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Grafting scions of trees with desirable features is an important step for the domestication of indigenous forest fruit trees. Two experiments were carried out in the World Agroforestry (ICRAF) expe...

Aims: Cancer is the second leading cause of death globally. Therefore, the knowledge on medicinal plants used to cure human cancer could be of great importance for their widespread use and scientific validation. The present study records information on anticancer plants in Boyo Division, in the western highland of Cameroon. Methods: Thirty traditional healers, were interviewed to document their know-how on the type of human cancer allegedly cured, the plant species used as well as their use pattern. Guided field walks were made to the collection sites for plant and its habitat characterization as well as herbarium voucher collection. Ethnobotanical quantitative tools were used to analyze and summarize collected data. Sustainability of harvest was assessed using a vulnerability index based on seven parameters. Results: A total of 25 medicinal plants cited were identified as belonging to 13 families and 23 genera. The most represented families were Asteraceae (28%), Lamiaceae (16%), Fabaceae (12%) and Acanthaceae (8%). Out of the seven categories of cancer diseases reported, the highest number of plants species were reported to treat stomach, pancreas, liver, skin and breast cancers, with informant consensus factor (ICF) ranging from 0.79 to 0.82. Leaves (60%) and bark (20%) were the major plant parts used mostly in form of decoction (45.45%) and concoction (38.18%). The result of Relative frequency citations (RFCs) revealed that 9 of the 25 plants species cited were the most frequently used with fidelity levels ranging from 92% (Geniosporum rotundifolium and Ocimum tenuiflorum Aframomum melegueta and Entada abyssinica) to 100% (Coleus blumei, Ocimum gratissimum, Eremomastax speciosa, and Dichrocephala integrifolia). Six species were assessed as vulnerable (Vi ≥ 2), while two species were rated as highly vulnerable namely G. rotundifolium (Vi = 2.71) and E. abyssinica (Vi = 2.85). Conclusion: New traditionally effective anticancer plants were identified in the present study, some of which were already vulnerable for exploitation in their actual habitat. Plants with high ICF, RFCs and FL values should be subjected to further phytochemical and pharmacological investigations for scientific validation while those with high Vulnerability index should be recommended for participatory domestication by the main users.

Vitellaria paradoxa (C.F.Gaertn.) is a multi-purpose tree species distributed in a narrow band across sub-Saharan Africa. The species is integrated into cropping and agroforestry systems as a nutritional and economic resource, which provides a range of environmental services. Integration of the species into land-use systems provides an essential source of livelihoods and income for local populations. The economic potential of the shea butter tree derives from its edible products, which also serve cosmetic and pharmaceutical applications. To understand the current state of knowledge about V. paradoxa, this paper summarizes information about the ecology, population structure, and genetic diversity of the species, also considering compositional variation in the pulp and kernels, management practices, and efforts towards its domestication. Despite the great potential of the shea butter tree, there are some gaps in the understanding of the genetics of the species. This review presents up-to-date information related to the species for further domestication and breeding purposes.

Garcinia kola Heckel (Clusiaceae), known as bitter kola, is a multipurpose tree indigenous to West and Central Africa. This highly preferred species is called “wonder plant„ because all of its parts can be used as medicine. Its seeds, the most valued product of the tree, are commonly eaten to prevent/cure gastric disorders and for their typical astringent taste. There is a vast evidence that bioactive components of the seeds can serve as alternative medicine to treat/prevent severe illnesses such as malaria, hepatitis and immune-destructive diseases. Despite the species’ pharmaceutical potential and its high preference by West and Central African communities, G. kola is still at the beginning of its domestication process. Even though, there are numerous scientific articles published on species‘ biological activities, it is a difficult task to find basic information on its diversity, distribution, genetics, silvicultural management or botany. Therefore, in this very first review published on G. kola, we summarize all relevant information known about the species, target some of the challenges connected with its cultivation and propose a leading direction for future research and domestication process.

A study was carried out to assess the growth, flowering and fruiting of stecklings (rooted cuttings), grafts and seedlings of Allanblackia floribunda in Cameroun. Thirty-one individuals of each plantlet type were planted in May 2006. Height, collar and crown diameters were recorded in September and October, while flowering and fruiting were recorded each month from January to December. In 2014, the trees with the greatest height were those from seeds (6.98 ± 0.25 m), followed by those from grafts (1.65 ± 0.23 m) and cuttings (1.09 ± 0.21 m). Grafts started flowering and fruiting 3 years after planting, while seedlings started flowering and fruiting after four and 6 years, respectively. Stecklings still had not flowered 8 years after planting. Fruit weight and length from seed-origin trees are about seven times higher than grafts. Correlations between height and crown diameter were significant and positive irrespective of the nature of the planting material. In conclusion, grafts fruited earlier, while seedlings grew faster and had greater yields than grafts and stecklings of A. floribunda.

