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.
Sesamum indicum (Image: S. Wood, RBG Kew)
This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
This species has oily seeds which will absorb relatively less water than similarly-sized non-oily seeds. Be aware that when these seeds are dried to the recommended 15% relative humidity, the equilibrium moisture content will be lower than for non-oily seeds.
Germinate on agar or germination paper at a constant temperature of 25ºC, or using an alternating temperature regime of 30/20ºC or 35/20ºC (with an 8/16hr photoperiod). It may be necessary to add 250 mg/l gibberellic acid to the germination medium to encourage growth.
The seeds of this species are expected to be physiologically dormant (based on members of the same family). 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.
The capsule (3 x 1 cm) is glabrous or hirsute, erect, oblong, rectangular in section, deeply grooved, with a persistent calyx and a conspicuous subulate beak, dehiscing by 2 apical pores. The seeds are small (3 x 1.5 mm) and ovate, smooth or reticulate.
The pods are brown or purple in colour. The seeds can be white, yellow, grey, red, brown or black at maturity.
See more images of this species at the Digital Atlas of Economic Plants.
(Image: S. Wood, RBG Kew)
Accepted name: Sesamum indicum L.
Synonyms: Sesamum orientale L., Volkameria orientalis (L.) Kuntze, Sesamum hopkinsii Suess., Sesamum indicum var. integerrimum Engl., Sesamum somalense Chiov., Anthadenia sesamoides Lem.
Common name: sesame
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.
- Purseglove, J.W. (1968). Tropical Crops: dicotyledons. Longman Group Ltd., UK.
- 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: Sesamum indicum.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Sesamum indicum.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Sesamum indicum.
- Tropicos - Missouri Botanical Garden, USA: Sesamum indicum.