As part of the reform process of the Consultative Group on International Agricultural Research (CGIAR), its Technical Advisory Committee is being transformed into a Science Council. An interim Science Council has been operating since January 2002. The primary role of the Council will be to enhance and guard the relevance and quality of science in the CGIAR System. Relevance is viewed as researching the ‘right things’ to address the System's goals, and deals with the relevance of identified research priorities and strategies and the nature of the planning and consultation process. Ex-ante analyses of need and potential impact to formulate the priorities and strategies are important elements in defining relevance. Quality is viewed as researching the ‘right things well’ and deals with the efficient use of state-of-the-art knowledge, research methods and protocols. The paper outlines the interim Council's suggestions for an operational framework of the Science Council. It serves as a starting point for the development of specific criteria, procedures and guidelines for carrying out the envisioned responsibilities. The Science Council must act in a strategic advisory role, basing its advice on: (i) planning and strategy development in the context of CGIAR goals; (ii) internal self-assessments by CGIAR Centres and Programmes and independent external monitoring and evaluation; and (iii) impact assessments. The paper discusses these three complementary functions. Each depends on the other in a dynamic feedback process that is essential if the CGIAR is to remain at the frontiers of science and development, maintain its science relevance and quality, and contribute in the most effective and efficient manner to the mission and goal of the Group.

The effects of on-farm seed priming (i.e. seed soaking) on the emergence, growth and yield of cotton and maize were studied in the field in the south-eastern lowveld of Zimbabwe. Experiments were conducted on both crops in the 1999/2000 and 2000/2001 seasons and, in the 2001 winter season, on maize only. The interaction of priming with tillage (ox-drawn ploughing or hand-hoeing) and simulated sowing rainfall regimes (irrigations of 15 mm, 30 mm or 45 mm at planting) was studied. Priming usually increased the rate of emergence in maize, but always decreased final percent emergence in cotton. In the 2000/2001 season, there was an interaction between priming and simulated sowing rainfall regimes such that the 15 mm treatment gave a smaller adverse effect of priming in cotton than the 30 and 45 mm treatments. In maize, however, the 15 mm treatment gave an adverse rather than a positive effect of priming on emergence. There was little effect of tillage on emergence or growth. Priming did not affect the relative growth rate of cotton or maize, although plants grown from primed maize seed were consistently larger at any given date throughout the 2001 winter season. Plants from primed seed also flowered and matured earlier in the winter 2001 season. There were no significant effects of priming on yield, except in the 1999/2000 season, where priming decreased yield in cotton. It was concluded that the effect of priming can depend on crop species.

Farmers grow vegetables widely during the dry season in wetlands known locally as dambos in southern Africa. Declining soil fertility is one of the major factors limiting smallholder vegetable production in the dambos of eastern Zambia. An experiment was initiated with 43 farmers with the objective of assessing the agronomic and economic feasibility of foliar biomass of gliricidia (Gliricidia sepium) and leucaena (Leucaena leucocephala) for production of cabbage, onion and a subsequent maize crop during the dry season. The treatments were, on a dry-matter basis, 8 and 12 t ha−1 gliricidia, 12 t ha−1 leucaena and 10 t ha−1 manure+half the recommended fertilizer rate, inorganic fertilizer at recommended rate, and a control without any inputs. Direct field measurements and informal enquiries were used for evaluating the effects of different treatments. The highest cabbage and onion yields were obtained from manure+half-rate fertilizer application. The gliricidia biomass transfer technology produced cabbage, onion and maize yields comparable with the full fertilizer application. In both cabbage and onion, manure+fertilizer gave generally higher net incomes. Biomass transfer also recorded higher net incomes than the control, and required lower cash inputs than the fully fertilized crop. Net incomes of the biomass treatments were substantially reduced by the labour costs for pruning and incorporation of the biomass. The results indicate that the gliricidia biomass transfer technology could be used as an alternative to inorganic fertilizers for vegetable production in dambos.