Cameroon introduced community forestry (CF) in 1994 as a means of improving community engagement in forest management, enhancing forest conservation, and reducing poverty for forest-dependent people. More than 20 years on, reflection on uptake, conceptual evolution, and innovation is necessary to understand how best community forests can contribute to Cameroon's post-2015 sustainable development goals. We investigate, review, and reflect on how community forestry has evolved from an innovation ecosystem perspective, with a view to enhancing innovations and performance. Interest and momentum in community forestry remains strong in Cameroon, with the number of community forests growing, reaching 430 and covering 1.7 million ha (7% of total forest area). Major innovations identified are the introduction of pre-emption rights and steps toward sustainable forest management (ban on industrial logging, development of certification standards, and the introduction of the environmental notice in lieu of a full environmental impact assessment for CF activities). Little or no innovation is registered in areas related to forest enterprise (i.e., products and services value chains) and in terms of practicing sustainable forest management. Evidence suggests that knowledge generated directly feeds innovation. Coincidentally, areas for which little progress was made (enterprise and sustainable practices) also recorded few publications, suggesting that partnerships aimed at improving knowledge generation and sharing could help catalyze innovation. Other options for unlocking innovations within community forestry discussed include: enhancing intercommunity forest and private sector community forests partnerships and collaboration, increased capacity development and capital investments, and deploying incentives (financial and nonfinancial). Together these options can potentially transform community forestry in Cameroon.

The conversion of forests to other forms of land use has profound effects on the distribution and supply of soil nutrients. Understanding the effects of land use on soil is essential for addressing agroecosystem transformation and sustainable land productivity. Although soil carbon stock has been previously examined in the humid forest zone of Cameroon, the dynamic and interactions between other soil chemical properties has been poorly addressed to date. The present study used the quadrat approach to assess the effect of four land use types (secondary forest, fallow, cocoa plantation and mixed cropping) on soil chemical properties. Soil samples were collected at two different depths (0–10, 10–30 cm) in all land use types and analyzed for pH, total carbon, soil organic carbon, total nitrogen, cation exchange capacity (CEC), calcium (Ca), potassium (K), magnesium (Mg) and boron (B). Land use type significantly affected B, Ca, K and pH: in general, these properties were higher in cocoa plantation and mixed cropping than in secondary forest and fallow. All soil properties were significantly greater in the upper than in the lower soil depth. In addition, all soil properties differed significantly among sites and villages within sites. Pearson correlations between soil chemical properties were positive and generally significant in the four land use types, except for some correlations with B, pH and CEC. Despite the fact that some of the fundamental soil chemical properties (carbon, nitrogen, CEC and Mg) did not differ among the four land use types, high density tree-based production systems are recommended for the storage of these elements in the soils.

Our study addressed the effect of granular NPK 20-10-10 doses (0, 25 and 50 g/plant) applied to A. floribunda stockplants on growth of stockplant and the effect on rooting ability of foliar NPKs (15-15-30, 20-20-20 and 30-10-10) applied on leafy stem cuttings in propagators at different physiological stages of rooting process (setting, callus initiation and both). Results show that fertilizer doses significantly (p = 0.03) affect the number of cuttings that could be produced by stockplants 6 months after application. The mean number of cuttings per plant increased with fertilizer doses with the highest value of 11.06 ± 0.41 % for 50 g. Application of NPK 20-20-20 foliar fertilizer on stem cuttings at callus stage, significantly (p = 0.04) boosted rooting of stem cuttings after 28 weeks (85.71 ± 4.1 %). Number of roots per cutting was not significantly different (p = 0.98). However, the highest frequency of cuttings displayed three roots was observed on NPK 20-20-20 (To + Cal) and NPK 30-10-10 (To + Cal). From this study, we can conclude that, 50 g of NPK 20-10-10 fertilizer application on stockplants produced the greatest number of vegetal material. Treated with NPK 20-20-20 at callus initiation stage or both (i.e. at setting and at callus initiation stage), rooting performs better.

