Objective:
To continue a long-term study on seed deterioration to aid in the development of models to predict deterioration rates for seed stored at -18C. This information will be used to develop seed monitoring schedules and provide information to seed producers and merchandisers for handling their inventory.

Approach:
Samples of seed stored for varying periods of time and from a wide range of species will be pulled from long-term storage at the National Center for Genetic Resources Preservation (NCGRP) and germination tests will be done by the Colorado Seed Laboratory (CSL). The results of these germination tests will be compared to initial, and in a few cases subsequent germination tests, to determine how fast seed deteriorates at -18oC storage. At the NCGRP we have seed which has been in storage for 30+ years and research is needed to confirm longevity of this stored material. In these studies, seed which does not germinate will be evaluated chemically to determine if ungerminated seeds are dormant or dead. All data obtained from these studies will be permanently stored in GRIN and the storage information will be compared and compiled with storage information from other sites. The modeling of seed deterioration will be done using seed deterioration curves on individual species once adequate data for that species is obtained. Critical factors in selecting accessions to evaluate will be time since the last germination test, accession with suspected declines in viability and accession with sufficient previous viability data to plot a seed deterioration curve.