Domesticating and Commercialisation of Indigenous Fruit and Nut Tree Crops for Food Security and Income Generation in the Kingdom of Eswatini

Current Journal of Applied Science and Technology

39(16): 37-52, 2020; Article no.CJAST.57709 ISSN: 2457-1024 (Past name: British Journal of Applied Science & Technology, Past ISSN: 2231-0843, NLM ID: 101664541)

Emmanuel N. Kunene1*, Kwanele A. Nxumalo2, Menzi P. Ngwenya1 and Michael T. Masarirambi2

1Eswatini Institute for Research in Traditional Medicine, Medicinal and Indigenous Food Plants (EIRMIP), University of Eswatini, Private Bag 4 Kwaluseni, Eswatini. 2Department of Horticulture, Faculty of Agriculture, University of Eswatini, P.O. Luyengo, Luyengo M201, Eswatini.

Authors’ contributions

This work was carried out in collaboration among all authors. Author ENK compiled the final manuscript and provided literature on domesticating indigenous fruit and nut trees. Author KAN developed the introduction and abstract. Author MPN compiled literature on commercialisation prospects of indigenous fruits and nuts. Author MTM provided literature on both domesticating and commercialisation of indigenous fruit and nut trees. All authors read and approved the final manuscript.

Article Information

DOI: 10.9734/CJAST/2020/v39i1630733 Editor(s): (1) Dr. Hamid El Bilali, University of Natural Resources and Life Sciences, Austria. Reviewers: (1) Anwaar Mohyuddin, Quaid i Azam University, Pakistan. (2) Neetu Sharma, Graphic Era Deemed to be University, India. Complete Peer review History: http://www.sdiarticle4.com/review-history/57709

Received 01 April 2020 Review Article Accepted 06 June 2020 Published 24 June 2020

ABSTRACT

Indigenous fruit and nut tree crops are very important to the human diet and subsequent food security and income generation in the Kingdom of Eswatini. Indigenous fruits and nuts are important for the nutritional contribution as sources of Vitamins and minerals. They also provide fibre which is essential for proper digestion of food. Fruits, particularly nuts provide man with unsaturated fats which are good for the heat and the cardio vascular system. Indigenous fruits and nuts are aesthetic as they provide interesting colour, texture and variety. Despite the immense benefits of indigenous fruits and nuts to the people of the Kingdom of Eswatini, there has not been enough effort put towards domesticating the indigenous fruit and nut trees and subsequent commercialising their ______

*Corresponding author: E-mail: [email protected];

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products. The objective of this paper was to document strategies towards domestication and commercialisation of indigenous fruits and nuts for improved livelihoods of Emaswati citizens, which in turn will help achieve sustainable development goals (SDGs) pertaining to human health and food security in the Kingdom of Eswatini. It can be concluded that domesticating indigenous fruit and nut trees can be achieved through a multi-stakeholder involvement. Domestication can also help in conservation of indigenous fruit and nut trees. Value addition on indigenous fruits and nuts can generate more income.

Keywords: Biodiversity; food security; value addition; conservation; propagation; intellectual property rights; sustainable development goals.