Garcinia lucida Vesque (Clusiaceae) is a tree species that is highly valued for its medicinal properties by rural households in the humid forest zone of Cameroon. However, the unsustainable exploitation of the species threatens its long-term regeneration. This study focuses on its vegetative propagation via stem cuttings in non-mist propagators and through grafting. The study tests the effects of three rooting media (sand, sawdust, sand + sawdust (1/1); three leaf sizes (0,25 and 50 cm2); and three types of hormone [indole butyric acid (IBA), indole-3-acetic acid (IAA) and naphthalene acetic acid (NAA)], applied as a single dose. Furthermore, three grafting techniques (cleft, side tongue and whip-and-tongue grafting) were tested. All experiments were designed as completely randomized blocks with three replicates. Results showed that cuttings require a medium that has low water holding capacity and high porosity, and a leaf area of 50 cm2 and NAA treatment; grafting success was affected by the technique used, with top cleft grafting yielding a 100% success rate. From this preliminary study, it is concluded that G. lucida is amenable to vegetative propagation by cuttings and grafting. Key words: tree domestication, leaf area, non-mist propagator, rooting hormone, rooting medium, under-utilised species

Garcinia lucida Vesque (Clusiaceae) is a tree species that is highly valued for its medicinal properties by rural households in the humid forest zone of Cameroon. However, the unsustainable exploitation of the species threatens its long-term regeneration. This study focuses on its vegetative propagation via stem cuttings in non-mist propagators and through grafting. The study tests the effects of three rooting media (sand, sawdust, sand + sawdust (1/1); three leaf sizes (0,25 and 50 cm2); and three types of hormone [indole butyric acid (IBA), indole-3-acetic acid (IAA) and naphthalene acetic acid (NAA)], applied as a single dose. Furthermore, three grafting techniques (cleft, side tongue and whip-and-tongue grafting) were tested. All experiments were designed as completely randomized blocks with three replicates. Results showed that cuttings require a medium that has low water holding capacity and high porosity, and a leaf area of 50 cm2 and NAA treatment; grafting success was affected by the technique used, with top cleft grafting yielding a 100% success rate. From this preliminary study, it is concluded that G. lucida is amenable to vegetative propagation by cuttings and grafting.

Gnetum africanum Welw. (Gnetaceae) is a forest vine that is highly valued for its leaves which are a source of food and income. Because wild populations are threatened by over-harvesting, there is an increasing need to cultivate the plant, which in turn entails a need for developing good quality planting material. This study investigates the effects of four provenances, four substrates and their interactions on rooting and shoot development of vine cuttings of G. africanum using the non-mist propagation system developed by ICRAF. Single-node, half-leafed vine cuttings were used and data on rooting and leaf production were collected monthly from the second to the fifth months. Rooting percentages were subjected to analysis of variance using logistic regression procedures in Genstat version 12. Provenance (P

The reducing emissions from deforestation and forest degradation (REDD+) initiative has emerged in recent years as a mechanism to simultaneously address climate change, biodiversity, and poverty re...

In developing countries seedlings are often produced in small-scale nurseries as a means to raise tree planting materials and, provided they are of high quality, these can form the basis for successful forest plantation initiatives. This study uses morphological characteristics to assess the quality of seedlings of three tree species (Persea americana, Cola acuminata and Dacryodes edulis) in the Western Highlands of Cameroon. The growth characteristics and quality indicators of seedlings produced in two nursery categories were compared—three nurseries collaborating with the tree domestication program implemented by the World Agroforestry Centre (Category 1) and three nurseries collaborating with government and non-governmental projects (Category 2). Seedlings produced in nurseries in the first nursery category were found to be uniform in terms of growth characteristics and quality indicators. In the second category, there were relatively higher seedling proportions having measured parameters out of threshold standards for root to shoot ratio and for sturdiness quotient. Significant differences between nursery categories (at α = 0.05) were detected in root collar diameter of C. acuminata and D. edulis and in shoot dry weight of D. edulis. These differences could be attributed to better nursery management as a results of training and technical backstopping received by nursery operators in Category 1. The level of experience of nursery operators in both categories was found to be insufficient and greater exposure to skills and knowledge could enhance the production of high quality seedlings.

