Cucumis metuliferus

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.

Send your image to difficultseeds@kew.org

Seed Storage

This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.

Germination Requirements

Germinate on agar, germination paper or sand at constant temperatures of 25 or 30ºC, or at alternating temperatures of 35/20ºC or 30/20ºC (with 8hrs light and 16hrs darkness), 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.

Seed Morphology

The fruit is an indehiscent pepo. The seed (6.30-6.46 mm x 1.51-1.63 mm x 2.90-2.92 mm) is fusiform and laterally compressed, and is beige in colour. The seed coat surface is smooth and the seed has a raphe and a small hilum. The seed configuration is anatropous. The embryo is axial-spatulate, yellowish-white in colour, and fills the seed.

See images of this species at the Digital Atlas of Economic Plants.

Taxonomy

Family: CUCURBITACEAE

Accepted name: Cucumis metuliferus E.Mey. ex Naudin

Synonyms: Cucumis tinneanus Kotschy & Peyr.

Common name: horned cucumber, horned melon, kiwano, melano, metulon

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 metuliferus.
AVRDC - The World Vegetable Centre, Taiwan: fact sheet on Cucumis metuliferus.
PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Cucumis metuliferus.
SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Cucumis metuliferus.
Tropicos - Missouri Botanical Garden, USA: Cucumis metuliferus.