Economic Plants
April 1996: Issue 9

Miscanthus Genetic Resources

NATIVE to SE Asia and S Africa, the grass genus Miscanthus is also grown in the UK as a horticultural plant producing stunning inflorescences. Attention is currently focused on Miscanthus as a biomass crop for sustainable energy and fibre production. MAFF-funded work at Kew aims to clarify the taxonomy of the genus and characterise its genetic resources. If research and development are successful it may not be long before stands up to 4m tall are scattered throughout the agricultural landscape of southern England. DNA sequence analysis and fingerprinting have already provided much information about the evolution and inter-relationships of its taxa; e.g. the discovery that the third, previously unknown genome of M. x giganteus, a sterile clone with most potential as a biomasscrop, is probably M. purpurascens. A morphological review of the genus is also being produced for which the Herbarium's World Grass Database is proving to be an invaluable tool.

Left: Steve Renvoize at ADAS field trials of Miscanthus in Cambridgeshire following the drought of 1995.

Right: Miscanthus grown in the Grass Garden at Kew by Mary Thorp.

Contact: Trevor Hodkinson (0181-332 5371)

Email: Trevor Hodkinson

Allium section Allium Reviewed

THE recently published Kew book A Review of Allium Section Allium by Brian Mathew (ISBN 0947643 93 1, £21) is the product of a two-year survey funded by the International Board for Plant Genetic Resources. Section Allium of the large genus Allium includes the economically important leek (A. porrum) and garlic (A. sativum). The ancestry of these crops is unknown, so one aim of the study was to provide a practical taxonomic account identifying species that appeared most closely related. This would assist workers in other fields, such as plant breeding.

The review provides descriptions of the 114 species that were found to share the set of basic characteristics defining section Allium. Although these descriptions were made largely from herbarium material, enlargement of Kew's living collections enabled about half the number of species to be studied from living material. In addition, extensive cytological work was carried out by Kew's Margaret Johnson and Neriman Özhatay (Istanbul University), leaf anatomy was examined by Mary Gregory and flavonoid chemistry was surveyed by Prof. Jeffrey Harborne and Christine Williams (University of Reading).

For those who think that leek and garlic are relatively unimportant crops, it is worth considering that in the UK alone the annual production of leeks is something of the order of 15,000 tonnes, and that Spain probably grows around 100,000 tonnes of garlic per year!

Above: Allium dictyoprasum.

Contact: Brian Mathew (c/o The Herbarium)

Email: Brian Mathew

Basil Taxonomy

BASIL, Ocimum basilicum, is an important economic crop producing annually c.100 tonnes of essential oil worldwide and with a trade value as a pot herb of around US$15 million per year. It is also widely used in systems of indigenous medicine. Nevertheless, much confusion surrounds basil taxonomy with several forms having different attributes being recognized under the same name. This was shown in a multi-disciplinary study undertaken by Dr Eli Putievsky (Newe Ya'ar Research Centre, Haifa, Israel) during a sabbatical year at Kew, where crossing experiments and analysis of chromosome numbers revealed that the current practice of referring to forms by varietal names obscures a great deal of useful information. The study standardised specific names by reference to type material and suggested that a series of standardised descriptors should be produced to allow easy identification and communication of the different forms. Chemical studies also suggested that the profile of dominant essential oils could be used alongside these descriptors to provide unique characterisation of plants. Such a standardisation of attributes is required if the full economic and medicinal potential of this most useful herb is to be developed.

Above: Ocimum basilicum var. purpurascens.

Contact: Dr Alan Paton (0181-332 5295)

Email: Alan Paton

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