To address the decline in crop productivity in the drylands of West Africa, many initiatives have focused on combating soil degradation. Various practices including (1) parkland trees associated with crops, (2) coppicing trees, (3) green manure, (4) mulching, (5) crop rotation and intercropping, and (6) traditional soil/water conservation have been tested. The present study attempts to provide a comprehensive, quantitative synthesis of existing reports on the effect of conservation agriculture (CA) practices on crop yield response in Burkina Faso, Mali, Niger and Senegal. Out of a total of 155 reports found, 63 fulfilled all the appropriate criteria to be included in the meta-analysis of the effect of various conservation agriculture practices on the yield response of maize, millet and sorghum. The study revealed significant variability in cereal yield response (and hence risk) with all the practices examined. Despite the variability, the mean effects of the six CA practices on crop yield were more positive than negative except with parkland trees. However, for this last practice, species like Faidherbia albida exerts more positive impact on crop yield. Yield increases relative to the control were higher with green manure and mulching than with coppicing trees and parklands. Increases in yield in the six CA practices were higher on low to medium productivity sites for maize, millet and sorghum. Coppicing trees and rotations improved yields when the rainfall is >800 mm whereas the opposite happens with parkland and soil–water conservation measures. Mulching performed better when the rainfall is

†SUMMARY The cultivation of indigenous and exotic fruits for sub-Saharan Africa’s 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.

Modern agriculture has deprived local communities in the tropics of their natural life-support system—the forest resource and the traditional knowledge about indigenous species—and this has not been replaced by employment opportunities or social services. This project in the west and northwest regions of Cameroon takes an innovative three-step approach to improving the lives of local people by establishing rural resource centres (RRCs) to: (i) Rehabilitate degraded land and promote food security through the use of nitrogen-fixing trees to restore crop yields and then the diversification of the farming system with new crops; (ii) Create income generation opportunities from village tree nurseries and the domestication of indigenous fruits and nuts for local and regional trade. Income is rising annually and currently averages $150, $16,000 and $21,000 per RRC after 2, 5 and 10 years, respectively; (iii) Encourage the processing and marketing of food crops and tree products in order to create employment and entrepreneurial opportunities for community members. Income is currently $2400 per enterprise. The project's philosophy is one of helping smallholder farming communities to help themselves: first to become self-sufficient and economically independent, and then to be a hub for the dissemination of knowledge and skills to neighbouring communities.

Research on participatory domestication of indigenous trees in West and Central Africa started in 1996 with the objectives of increasing incomes of rural communities and improving their livelihoods by cultivating indigenous trees and developing strategies for marketing the produce. Though the study was conducted in Democratic Republic of Congo, Equatorial Guinea, Gabon, Nigeria, the present paper only presents data from Cameroon. In Cameroon, the original pilot nurseries have subsequently developed and grown to become Rural Resource Centres providing training in a wide range of skills as well as being the focal points for the diffusion of innovations. Some 200 village nurseries are now active and have become on-farm enterprises producing planting material both for local use and for marketing. Over the years, rural communities have increasingly reported improvements in their livelihoods, diet, health, income generation which have transformed their lives and given them encouragement for a better future. Livelihood surveys conducted in 2008 involved 298 farmers from 15 communities. Interestingly, one of the impacts has been that some young people have chosen to stay in their villages rather than to seek offfarm employment in local towns. Since 2008, tree domestication in Cameroon has also been integrated in a wider rural development programme in the West and North-West Regions, based on the concepts of multifunctional agriculture. This integrated approach to meeting the needs of poor rural communities is further empowering smallholder farmers to develop superior cultivars of indigenous fruits and nut trees and to produce planting stock of leguminous trees and shrubs for soil fertility replenishment. It has also encouraged entrepreneurism in the processing of agricultural products as well as tree products, and stimulated the development of markets for agroforestry tree products. Currently, over 6000 farmers from around 300 communities are engaged in this integrated rural development programme. This has been achieved by enhancing the capacity of technicians from NGOs, extension services and community-based organizations in the skills needed for tree domestication, agroforestry and value-addition at the community level.

Agricultural intensification has been recognized as one of the solutions to increase food production to feed the ever-increasing population in sub-Saharan Africa. This can partly be achieved if quantitative and up-to-date information on soil health indicators are not available. This study used the land health surveillance framework, which combines ground-sampling schemes based on sentinel site and infrared spectroscopy to select a minimum dataset of soil health indicators to identify key land constraints for maize production and target potential interventions. We found high variability in soil properties in the study area which was mainly due to inherent soil conditions and land management practices. The most variable soil properties (CV > 0.38) were nitrogen (N), electric conductivity (ECd), exchangeable bases (ExBas), boron (B), calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn) and phosphorus (P). Moderate variability (0.2 < CV < 0.38) was observed for carbon (C), silt and sand, while properties with least variability (CV < 0.2) were pH and aluminium (Al). The effects of land-use and soil depth were significant (p < 0.05) for most of the soil properties. Principal component analysis (PCA) identified soil nutrient availability, metal concentration and texture as the three main factors that explain most of the variability observed. Significant interactions were observed between soil properties confirming the need for a minimum dataset of indicators. ExBas, B, pH, Mn, ECd, P and clay content formed the minimum dataset of soil health indicators for the study area. The results also showed that the soils of the study site are marginally suitable for the production of maize (Zea mays L.). Low limitations with respect to exchangeable bases (Ca, Mg, K and Na) and severe limitations with respect to B (63%) were detected. However, potential for improvement exists through integrated soil management practices that include the use of organic and inorganic fertilizers, minimum soil tillage, and inclusion of legumes in crop rotations that could improve soil physical and chemical properties. © 2015 Elsevier B.V.

