Wild Loquat Uapaca Kirkiana (Müell) Arg

Wild Loquat Uapaca kirkiana (Müell) Arg. Family Euphorbiaceae # 97 Festus K. Akinnifesi1, T. Chilanga1 and F. Kwesiga2 1. International Centre of Research in Agroforestry (ICRAF), SADC-ICRAF Agroforestry Project, Chitedze Agricultural Research Station, P.O. Box 30798,Lilongwe, Malawi (Author for correspondence; [email protected] ). ICRAF Southern Africa Regional Programme, PO Box 128, Mount Pleasant Harare, Zimbabwe.

Uapaca kirkiana (Family Euphorbiaceae), known as wild loquat, is a tropical indigenous fruit tree native to the miombo ecological zone. The ecological zone stretches over eight countries in central and southern Africa, from Angola and northern Namibia in the West across northern Botswana and northern South Africa, Zimbabwe, Zambia, south of the Democratic Republic of Congo and Malawi, to Tanzania and Mozambique in the East. The zone is mostly deciduous, non-spinescent woodland with a shrub layer of variable density and composition. The total flora consists of about 650 species, including more than 50 indigenous fruit tree species. Ethnobotanical surveys conducted in 451 households surveyed in Malawi, Tanzania, Zambia and Zimbabwe, have shown that wild loquat is the preferred fruit tree in the region. This preference in southern Africa is based on its role in food security, potential for income generation, and nutrition. The fruit forms a vital part of the diet in rural households, and plays a significant role during periods of famine in Malawi, Zambia, and Mozambique. Since Uapaca kirkiana occurs in eight southern Africa countries, it has many vernacular names (Table 1). A number of them simply reflect different ways of spelling the same word in the different Bantu languages or dialects.

World Production and Yield The market is largely informal and there is no standard pricing system or product differentiation. Substantial amount of trade and consumption of the fruit exist in both rural and urban areas. Fruit are collected from the wild or semi-wild conditions. Numerous collectors and retailers exist but few wholesalers. About 95% of the fruit traded in Malawi were collected from the wild and sold at roadsides. Fruit production varies between trees within populations, with tree size, with seasons in the miombo. Fruit loads exceeding 2,000 fruit per tree have been reported in Zaire, Zambia, and Malawi. In Zambia, tree with cream fruit trees bare most frequently and were the most productive.

Uses and nutritional composition The fruit is the only part of the plant used as a food source and it is consumed fresh. The fleshy yellow pulp of the ripe fruit is sweet with a pear-like taste. The sugary pulp forms 40 to 60% of the fresh fruit. The skin accounts for approximately 38% of the total fruit weight. The fruit is processed by women to produce a refreshing beverage and a variety of local beer and wines, juice and jams, in Malawi, Zambia, and Zimbabwe. A private company is producing jam in Zimbabwe. The fruit is low in fat and high in potassium (Table 2). The wood is uniform, pale pink-red when freshly cut, changing to deep pink-red when exposed. The texture is medium and even, and is used to make domestic utensils, furniture, carvings and boxes. It is also used for construction of houses and fences and as a source of firewood and charcoal. A salt for seasoning food is obtained from the wood ash The leaf, bark, and root are used as traditional medicines. An infusion of the roots is boiled as a local remedy for indigestion, dysentery and intestinal problems. A blue dye is made from the roots. The thick and broad leaves are used as wrappers for storing processed food. The flush of leaves at the end of the dry season is used by cattle as fodder in the absence of palatable alternatives. The tree provides good shade in homesteads and on farms during the dry and hot season.