On a large coconut plantation planted on a deep peat soil in Sumatra, Indonesia, hybrid coconut yields are stabilizing at values well below their potential, even in plots where known production factors have been mastered since the outset: land preparation, water control, and mineral fertilization. To explain this situation, five hypotheses have been proposed. They were tested one by one in field trials. The authors have demonstrated that the main reason for stabilized yields was the Lepidoptera root pest Sufetula spp. and conclude by considering lines of research for controlling this pest in the context of rehabilitation and replanting.

A field experiment in an alluvial sandy loam saline soil was conducted during the winter (rabi) season from 1997–98 to 1999–2000 at the Central Institute for Research on Buffaloes, Hisar, to study the effect of saline drainage water (EC=3.6 –7.4) on five (rabi) forage crops: oat (Avena sativa), rye grass (Lolium rigidum), senji (Indian clover) (Melilotus indica) berseem (Egyptian clover) (Trifolium alexandrinum) and shaftal (Persian clover) (Trifolium resupinatum). All the crops were established using canal water as pre-sowing irrigation and the various irrigation strategies were imposed subsequently. Irrigation with canal water resulted in a 115% increase in forage yield compared with the saline drainage water. The results suggested that alternate irrigation with saline drainage water increased the yields of all the forage crops compared with using saline drainage water only. Further, alternate irrigation, starting with canal water, was superior to alternate irrigation starting with saline drainage water because less salt was added in total. Oat produced the largest green-forage yield (32.3 t ha-1) in the first year while rye grass gave its maximum in the second (34.6 t ha-1) and third years (37.0 t ha-1). Persian clover performed better than did Egyptian clover in all the three years. Interaction between species and irrigation treatments was significant. In comparison with canal irrigation water, there was a 36 %, 42 %, 54 %, 68 %, and 85 % yield reduction in rye grass, oat, Persian clover, Egyptian clover and senji, respectively when only saline drainage water was used for irrigation reflecting their relative tolerances of salinity. Yields declined linearly for all crops with increases in the quantity of salt applied.

Canavalia ensiformis, Crotalaria grahamiana, Dolichos lablab, Mucuna pruriens, Tephrosia vogellii and Tithonia diversifolia were evaluated as potential species for soil fertility replenishment in on-farm adaptive trials, farm visits and field days in Tororo District, eastern Uganda. Farmers used multiple criteria for assessing and selecting those species that fitted within their production systems and production objectives. Farmers also adapted the technologies to allow for local opportunities and constraints. A preference ranking and logit regression analysis of probabilities of acceptance of the species conducted in 19 farmer groups showed that Mucuna had high, Tithonia and Crotalaria intermediate, and Canavalia, Lablab and Tephrosia low probabilities of being accepted or adopted. The evaluations showed that whilst technologies need to be adapted, a single-use technology had little chance of large-scale adoption. This paper highlights adaptations/innovations by farmers, and opportunities for participatory action research targeting farmers' production objectives.

Through years of research, the Ethiopian Agricultural Research Organization has recommended a number of improved bread-wheat varieties for production in the different climatic zones, along with accompanying technology packages. In areas such as the Jijiga plains, however, adoption of these varieties by the farmers has been very limited. The principal objective of the study was, therefore, to investigate the reasons why farmers are reluctant to adopt high-yielding improved wheat varieties, and to identify farmers' preferences. An assessment study followed by participatory evaluation of the performance of five improved bread-wheat (Triticum aestivum) varieties and a local control was carried out under farmers' management practices. The trial was conducted at 10 locations (across three districts) on the Jijiga plains for two consecutive years (the 1999 and 2000 cropping seasons) and involved 30 farmers. Farmers' preferred varieties were identified using preference ranking. The results showed that farmers refrained from the adoption of some ‘improved’ varieties of bread wheat that were provided through the extension services because the varieties performed poorly under farmers' conditions. The study also showed that farmers do have multiple criteria for evaluating the varieties apart from yield, though the latter was the major parameter for recommending and releasing varieties for multi-locations. Farmers identified earliness, yield, and quality as the main criteria for adoption of wheat varieties. Accordingly, variety HAR-710 stood first in terms of yield (2.56 t ha−1) and other parameters, followed by PAVON -76 (2.49 t ha−1). Though its grain yield was relatively lower than the improved ones, the local control was preferred to some improved varieties used in this study for other quality parameters. The study highlighted the need for re-orienting agricultural research towards involving farmers at the appropriate stages of technology identification.

