Local knowledge is intimately connected with cultivation practices and therefore plays an important role in the conservation of crop diversity. At the same time, a formal scientific approach is essential for local knowledge to be expressed, particularly when diversity is under an ever-increasing threat.

What is local knowledge?

Local knowledge is a resource that develops, becomes shared, and is used by a particular social group (for example a farming community, social network or ethnic group) in the pursuit of certain goals and interests.

It generally emerges from people's direct experiences as they learn — deliberately or by chance — about their biophysical and social environments. It may also include knowledge handed down from previous generations, shared by other communities, and acquired from external research institutions. Thus it forms a body of knowledge that usually extends beyond the indigenous, traditional and technical. Since it is shaped by particular social, cultural, physical and temporal contexts, local knowledge is inherently diverse.

Local knowledge has historically served as an important resource for farming communities in managing their livelihoods, and in continuously adapting to changes in their environment. Gaining a full understanding of the knowledge that exists in a local community is therefore a necessary first step for agricultural research and development programmes.

In this paper we will look at the role local knowledge plays in the conservation and cultivation of sweetpotato — an important crop for farmers in Southeast Asia, but one that is neglected by formal science in favour of cereals and other commercial food crops.

Secondary crops

Researchers have shown relatively little interest in secondary crops despite the role they play in nutrition, and in generating income and employment. They are considered less important than staples, such as rice and maize, and consequently receive much less investment from either the public or the private sector [1]. A notable exception is the research on sweetpotato and other secondary crops conducted by the Users' Perspectives With Agricultural Research and Development (UPWARD) network of the International Potato Centre (CIP).

Sweetpotato is widely grown and important to many people's livelihoods throughout Asia. Though farmers have little access to the latest scientific research, they have for many years generated, shared and used local knowledge about the crop.

Sweetpotato in Indonesia and the Philippines

Indonesia is generally regarded as the world's second centre of genetic diversity of sweetpotato after northwest South America. In the eastern Indonesian province of Irian Jaya, sweetpotato is the staple food both for people living in the highlands and for their pigs. Ethnobotanical and anthropological research shows that farmers have maintained a wide range of sweetpotato cultivars for different agronomic characteristics, for different food qualities (for both humans and animals), and for ritual purposes [2].

In the Philippines, sweetpotato is grown using three main production systems — commercial farms in the lowlands, 'slash and burn' fields in the uplands, and small-scale home gardens. In one highland province in the northern Philippines where sweetpotato is a staple food, over 200 cultivars have been recorded. In an upland municipality in the southern Philippines, 55 cultivars had been grown over several decades, but changing market demands mean that nearly half of these are no longer cultivated [3]. Similarly, increased commercialisation of sweetpotato production in the lowlands of the northern Philippines has reduced the number of cultivars from 25 to just two dominant types over the past 50 years [4].

Local knowledge about sweetpotato diversity

Local knowledge about sweetpotato has developed out the need for farmers to learn about the crop and its management, given the limited availability of relevant scientific knowledge. Poor farming households in marginal agricultural environments have few resources to aid their work other than local knowledge. Empirical studies undertaken by the UPWARD network and other CIP research projects have shown that local knowledge plays an important role in the cultivation of this crop [4,5,6].

Local knowledge about diversity of sweetpotato cultivars is particularly important in Indonesia and the Philippines. Maintenance of this diversity helps to ensure that specific cultivars are available when and where farmers need them. To achieve this, local knowledge is an essential resource for identifying, cultivating, utilising and maintaining different cultivars for different purposes.

Both in Indonesia and the Philippines, cultivar diversity is a key element of local sweetpotato production systems. Local dietary patterns and preferences, adaptability to local growing conditions, and traditional beliefs and practices serve as a major impetus to conserve sweetpotato diversity.

However, increased market orientation and new livelihood opportunities have reduced this diversity, mainly threatening those cultivars that have no immediate economic value. This underscores the need for farmers to conserve cultivar diversity for strategic purposes against the backdrop of changing socio-cultural, economic and agro-ecological environments. Local knowledge is one tool available to farmers in meeting this challenge.

The complexity of local knowledge

UPWARD research has concluded that local knowledge consists of a complex set of concepts, beliefs, values, practices, methods, materials, tools, organisations and events. These different aspects of local knowledge become apparent in a number of issues:

People choose descriptive labels for sweetpotato cultivars according to various aspects of their environment. For instance, in the Philippines, they might assign names based on a distinguishing characteristic (e.g. Amsitan for a bland taste), the person who introduced the cultivar (e.g. Bentong), the place it came from (e.g. Kapangan) or even a popular personality (e.g. Imelda). However, cross-checking with standard scientific nomenclature is also necessary because the use of local names is highly arbitrary and variable.

Local people develop constructs to represent particular agricultural activities, outputs or preferences. One example is nabukag, a multi-dimensional trait associated with a mealy taste that is popular among subsistence-farming households in the Philippines. Generally, farmers articulate a wide range of sweetpotato attributes — morphological, gastronomic, physiological or ecological, or based on familiarity, function or use — that no single cultivar can fully satisfy. As a consequence, farmers grow a mix of cultivars with complementary traits.

Beliefs and values
Traditional beliefs and values influence agricultural decisions and actions. In the male-dominated and polygamous culture of Irian Jaya in Indonesia, the ability to cultivate a larger area, and thus to maintain a greater number of cultivars, is determined by the number of wives in a household. Women provide farm labour and are usually more knowledgeable about cultivation and uses of sweetpotato cultivars.

Crop management practices
Intimate knowledge of crops and varieties is part and parcel of local agricultural knowledge systems. People learn and adopt different practices of maintaining a variety of cultivars for various uses. Subsistence farmers in the Philippines deliberately cultivate a mix of short-maturing cultivars (e.g. Manobo, harvestable after three months) and late-maturing cultivars (e.g. Kaledades, harvestable after seven months). This ensures a steady supply of sweetpotato roots to meet household food needs for a long period.

