Organic coffee is one of several types of speciality coffees selling at a premium over mainstream coffees because of distinct origin and flavour, environment-friendly production or socio-economic concerns for the smallholder coffee growers. The demand for organic coffee in Western Europe, North America and Japan exceeds the present supply, which is still small (<1% of annual world production). More than 85% of organic coffees come from Latin America and practically all is (washed) arabica coffee. The production of certified organic coffee follows the principles of organic farming developed in Europe and the United States out of concern for the perceived negative effects of conventional high-input agriculture on health and environment. It claims superior ecological sustainability in combination with sound economic viability. A rather complex and expensive system of certification has to be passed before such coffees can be sold as truly organic. Growers adhering to the strict rules of organic coffee production may to some extent share the concern of the health- and environment-conscious consumers, but they are motivated primarily by the economic benefits from the premium received for certified organic coffee. Nevertheless, there appears to be considerable injustice between the extreme preconditions demanded for ‘organics’ by the largely urban consumer of the industrialized world and the modest rewards received by the organic coffee growers for their strenuous efforts. From an agronomic point of view, there is also considerable ground for criticism on the principles of organic farming when applied to coffee. For instance, to sustain economically viable yield levels (1 t green coffee ha−1 year−1) large additional amounts of composted organic matter will have to come from external sources to meet nutrient requirements (especially N and K). Most smallholders will be unable to acquire such quantities and have to face declining yields. Organic farming does not necessarily reduce incidence of diseases and pests below economically harmful thresholds, while the humid conditions of heavily shaded coffee may actually stimulate the outbreak of others. These and other aspects peculiar to the preconditions of organic coffee production are addressed in this review. It is concluded that the concept of organic farming in its strict sense, when applied to coffee, is not sustainable and also not serving the interests of the producer and consumer as much as the proponents would like us to believe. On the other hand, agronomically and economically sustainable coffee production is feasible by applying best practices of crop production and post-harvest processing.

INDEX WORDSCoffee arabica, arabica coffee, coffee berry disease, Colletotrichum coffeanum, resistance breeding. SUMMARYTwo methods of preselection for resistance to coffee berry disease, by artificial inoculation of young coffee seedlings, have been developed recently at the Coffee Research Station in Kenya. The efficiency of these methods has been investigated in a series of experiments by comparing the results of the preselection tests with mature plant resistance, as indicated by visual field scores and artificial inoculation of berries and bud leaves of mature trees and including a large number of varieties and cultivars of Coffea arabica. The preselection test, by which the hypocotyl stems of 6-week old seedlings are inoculated with a spore suspension of the pathogen, proved to be more reliable than the second preselection test with shoot-tips of 10-month old plants. Correlation coefficients between the preselection test and mature plant resistance were resp. r --0.734).80 for the first test against r 0.60 for the latter.

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SUMMARYTraditional cultivars of arabica coffee (Coffea arabica) are susceptible to coffee leaf rust (CLR, Hemileia vastatrix) and coffee berry disease (CBD, Colletotrichum kahawae). CLR is of worldwide importance, while CBD is still restricted to Africa. Host resistances present in C. canephora to both destructive diseases have been successfully introgressed into C. arabica, after several decades of breeding and selection notably in Brazil, Colombia, India and for CBD resistance in East Africa. CLR resistant cultivars have since been grown on hundreds of thousands of hectares in Latin America and elsewhere, while CBD (and CLR) resistant cultivars are now increasingly being planted in East and South Eastern Africa. They contribute to ecologically sustainable coffee production and to considerable socio-economic benefits for the coffee growers. Nevertheless, some representatives of the international coffee trade continue to be sceptical about the cup quality of these modern cultivars. This paper presents an overview of the considerable amount of scientific evidence accumulated over the years showing that, with all environmental factors at optimum level, disease-resistant cultivars can produce quality coffees as good as those from the best traditional varieties.