Why are the seeds of this species difficult? Some species of the Poaceae family can produce a high proportion of empty seeds, which collectors and curators must take account of. The seeds may have physiological dormancy.
Andropogon gayanus (Image: W. Stuppy, RBG Kew)
This species has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
Remove the seed covering structures if necessary and sow the seeds on agar, germination paper or sand. Germinate under an alternating temperature regime of 35/20ºC (with an 8/16hr photoperiod). Perform a cut-test on any seeds that have not germinated, to check for empty seeds. All empty seeds are non-viable in germination tests.
The seeds of this species may have Physiological Dormancy. If germination is low, this type of 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 occurrence of empty seeds is common in wild-collected accessions of some Poaceae species. Empty seeds may have a normal seed coat but an absent or under-developed embryo, or limited storage tissue.
Accepted name: Andropogon gayanus Kunth
Synonyms: Andropogon guineensis Schumach., Cymbachne guineensis (Schumach.) Roberty, Andropogon brieyi De Wild.
References and Links
- Baskin, C.C. and Baskin J.M. (1998). Seeds: ecology, biogeography, and evolution of dormancy and germination. Academic Press, USA.
- Black, M., Bewley, J.D. and Halmer, P. (2006). The Encyclopaedia of Seeds: science, technology and uses. CAB International, UK.
- 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.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Andropogon gayanus.
- PROTAbase (Plant Resources of Tropical Africa) - Wageningen, Netherlands: Andropogon gayanus.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Andropogon gayanus.
- Tropical Forages - CSIRO, DPI&F(Qld), CIAT and ILRI, Brisbane, Australia: Andropogon gayanus.
- Tropicos - Missouri Botanical Garden, USA: Andropogon gayanus.