1. INTRODUCTION fruit and nuts can make a difference during period of famine and food scarcity, and are not The problem of food security especially in prone to issues of climate change [5,8]. Value- resource-poor third world countries has recently addition of fruit and nut either from the wild or been complicated by climate change, poverty semi-domesticated trees growing on-farm and and threats to biodiversity. Indigenous fruits and homesteads, can have a substantially boost in vegetables have been serving in-situ soil rural income and employment opportunities in conservation due to their adaptation to the rural communities [6,10]. Market and financial natural ecosystem. Considerable efforts have analyses studies done in southern Africa show been taken towards conservation and that indigenous fruits contribute to household management of indigenous plants by the income, and the major beneficiaries are women Eswatini government and relevant stakeholders and children through value addition and fruit such as Eswatini National Trust Commission processing [11,12]. (ENTC) [1]. Wild fruit trees have become severely prone to The Swaziland Flora Protection Act of 2000 was over-exploitation and extinction as forests recede established by the government of Eswatini to due to deforestation, and most Africans are using provide legal protection of certain species and them for their medicinal purposes without special habitats. There are also in-situ replacing the cut trees [15]. Regardless of their conservation measures which involve the importance as fruit crops and for their medicinal establishment of protected areas such as game purposes, little research and development and nature reserves. The Ministry of Agriculture attention has been given to the development of runs a gene bank which preserves plant genetic indigenous trees as tree crops for wider resources mostly of crops and their relatives [2]. cultivation. Domestication of indigenous fruit Eswatini supports a large variety of landscapes, trees, emerged as a farmer-driven and market- geology, climate, and corresponding habitat and led process, has become an important biodiversity. With her divergent geology, climate, agroforestry initiative in the tropics [6,13-15]. and subsequent landforms, the physiographic regions within the country’s boundaries are very There is increased interest among researchers, distinct, thus a variety of indigenous fruit and nut development practitioners and the food trees found in the four agro-ecological zones [1]. processing industry to explore opportunities to meet the food needs of humanity through The Sub-Saharan African region is rich with a indigenous fruit trees. More emphasis is put on variety of indigenous fruits which provide a promoting indigenous plants with economic variety of uses and benefits to the population potential as new cash crops, and for product [3,4]. Research on indigenous fruit and nuts has development in the Kingdom of Eswatini. Hence, accumulated considerably in Sub-Saharan this review paper explores the prospects of African countries including Eswatini, and their commercialising and domesticating some role are being recognized in the domain of indigenous fruit and nut tree crops for food poverty reduction. An ex ante impact analysis in security, and income generation in the Kingdom southern Africa indicated that indigenous fruit of Eswatini. can reduce vulnerability of rural households to overcome poverty [5]. Harvesting and utilisation 2. METHODOLOGY of indigenous fruit and nuts have played a pivotal role in the livelihoods of African communities The study was carried out in the Kingdom of especially those in rural areas [6-10]. Indigenous Eswatini in southern Africa. The Kingdom of

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Eswatini covers an area of about 17,364 km2, This was a qualitative study. Information was and lies between latitudes 25o43’ N and 27o 19’ obtained through literature review and S, longitudes 30o47’ W and 32o08’ E [16,17]. The informal surveys in the four agro- Kingdom of Eswatini is comprised of four agro- ecological zones of Eswatini. Local ecological zones which are the Highveld, indigenous knowledge systems (links) were Middleveld, Lowveld and Lubombo region utilised. (Fig. 1).

Fig. 1. Ecological zones of the Kingdom of Eswatini

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3. POTENTIAL AREAS FOR Fermentation has a good potential to add value COMMERCIALISING INDIGENOUS to the underutilised indigenous fruits in Eswatini. FRUIT AND NUT TREES 3.2 Jams and Jellies from Fruits