BOTANY Description This profusely branched evergreen or semi-deciduous tree has a short trunk and spreading branches that form a dense rounded crown. It commonly reaches 5 to 13m, averaging 9m. The stem is generally short but sometimes can have up to a 9m clear bole. The diameters of mature trees fall within the range of 15 to 25cm with diameters of up to 40cm being recorded in Zimbabwe. The stem bears stout and short branches with prominent leaf scars. The bark is dark grey or grey-brown, thick and deeply fissured in mature individuals. The root system is a mass of small laterals and deeply penetrating root emerging from the base of the stem. Taproot length varies with tree size, and generally ranges from 50 to 150cm. The dark, shiny green leaves are usually clustered at the ends of the branches, in a spiral arrangement. When young, the leaves have short grey to rust colored woolly hairs beneath and become glabrescent when mature. Dimensions vary but most fall within the range 12 to 36cm long and 8 to 24cm wide. The smallest leaf is 7 cm long and 4 cm wide. The shape is obovate or sub circular-obovate with a rounded apex and a cuneat base. The leaves have a prominent midrib and 12 to 24 pairs of prominent parallel secondary veins, diverging almost at right angles from the midrib. The petioles are velvety, short (up to 3.5cm long) and stout. The stipules are pubescent, 3 to 4mm long and deciduous. The tree is dioecious and therefore allogamous. The unisexual inflorescences originate from axillary positions among the leaves or more often below them on the second or third seasons wood of the branchlets. The staminate and pistillate flowers are yellow in color and globose in shape. The staminate peduncles (up to 10mm long in bud sometimes extending to 20mm) occur in fascicles, usually of 4 to 8, but sometimes with more than 12 inflorescences. Each staminate inflorescence consists of 4 to 8 oblong-elliptic or broadly elliptic pale yellow- green bracts. When fully open, the head of the flowers is 5 to 10mm long and 12 to 18 mm across, each of the 10 to 20 flowers with 5 triangular and laciniate or linear calyx lobes (2mm long and 5 to 7 in number). Pistillate peduncles are about 6 to 8mm long but sometimes exceed 10mm in length. Pistillate bracts are tinged pink and resemble those of staminate flowers. Within the bracts, the pistillate flowers are solitary, with a shallow copular 5 to 8-lobed calyx. The ovary is ovoid sub-globose and usually 3 to 4 locular, 3 to 4 mm long and wide and densely fulvous– tomentose. The number of styles matches the number of locules. Each style is flabelliform and about 4 mm long, ending in a truncate and laciniate apex. The styles are reflexed on to the surface of the ovary. The fruit is a drupe and borne on a thick short peduncle, usually less than 10mm. The tough skin is smooth, pubescent-puberulous at first but glabrescent later. Fruit may have thick or thin skin. At the mature stage, a hard thick exocarp encloses a thin yellow mesocarp of about 1.5mm thick when dry. The round mature fruit is yellow, yellow-brown, brown or reddish and 3.3 cm in diameter, ranging from 2 to 4 cm. Additional fruit colour variations reported to include cream, brownish-red or brownish yellow. The yellow fruit pulp encloses three to five seeds (pyrenes), but 3-4 seeds are most common and are generally whitish, cordate, carinate and apiculate with a tough fibrous sclerotesta. The 4-seeded fruit are larger, have thinner skins and contain more pulp. Seed lengths of up to 2cm long and 1.4cm wide have been noted, all with a rather brittle seed coat. One side is almost flat and on the opposite side, there is a longitudinal ridge terminating with a sharp edge at the base. The seed has an inner membrane, endosperm and two leafy green cotyledons. There are 2,500 seeds per kilogram. The seed has a moisture content of about 48% .

Taxonomy Known by the natives of the miombo ecological zone for centuries, the species has not been explicitly described until recently. The species is a member of the family Euphorbiaceae (synonym Uapacaeceae and formerly referred to as “Airy Shaw”) subfamily Phyllanthoideae in the tribe Antidesmeae, and Uapaca is the sole genus in the subtribe Uapacinae. The name Uapaca is derived from the Malagasy name “Voa-paca” used for the Madagascar species Uapaca thouarsii, scientifically described by Baillon in 1858. The genus is distinctive within the Euphorbiaceae based on wood, vegetative, and floral characters. The genus Uapaca includes 61 species but there has been no recent revision on a continental scale and the number of distinct species is probably less. The greatest diversity occurs in the Zaire basin and further south in the miombo region. Uapaca kirkiana has five synonyms: U. albida, U. banguelensis, U. goetzei, U. homblei, and U. greenwayi. Other important close relatives of U. kirkiana are: U. nitida, U. paludosa (syn. U. guineensis) and U. sansibarica (syn. U. macrocephala).

