Why are the seeds of this species difficult? The seeds may have physiological dormancy, which would have to be overcome before they will germinate. The seeds are relatively short-lived, so may not remain viable for a long time in storage.
Allium cepa (Image: S. Wood, RBG Kew)
This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
The seeds are relatively Short-lived in storage. Monitor viability at least every five years, and more frequently once viability begins to decline. When viability falls close to the regeneration standard, the collection will need to be re-generated or re-collected.
Germinate on agar, germination paper or sand at 10ºC.
The seeds of this species may be Physiologically Dormant (based on other species in same genus). If germination is low, use a moist pre-chill treatment before germination at 20ºC. Alternatively, try performing delicate surgery to enable the embryo to grow. Excise the tissue near the root tip.
See other images of this species at the Digital Seed Atlas of the Netherlands.
Allium cepa seed
(Image: S. Wood, RBG Kew)
Accepted name: Allium cepa L.
Synonyms: Allium nigritanum A.Chev., Allium angolense Baker
Common name: onion
References and Links
- Food and Agriculture Organization of the United Nations and International Plant Genetic Resources Institute (1994). Genebank Standards. FAO/IPGRI, Rome, Italy.
- International Seed Testing Association (2010). International Rules for Seed Testing: edition 2010. ISTA, Bassersdorf, Switzerland.
- Rao, N.K., Hanson, J., Dulloo, M.E., Ghosh, K., Nowell, D. and Larinde, M. (2006). Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy.
- Walters, C., Wheeler, L.M., Grotenhuis, J.M. (2005). Longevity of seeds stored in a genebank: species characteristics. Seed Science Research, Vol 15 (1): pp1-20.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Allium cepa.
- AVRDC - The World Vegetable Centre, Taiwan: fact sheet on Allium cepa.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Allium cepa.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Allium cepa.
- Tropicos - Missouri Botanical Garden, USA: Allium cepa.