Estimating the longevity of wild potato species through seed storage experiments

Estimating the viable lifespan of botanical seeds during storage is an important factor in managing seed germplasm collections. In this research, true potato seeds from 22 accessions (23 samples in total) of six wild potato species were used to estimate seed longevity in experimental storage, analyse the differences between species and determine if there is a pattern of longevity associated with the geographical origin of these species and accessions. An accelerated ageing method using controlled conditions (60% relative humidity, 45C) was used during storage, removing seeds at different times to test for viability. The emergence of a 3 mm-long radicle was used as a positive indicator of seed viability in a standard germination test. A seed survival curve was plotted and the time at which germination declined to 50% ( p 50 ) was determined. The ( p 50 ) ranged between 23.6 days for accessions CIP 760355 and CIP 761977 (both Solanum raphanifolium ), to 53.1 days for accession CIP 764506 ( S. wittmackii ), with an average of 36.7 days across all accessions. Based on our studies, the seeds of these 22 wild potato accessions appear to have intermediate seed longevity. Overall, these data can help prioritise and inform regeneration and conservation strategies of potato species held in long term conservation in genebank collections.