Why are the seeds of this species difficult? The seeds may have physiological dormancy, which can be overcome by mimicking the seasonal patterns of the species' native habitat.
Cucumis zeyheri (Image: S. Wood, RBG Kew)
This species most probably has Orthodox seeds (based on other species in the same genus) - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
Germinate on agar, germination paper or sand at 25ºC or under an alternating temperature regime of 35/20ºC or 30/20ºC (with an 8/16hr photoperiod), depending on local climatic conditions. Incubating the seeds in 24hr darkness may also help germination.
The seeds of this species may be Physiologically Dormant (based on other species in the same genus). If germination is low, this type of seed dormancy can be overcome by mimicking the seasonal patterns of the species' native habitat. Use a moist pre-chill or pre-heat treatment (depending on local climatic conditions) or a dry after-ripening treatment, before germinating the seeds on agar, germination paper or sand at their optimum temperature. If this does not work, you can perform delicate surgery to enable the embryo to grow. Excise the tissue near the root tip.
(Image: S. Wood, RBG Kew)
Accepted name: Cucumis zeyheri Sond.
Synonyms: Cucumis africanus var. zeyheri (Sond.) Burtt Davy, Cucumis prophetarum subsp. zeyheri (Sond.) C.Jeffrey
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.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Cucumis zeyheri.
- AVRDC - The World Vegetable Centre, Taiwan: fact sheet on Cucumis zeyheri.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Cucumis zeyheri.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Cucumis zeyheri.
- Tropicos - Missouri Botanical Garden, USA: Cucumis zeyheri.