Storage-Dependent Responses of KDML 105 Rice (Oryza sativa L.) Seeds Across Dynamic Magnetic-Field Treatment Conditions: Germination, Seedling Growth, and Dual-Phase Hydration Modelling

Seed ageing reduces germination and seedling performance, but variation in these responses and hydration kinetics across dynamic magnetic-field exposure (DMFE) conditions is poorly defined. Khao Dawk Mali 105 rice seeds (Oryza sativa L.) stored for 10–13 months were treated for 3, 6, or 9 min at nominal maximum surface flux densities of 150, 270, 370, or 470 mT. Untreated controls were excluded from the factorial analyses and used as descriptive references. Water uptake was modelled kinetically, and germination, vigour, and seedling growth by response surfaces; for early germination the arcsine-square-root scale was adopted after grouped cross-validation. Storage duration dominated every endpoint, especially early germination (ηp2 = 0.991), declining approximately 28 percentage points per month. DMFE-associated differences were concentrated during early imbibition: treated seeds took up 2.9–4.9 percentage points more water than controls at 6 h, narrowing to 0.6–1.2 points by 42 h. The Reduced Dual-Phase Gompertz model was decisively favoured (ΔAICc = 260.2–347.2). Flux density was retained in the earlier hydration amplitude and all six seedling-growth models, and on the arcsine scale in a shallow early-germination profile whose selection was sensitive to design support and which did not improve cross-validated prediction. Independent seed lots, airflow-only controls, and field validation are required before practical recommendations.