The contribution that domesticated indigenous fruit trees make to many farmers' livelihoods is often not acknowledged in either national- or international-level poverty reduction strategies. Current agricultural data tend to be restricted to a narrow range of exotic fruit (e.g. mango, avocado, citrus). Existing data on indigenous fruit are often not presented in the kinds of income-related terms used in the policy debate, nor are they linked to simple policy recommendations. Drawing predominantly on the examples of Dacryodes edulis and lrvingia gabonensis in Cameroon and Nigeria, this paper presents evidence for the contribution of these fruit trees to poverty reduction. Evidence on the numbers and types of people obtaining an income from indigenous fruit trees, the proportion and value of that income and whether the income acts as a safety-net or can help to move people out of poverty, is presented. Non-income related impacts on health and the environment are also discussed. Finally, key policy ...

The World Agroforestry Centre (ICRAF) has been working in the African Humid Tropics (AHT) since 1987. Despite its natural wealth, small-scale farmers of AHT are among the poorest people in the world and have relied on extractive harvesting of forest products and traditional shifting cultivation for their food and other needs. After years of severe deforestation, alternatives now have to be found as land pressure has increased and commodity prices of cash crops have declined. To overcome these problems, the Participatory Domestication of high-value indigenous fruit, nut and medicinal trees is seen as one way of empowering rural households to improve their own situation. Many products of indigenous trees have existing local and regional markets, with additional potential niches in international commerce. In Participatory Domestication, villagers are helped to develop local nurseries, taught skills of vegetative propagation, and assisted with the technical implementation of selecting superior trees ...

Dika nut kernels were extracted from the nuts of 24 Irvingia gabonensis fruits collected from 151 trees in three villages in Cameroon and Nigeria. Methods were developed for the milling, de-fatting, hot-water pasting and rapid visco-analysis of the samples, to simulate the cooking of dika nut meal as a food-thickening agent. Two parameters (viscosity and drawability), thought to relate to the soup-thickening quality of dika nut meal, were derived from the traces. The samples exhibited significant tree-to-tree variation in viscosity, drawability and fat content, and differences between their villages of origin were significant. Thickening was found not to be directly associated with protein content. Similarly, the fat content did not contribute to the thickening properties at temperatures above fat melting point. Fat determination and fatty acid profiling indicated that the fat content ranged from 37.5% to 75.5% and identified myristic and lauric acids as the major fatty acid components. This study is part of a wider tree domestication project characterising tree-to-tree variation in fruit, nut and kernel traits of I. gabonensis with the aim of improving the livelihoods of subsistence farmers.

A participatory approach to tree domestication is being pioneered by ICRAF and international partners in Cameroon and Nigeria. The domestication of Dacryodes edulis offers opportunities to improve the livelihoods of subsistence farmers and to diversify farming systems, such as cocoa farms. The trees produce marketable fruits as well as shade for cocoa and coffee. Twenty-four ripe fruits were collected from each of 100 D. edulis trees in Mgbuisi, southeast Nigeria by subsistence farmers. There was continuous and significant tree-to-tree variation in fruit mass (10.2±0.5–71.4±1.3 g), flesh mass (6.8±0.3– 62.2±1.2 g) and kernel mass (1.3±0.5–15.1±0.4 g). Mean fruit mass did not differ significantly between different land uses. Flesh mass:kernel mass ratio varied from 0.79 to 29.0. Two trees had fruits without kernels. There was also continuous and significant tree-to-tree variation in fruit length (39.0±0.6– 95.1±1.2 mm), fruit width (21.82±0.16–43.75±0.33 mm) and flesh thickness (1.82±0.1–6.39± 0.1 mm). Fruit length:width ratio varied from 1.35 to 3.18. Cooked fruits varied in taste with only 14% of trees getting the highest score. Similarly, fruits varied in oiliness with only 3% of trees getting the highest score. Thirteen skin colours were recorded, with the most common being dark blue (31%), greyish violet (29%) and deep blue (9%). Ninety-nine percent of the trees had been planted, with 57% in homegardens, 22% in crop fields, 17% in fallow land and 4% in cocoa. Tree height ranged from 4 to 22m, and DBH from 9.55 to 63.65 cm. Tree age ranged from 5 to 64 years. Farmers reported first fruiting from age 3 up to 22 years (average of 9.4 years). Most trees originated from seeds bought in markets (63%). Market prices of fruits from different trees, ranged from 2 to 12 fruits for 10 Naira (US0.07). These quantitative results will help in the identification of elite trees of D. edulis for cultivar development through clonal propagation.