Local people develop ingenious methods to accomplish key tasks in crop management as they face limited resources and difficult circumstances. In remote Indonesian communities with no direct access to post-harvest and marketing facilities, farmers use various methods of storing and processing sweetpotato. The roots of cultivars destined for human consumption are preserved by cleaning, boiling, slicing and smoking over a fire. Of the roots intended for animal feed, a small amount is boiled and given to the pigs for them to eat immediately. The rest is given raw and take the pigs longer to eat, which appears to fill them up more.

Exchange of planting materials
In the Philippines, women's informal social networks are key channels for diffusion of cultivars through the exchange of planting materials. Kinship ties and traditional leadership authorities are also key factors in sustaining collective efforts to conserve sweetpotato diversity, such as the establishment of community-managed gene banks.

Supporting the management of local knowledge

Efforts to help local people conserve the diversity of their biological materials need to be accompanied by efforts to conserve associated local knowledge. It may be argued that knowledge becomes lost even more quickly than the materials themselves; loss of knowledge leads to loss of materials, as people no longer know how to use them.

In CIP-UPWARD's experience [2,7,8,9], potential strategies for enhancing local knowledge of sweetpotato diversity include:

Documentation of local knowledge associated with cultivars
There is potential for expanding conventional modes of collecting germplasm material to put in gene bank collections. During germplasm collection trips, documentation of relevant local knowledge and other cultural information could be a complementary goal to the gathering of routine data such as morphological, physiological and ecological characteristics of cultivars. An example is 'memory banking', which is a participatory methodology for documenting, reconstructing and systematising local knowledge associated with agricultural biodiversity. Developed and piloted through sweetpotato conservation projects in the Philippines, 'memory banking' combines ethnographic and rapid-appraisal methods such as interviews, diagramming and mapping, sorting and ranking exercises, participant observation, and specimen collection and preservation.

Conservation of biological materials
In situ (maintaining in the 'wild', including on farms) and ex situ collections (conserving outside the original habitat) are complementary means for ensuring that cultivars are maintained for short- and long-term use by the community. In Indonesia, in situ conservation through community-based 'gene banks' ensures local availability, regular supply and dynamic evolution of adapted materials. The importance of maintaining an ex situ duplicate collection was realised during a prolonged period of drought, when crops were lost. To resuscitate local agriculture, cultivars were reintroduced through the distribution of planting materials to farmers.

Conservation through diversified uses and markets
Emerging market demands, which often have narrow and specific varietal requirements, tend to be perceived by farmers as a disincentive to conservation efforts. In the Philippines, increased demand for high-starch varieties resulted in a shift towards two dominant varieties accepted by processing factories. However, the subsequent collapse of the local sweetpotato starch industry made farmers realise the importance of catering to a broad range of markets and uses. To achieve this, they have re-cultivated a number of cultivars that meet the specific requirements of local markets, animal feed factories and snack food enterprises.

Facilitation of learning and sharing knowledge
Participatory experimentation — among farmers and with researchers — helps support local interest in learning about conserving diversity. Setting up activities to strengthen informal networks can also encourage the exchange of both planting materials and information. One example is a conservationists' workshop piloted in the Philippines, which brought together indigenous farmer-curators from various sweetpotato-growing communities. Through such workshops, farmers learned that cultivars they thought were lost had survived in other communities. In addition, farmers acted as consultants to scientists as they sought to define the locally relevant research agenda and to conceptualise follow-up projects.

Complementing local knowledge with formal scientific knowledge
Local conservation efforts can benefit from the tools and knowledge available from formal science. To assist farming communities in Indonesia make strategic decisions for conservation of sweetpotato diversity, a team of technical scientists conducted genetic characterisation, taxonomic classification, identification of duplicates and in vitro conservation.

Dindo M Campilan is social scientist at the International Potato Center and coordinates the UPWARD Network based in Los Banos, the Philippines. (email [email protected])



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[2] Prain, G., J. Schneider and C. Widyastuti. 2000. Farmer maintenance of sweetpotato diversity in Irian Jaya. In: Encouraging Diversity, The Conservation and Development of Plant Genetic Resources (C. Almekinders and W. de Boef, eds). Intermediate Technology, London, UK. 54-59.

[3] Prain, G. and C. Bagalanon (eds). 1994. Local Knowledge, Global Science and Plant Genetic Resources Conservation: Towards a Partnership. CIP-UPWARD, Los Banos, Laguna, Philippines.

[4] Prain, G. and D. Campilan. 1999. Farmer maintenance of sweetpotato diversity in Asia: dominant cultivars and implications for in situ conservation. In: Impact on a Changing World, CIP 1997-98. CIP, Lima, Peru. 317-328.

[5] Prain, G. and C. Bagalanon (eds). 1998. Conservation and Change, Farmer Management of Agricultural Biodiversity in the Context of Development. CIP-UPWARD, Los Banos, Laguna, Philippines.

[6] Schneider, J. (ed). 1995. Indigenous Knowledge of Crop Genetic Resources. CIP-ESEAP/CRIFC, Bogor, Indonesia.

[7] Boncodin, R. and B. Vega. 1998. Local views on genetic resources conservation. UPWARD Fieldnotes 7(1): 12-13.

[8] Campilan, D. 2002. Farmer management of sweetpotato diversity in a changing livelihood system. In: In situ Conservation of Agrobiodiversity, Lessons from the Field (G. Prain and M. Holle, eds). CIP, Lima, Peru. (In press)

[9] Nazarea, V. 1998. Cultural Memory and Biodiversity. University of Arizona Press, Tucson, Arizona, USA.