Roger Leakey

Agriculture at a Crossroads

The present path of agricultural development will not achieve development goals according to a recent assessment, but a solid foundation for improvements exists.

Deliberate Introductions of Species: Research Needs Benefits can be reaped, but risks are high

The silent invasion of Hawaii by insects, disease organisms, snakes, weeds and other pests is the single greatest threat to Hawaii’s economy and natural environment.... Even one new pest-like the brown tree snake--could forever change the character of our islands. (Coordinating Group on Alien Pest Species 1996, P. 1). Reforestation in the tropics is so vastly behind deforestation that we cannot wait to fully appraise all the potential negative elements of domestication. Weediness is of consequence perhaps in Honolulu, but not in Addis or Delhi. (James Brewbaker, quoted by Hughes 1994, p. 244 ).

Potential for novel food products from agroforestry trees: a review

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.

Tree domestication in tropical agroforestry

We execute tree ‘domestication’ as a farmer-driven and market-led process, which matches the intraspecific diversity of locally important trees to the needs of subsistence farmers, product markets, and agricultural environments. We propose that the products of such domesticated trees are called Agroforestry Tree Products (AFTPs) to distinguish them from the extractive tree resources commonly referred to as non-timber forest products (NTFPs). The steps of such a domestication process are: selection of priority species based on their expected products or services; definition of an appropriate domestication strategy considering the farmer-, market-, and landscape needs; sourcing, documentation and deployment of germplasm (seed, seedlings or clonal material); and tree improvement research (tree breeding or cultivar selection pathways). The research phase may involve research institutions on their own or in participatory mode with the stakeholders such as farmers or communities. Working directly with the end-users is advantageous towards economic, social and environmental goals, especially in developing countries. Two case studies (Prunus africana and Dacryodes edulis) are presented to highlight the approaches used for medicinal and fruit-producing species. Issues for future development include the expansion of the program to a wider range of species and their products and the strengthening of the links between product commercialization and domestication. It is important to involve the food industry in this process, while protecting the intellectual property rights of farmers to their germplasm.

Agroforestry Tree Products (AFTPs): Targeting Poverty Reduction and Enhanced Livelihoods

Agroforestry tree domestication emerged as a farmer-driven, market-led process in the early 1990s and became an international initiative. A participatory approach now supplements the more traditional aspects of tree improvement, and is seen as an important strategy towards the Millennium Development Goals of eradicating poverty and hunger, promoting social equity and environmental sustainability. Considerable progress has been made towards the domestication of indigenous fruits and nuts in many villages in Cameroon and Nigeria. Vegetatively-propagated cultivars based on a sound knowledge of ‘ideotypes’ derived from an understanding of the tree-to-tree variation in many commercially important traits are being developed by farmers. These are being integrated into polycultural farming systems, especially the cocoa agroforests. Markets for Agroforestry Tree Products (AFTPs) are crucial for the adoption of agroforestry on a scale to have meaningful economic, social and environmental impacts. Important lessons have been learned in southern Africa from detailed studies of the commercialization of AFTPs. These provide support for the wider acceptance of the role of domesticating indigenous trees in the promotion of enhanced livelihoods for poor farmers in the tropics. Policy guidelines have been developed in support of this sustainable rural development as an alternative strategy to those proposed in many other major development and conservation fora.

Indigenous Fruit Trees in the Tropics: domestication, utilization and commercialization

[Extract] This book comprises 5 parts and 21 chapters discussing the domestication of indigenous fruit trees in Africa, Oceania, Latin America and Asia; and describes the biophysical and socio-economic aspects of Miombo fruit trees.

DIVERSIFICATION OF TREE CROPS: DOMESTICATION OF COMPANION CROPS FOR POVERTY REDUCTION AND ENVIRONMENTAL SERVICES

New initiatives in agroforestry are seeking to integrate indigenous trees, whose products have traditionally been gathered from natural forests, into tropical farming systems such as cacao farms. This is being done to provide from farms, marketable timber and non-timber forest products that will enhance rural livelihoods by generating cash for resource-poor rural and peri-urban households. There are many potential candidate species for domestication that have commercial potential in local, regional or even international markets. Little or no formal research has been carried out on many of these hitherto wild species to assess potential for genetic improvement, reproductive biology or suitability for cultivation. With the participation of subsistence farmers a number of projects to bring candidate species into cultivation are in progress, however. This paper describes some tree domestication activities being carried out in southern Cameroon, especially with Irvingia gabonensis (bush mango; dika nut) and Dacryodes edulis (African plum; safoutier). As part of this, fruits and kernels from 300 D. edulis and 150 I. gabonensis trees in six villages of Cameroon and Nigeria have been quantitatively characterized for 11 traits to determine combinations defining multi-trait ideotypes for a genetic selection programme. I. gabonensis fruits are rich in vitamin A (67 mg 100 ml −1 ), while the kernels are rich in fat (51.3%) and contain a polysaccharide that is a food thickener. The fruits of D. edulis are also rich in oil (31.9%) and protein (25.9%). This poverty-reducing 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-burn agriculture. To meet the objective of poverty reduction, 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 (such as fruit and kernel mass) that benefit the farmer are relatively easy to identify, there are undoubtedly others that are important to the food, pharmaceutical or other industries which require more sophisticated chemical evaluation. There is a need, therefore, for better linkages between agroforesters and the private sector. The domestication activities described are relevant to the enrichment of smallholder cacao farms and agroforests. This diversification is seen as being important for the support of the cacao industry.

