actions are judged by current values or by those of only one set of actors. The drivers are assessed at three levels-local, regional, global. The assessments are further elaborated (2.3) in order to provide depth and detail in terms of three thematic narratives-(1) genetic resources management; (2) pest management; (3) food system management.

2.1.1 The specificity of agriculture as an activity

At the beginning of the period under assessment, policy makers and other knowledge actors around the world had vividly in mind the fact that food is a basic necessity of life and that its supply and distribution is vulnerable to a range of disruptions that cannot always be well controlled. Only for those for whom food is reliably abundant can food be treated as an industrial good subject to the laws of elasticity of price. The special characteristics of farming as a human activity for supplying a basic necessity of life and as the cultural context of existence for a still large if declining proportion of the world's people are central to meaningful historical assessment of AKST.

2.1.1.1 The characteristics of agriculture as a multidimensional activity

Agriculture is based on local management decisions made in interaction with the biophysical, ecological and social context, this context to a large extent itself evolving independently of agriculture. It follows that AKST includes both a set of activities that happen to deal with the particular domain of agriculture and activities that necessarily coevolve with numerous other changes in a society. AKST thus involves many types of knowledge and many suppliers of that knowledge acting in relation to vast numbers of (semi) autonomous enterprises and decision makers. This characteristic has provided special challenges but also opportunities in the design of institutional arrangements for AKST (Yunus and Islam, 1975; Yunus, 1977; Izuno, 1979; Symes and Jansen, 1994; Scoones et al., 1996; Buck et al., 1998; Stroosnijder and Rheenen, 2001; Edgerton, 2007).

A place-based activity. Agriculture as a place-based activity relies on unique combinations of bioclimatic conditions and local resources in their natural, socioeconomic and cultural dimensions. Agricultural practices depend on and also influence these conditions and resources (Herdt and Mellor, 1964). Specific knowledge of the locality is an asset decisive for the outcomes actually achieved through application of any technology (Loomis and Beagle, 1950; Hill, 1982; Giller, 2002; Tittonell et al., 2005, 2007; Vanlauwe et al., 2006; Wopereis et al., 2006; Zingore et al., 2007) yet a dominant trend over the period is the evolution of agricultures driven by nonlocal changes and by the introduction of technologies designed by actors and in places far removed from their site of application (Merton, 1957; Biggs, 1978; Anderson et al., 1991; Seur, 1992; Matson et al., 1997; Harilal et al., 2006; Leach and Scoones, 2006). This trend has been tightly associated with the adoption of a science-based approach to the industrialization of farming. It has allowed greater control by farmers of production factors and the simplification and homogenization of production situations particularly for internationally-traded commodities and

high-value crops (Allaire, 1996).This has enabled large surpluses of a narrow range of basic grains and protein foods to be generated, traded and also moved relatively quickly to meet emergency and humanitarian needs. It has eased hunger and reduced poverty as well as kept food prices stable and low relative to other prices and allowed investment in other economic sectors (FAO, 2004). However, the ecological and cultural context of farming is always and necessarily "situated" and cannot-unlike functions such as water use or carbon trading-be physically exchanged (Berkes and Folke, 1998; Hubert et al., 2000; Steffen et al., 2004; Lal et al., 2005; Pretty, 2005). Advances especially in the ecological sciences and socioeconomic research as well as drivers originating in civil society movements (2.2, 2.3) have mobilized science, knowledge and technology in support of approaches appreciative of place-specific, multidimensional and multifunctional opportunities (Agarwal et al., 1979; Byerlee, 1992; Symes and Jansen, 1994; Gilbert, 1995; de Boef, 2000; Fresco, 2002). Examples include (Cohn et al., 2006), trading arrangements connecting those willing to pay for specific ecological values and those who manage the resources that are valued (Knight, 2007), urban councils using rate levies to pay farmers for the maintenance of surrounding recreational green space or for ecosystem services such as spreading flood water on their fields; hydroelectric companies such as Brazil-Iguacú paying farmers to practice conservation tillage to avoid silting behind the dams and improve communal water supplies; farmers' markets; and community-supported agriculture.

An embedded activity. The resulting flows of products and services are embedded in a web of institutional arrangements and relationships at varying scales, such as farmers' organizations, industrial districts, commodity chains, terroirs, production areas, natural resource management areas, ethnic territories, administrative divisions, nations and global trading networks. Farmers are simultaneously members of a variety of institutions and relationships that frame their opportunities and constraints, offering incentives and penalties that are sometimes contradictory; farmers require strategic ability to select and interpret the relevant information constituted in these institutions and relationships (Chiffoleau and Dreyfus, 2004). The various ways of organizing science, knowledge and technology over the last sixty years have taken different approaches to farmers' strategic roles (see 2.1.2).

A collective activity. Farmers are not wholly independent entrepreneurs; their livelihoods critically depend on relationships that govern access to resources. With asymmetrical social relations, access is not equitably or evenly distributed. Individuals, groups and communities attempt to cope with inequalities by developing relational skills and capacity for collective action that help them to protect or enhance their access to and use of resources (Barbier and Lémery, 2000); the form that collective action takes changes over time and place and between genders. As commercial actors such as supermarkets have become dominant in food and farming systems, many farmers have transformed their production-oriented organizations into market-oriented organizations.