The domestication of trees for agroforestry approaches to poverty alleviation and environmental rehabilitation in the tropics depends on the expansion of the market demand for non-timber forest products. This paper reviews published data on the nutritive values of the flesh, kernels and seedoils of the seventeen fruit tree species that have been identified, in four ecoregions of the tropics, by subsistence farmers as their top priorities for domestication. In some species, genetic Variation in nutritive value has been reported, but in most species there is still inadequate information on which to base programmes for the genetic improvement of these species. Farmers and agroforesters have identified many of the biological constraints relevant to their viewpoint on production, but there is a need for inputs from the food industry into the identification of the desirable traits and characteristics of potentially novel food products. This paper calls for greater collaboration between agroforesters and the food industry in the effort to promote the domestication and commercialization of under-utilized tree products.

New initiatives in agroforestry are seeking to integrate into tropical farming systems indigenous trees whose products have traditionally been gathered from natural forests. This is being done in order to provide marketable products from farms that will generate cash for resource-poor rural and peri-urban households. This poverty-alleviating agroforestry strategy is at the same time linked to one in which perennial, biologically diverse and complex mature-stage agroecosystems are developed as sustainable alternatives to slash-and-bum agriculture. One important component of this approach is the domestication of the local tree species that have commercial potential in local, regional or even international markets. Because of the number of potential candidate species for domestication, one crucial first step is the identification of priority species and the formulation of a domestication strategy that is appropriate to the use, marketability and genetic potential of each species. For most of these hitherto wild species little or no formal research has been carried out to assess their food value, potential for genetic improvement or reproductive biology. To date their marketability can only be assessed by their position in the local rural and urban marketplaces, since few have attracted international commercial interest. To meet the objective of poverty alleviation, however, it is crucial that market expansion and creation are possible, hence for example it is important to determine which marketable traits are amenable to genetic improvement. While some traits that are relatively easy to identify do benefit the farmer, there are undoubtedly others that are important to the food, pharmaceutical or other industries that require more sophisticated evaluation. This paper presents the current thinking and strategies of ICRAF in this new area of work and draws on examples from our program.