Taste versus shelf life: Intended use should guide selection of indigenous strains of Gnetum L. (Gnetaceae) for domestication in Africa

Species of Gnetum L. are used for a number of purposes, the most important of which is to make a soup or stew, which is called ‘eru’ in Cameroon. Material is heavily harvested for use in Cameroon, export to Nigeria and to Europe and America. Gnetum has been extirpated in some areas and is becoming rare in others because levels of harvesting are unsustainable. Programmes have been initiated to cultivate and domesticate Gnetum. Two additional African species of Gnetum were recently described — one, G. latispicum E.H.Biye, is traded along with G. africanum Welw. and G. buchholzianum Engl., whereas G. interruptum E.H.Biye was not found in the markets. It had been noted that some strains of Gnetum were not harvested because they tasted bitter. It is thus desirable to select good tasting strains of Gnetum for cultivation and domestication. Twenty tasters, who could taste bitterness, scored meals made from different species of Gnetum, from Gnetum that had been bought in geographically separate markets and Gnetum leaves of different ages on a Likert-type scale. When meals are prepared from freshly harvested leaves, there is preference for fresh G. buchholzianum over the other species. Material from some localities was preferred over others and this does not seem to have a geographical pattern, nor correlate to vegetation type or soil type and it is thus concluded that pleasant taste is genetically determined. There is also a preference for young leaves. These preferences contrast with the preferences recorded in Nigeria, because the factors that give fresh material the best taste, give material a shorter shelf life. It is recommend that in cultivation and domestication programmes, taxonomy should be resolved before selecting material and that it should be borne in mind that different factors may have to be prioritized depending on the purpose for which the product will be used.