Moisture sorption isotherms and comparative storage longevity of Corchorus olitorius and C. capsularis accessions under genebank conditions

Abstract Ex situ conservation of jute mallow genetic resources depends on a reliable estimate of how long stored seeds remains viable. Comparative longevity assays based on controlled deterioration conditions only deliver meaningful contrasts when every sample enters storage at the same moisture content. This study constructed moisture sorption isotherms at 20°C for (MIX; Corchous olitorius ) and (TOT 4157; C. capsularis ) by equilibrating seeds over non-saturated LiCl solutions at around 40, 50, 60 and 70% relative humidity, and identified the RH at 20°C that yields an equilibrium moisture content equivalent to that attained at a standard accelerated ageing benchmark (45°C/ 60%RH). Linear interpolation across 20°C isotherms identified Corchorus olitorius accession MIX (59.71%) and C. capsularis accession TOT 4157 (59.83%) RH at 20°C as the equivalent moisture environment that yields the same equilibrium moisture content as 45°C/ 60% RH. Three accessions of each species were then equilibrated at the resultant eRH/ 20°C for each species, transferred for 24 hours to 45°C/ 60% RH, then sealed at 45°C and withdrawn for germination tests across 120 days. C. olitorius accessions were shorter-lived (58.9–84 days) than those of C. capsularis accessions (52.2–112.1 days). The slightly higher moisture affinity observed in C. olitorius is likely associated with increased rates of deterioration, unlike that of C. capsularis . The findings highlight the central role of precise moisture-temperature management in maintaining postharvest quality of jute mallow germplasm, providing guidance for genebank management, cold-chain storage and commercial applications.