Schriften zu Genetischen Ressourcen - Genres

Diversity of African vegetable Solanum Species
robust perennials with large deeply lobed leaves, but other cultivars, especially in
West Africa, are smaller much branched herbs with smaller often simple leaves and
the young shoots are picked as a ‘cut-and-come-again’ vegetable.
The wild ancestor is S. dasyphyllum Schum. and Thonn., a rather different looking
plant, covered with hairs and prickles, which occurs wild throughout tropical Africa. It
originated probably in East Africa, and spread from there. The place and mode of
domestication is not certain, but fruits of S. dasyphyllum are used for folk medicine
(BUKENYA and CARASCO 1999). Although most forms of S. macrocarpon and S. dasyphyllum
are distinct, and are conveniently treated as distinct morphological species,
they are completely interfertile, and intermediate forms occur. Thus they can all be
regarded as a single biological species (BUKENYA and CARASCO 1994). DNA analyses
by AFLP showed four accessions of these taxa to be very similar to each other and
completely distinct from S. sessilistellatum, S. cerasiferum or any other species analysed
(MACE et al. 1999). However, many more accessions of all kinds and from all
parts of Africa should be analysed using molecular markers, to clarify their evolution
and to find their closest relatives.
4. Solanum aethiopicum L. – Scarlet Eggplant
Solanum aethiopicum (classified in Solanum subgenus Leptostemonum section Oliganthes
(Dunal) Bitter) is a very important vegetable throughout tropical Africa, especially
in the less humid regions: in the Ivory Coast S. aethiopicum and S. macrocarpon
are second only to okra (Abelmoschus spp.) in production (LESTER et al. 1990).
The fruits are scarlet red when mature, but the green immature fruits of Gilo and
Kumba Groups are stewed with other vegetables and meat or other protein rich
foods, or even eaten raw, whilst the glabrous leaves of Shum and Kumba Groups are
boiled as green vegetables, like spinach (SCHIPPERS 2000). There is a vast diversity
of shapes and sizes of fruits (DAUNAY et al. 2001a, plate IX, 2), and also of leaves.
According to their usage, four cultivar-groups are recognised, which were treated
previously as several different species (BITTER 1923, LESTER 1986, LESTER et al.
1986, LESTER and NIAKAN 1986, DAUNAY et al. 2001a, LESTER and HAWKES 2001).
These are as follows:
1. S. aethiopicum Gilo Group typically has fruits the size and shape of hen’s
eggs, but there are very many other shapes (depressed spherical to ellipsoid)
and sizes (2-8 cm diam.). The leaves are hairy and are not eaten.
2. S. aethiopicum Shum Group is typically a short much branched plant with
small glabrous leaves and shoots that are plucked frequently as a green
vegetable. However, the small (1.5 cm diam.) very bitter fruits are not eaten.
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