Ecology Uapaca may occur in extensive pure stands in deciduous woodlands, upland wooded grasslands and along streams, often on stony soils, or rocky slopes, from 700 to 2000m. The rainfall of this eco-zone ranges between 600 to 1000 mm on average, and is unimodal. Three seasons are distinguished: hot-dry (September to November), hot-wet season (November/December to March) and cool dry season (April – August). The main cropping season is November to April. In natural populations, U. kirkiana is easily distinguished from other Uapaca species on account of its distinctive broad and leathery leaves and rounded crown. It is widespread and abundant in mixed communities of Brachystegia-Julbernardia woodland vegetation either as a dominant or co-dominant species and is usually gregarious, forming very dense groves. Where rainfall is greater than 1200 mm, it forms pure woodland communities with either closed or open canopies. Under such situations, the ground flora is sparse or absent due to the shade cast by the large leaves. The zone has a range of soil with a prevalence of ferralsols and luvisols. It also grows on acrisols, cambisols and regosols in parts of Tanzania, on arenosols in Angola, Zaire and Zambia and on nitosols in Malawi, Tanzania and Zimbabwe. Uapaca is general associated with sandy or gravelly soils that have good drainage on the middle slopes of escarpments where Uapaca dominates over Brachystegia species. The soils are characterized by low cation exchange capacity, low organic matter content and low macro-nutrients (nitrogen, phosphorus and potassium). The species is totally absent from hydromorphic soils with high organic matter content that overlie gravelly soils and where seasonal flooding occurs. The tree is regarded as an indicator for poor agricultural soils. Reproductive Biology The juvenile period is from 9 to 10 years for unimproved material while vegatively propagated trees in Malawi fruited in three years. In Zambian populations, staminate and pistillate trees are randomly distributed with a 1:1 ratio. Staminate flowers develop in about 16 days and twice as long for pistillate flowers. During anthesis, pistillate flowers remain open 10 to 14 days whereas staminate flowers shrivel 3 to 7 days after anthesis. Staminate flowers have a mild but non-distinctive scent while the pistillate flowers have no detectable odor. Abortion of inflorescences in males is about 9% while abortion of pistillate inflorescences is about 45%. Flowers turn brown following anthesis.The tree is presumed to be insect pollinated. The most common insects include bees, flies, beetles, ants and wasps. Moths are also potential pollinators. Flowering coincides with the onset of the rainy season (October/November), and the period extends over the entire 5 to 6 months rainy season. Flowering intensity is also variable throughout the period with higher proportion of trees flowering between January and March (Ngulube 1996). Staminate trees flower earlier than pistillate trees. Fruiting is biennual, i.e. in alternate years, a well-known pattern for many tropical fruit trees. In the natural environment, a large number of birds, ungulates and primates feed on the pulp, dispersing the seed (after sucking the pulp).

Fruit Development Variation occurs in fruit size, skin, pulp content, seed weight and seed volume between and within populations and trees. At maturity, each fruit may weigh 5g to 50g, and amount of pulp ranges from 0.2 to 30g but this varies with location. Larger trees are more productive than smaller tree and fruit load is related to tree size and is not affected by thinning treatments. The fruit set between January and February, mature in August and November (Mwamba, 1995). Some Uapaca trees produce a mixture of small and large fruit while others habitually produce either large or small ones.

HORTICULTURE. Propagation The recalcatrant seed has no dormancy period and once dispersed, germinates readily. Fruit maturation and fall coincide with the rainy season, ensuring immediate germination. Seedling growth is better in open than in the closed canopy. Seeds cannot tolerate desiccation below 26% moisture content and should not be stored at freezing temperatures and seeds should be sown within two weeks after collection. Germination is intermediate between epigeal and hypogeal. The seed coat cracks and the radicle protrudes from the scar end and develops into a taproot. The seed coat splits longitudinally into equal halves and the two cotyledons unfold and expand rapidly. The sclerotesta is ejected by the unfolding cotyledons. The hypocotyl is very short and the cotyledons remain partly submerged in the germination medium. Germination is fairly uniform reaching 30% after four weeks, and, 90% after six weeks. No pretreatment is required though soaking in cold tap water overnight hastens germination . The two opposite primary leaves are stalked and develop from cotyledons (about 3cm x 2.5cm). Shoots are green, occasionally reddish. At 6 months seedlings attain 6-8 and 12-16 cm shoot and tap root length, respectively. The tree readily produces epicormic shoots when coppiced. Up to 1700 stump or stool sprouts per hectare were observed in a natural woodland in Zambia. Regeneration of shoots from the hypocotylar region (close to the soil surface) of seedlings following seasonal fires is also common. Grafting success rates of 80% has been achieved using wedge or splice grafts onto seedling rootstocks. Topworking also has been successful. The time of grafting and grafters skill has an overriding effect on success. Scions collected and grafted in October to December at the onset of the rainy season give >80%, while grafting in January to August give from 0 to 30% scions. Scions kept at room temperature are superior to other methods. (Example?) Air layering has potential with up to 63% rooting of marcots being achieved in the wild. However, field survival of marcots is still a challenge, as survival may decline with time due to (absence?) difficulty of taproot development, Tissue culture has been investigated but promising results have not been reported.

