Using experience with bambara groundnut (Vigna subterranea), this paper examines how local knowledge, genetic evaluation, research in fields, glasshouses and laboratories, and crop simulation modelling might be linked within a methodological framework to assess rapidly the potential of any underutilized crop. The approach described is retrospective in that each activity was not clearly defined and structured at the outset. However, the experience gained may help to establish a methodology by which growers, researchers and international agencies can integrate their knowledge and understanding of any particular underutilized crop and apply similar principles to accelerate the acquisition of knowledge on other underutilized species. The use of a methodological framework provides a basis for activities that maximize knowledge, minimize duplication of effort, identify priority areas for further research and dissemination, and derive general principles for application across underutilized crops in general. It also allows policy makers and planners to make comparative decisions on the nutritional, economic and research importance of different underutilized and more-favoured species. In particular, the incorporation of a generic crop simulation model within the methodological framework may assist growers, extension agencies and scientists to refine general recommendations for any particular crop to local conditions. Also, the incorporation of information gathered from the field, laboratory or market can be used to update rapidly the predictive capacity of the model for each crop.

The concept of an integrated pest management (IPM) strategy is explored using case-study evidence from smallholder agriculture in southern Malawi. The conventional concept of strategy as a ‘plan’ is contrasted with the use of strategy as a game, as a performance, and as an accident. This pluralistic view is echoed in recent literature on business strategy. A typology is developed that relates farmers' choice of IPM strategy to the predictability of crop losses, the stability of the crop environment, and farmers' knowledge of pests. Some implications for IPM are explored. Where conditions favour ‘adaptive’ rather than planned IPM strategies, formal experimentation to verify farmers' strategies may be an inefficient use of resources. Where the crop environment is volatile and several pests attack the crop simultaneously, there may be limited scope to increase the adoption of IPM strategies by improving farmer knowledge of pest biology. Addressing the interactions between pest and crop management is critical in making IPM relevant for resource-poor farmers. A deeper understanding of farmers' management strategies is required to frame meaningful recommendations.

In the process of developing an improved fallow system based on forage legumes, the potential interest of crop-livestock farmers in enhancing soil fertility restoration and dry-season feed supply was assessed during a socio-economic study on 11 farms of settled agro-pastoralists in the subhumid zone of West Africa. Simultaneously, eight farmers in the group participated in simple and largely farmer-managed on-farm experiments testing the establishment of selected forage legumes on fallow land. In addition to agronomic parameters, the participatory approach included an evaluation of the technology by farmers both during farm visits and field days.

With cropping and dry-season feeding strategies increasingly being limited by land availability, the agronomic performance of some of the tested legume species, in particular Stylosanthes guianensis, promised substantial productivity gains once they could be integrated into the traditional fallow system. The major concerns of the farmers were animal health and labour supply for cropping activities, rather than soil fertility and feed constraints. The need for initial weed control within most of the legume species, therefore, limited their acceptability by farmers at this early stage of innovation testing. Nevertheless, farmers' interest grew remarkably in the course of the study. Options for the selection of appropriate species and management practices, which aimed at facilitating the establishment of legumes on fallow land, are discussed as a means of enhancing further adoption of the innovation.

Chickpea (Cicer arietinum) is a promising post-wet-season crop to follow rainfed rice (Oryza sativa) in the High Barind Tract of northwestern Bangladesh. Yields in farmers' fields, however, remain low (<1 t ha−1) primarily due to such factors as poor crop establishment, late sowing, and terminal drought and heat stress. Having been shown to improve plant stand and yield of chickpea in other environments, seed priming – soaking the seed overnight before surface drying and sowing the next day – was tested for its efficacy under Barind conditions.

In the 1998–99 season, 30 trials grown entirely on residual soil moisture were conducted in farmers' fields. A statistically significant mean yield response to priming of 47% was obtained. In 1999–2000, 105 on-farm trials and 15 demonstrations comparing presence and absence of priming were conducted. The crop received rain during this growing season. In a randomly chosen subset of 35 trials, scientists recorded a mean yield increase due to priming of 20%; it was 22% (from 1.02 to 1.25 t ha−1) in the remaining 64 trials (6 of the 105 trials were abandoned) where farmers recorded yields. Using a different variety, the mean yield response to priming in 15 demonstrations was 17% (from 1.25 to 1.46 t ha−1).

The priming response was attributed mainly to rapid seedling establishment, with higher plant stand and earlier crop maturity allowing escape from end-of-season stresses. Priming also reduced the incidence of stem and root diseases, and increased nodulation by native rhizobia. This simple technology can substantially increase chickpea yields to remunerative levels for the resource-poor farmers in this difficult environment. Further, it is suggested that this technology can act as a catalyst for the introduction of further technologies that will permit reliable and profitable cultivation of post-rainy-season crops and thus improve the livelihoods of the rural population.

In Mozambique the sweet potato (Ipomoea batatas) is often grown as both a leafy vegetable, the terminal shoots or vines being progressively harvested during the season, and as a root crop. This paper reports the results of experiments designed to evaluate the effects of drought and vine harvesting frequency on the productivity of both yield components (cv. TIS 2534). Experiments were conducted during the rainy and dry seasons, with supplementary irrigation treatments superimposed. As the frequency of vine harvesting (equivalent to the number of harvests) increased, the total fresh weight of vines increased. There was a corresponding reduction in the yield of storage roots, however, particularly under well-watered conditions. As a result, the total harvested yield (vines plus roots) was remarkably stable in both wet and dry seasons (43–45 t ha−1 fresh weight). The cumulative dry weight of harvested vines increased with the number of harvests at constant rates, depending on water availability (from +150 to +250 when rain-fed, up to +340 to +440 kg ha−1 harvest−1 when irrigated). The corresponding rates of reduction in storage root yields varied from −3 to −130 (rain-fed) down to 310 to 400 kg ha−1 harvest−1 (irrigated). Total dry weight yields under well-watered conditions were constant at about 11 to 13 t ha−1, or double this on an annual basis. Irrigation water-use efficiencies (by dry weight of harvested crop) were generally higher in the dry season than in the rains. For vine production they increased with the number of harvests from 1.6 to 3.5 (rains) up to 0.9 to 6.7 kg ha−1 mm−1 (dry season). The corresponding values for root production were 7.5 to 13.1 (rains) and 12.2 to 19.1 kg ha−1 mm−1 (dry season). For the combined dry weight yields the water-use efficiencies were, with one exception, independent of harvesting frequency at 11.2 (rains) and 19.0 kg ha−1 mm−1 (dry season). Irrigated plants harvested at weekly intervals yielded vine dry weights of about 0.5–0.6 t ha−1 week−1. Compensatory vine growth (reported elsewhere) was observed in previously droughted plants following a rainfall event. The practical implications of these results are discussed. Future papers describe in more detail the physiological aspects of the observed yield responses.

In the semi-arid Mwea Division of Kenya's Eastern Province, the modern pigeonpea (Cajanus cajan) variety Nairobi Pigeonpea 670 (NPP 670) had become known to all farmers and was being grown by 68% of them within a period of 12 years. The only injection of this seed to the area was from a single on-farm demonstration. Three-quarters of farmers found out about the variety from observing it growing in the field, and obtained seed primarily from other farmers in the village. Factors favouring the diffusion of the variety included its attractiveness as a cash crop, the ease with which it could be distinguished from other varieties, the low seed rate, and the relative ease with which growers were able to maintain seed purity. Farmers expressed a willingness to pay for fresh seed, which suggests that more effort needs to be made to involve the formal seed sector. The present regulatory system does not favour the development of a formal supply system. NPP 670 was released more than 10 years after it was first tested.