In Eswatini, indigenous fruits are mostly enjoyed The amount of acid, pectin, sugar in the form of during the summer and autumn seasons when sucrose and moisture in a fruit are determinants they occur in abundance. These fruits are mostly for their suitability for jam and jelly making consumed raw, and occasionally sold in informal [27,28,24]. Ascorbic acid imparts a brighter local markets. Some of these fruits are colour in the jelly [33,34], and colour is one of the processed into value-added products at small- attributes that affect the quality of jam [35]. scale subsistence level for economic gain Pectin is a plant cell-wall polysaccharide [18,19]. Adding value to indigenous fruits, either consisting of a linear chain composed of D- harvested from the wild or from the semi- galacturonic acid residues linked via a (1-4)- domesticated trees, through processing has glycosidic bonds [35,36,37]. It has a number of been appreciated to make an economic impact uses in the food industry which include [20]. The indigenous fruits hold a great potential thickening agent, a gelling agent, colloidal in the development of new food products that will stabilizer and imparting texture [38,39]. The increase the food base, locally and internationally pectin immobilises the aqueous component by [21]. Some indigenous fruits have been preventing it from separating, thereby providing a technologically exploited into development of stable matrix [36]. The addition of sugar in jelly commercial products that include, sweets, fruit making increases the gel strength and reduces juices, jams, jellies, chutneys, vinegars, wines, syneresis [36]. The acidity in the fruits helps the liqueurs, novel flavours and gums [17,18]. It is pectin to set and create a stable gel. Indigenous from this knowledge base that science and fruits with the previous characteristics need technology can explore ways to improve the further studying so that they are properly production, domestication and commercialisation exploited for commercialisation and industrial use of these plants. [40]. Some of these fruits are already used for such products and may need improvement. 3.1 Fermentation of Indigenous Fruits 3.3 Other Uses A number of fruits that are available and consumed in Eswatini are widely processed by Most fruits have flavour characteristics that make fermentation. Fermentation is basically a process them attractive to consumers. Flavour in fruits where micro-organisms catabolise organic develops during the ripening where compounds to produce mass culture, enzymes, carbohydrates, lipids, proteins and amino acids metabolites or new products [22,23]. are converted to volatile flavours [41]. Flavour in Fermentation is an old economic processing fruits can be grouped into acids, carbonyls, technology that improves the quality of the fruits esters, lactones and phenols. Fruit flavours may either by prolonging its shelf life or its nutritional also be derived from esters and other volatile and sensory characteristics [23,24,25,26]. compounds in the fruits [21]. Consumers have Normally, the fermentation is spontaneous, developed a trend to prefer natural and naturally making use of indigenous and natural microflora produced food as a health concern, which has found in the surrounding environment and the directed more research to that area [42]. fruits themselves. This theory holds a possibility Therefore, some unique and new flavours can be of discovering new and unique strains of discovered from our indigenous fruits and nuts. microorganisms [27,28] which may be useful in the food and pharmaceutical industries. In the Dried fruits are consumed as snacks or added to food industry, fermentation technology has been porridges for flavour [43]. Drying is a traditional used with various foods as substrates to develop method of preserving food by reducing the water other food products and food ingredients content and water activity. The dried fruits can be [23,24,25]. Commonly used microorganisms in eaten as they are, or pounded into a powder. the food industry are fungus and lactic acid Dried fruits can also be used to add nutritious bacteria. Some strains of lactic acid bacteria and organoleptic value to snacks and other foods such as the Leuconostoc mesenteroides 12b [42,43]. When the fruits are dry, they can be kept have the ability to increase the antioxidant at ambient temperatures in dry, dark areas to activity of the fermented fruit or juice, [29-32]. extend the shelf life. They also become easy to