The aim of this work was to determine the importance of the genotype-by-environment interaction in true potato seed breeding. In order to establish the importance of this type of interaction, experiments were sited across three Peruvian locations, San Ramon (warm mid-altitude slopes), Huancayo (cool Andean highlands), and La Molina (coastal desert). The genotype by environment interaction significantly affected tuber yield in all breeding materials (4x-4x from random or selected parents, and 4x-2x crosses). For example, the 10 most outstanding 4x-2x crosses for tuber yield were different when tested in warm and cool locations. Similarly, two clones derived from 4x-4x crosses were among the best 15 hybrids assessed in the two lower altitude locations. These two offspring provide examples of crossover genotype-by-environment interaction for tuber set, non-cross order genotype-by-environment interaction for tuber yield and lack of genotype-by-environment interaction for days to flowering. Because top yielding true potato seed offspring for each location were locally adapted, cultivars or advanced selections from the target area should be the parental sources of true potato seed offspring.

The changes taking place in the mixed farming systems of northwest Syria were examined by re-visiting, in 1996 and 2000, five villages along a rainfall gradient. The villages had been surveyed first in 1977–79. In those villages with moderate rainfall, intensification of crop production, namely a trend towards cereal monoculture and the planting of tree crops, did not lead to specialization in cropping at the expense of sheep ownership. In contrast, households in the areas too dry for most rainfed crops except barley (Hordeum vulgare) were more likely to sell their sheep because they depended heavily on off-farm income. Increases in crop yields were found but these only benefited the families in villages in the higher rainfall zones. Conversely, with the exception of ewe fertility, there was little evidence of improvements in sheep productivity. The mixed farming systems in the five villages sampled are still passing through a period of transition, and the cropping component will undoubtedly continue to change. This is less likely to happen to the small ruminant component in the near future unless the sector is given higher priority in national policy. As a strategy to increase feed production and balance the crop rotations, the prospects for closer crop/livestock integration at the farm level are limited by the many difficulties associated with the introduction of leguminous pasture and forage crops.

There are currently concerns within some sugar industries that long-term monoculture has led to soil degradation and consequent yield decline. An investigation was conducted in Swaziland to assess the effects of fallowing and green manuring practices, over a seven-month period, on sugarcane yields and the physical properties of a poorly draining clay soil. In the subsequent first sugarcane crop after planting, yields were improved from 129 t ha−1 under continuous sugarcane to 141–144 t ha−1 after fallowing and green manuring, but there were no significant responses in the first and second ratoon crops. Also, in the first crop after planting, root length index increased from 3.5 km m−2 under continuous sugarcane to 5.2–6.8 km m−2 after fallowing, and improved rooting was still evident in the first ratoon crop where there had been soil drying during the fallow period. Soil bulk density, total porosity and water-holding capacity were not affected by the fallowing practices. However, air-filled porosity increased from 11 % under continuous sugarcane to 16% after fallowing, and steady state ponded infiltration rates were increased from 0.61 mm h−1 to 1.34 mm h−1, but these improvements were no longer evident after a year back under sugarcane. Levels of soil organic matter were reduced in all cases, probably as a result of the tillage operations involved. In the plant crop, root length was well correlated with air-filled porosity, indicating the importance of improving belowground air supply for crop production on poorly draining clay soils.