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Conservation and utilization of indigenous vegetables in Botswana

M.E. Madisa1 and M.E. Tshamekang2

1 Dept. of Agricultural Research, Ministry of Agriculture, Gaborone, Botswana
2 Thusano Lefatsheng, Gaborone, Botswana
Botswana is endowed with a variety of indigenous vegetables which grow wild every year despite erratic rainfall. These plants are widely harvested and consumed, especially by villagers, but there is an increasing concern that their use is declining in the rural areas. Many people look down on indigenous vegetables, which are gradually being replaced by exotic vegetables. However, in the Sahelian, semi-arid and other parts of the dry savanna areas of Africa, the deficiency of vegetables in the diet is a major cause of vitamin A or carotene deficiency. This causes blindness or xerophthalmia, and even death in young children. Vegetables also contain fibre, which adds bulk to the food, thereby minimizing the feeling of hunger in addition to enhancing movement of food through the digestive system (Okigbo 1990). Concerns have been raised by medical personnel and nutritionists in Botswana that the decline in the use of indigenous vegetables is resulting in nutritional deficiencies, especially among children in the rural areas. Most rural people do not earn a regular income and cannot purchase exotic vegetables, even if these were available. This has resulted in calls to promote the use of indigenous vegetables, especially among low-income rural dwellers.

Nutritional importance

There are several important indigenous vegetables whose leaves are harvested to make morogo, which can be cooked, dried and stored. These leaves are highly popular and nutritious, having protein contents of up to 36%. The vitamin content of morogo is dependent on the age of the plant (Wehmeyer, pers. comm.). It must be noted that when the vegetables are cooked they lose a substantial percentage of their vitamin C. Morogo contains both vitamin A and vitamin C. Morogo also complements the low calcium, magnesium and iron contents of maize.

The three most popular indigenous vegetables in Botswana are described below. Several other morogos are eaten by rural people in specific areas of the country, including for example delele in the northeast and west.

Thepe: Amaranthus thunbergii

This is widespread in southern and central Africa. It spreads rapidly in cultivated land. It grows on various soil types, under a wide range of environmental conditions. The plant grows weedy around settlements in Botswana. The first leaves and shoots are ready to eat 2-3 weeks after the first rains, and the plants continue to grow throughout the summer. Picking the leaves stimulates growth (Moss 1988). The seed is ready for harvesting around March-April. There is considerable scope for increased domestic use. During severe droughts there is little to be harvested. Cultivation could ensure that some is available even during dry years. The leaves and shoots are a popular vegetable widely eaten throughout Botswana, and in several other parts of southern Africa. They may be eaten fresh or dried, and are prepared in several traditional ways. The plant can be eaten as a relish or together with sorghum or maize meal to make porridge. The cooked leaves may be eaten with milk, and salt or fat can be added.

Lothue: Cleome gynandra

According to records at the Natural Herbarium, this species occurs throughout most of Botswana, often becoming a weed in cultivated land, overgrazed areas and waste places. It is generally more common around human settlements. It apparently tolerates a wide range of soils and habitat types and is reasonably frost- and drought-resistant. Rainfall is the major factor limiting its distribution, but this species has nevertheless been recorded from some of the drier areas of western Botswana. The leaves are extremely popular and much sought after in Botswana. The methods of preparation are much the same as for other wild vegetables and the leaves may be eaten fresh or dried. The leaves and the flower buds are washed and boiled in water with a little salt. A relatively long cooking time (2 hours) is normally used to remove the bitter flavour. For drying, the boiled leaves are made into small balls and placed out in the sun. To reconstitute the dried material, which can be stored indefinitely, it is soaked in water and then prepared in the usual manner. The first leaves are ready to eat 4-6 weeks after the first rains, sometimes sooner. The plants grow throughout the summer, and, according to local knowledge, picking the leaves stimulates growth.

Morogo wa dinawa: Vigna unguiculata

Wild plant leaves cannot be harvested in sufficient quantities for large-scale commercial operations, but the cultivated cowpea appears to be very suitable for such level of commercialization, as its leaves are a popular vegetable. The plant is cultivated throughout Botswana, and yields are reasonable during years of adequate rainfall. A significant amount of leaves can be harvested from the plant without detrimentally affecting its seed yields, and thus its potential is very high (Taylor and Moss 1982).

Economic importance

Vegetables in Botswana are mostly imported from neighbouring South Africa, despite efforts by the Financial Assistance Policy and the Botswana Development Corporation to finance products (90% of total costs) and produce respectively. Thus, limited foreign exchange is used to purchase products which could be supplied locally. However, exotic vegetables demand high inputs for production and yields are often low. Indigenous vegetables of equal or better nutritional status could perform better under cultivation with relatively low input levels. Currently, however, supply from the wild meets local demand, although the market is still disorganized. This exploitation of wild resources is an important source of income and food, especially for the rural poor, who are also underemployed. These vegetables are cheaper than exotic imports and thus affordable by an average Motswana.

If the market were more organized, it could provide a more efficient service to harvesters and consumers alike. A middleman like Thusano Lefatsheng could assist if a market survey can be undertaken to assess the viability of such a project. Morogo, like many other veld products, has been identified as a potential sector for diversification of the economy and has even been included in the National Development Plan VIII of Botswana. Dried morogo has economic potential on the local market for three reasons:

1. It is extremely easy to produce, and production is by traditional methods.

2. It is popular and apparently marketable. In test marketing in Gaborone, dried morogo proved to be extremely popular among the townsfolk, who could not get it in the town and missed it.