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handle when taken to trading areas such as 4.2 Black monkey orange (Strychnos markets [44-46]. Nutrient preserving techniques madagascariensis) – (SiSwati name: and packaging materials can be applied to make Umhlala) and green monkey orange sure that nutrients are not lost during processing. (Strychnos spinosa) – (SiSwati name: These fruits can help meet the demands for Umkhwakhwa) healthy snacks, especially among the working class. In the areas where access to nutritious foods is limited, such snacks help curb The Strychnos madagasgarensis and Strychnos malnutrition before it advances [46]. spinosa fruits are round and yellow with hard wood shell that encloses a yellow or brown 4. ESWATINI INDIGENOUS FRUIT AND sweet-sour juicy pulp [60]. These fruits can be consumed fresh or processed into several NUT TREES WITH COMMERCIALISA- products. When consumed fresh, the hard shell TION POTENTIAL is cracked and the pulp immediately eaten before they spoil [60]. Strychnos madagasgarensis and 4.1 Sour Plum (Ximenia caffra) – (SiSwati Strychnos spinosa fruits are good sources of Name: Umtfundvuluka) micronutrients such as Vitamin C, zinc and iron [60]. People in most parts of the world have been The Ximenia caffra is an indigenous fruit tree found to be deficient in the micronutrients [61], with oval shaped red fruits that have a and ascorbic acid intake declines during the dry pronounced astringent taste which intensifies season [62] which is when the Strychnos spp. during storage [47]. It is the juicy pulp are available where they play a vital role in surrounding the stone that is edible as a fruit, supplying the much needed nutrients [63]. however, the seed is also edible and is a rich source of proteins (18.8 %) and fats (48%), As the fruits ripen, there is accumulation of [22]. The seeds can potentially be used as a sugars and organic acids which owe to the protein supplement in meals for adults [48]. The characteristic pungent sweet sour taste [19,64]. X. caffra fruit peel is reportedly rich in total Fresh monkey orange fruits release unique phenolic and flavonol content, while the fruit pulp mixture of aromatic volatile flavour compounds is rich in ascorbic acid (27%) [22,47]. Fruit [19] when opened. The Strychnos cocculoides extracts of X. caffra showed significantly higher volatile flavour compounds found are mainly from ferrous ion chelating, and free radical scavenging the alcohol and ester groups, which impart a capacity when they were compared with sweet fruity aroma [65]. These compounds synthetic antioxidants [49]. These compounds present a potential study area for further are good for health because they remove research on value addition of the fruits. As the elements that cause degenerative diseases in fruits ripen, some enzymes solubilise the pectin the human body, maintain proper functioning of and cellulose, making them juicier [66]. vital organs and reduce oxidative stress [48,49,50]. The fruits are preserved through domestic processing that include, jam making, drying, juice The seed nut of X. caffra has 59% oleic acid [51- extraction, wine, beer, fritters and muffin making 53] which compared with olive oil (50-58%) [54]. or dried fruit leathers [67]. Most of the processes Oleic acid can prevent the development of breast that the fruits undergo involve thermal treatment cancer tumours by suppressing the oncogene for several reasons that include convenience, that causes breast cancer tumours [55,56], drying, and preservation [60]. The juice and the reduce high blood pressure [57] and slow the jam made from the pulp of the Strychnos spp. progression of atherosclerosis [58]. fruits are preferred over other fruits’ products [68]. The pulp of the fruits can be added to The juice of and dried X. caffra fruits are added porridges to impart an acidic flavour as well as to porridge to flavour it, while the fruit jelly is used micronutrient fortification [19]. as an ingredient in tarts [22]. These practices are evidence that the fruit has some desirable When making jams, no pectin is added to the flavours that they impart to other dishes. These mixture which means the fruits have sufficient flavours may be unique and need further amount of pectin for jam making and possibly low research and exploitation for industrial use. It enough pH [63]. These fruits present a great was found that the fruit juice and pulp are potential for industrial scale production of new processed into a beverage [59]. food products and food ingredients because of

