Safeguarding seed longevity under genebank storage: Evidence based viability monitoring intervals for six tropical species at the Australian Grains Genebank (AGG)

Abstract The Genebank Standards for Plant Genetic Resources recommend that genebanks periodically monitor the change in viability of their stored germplasm to ensure timely regeneration. The Australian Grains Genebank (AGG) has been recording germination data on orthodox seeds from tropical grain crops, stored under long-term storage (−20°C), for 40 years. Real-time viability data, collated from germination tests carried out on seedlots which had been in storage for a minimum of 20 years, from six agriculturally important grain crops ( Sorghum bicolor, Phaseolus vulgaris, Glycine max, Vigna radiata, Cajanus cajan and Vigna angularis ) was analysed by probit analysis. For each species independently, a common loss in viability was observed for all seedlots showing a consistent decline in viability during storage; with observed longevity estimates (σ; time for viability to fall by 1 NED/probit) of 17.4, 30.7, 33.2 49.6, 48.8, 63.5 and years for Vigna angularis, Cajanus cajan, Phaseolus vulgaris, Glycine max, Sorghum bicolor , and Vigna radiata , respectively. Common values of σ were subsequently used to determine species-specific viability monitoring intervals, based on the results of the last germination test. Dynamic monitoring intervals are a cost-efficient strategy that will avoid the over-use of seed through too frequent viability monitoring whilst still ensuring the timely regeneration of material. With funding shortfalls often reported as the main contributing factor to regeneration and viability testing backlogs, the ability for genebanks to maximise cost-efficiencies, where possible, is paramount to secure the genetic integrity of stored germplasm; particularly as collections continue to grow.