Cultivation No conscious effort has been made to cultivate Uapaca in southern Africa. The absence of cultivation has resulted in the wild population being severely threatened by the high deforestation rates of the miombo woodlands. Wild harvesting is the predominant management method and conservation has been inconsistent or non-existent in some countries. During land clearing for agricultural use, pistillate trees are often retained around the homesteads or communal lands, depending on the fruit traits, such as productivity, sweetness, and size.

Attempts to domesticate Uapaca is supported by various projects. Small field research plantings have been made with 100% survival using seedlings inoculated with ectomycorrhizae in the nursery. Seedlings from natural stands are superior to uninoculated nursery–raised stock. Direct field seeding is not advisable due to the low germination success and low subsequent survival. The seedling grows slowly under little or no management, but weeding and use of suitable inoculation enhances growth and the early development of multiple stems (2 to 6 stems per plant within three years). At Makoka in Malawi, Uapaca trees have grown up to 4m tall in eight years after establishment. Little tertiary branching occurred while primary and secondary branching occurred in all field tests.

Fruit harvesting Mature and ripe fruit fall naturally from the trees and are easily collected from the ground. Collection of fruit from short trees or trees with low branches is done directly while for tall trees, collection involves climbing or beating the tree using a stone or other tool to shake off the fruit.

Pests and diseases No serious pests and diseases have been reported in both natural and planted stands. However, necrosis associated with Pestalotiopsis versicolour, leaf spots caused by Cercospora species, and mildews and sooty molds caused by Cladosporium cladosporioides have been reported but have not caused any serious damage to foliage. Several phytophagous insects (Cercoplastes uapacae, Ledapis spp., Microsyagrus rosae. and Euphoria spp) may cause 10 to 20% leaf damage. Carpohilus fumatus and Deudorix sp, Drosophila enanasse and Ceratitis cosyrae, feed on the pulp of the mature fruit thereby degrading the ripe fruit. Animal damage through browsing and trampling is a major problem during establishment. In the wild, elephants, eland and zebra are the major browsers. Damage by fire can be severe during early growth stages.

Plant Breeding and Improvement Molecular analyses using random amplified polymorphic DNA (RAPD) of 17 populations (132 RAPDs) has been undertaken (Agufa, 2002). High, geographically structured variability is observed with 75% within location variation, emphasizing the need for range-wide collection to properly capture diversity. Cluster analysis of genetic distances, suggests that a historical interpretation of patterns of variation is likely to be complex. Multilocational screening trials have been undertaken by Southern Africa Regional Programme (ICRAF) since 1996 in five countries. Tree seeds were collected from superior trees of 26 selected locations with 5 to 6 each from Malawi, Tanzania, Zambia, Mozambique and Zimbabwe. The seedlings were established in multi-location trials (12 to 16 per country). After 42 months, the best performing lines were ‘Phalombe’ for Malawi, ‘Murelwa’ for Zimbabwe and ‘Chipata’ for Zambia. Tree height was strongly correlated with geographic and climatic variables e.g. latitude x height (r = 0.71; p<0.05), with significant genotype by environment interactions in height growth across the three countries. Fruit characters probably can be improved by selection and breeding though no improvement has been done except in the above pioneer domestication work by Southern Africa Regional Programme. Identified varieties exist in the region. The varieties were selected using participatory rural appraisal (PRA) approaches that involved village workshops, focus group discussions with communities, traditional leaders, school children and vendors in four countries to capture superior clones from the wild. A total of 190 superior trees were identified based on jointly defined criteria (fruit size, sweet taste, late or early fruiting, color). Selected trees were named for scion or rootstocks. Selected rootstocks were collected for establishment of clonal orchards. In Malawi, villagers were able to identify certain individual trees with unique fruit traits. An example is the heavily loaded tree in Yesaya village of Dedza, having 6,232 exceptionally sweet fruits, called “Gundete Okolera” (meaning big and sweet fruit). This clone was named as ‘ICR02 Mponda MW18’. In Phalombe. Malawi, such a tree is described as “Mapumbu Amutiye,” an expression used to describe an exceptionally beautiful young and unmarried lady in the village. The largest fruited clone selected so far was from Malawi and is named ‘ICR02 Alena’.