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their biochemical make up, and as a result and citric acid, as well as sugars. These improve the food industry landscape of not only compounds play a very vital role during the the Kingdom of Eswatini but the southern Africa processing of the fruits. The acids may work with region as a whole. The ripe fruits are used to some pectin which is in abundance in the pulp, to treat coughs when mixed with honey [67]. create a firm jelly [74,75]. Ascorbic acid and the pectin are also important in human nutrition as 4.3 Wild Medlar (Vangueria infausta) - they boost the immune system and bowel (SiSwati Name: Umntulwa) movement, respectively. The aromatic flavours have made this fruit very popular and been able The ripe fruits of Vangueria infausta are round, to gain space in the commercialisation of the fruit brown in colour, with a leathery skin enclosing in liqueur and spirits. The peel of the fruit has an three to five seeds embedded in a soft pulp that oil that is used in the manufacturing of cosmetics tastes like an apple with a sweet, sour, [74]. Other parts of the plants such as leaves and somewhat bitter, slightly astringent taste [69]. the bark, are largely used for and have been The pulp and skin are the edible parts which are tested for medicinal importance [74]. A clinical consumed either fresh or dried, while the seeds trial of the juice administered on patients, are discarded [69]. The fruit contains sugars, resulted in a reduced total serum cholesterol of dietary fibre, essential micro- and macro- about 8% [74]. In Eswatini and Namibia, this nutrients as well as organic acids, contributing to fermented alcoholic beverage made from the the diets of human beings [70]. The fruits are fruits of marula play a socio-cultural role where widely dried and sometimes ground into powder the brew is presented to the King and Chief, because of their short shelf life. V. infausta dried respectively, as gifts from the people. The with sucrose and by solar-assisted pervaporation different uses and applications of the marula tree (SAP) had a softer texture when compared with and fruits present a potential for domesticating other commercially dried fruits, and prolonged and protecting the tree for commercial and drying was shown to lose some volatile aroma industrial use. compounds [71]. Fruits dried by this method are good as snack food and the nutrients are well 4.5 Waterberry (Syzygium cordatum) – retained. The volatile flavour compounds (SiSwati Name: Umncozi) associated with the V. infausta fruits are mainly from the ester group [72], which contribute to the The fruit of Syzygium cordatum is an oval berry, pungent and fruity flavour. sweet and succulent fleshy fruit that has a deep purple colour when ripe. The flesh surrounds a Local communities in southern Africa, including seed that is discarded by humans during those in Eswatini, prepare juice, jam and consumption of the fruit. The fruit has a slightly puddings by adding water and sugar, or cook the acidic flavour and is widely consumed by animals fruits to make marmalade. The pulp can also be such as birds and monkeys [76]. The fruit has a fermented to produce an alcoholic drink. Some protein content of 5.91% and a lipid content of households in Eswatini extract the pulp in water 0.72% [51]. The fruits pulp is also processed into and use the juice to flavour maize-meal porridge an alcoholic drink, and jam [40]. A combined [69]. Other plant parts contain some useful formulation of up to 32% of S. cordatum with phytochemicals such as alkaloids, other fruits in jam making produced a highly anthraquinones, coumarins, glycosides, desirable jam with a score of 0.914 [40]. A polyphenols, saponins, secoiridoids, steroids, concoction of the leaf, fruit and bark of the tannins and terpenoids, which are associated stem of the S. cordatum is used to treat mouth with different biological activities [69]. sores in South Africa [77] and has a fair content of antioxidants which are associated with 4.4 Marula (Sclerocarya birrea subsp. reducing chances of chronic diseases [78]. The caffra) – (SiSwati Name: Umganu) S. cordatum fruit tree is widely used for medicinal purposes in South Africa, treating a wide range The pulp of the Sclerocarya birrea subsp. caffra of ailments [77], however, there is little research is edible and can be eaten fresh, made into a that has been conducted on the fruits as food. jelly and jam as well as fermented into an Since this fruit is used and/or consumed during alcoholic or non-alcoholic beverage [73]. The its abundance, it would be justifiable to conduct juicy flesh is fibrous and mucilaginous with a studies that will establish its physicochemical sweet-sour taste and a burst of aroma [74]. The composition and how it benefits the juicy pulp is rich in ascorbic acid (168mg/100g) consumers.

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Interestingly, most of the indigenous fruit and nut have some cultural use as well. Table 1 shows trees in Eswatini have some medicinal properties some indigenous plants with different uses in the which are used in traditional medicine, and they Kingdom of Eswatini.

Table 1. Some indigenous fruit and nut trees and their uses in Eswatini [26,78]

Common Name Scientific Name SiSwati Name Uses

Wild custard apple Annona senegalensis Umtelemba Edible fruits. Treatment of parasitic worms, diarrhoea, gastroenteritis, lung infections, toothaches, and snakebites

Bird plum Berchemia discolor Vuka Edible fruits are high in sugar and Vitamin C content; Wood for furniture; bark for medicinal purposes

Red ivory Berchemia zeyheri Umneyi Furniture and ornaments. Used to treat anaemia, and bark used for back pains. Edible fruits which could be made into sugary sweetmeat or condiment

Dwarf Turkey- Canthium ciliatum Umvutfwamini Bark and leaves used as enemas. berry Edible fruits.