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 ...

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.

Pausinystalia johimbe (K. Schum), a tree of the Central Africa humid lowlands, is exploited for its bark to supply both export and local medicinal plant markets. The gradual destruction of the forests in which Yohimbe grows coupled with unsustainable bark harvesting methods, has resulted in local scarcity of this tree species. The study examined the amenability of P. johimbe to vegetative propagation through the rooting of leafy stem cuttings using low-cost technology polythene propagators. Using single-node leafy cuttings, three experiments were investigated in Cameroon: (i) Three propagation media (sawdust and 50:50 mixture of sand and sawdust). Initially, rooting was best in the mixed medium, but subsequently, cuttings set in the sawdust rooted better than those in sand and the mixture of sand/sawdust. However, there was no significant ( P >0.05) treatment effect on rooting percentage or on the mean number of roots per cutting. (ii) Three types of auxin at 50 μg per cutting (IAA, indole-3-acetic acid; IBA, indole-3-butyric acid and NAA, 1-naphthalene acetic acid) dissolved in 10 μl of alcohol. The control treatment received 10 μl of alcohol only. Significant differences in rooting percentage occurred after 3–4 weeks between the auxin-treated cuttings and the control. Within the same period IBA-treated cuttings rooted better than those with NAA and IBA. (iii) Four leaf areas: 0, 50, 100 and 200 cm 2 . Leafy cuttings rooted better than leafless cuttings after 4–5 weeks, with 50 cm 2 leaf area being the best from week 6. Significantly higher cutting mortality ( P P. johimbe is amenable to vegetative propagation technique using juvenile single-node leafy cuttings.

This study obtained quantitative data on fruit and nut traits from two indigenous fruit trees in West Africa (Irvingia gabonensis and Dacryodes edulis), which have led to the identification of trees meeting ideotypes based on multiple morphological, quality and food property traits desirable in putative cultivars. The same data also indicates changes in population structure that provide pointers to the level of domestication already achieved by subsistence farmers. D. edulis represents 21-57% of all fruit trees in farmers' fields and plays an important part in the economy of rural communities. An investigation of the socio-economic and biophysical constraints to indigenous tree cultivation found that indigenous fruits could play an even greater role in the rural economy of West and Central Africa. The opportunity to build on this through further domestication of these species is considerable, especially as retailers recognise customer preferences for certain D. edulis fruit traits, although at present the wholesale market does not. This project was linked to a larger participatory tree domestication programme within ICRAF's2 wider agroforestry programme with traditionally valuable indigenous trees. Together these projects provided insights into the value of domesticating indigenous fruit trees, which are of strategic importance to poverty alleviation and sustainable development worldwide.

New initiatives in agroforestry are seeking to integrate trees with marketable products into farming systems. This is being done in order to provide marketable timber and non-timber forest products from farms that will enhance rural livelihoods by generating cash for subsistence farmers. Dacryodes edulis (Safou) is one of the candidate tree species in West and Central Africa for domestication, which has commercial potential in local, regional or even international markets. This paper describes: (i) the characterisation of tree-to-tree variation in fruit traits and the opportunities for selecting D. edulis cultivars based on the intraspecific variation found in local populations in Cameroon and Nigeria, (ii) the identification of multi-trait ideotypes for potential cultivar development, (iii) the organoleptic attributes which are important traits for selection, and (iv) an assessment of the relationships between fruit mass and market prices in fruit samples from three markets, at the peak of season, in Cameroon.