References and Further Reading Agufa, 2002 - need full citation Akinnifesi F.K., F. Kwesiga, A. Simons, J. Mhango, T. Chilanga, A. Mkonda, C.A.C. Agufa, C. Ham, D. Jordaan, Russell, D., Franzel, S., I. Kadzere, D. Mithofer, T. Ramadhani, J.D.K. Saka, R. Swai, E. Sambane, P. Dhliwayo, G. Sileshi. 2005. Towards Developing the Miombo Indigenous Fruit Trees as Commercial Tree Crops in Southern Africa. Forest and Livelihoods. Special issue (in press). Drumond, RB. 1981. The common trees of the central watershed woodlands of Zimbabwe. The Department of Natural Resources, Causeway. pp112-113. FAO 1983. Food and fruit-bearing forest species, 1. Examples from eastern Africa. FAO Forestry paper 44/1: 1-172. Goldsmith, B., DT Carter. 1981. Indigenous timbers of Zimbabwe. Zimbabwe Bulletin of Forestry Research. 9: 1-331. Hans AS 1981. Uapaca kirkiana Muell Arg. (Euphorbiaceae). Musuku (local name). Zambia National Council for Scientific Research. Tree Improvement Research Centre Technical Report 48pp. Hans, AS., EE Chembe., LK, Mwanza. 1982. Mathematical treatment of vegetation trustland and miombo woodland of Chipata district with reference to multipurpose fruit species. National Council for Scientific Research. Tree Improvement Research Centre, Research Paper 19pp. Lawton, RM. 1978. A study of the dynamic ecology of Zambian vegetation. Journal of Ecology 66: 175-198. Maghembe JA, F. Kwesiga, M. Ngulube, H. Prins, FM. Malaya. 1994. Domestication potential of indigenous fruit trees of the miombo woodlands of southern Africa. In: Leaky RRB and Newman AC (eds). Tropical trees: potential for domestication and rebuilding of forest resources. HMSO, London. pp220-229. Malaisse FP. G. Parent. 1985. Edible wild vegetable products in the Zambezian woodland area: A nutritional and ecological approach. Ecology of Food and Nutrition, 18: 43-82. Mwamba, CK. 1983. Ecology and distribution of Zambian wild fruit trees in relation to soil fertility: status of representative areas. MSc Thesis. University of Ghent, Belgium. 102pp. Mwamba, CK. 1989a. An outlook on the role of indigenous fruit trees in agroforestry. Paper presented at the first agroforestry workshop, 16-19 April 1989, Lusaka, Zambia. 13pp. Mwamba., CK. 1989b. Natural variation in fruits of Uapaca kirkiana in Zambia. Forest Ecology and Management 26: 299-303. Mwamba, CK. 1992. Influence of crown area on empirical distribution of growth parameters and regeneration density of Uapaca kirkiana in a natural miombo woodland forest. Natioanal Council for Scientific Research, Tree Improvement Research Centre. Research paper #14pp; 1-12. Mwamba, CK. 1995. Variations in fruits of Uapaca kirkiana and effects of in situ silvicultural treatments on fruit parameters. In: JA Maghembe, Y Ntupanyama and PW Chirwa (eds). Improvement of indigenous fruit trees of the miombo woodlands of southern Africa. Primex Printers, Nairobi. Pp27-38. Ngulube, MR. 1996. Ecology and management of Uapaca kirkiana in southern Africa. PhD Thesis University of Wales pp 183. Ngulube, MR. 1996. Short term storage of Uapaca kirkiana seed. Unpublished report of the Forestry Research Institute of Malawi. 13pp Pardy AA 1951. Notes on indigenous trees and shrubs of southern Rhodesia. Rhodesian Agricultural Journal 48:261-266. Parker, EJ. 1978. Causes of damage to Zambian wild fruit trees. Zambian Journal of Science and Technology, 3: 261-266. Phipps, JB., R. Goodier. 1962. A preliminary account of the plant ecology of the Chimanimani mountains. Journal of Ecology 50: 291-319. Radcliffe-Smith, A. 1988. Euphorbiaceae (part 2): Uapaca. Pp566-571. In: Polhill RM(ed). Flora of tropical east Africa. Balkem Rotterdum/Brookfield. Radcliffe-Smith, A. 1993. Notes on African Euphorbiaceae XXIX: Uapaca. Kew Bulettin 48:611-618. Saka, JDK., JD. Msonthi, EY. Sambo. 1992. Dry matter acidity and ascorbic acid contents of edible wild fruits growing in Malawi. Tropical Science 32: 217-221. Seyani, JH. 1991. Uapaca kirkiana: Underutilized multipurpose tree species in Malawi worth some development. Paper presented at the International Workshop on the biodiversity of traditional and underutilized crops, 12-15 June 1991, Valletta, Malta. 10pp. Shorter, C. 1989. An introduction to the common trees of Malawi. The Wildlife Society of Malawi, Lilongwe 115pp. Storrs, JH. 1951. Notes on indigenous trees and shrubs of southern Rhodesia. Rhodesia Agriculture Journal, 48: 261-266. White, F. 1962. Forest Flora of Northern Rhodesia. Oxford University Press, London. 455pp. Table 1. Vernacular names of Uapaca kirkiana from different countries within the species native range (Ngulube 1996). Names with an asterisk were taken from herbarium specimens.