Tree strawberry Cephalanthus Umfomfo Edible fruits and leaves. Leaves natalensis made into powder and used for the treatment of eye problems in cattle

Cape fig Ficus sur Umkhiwa Edible sweet fruits which could also be processed into jam. Latex used for burns and septic conjunctivitis.

Sycamore fig Ficus sycomorus Umkhiwabovane Edible fruits and leaves. Bark and latex for chest, glandular complaints, diarrhoea and inflamed throats

Governor’s plum Flacourtia indica Umtabhala Edible fruits. Bark and roots for sore throats and rheumatism. Leaf tonic for asthma

Shepherd’s tree Boscia albitrunca Ingwavuma Edible leaves and roots for beer or coffee substitute. Fruits used for juice making.

Mountain rock Ficus glumosa Inkhokho Bark used to treat diarrhoea. Edible lemhlophe fruits and leaves.

Wild date Fadogia homblei Ndhlaleni Fruits are edible.

Sour plum Ximenia caffra Umtfundvuluka For treatment of inflamed eyes, asthma, flue. Fruits processed into Jams and jellies.

Wild Medlar Vangueria cyanescens Umntulwa Edible fruits are high in Vitamin C content. Treatment of coughs, fevers

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and wounds. Roots for snake bites.

Black nightshade Solanum nigrum Umsobo Edible fruits and leaves. Treatment of eye inflammation, skin disorders, ulcers, eczema

Green monkey Strychnos spinosa Umhlala Edible fruits, delicious fresh pulp. orange Treatment of snakebites. Root an emetic for fevers and inflamed eyes.

Black monkey Strychnos Umkhwakhwa Edible fruit pulp and leaves. Roots orange madagascariensis and barks for treatment of stomach disorders.

Waterberry Syzygium cordatum Umncozi Edible fruits which could be processed into jelly and wine. Bark for the treatment of diarrhoea

Marula Sclerocarya birrea Umganu For the treatment of dysentery, diarrhoea and malaria. Used to process Wine, liquors, cosmetics, confectionary, livestock feed

5. DOMESTICATION OF INDIGENOUS distribution, value addition and availability FRUIT AND NUT TREES [80,83]. The potentials in recurrent selection programmes for breeding of indigenous fruit Domestication is a man-driven process involving trees are limited by the relatively long expected selection processes from wild species to cultivate time until first fruiting for many of the species them, thereby, increasing their usefulness to [80]. Gains from selection of superior phenotypes human beings by improving the yield and/or in the field may be harvested sooner if these quality of the desired product [79,80]. Through selected individuals are vegetatively propagated domestication, various propagation techniques and deployed directly as clones without any can also be developed for ex situ conservation additional breeding [51]. Vegetative propagation [81]. Domestication of any plant species consists refers to the regeneration of selected plants from of selection and management by humans, and is vegetative organs such as roots, stems, leaves, not only about breeding per se, but definitely an buds and even single cells/tissues; and it offers a aspect of whole species improvement [82]. This wide range of benefits for any domestication is an iterative procedure involving the programme of indigenous fruit and nut trees [82]. identification, production, management and Vegetative propagation techniques were adoption of desirable germplasm [82]. These developed to domesticate two important techniques can help clone elite specimens and indigenous nut tree species, Barringtonia procera avoid the long juvenile periods from seeds [81]. (cut nut) and Inocarpus fagifer (Tahitian Under domestication, and in response to chestnut), of Melanesia in the Solomon Islands, purposeful man-led selection, species like D. through single-node, leafy, stem cuttings [85,86]. edulis have reduced juvenile phase, larger fruit size, extended fruiting season, more Other vegetative propagation methods include complementary rooting system if intercropped in grafting, budding, marcotting (air-layering) and agroforestry context with companion crops and micropropagation. Marcotting or air layering is a are significant carbon sinks within the production technique that produces roots on the stem while system [83]. Farmers in southern Africa the stem is still attached to the parent plant [82], deliberately maintain indigenous fruit trees on and is commonly used for difficult-to-root species their farms mainly for their fruits and nuts [84]. from cuttings [86]. It is a technique used to make a genetic copy of a desirable genotype from a Most African native fruit species have not been mature tree [86]. It is one of the oldest methods brought up to their full potential in terms of quality of vegetative propagation, although it still has breeding and selection, scale of production and relevance in present day plant multiplication,