3. It stores for long periods, transports easily and carries little risk of contamination during preparation or storage.

The market for fresh morogo is also developing in big villages and towns, the only problem being that it loses freshness very quickly. However, the produce is not lost, since it can be cooked and sold dried.

Research

Indigenous vegetables are important supplements to the staple diet and are better adapted to the marginal soils and erratic rainfall often experienced in Botswana. Most of the important indigenous vegetables have been identified as having potential for commercial exploitation and production for human consumption (Taylor and Moss 1982). Recently, there has been a deliberate effort to identify the role of the indigenous underutilized plants in national food dynamics and how they can be mainstreamed into the country's agriculture. Initially, the work on wild/weedy plants concentrated on developing the utilization and processing of these plants.

Research in traditional vegetables is the mandate of the Department of Agricultural Research (DAR) of the Ministry of Agriculture, but is still in its infancy. The initial objective will be a survey of all the districts in the country for germplasm and data collection. The collections will be conserved at the national genebank, which is also housed by DAR. The material will be evaluated and selection carried out. Seed multiplication for the selected samples will be consequently possible and even breeding work as necessary. The other institutions involved in traditional vegetables research are the Food and Technology Research Service of the Botswana Technology Centre and the Botswana College of Agriculture.

References

Moss, H. 1988. Under-exploited Food Plants in Botswana. Unpublished report for Veld Products Research, Gaborone.

Okigbo, N.B. 1990. Vegetables in Tropical Africa. Pp. 29-52 in Vegetable Research and Development in SADCC Countries (R.T. Opena and M.L. Kyomo, eds.). Proceedings of a workshop held at Arusha, Tanzania, 9-13 July 1990. AVRDC Publication No. 90-328. Asian Vegetable Research and Development Centre, Taiwan.

Taylor, F.K. and H. Moss. 1982. The potential for commercial utilization of veld products in Botswana. Veld Products Institute, Gaborone.

Appendix I. The role of NGOs in the promotion of indigenous vegetables: the model of Thusano Lefatsheng

Background

Thusano Lefatsheng is a rural development organization engaged in agriculture, set up in 1984. It has been involved in two pilot projects in Botswana which involved experimental cultivation and propagation trials of medicinal and aromatic plants and fruit and nut trees. In the context of these pilot projects, a farm was set up in 1986 in the Kweneng District of Botswana which employs rural people from the surrounding area. The farm serves as the organization's research centre and as a demonstration area for local subsistence farmers.

Objectives

· Thusano Lefatsheng aims to meet the needs of rural people for alternative sources of income by developing new cash crops and techniques, and extending these to the farmers in the project area. The organization is engaged in all aspects of the introduction of these new crops from research and extension among local farmers to processing and marketing, both locally and abroad.

· Thusano Leftasheng is very concerned about the conservation of indigenous plants and strives to ensure that the commercialization of these plants will not lead to their overexploitation in the wild. Therefore, the organization advocates controls over the harvesting of wild plants and recommends the use of ecologically sound harvesting techniques. In addition, Thusano Lefatsheng attempts to protect wild populations by developing successful cultivation techniques at its research farm. The organization is particularly interested in the traditional medicinal plants of Botswana.

· The activities of Thusano Lefatsheng are directed toward the overall objective of the development of a profitable but sustainable farming system for small farmers in Botswana. This involves a 'whole-farm' approach, whereby traditional crops, new crops, medicinal plants, trees and livestock are integrated to produce a stable ecological system.

· Thusano Lefatsheng aims to provide significant employment opportunities for rural women, especially through processing activities.

Research and conservation efforts

The research department of Thusano Lefatscheng was established in 1986 and is concerned with the conservation of indigenous plants which are commercialized by the organization and are exploited from the wild by rural dwellers. The plant species on the agenda include grapple plant (Hapargophytum procumbens), morama bean (Tylosema esculentum), mosukudu (Lippia scabberima), mosukujane (Lippia javanica) and lengana (Artemisia affra).

The initial step was collecting germplasm of these species from the nearest localities, to be used for experiments and seed exchange. Methods of raising seedlings have been developed. Trials of ecologically sound and sustainable harvesting methods are at an advanced stage. Population density experiments are also underway. Ecological studies have been undertaken through a collaboration involving the National Institute of Research of the University of Botswana and universities in the Netherlands as well as Thusano Lefatsheng. Resource potential surveys and management options as well as socioeconomic aspects of grapple plant production have been documented and recommendations are being followed up. A participatory research project is to commence at the end of 1995 in the Kgalagadi district. Germplasm-collecting expeditions are continuing to capture as much genetic variability as possible and to exploit this for genetic improvement. Resource-user groups are closely involved in this endeavour. Multilocational trials are being set up to take into account the gradient in environmental factors across the ecological zones of the country.

A programme on drought- and salt-tolerant subtropical fruit and nut trees was set up to evaluate the relative performance of indigenous and exotic species.

Extension

The Extension Department of Thusano Lefatsheng is responsible for the dissemination of recommended research technologies. This is achieved through visits and workshops. Demonstration plots have also been set up in all extension areas.


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