Evidence that subsistence farmers have domesticated indigenous fruits (Dacryodes edulis and Irvingia gabonensis) in Cameroon and Nigeria

Ten fruit and kernel traits were measured in 152 Irvingia gabonensis and 293 Dacryodes edulis trees from 6 villages in Cameroon and Nigeria. Frequency distribution curves were used to examine the range of variation of each trait of each species in each village and aggregated into national and regional populations. There were differences between the village sub-populations, with regard to the normality (e.g., mean kernel mass of D. edulis) or skewness (e.g., mean flesh depth of D. edulis) of the distribution curves and in the degree of separation between the individual village populations along the x axis, resulting in the development of a bimodal distribution in the regional population. For all traits, populations of both species differed significantly between countries, but only in D. edulis were there significant differences between the Cameroon populations. On the basis of the results of this study, D. edulis can be said to be virtually wild in Nigeria but semi-domesticated in Cameroon, while I. gabonensis is wild in Cameroon and semi-domesticated in Nigeria. These results are discussed with regard to a hypothesis that the range and frequency of variation in the different populations can be used to identify five stages of domestication. From a comparison of the frequency distribution curves of desirable versus undesirable traits, and statistically identifyable changes in skewness and kurtosis, it is concluded that as a result of the farmers’ own efforts by truncated selection, D. edulis is between Stages 2 and 3 of domestication (with a 67% relative gain in flesh depth) in Cameroon, while I. gabonensis in Nigeria is at Stage 2 (with a 44% relative gain in flesh depth). In this study, genetic diversity seems to have been increased, and not reduced, by domestication.

Domestication potential of Marula (Sclerocarya birrea subsp caffra)in South Africa and Namibia: 1. Phenotypic variation in fruit traits

Studies of tree-to-tree variation in fruit traits are a pre-requisite for cultivar development. Fruits were collected from each of 63 marula (Sclerocarya birrea) trees in Bushbuckridge, South Africa and from 55 trees from the North Central Region of Namibia. The South African trees were in farmers fields, communal land and natural woodland, at three sites: Acornhoek road, Allandale/Green Valley and Andover/Wits Rural Facility. The Namibian trees were all from farmers fields in three areas: North east, North west and West. The fruits were partitioned into skin and flesh/juice to examine the extent of the variation found in different components of marula fruits from different trees. Namibian fruits were significantly larger than those from South Africa (26.7 vs 20.1 g), due to their greater pulp mass (22.2 vs 16.2 g), especially the flesh/juice component. In South African fruits, those from farmers fields were significantly larger in all components (Fruit mass = 23.6 vs 19.3 and 18.0 g in natural woodland and communal land respectively). In Namibia, mean fruit mass did not differ significantly across sites (25.5 − 27.0 g). However, within each sample there was highly significant and continuous variation between trees in the pulp (S Africa = 7.5 − 31.3 g; Namibia = 8.3 − 36.0 g) and flesh/juice mass (S Africa = 2.2 − 7.6g; Namibia = 3.8 − 22. 6g), indicating the potential for selection of trees producing superior products. The fruits of the Namibian trees were compared with the fruits from one superior tree (‘Namibian Wonder) with a mean fruit mass of 69.9 g The percentage frequency distribution of fruit mass from trees in farmers fields in South Africa was skewed, while being bimodal in North east and North west populations from Namibia, suggesting that at these sites farmers are engaged in domestication through truncated selection of the best mother trees. It is concluded that there are trees in on-farm populations that have great potential to be propagated vegetatively as selected cultivars.

Improving livelihoods and nutrition in sub-saharan africa through the promotion of indigenous and exotic fruit production in smallholders' agroforestry systems: A review

SUMMARY The cultivation of indigenous and exotic fruits for sub-Saharan Africas domestic markets can bring increased revenues for smallholders and improve the diets of local consumers. There are, however, many bottlenecks which need to be addressed so that wider benefits from such activities are realised. Here, we describe key interventions being taken to address current constraints. For indigenous fruit trees, it is necessary to set priorities for which species to promote and to engage in participatory domestication for the improvement of yield, quality and germplasm delivery to farmers. For exotic fruits, ‘south-south’ transfer of advanced cultivars and the development of small-scale commercial suppliers of planting material are required to reinvigorate production. For both indigenous and exotic species, a focus on improving market value chains to bring greater benefits to producers is needed. We describe where further work is required to increase efficiency in the sector and to favour smallholder involvement.