Microbial bio priming enhances germination, growth, and vigour indices in rice (Oryza sativa) varieties

Abstract

Seed priming is a vital pre?sowing strategy that enhances metabolic readiness and stress tolerance in crops. This study investigated the efficacy of bio?priming with Pseudomonas fluorescens on four paddy varieties (ADT 53, ASD 16, CO 51, and CO 55) using concentrations of 0%, 15%, 20%, and 25% for 12 hours. The impact was assessed on germination percentage, seedling growth, biomass accumulation, and seedling vigour indices. Results revealed that bio?priming significantly influenced early developmental parameters, though responses were variety?specific. Germination improved noticeably in ADT 53, CO 51, and CO 55 at 15% concentration, with CO 51 showing the greatest increase (from 75% to 95%). In contrast, ASD 16 performed best under control conditions (90%), indicating sensitivity to microbial load. Greater shoot length and root elongation were observed at 20% in ADT 53 and CO 51, whereas CO 55 responded strongly at 15%. Biomass accumulation was consistently higher in primed seeds, particularly at moderate concentrations. Seedling Vigour Index I (SVI?I) reached maximum values in ADT 53 at 20% (3741.33) and CO 55 at 25% (4349.17), confirming enhanced elongation under microbial priming. Seedling Vigour Index II (SVI?II) was highest in ASD 16 at 15% (14.80), followed by ADT 53 16 at 20% (10.54), reflecting robust dry matter accumulation. P. fluorescens bio?priming emerges as a cost?effective, eco?friendly strategy to improve germination, seedling vigour, and early establishment in rice. However, optimal concentration must be tailored to the varietal genetic background to avoid inhibitory effects, underscoring the importance of genotype?specific standardization in sustainable rice cultivation.