmeric, tulsi, lantana), and fungicides (Carbendazim + Mancozeb, Difenoconazole, Trifloxystrobin, Fluxapyroxad, Penflufen) were evaluated using the standard blotter method (ISTA guidelines). Germination percentage, seedling length, and seed vigour index (SVI) were recorded from three replications in a completely randomized design, and treatment means were compared using Duncan's Multiple Range Test at the 5% probability level. Allium sativum (garlic) extract achieved the highest germination (96%), seedling length (4.1 cm), and vigour index (393.6), followed by Zingiber officinale (ginger) extract (92%, 3.8 cm, 349.6) and the Trichoderma harzianum + T. viride consortium (92%, 3.6 cm, 331.2). Under laboratory conditions, botanical extracts generally performed better than bioagents and fungicides in enhancing vigour, while fungicide treatments showed moderate efficacy with mild phytotoxic effects at the concentrations tested. The untreated control recorded the lowest values (56%, 2.0 cm, 112.0). Statistical analysis confirmed highly significant inter-treatment differences (SEm ± 0.91; CD₀₅ = 2.63 for germination percentage). These findings suggest that garlic and ginger extracts, as well as Trichoderma-based consortia, are cost effective and environmentally compatible alternatives to chemical fungicides for integrated seed health management in mustard cultivation.