The region of West and Central Africa is endowed with high-value fruit trees and medicinal plants, which are currently traded locally as well as on regional and international markets. Unfortunately, they are all exploited from the wild and there has been little or no focussed effort to domesticate and cultivate them. Prunus africana is one of these important medicinal plant under domestication. A series of nursery experiments were conducted to assess the effects of rooting medium (sawdust, sand and a 50:50 mixture of sand and sawdust), auxin concentration (0, 50, 100, 150, and 200 µg IBA), and leaf area (0, 5, 10, 20, and 25 cm2) on rooting success of juvenile cuttings of P. africana. The percentage of cuttings rooted was significantly greater (P < 0.05) in sawdust (80%), than in sand alone (72%) or in mixture with sawdust (71%). Leaf area also significantly affected the percentage of rooting. Leafless cuttings did not root and were all dead by week 6, but in leafy cuttings rooting ability increased proportionally with leaf area up to 20 cm2 (79%). Larger leaf cuttings (25 cm2) rooted at the same level as those of 20 cm2. The cuttings with the largest leaves also had the greatest mean number of roots per cutting (14 roots cutting−1), while those with the smallest (5 cm2) leaf area produced the fewest roots (5 roots cutting−1). The application of auxin (IBA) promoted rooting (P < 0.05) up to an optimum application of 100–200 µg IBA per cutting, but 300 µg was supraoptimal. It can be concluded that P. africana is amenable to vegetative propagation.

Ten fruit and kernel traits were assessed in 24 fruits of each of 152Irvingia gabonensis trees in three distinct populations in west and central Africa [2 populations of non-planted trees in Cameroon: Nko'ovos II (21 trees) and Elig-Nkouma (31 trees) and 1 population of planted trees in Nigeria: Ugwuaji (100 trees)]. Strong relationships were found between fruit weight and other fruit traits (e.g. flesh weight[r2 = 0.99: P < 0.001],fruit length [r2 = 0.74–0.83:P < 0.001], fruit width[r2 = 0.77–0.88: P< 0.001]). In contrast, relationships between kernel weight and other kernel/nut traits (e.g. shell weight and nut weight) were found to be weak[r2 = 0.009–0.37, P =0.058–0.001], with the exception of nut weight at Nko'ovos II(r2 = 0.65, P < 0.001).Relations hips between fruit and kernel traits (fruit massv. kernel mass, fruit mass v. shell mass, flesh mass v. kernel mass, nut massv. fruit mass and flesh depth v.kernel mass) were found to be very weak. This indicates that domestication through the selection and vegetative propagation of multiple-trait superior phenotypes is unlikely to be able to combine good fruit characteristics and good kernel characteristics within cultivars. Consequently, domestication activities should independently focus on ideotypes representing: 'fresh fruit' traits, and 'kernel' traits, that combine high values of the different fruit and kernel characteristics respectively. Evidence from this study indicates that selection of the three trees closest to the fruit ideotype per village as the mother plants for vegetative propagation and cultivar development, should give village level gains of 1.3 – 2-fold in fruit mass, and up to 1.5-fold in taste. Similarly for the kernel ideotype, selection of the three trees with the best fit would give potential gains in kernel mass of 1.4 – 1.6-fold.

Dacryodes edulis is one of the important local fruit tree species of West and Central Africa. This paper reviews the activities of a regional programme to domesticate high-value indigenous fruit trees in the region. This programme is coordinated by the International Centre for Research in Agroforestry (ICRAF) and implemented in Cameroon in collaboration with the Institute of Agricultural Research for Development (IRAD), National Agricultural Extension and Research Programme (PNVRA) agents and NGOs and universities of the region. It is based on a participatory approach to domestication that is in marked contrast to that of food crop domestication under the Green Revolution. The participatory process with farmers started with priority setting between species, progressed to germplasm collection and the establishment of village nurseries for clonal propagation of superior trees, and is currently involved in the selection of superior trees for cultivar development. Work is also in progress on post-harvest processing, market development and the integration of cultivars into agroforestry systems.

Dacryodes edulis (G. Don) H. J. Lam. (Burseraceae) is a high-value fruit tree in West and Central Africa. Air layering of this species is now under control, but uncertainty remains as to the effect of a number of factors on rooting; these include cloning the type of propagule, the orientation of branches and the position of the marcots in the crown. A series of experiments were conducted to evaluate the effect of cloning, the type of propagule (cuttings and marcots), position in the crown (lower and upper) and the orientation of branches (plagiotropic, oblic and orthotropic) on the tree ́s rooting ability. For the frst three factors, older clones of 10 years with a normal maturation were bedded in equal proportions of decomposed sawdust and arable soil. To test the orientation factor late maturing trees of over 20 years bedded in, decomposed sawdust were used. Ten months after the setting up of marcots, the results showed that the clonal effect significantly (p

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.

