How to Test Seeds for Germination

Germination Testing Program

Cheryl Birker, Rancho Santa Ana Botanic Garden

The California Seed Bank at Rancho Santa Ana Botanic Garden has a germination testing program to monitor the viability of its many conservation seed collections. Germination tests are conducted on all incoming seed collections before they are placed in freezer storage, and for all rare seed collections, follow-up germination tests are conducted periodically in order to monitor their viability throughout the storage term. Germination testing also allows for experimentation with different pretreatments for breaking seed dormancy to inform propagation protocols. Germination tests are conducted on agar and maintained in a temperature controlled germination chamber. Seeds must be treated with a bleach and Tween¨ solution to reduce microbial growth prior to sowing on agar, and this treatment must sometimes be repeated before the test is completed. Germination tests can run anywhere from two weeks to eight months, with weekly monitoring for new germinations and microbial growth. Seedlings are produced as a byproduct of germination testing, which can be transplanted from agar to soil and grown in a nursery for inclusion in a living collection or for second generation seed collecting as an extra means of ex-situ conservation.