Name Language (s) Countries Chilundu, Muhaka Lozi Zambia Ikusu Kisafwa Tanzania Kabofa Lunda Zambia Lihobohobo Ndebele Zimbabwe Mahobohobo, Shona Zimbabwe Mushuku, Muzhanzhi, Muzhunje, Unhobohobo Matu* Chuwabo, Quelimane Mozambique Mecunapa Macua Mozambique Mazhenje Bemba, Lozi Zambia Mguhu Hehe, Bena, Nyamwezi Tanzania Mhendabongo, Kilongo Tanzania Mugusu, Nugusa Migulu Ulugulu Tanzania Mkuhu Nyakyusa, Kibena Tanzania Mkuso Nyika Tanzania Mkusu Kibende, Kilongo, Kimbu, Hehe, Swahili Tanzania Mkuss Bende, Kilongo, Nyamwezi Tanzania Mompangwe* Lambya Malawi Mpotopoto Nyanja Malawi, Zambia Msuku Chewa, Lomwe, Nyanja, Sena Malawi, Zambia Mssuku Ngoni Tanzania Mtoto Chewa, Yawo Malawi Mulandenga - Angola Mumbola Chokwe, Huila Angola Musukuti, Sukwa Malawi, Zambia Musukutinbininga Masuku Bemba, Chewa, Lozi, Tonga, Sena, Malawi, Zambia Lambya Musuku Tumbuka Malawi, Zambia Ntalla Hehe Tanzania Oilumbula* Umbundo Angola Table 2. Proximal analysis of wild fruit of Uapaca kirkiana. The pulp has a pH of 5.05. (Saka et al., 1992).

Proximal Analysis g/100g Water 72.6 Energy KJ/100g 1456 Crude protein 1.8 Fat 1.1 Fiber 8.4 Carbohydrates 86.5 Fiber 8.4 Ash 2,2 Minerals mg K(g/g) 13.68 Mg 1.106 P (g/g) 0.555 Fe (g/g) 0.431 Na (g/g) 0.365 Ca (g/g) 0.033 Vitamins Ascorbic acid 16.8