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domestication and conservation efforts [82]. Air- protocol of Irvingia gabonensis, an African layering propagation was successful on indigenous tree, was developed, and could be Barringtonia procera and Inocarpus fagifer [86]. used as an alternative to conventional propagation and breeding [91]. An efficient These propagation techniques should encourage micropropagation protocol was established for use of locally available material e.g. river sand, Citrus megaloxycarpa Lush., a highly acidic wood shavings, compost, polythene citrus cultivar of Manipur, India, through shoot tip bags/containers etc. for the rooting of cuttings. explant culture [93] and for rudraksha This will enable even the community members to (Elaeocarpus sphaericus) through nodal explants be easily trained in the basic principles of [94,95]. A promising method for in vitro vegetative propagation so that they can, on their propagation of white sapota (Casimiroa edulis L.) own, produce and bulk up ‘cultivars’ from the was established through shoot tips and nodal trees that they know and value in their area [87]. segments [96]. A micropropagation protocol for olive (Olea europaea L.) was developed [92]. In Cameroon, farmers have selected certain trees based on their taste, fruit size and yield, Domesticating indigenous fruit trees has to resulting in the domestication of Dacryodes recognise, to a greater extent, the local edulis trees [88]. The degree of farmer-driven community people and their traditional domestication, in which farmers bring a species knowledge. They may provide valuable into a managed environment by planting or information on the use, growth and development retention indicates that farmers are convinced of the tree species, intra- and inter-specific that it is worth investing in indigenous fruit variations, and their favourable environmental species [86,87]. In South Africa, the mean fruit conditions as well. The selection, retention or yield of marula (Sclerocarya birrea subsp. caffra) deliberate planting and management of trees by trees is significantly higher from village trees than farmers can be considered as the beginning of protected area trees, and the fresh mass of the domestication process of the species individual fruits and mean kernel mass are also [87,95,96]. Indigenous people have good greater [88]. Marula domestication should be knowledge of how and when to utilise the fruits encouraged because there is a large and around them for their benefit [5,97,98]. This sustained demand for its products in both local approach conforms to the aims of the Convention and international markets [81]. In Eswatini, on Biological Diversity, which seeks to protect traditional marula brew has a significant annual the rights of local people to their indigenous cultural value [26]. Domesticating marula trees in knowledge and germplasm [83,85] and the land Eswatini could be well accepted since its intrinsic property rights [99-101]. A project that engages beverage value is intertwined with culture. and empowers the local people at the beginning Marula oil is extracted from the seed kernels. It is is likely to succeed, as rural communities have traditionally used in skin care and the treatment strong social and economic attachment to of leather [81]. This a clear indication that indigenous fruit trees [102]. Domesticating indigenous fruit and nut trees have a potential for indigenous fruit and nut trees has to start within diversified products. the communities in which they naturally occur, and then be introduced to new communities. If Another technique of domesticating the the tree domestication project is adopted and indigenous fruit and nut trees is the use of plant successful, every yard or farm of most biotechnological tools i.e. in vitro propagation homesteads in that particular community will [89,90]. In the modern age of science, plant have those tree species growing. In Eswatini tissue culture is an indispensable part of there are indigenous plant conservation biotechnology [91]. This method provides the communities which were established by a UNDP possibility of producing clones of native plants project called ‘Strengthening of National with appropriate attributes and mass Protected Areas Systems’ [103]. Since the reproduction [92], and is appropriate for those people from these areas were capacitated on plant species which are recalcitrant and lose conservation, they would be the right people to viability in a short period of time [93]. In vitro pilot the domestication and commercialisation of culture methods do not only offer the possibility indigenous fruit and nut trees in Eswatini. of cloning these genotypes, but also preserve them for an indefinite time, through Indigenous fruit and nut tree domestication cryopreservation, while field trials are being requires the support of the government. The carried out [88,92]. An in vitro propagation multifaceted nature of the support required for

