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GM coffee: brewing up a storm?

Ripe coffee berriesShiny, red and firm to the touch, a cluster of ripe coffee berries is as appealing to the eye as the aroma that emanates from freshly ground coffee. But is this picture actually as attractive as it appears?

Not all coffee berries ripen at once and, depending on the plant and climate, harvesting may occur from as little as once a year to as much as all year round. Harvesting is done by hand or by machine. Mechanical harvesting is faster and more productive but all the berries are simultaneously stripped or shaken from the branches regardless of ripeness. This process not only damages the trees by taking the berries, smaller branches and leaves but it also means that ripe and unripe berries have to be sorted. However, what would it mean to coffee production if all berries were to ripen at once?

In 1999, the first US patent involving part of the genetic make-up of coffee was granted to the University of Hawaii. The patent describes how biotechnologists have 'switched off' the natural ripening processes of coffee cherries. The purpose of this delayed ripening is to bring about uniform ripening with the result that all coffee cherries would develop to become green and hard but no further ripening would occur. Final ripening could then only be triggered after berries were exposed to a sprayed application of ethylene, a naturally occurring plant hormone. Harvesting would then be easier, and yields higher but there is, as yet, no indication that the quality of coffee produced in this way would be retained.

The delayed-ripening technology has yet to be tested in the field but it is possible that the first cup of GM coffee may be brewed within the next few years. Many feel that this development poses a considerable threat to smallholder coffee growers, particularly those that rely on a labour intensive system and who are already suffering from falling world prices. However, according to Peter Baker of CABI, it is likely that GM coffee varieties would be high yielding dwarf varieties requiring high inputs to perform well. These are therefore unlikely to be grown by smallholders as many poor farmers are reluctant to replace their trees and often have bushes over 40 years old. In addition, GM varieties are likely to be developed for the more industrial robusta coffee whereas many smallholders grow arabica varieties more suited for the speciality and organic sector.

Other developments in GM coffee may generate a caffeine-free coffee, which should reduce costs and potentially improve taste by removing the need to process the coffee to remove the unwanted stimulant. Scientists comparing new coffee varietiesHowever, caffeine is known to have insecticidal properties and has been linked to resistance to coffee berry disease so it is possible that costs of inputs would actually increase. But pests could be deterred, perhaps, through development of Bt coffees. CIRAD, in collaboration with Nestlé, have produced a transgenic plant with resistance to the coffee leaf miner (Perileucoptera coffeella), which attacks all cultivated species of coffee and can cause major defoliation. In order to assess agronomic characteristics, resistance to leaf miners and transfer of pollen to non-transgenic coffee trees planted around the trail plot, GM Bt robusta plants are currently being planted in French Guiana for field testing over the next five years.

As the trials are not in Africa, contamination of wild coffee species will not be a problem. But if Bt coffee were grown in Africa in the future there is a danger that cross-pollination could occur, particularly as seeds can be dispersed by birds or bats and cherries are often transported long distances. Smallholders growing coffee in the vicinity of GM coffee could be at risk from contamination and growers might find it more difficult to cash in on the organic or non-GM speciality markets. Non-target effects, for example on bees, will also be studied during the Bt trials but, as with other herbicide-resistant plants, there is considerable concern over the long-term implications of these species being grown with regard to biodiversity and the risk of selection of resistant insects and weeds.

GM technologies, and particularly those for coffee, are still relatively new on the scene. Admittedly, they are developing thick and fast but, ultimately, although cost-effectiveness of technologies will have an impact, the preferences and influence of the consumer is likely to determine when and if the GM storm over coffee breaks.

For further information contact Peter Baker, CABI

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