Twenty four fruits from each of 52 Irvingia gabonensis trees from two villages (Nko'ovos II and Elig Nkouma) of the humid lowland forest zone of Cameroon (West Africa) were assessed to determine the extent of variation in ten fruit, nut (endocarp), and kernel (cotyledon) characteristics. Highly significant differences were found in fruit length (Range = 46.2 to 77.3 mm), fruit width (45.1 to 72.5 mm), flesh (mesocarp) depth (11.2 to 21.8 mm), fruit mass (44.5 to 195.4 g), kernel mass (0.54 to 6.9 g) and shell mass (5.4 to 18.6 g). In each of these traits there was continuous variation. Differences were also observed in fruit taste and fibrosity. The most frequent skin and flesh color was yellow (Methuen Color Code 4A8). Mean fruit length, fruit width, fruit mass, shell mass and kernel mass differed significantly between villages, but did not differ between different landuses (homegardens, cocoa farms, crop fields or fallows). These results represent the first quantitative assessment of tree-to-tree variation in fruit traits for this species and are discussed with regard to the domestication potential of I. gabonensis.

Methods were developed to quantify variation in the fruit, nut and kernel traits using the fruits from four trees of Irvingia gabonensis, an indigenous fruit tree of west and central Africa. The measurement of 18 characteristics of 16–32 fruits per tree identified significant variation in fruit, nut and kernel size and weight, and flesh depth. Differences were also identified in shell weight and brittleness, fruit taste, fibrosity and flesh colour. Relationships between fruit size and weight with nut and kernel size and weight were found to be very weak, indicating that it is not possible to accurately predict the traits of the commercially-important kernel from fruit traits. Seven key qualitative traits are recommended for future assessments of the levels of genetic variation in fruits and kernels. These traits describe ideotypes for fresh fruit and kernel production.

Products and services provided by trees in forests and farmland support the needs and promote the wellbeing of hundreds of millions of people in the tropics. Value depends on managing both the diversity of tree species present in landscapes and the genetic variation within these species. The benefits from trees and their genetic resources are, however, often not well quantified because trade is frequently outside formal markets, there is a multiplicity of species and ways in which trees are used and managed, and genetic diversity within species is frequently not given proper consideration. We review here what is known about the value of trees to rural communities through considering three production categories: non-timber products harvested from trees in natural and managed forests and woodlands; the various products and services obtained from a wide range of trees planted and/or retained in smallholders' agroforestry systems; and the commercial products harvested from cultivated tree commodity crops. Where possible, we focus on the role of intra-specific genetic variation in providing support to livelihoods, and for each of the three production categories we also consider wider conservation and sustainability issues, including the linkages between categories in terms of management. Challenges to 'conventional wisdom' on tree resource use, value and management -such as in the posited links between commercialisation, cultivation and conservation -are highlighted, and constraints and opportunities to maintain and enhance value are described. © 2014 The Authors.

Applied auxin, node position, leaf area and cutting length were examined to investigate the requirements for rooting stem cuttings of Khaya ivorensis. All these variables were shown to be important factors affecting rooting, confirming the hypothesis that successful rooting can be achieved if these primary variables are optimised.

More than 420 research papers, involving more than 50 tree species, form the literature on agroforestry tree domestication since the 1992 conference that initiated the global programme. In the first decade, the global effort was strongly led by scientists working in humid West Africa; it was then expanded to the rest of Africa in the second decade, with additional growth in Latin America, Asia (mostly SE Asia) and Oceania. While the assessment of species potential and the development and dissemination of techniques for improved germplasm production were the principal activities in the first decade, the second decade was characterized by a growing research agenda that included characterization of genetic variation using morphological and molecular techniques, product commercialization, adoption and impact and protection of farmers’ rights. In parallel with this expanding research agenda, there was also an increasing use of laboratory techniques to quantify genetic variation of the chemical and physical composition of marketable products (e.g. essential oils, food-thickening agents, pharmaceutical and nutriceutical compounds, fuelwood). Looking to the third decade, suggestions are made for further development and expansion of both the science to underpin agroforestry tree domestication and applied research in support of development programmes to enhance the livelihoods of poor smallholder farmers worldwide.

3. Field pests of miombo fruit trees 5 3.1. Root-damaging pests 6 2.1.1. Fungal diseases 6 3.1.2. Insects 7 3.1.3. Plant parasitic nematodes 8 3.2. Trunk and leaf-damaging pests 9 2.2.1. Fungal diseases 9 3.2.2. Parasitic higher plants 12 3.2.3. Mites and insects 12 3.2.4. Mammals 14 3.3. Flower and fruit damaging pests 15 3.3.1. Bacterial and fungal diseases 15 3.3.2. Mites and insects 15 3.3.3. Birds and Mammals 18