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domestication of indigenous fruit trees demands like, if the community members are not involved a coherent and consistent policy approach that project may be bound to fail. [86,102,103]. The key issue at national policy level is for governments, in light of current The political will is also important. If the evidence, to give greater recognition to the government buys into the idea of potential of indigenous fruit trees to contribute to commercialising the indigenous fruit and nut poverty reduction as components of more trees it may speed up the process. The diversified, sustainable and environmentally government also has to ensure that the friendly livelihood options [86,98]. Enacting domestication and commercialisation process legislation ensures that the intellectual property adheres to the international conventions on rights of ‘farmer-breeders’ are protected, so that biodiversity and exchange of genetic material in the benefits of high-yielding cultivars produced which the government is a party to. Government by communities and individual farmers through might be able to facilitate establishment of participatory domestication are not unfairly processing companies for value addition, and exploited by large-scale commercial growers may help in securing markets for the products [88]. from indigenous fruits and nuts. Researchers, from various disciplines, are equally important in Domesticating and commercialising indigenous this project as they will bring in innovative ideas fruit and nut trees calls for all relevant and develop technologies to improve the stakeholder involvement e.g. farmers, extension industry. officers, researchers, processors, marketers, and consumers [86,104,105]. They all have important Tree domesticating will not only support roles to play in the indigenous tree domestication commercialisation of the tree products, but will and commercialisation process [96,104-107,98]. also ensure that these indigenous plant genetic resources are conserved even for future 6. CONCLUSION generations. This will of course, lessen pressure on the naturally occurring stands of the It is apparent that local people have been using indigenous fruit and nut trees. Therefore, it is the indigenous fruit and nut trees throughout their important that tree domestication should not be history. The indigenous knowledge on the use of viewed with the sole objective of these fruit and nut trees is a fundamental commercialisation, but with that of biodiversity component in scaling up their commercialisation. conservation too. Modern processing technologies are key in value addition of indigenous fruits and nuts. If the COMPETING INTERESTS benefits of the commercial aspect of these fruits Authors have declared that no competing are to be realised, a sustainable supply of the interests exist. raw material is vital. This could be achieved through domesticating these indigenous fruit and REFERENCES nut trees. Domesticating these indigenous fruit crops could be through plant propagation and 1. Swaziland Environment Authority. cultivation, using both conventional methods and Swaziland National Biodiversity Strategy plant biotechnology techniques. and Action Plan. Mbabane: Government of Swaziland; 2001. Domestication of indigenous fruit and nut trees is 2. Simelane ZP. Indigenous knowledge on not a top down approach. It is a multi-stakeholder tree conservation in Swaziland. University project where each and every stakeholder has a of Witwatersrand; 2009. role to play. The local people or the communities 3. McGarry DK, Shackleton CM. Children are very key in domesticating and navigating rural poverty: Rural children’s commercialising these indigenous fruit crops. use of wild resources to counteract food Their knowledge on the type of trees which exist insecurity in the Eastern Cape, South in their locality and their potential for Africa. J Child Poverty. 2009;15(1):19–37. commercialisation is very vital. Therefore, if the DOI: 10.1080/10796120802677594 indigenous fruit and nut trees of Eswatini are to 4. Aphane J, Chadha ML, Oluoch MO. be brought under domestication and Increasing the consumption of commercialisation, the community members micronutrient-rich foods through production have to be involved from the beginning of the and promotion of indigenous foods. FAO- project. No matter how good the project may look AVRDC Int Work Proc; 2003.

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