Quarantine and the Exchange of Crop Genetic Resources

Abstract

he international exchange of plant germ plasm for breeding programs and gene banks has increased spectacularly during the last few decades. A need to boost and stabilize crop yields worldwide has spurred this large-scale movement of breeding materials (Plucknett et al. 1987). But concern is mounting that the risk of spreading crop pests and diseases is also increasing as a result of the accelerated pace of plant germ plasm exchange. At the same time, accusations have been made that quarantine services are not keeping pace with the volume of germ plasm shipments, the latest information on disease and pest epidemiology, nor new screening techniques, particularly those involving biotechnologies. The expanding international distribution of germ plasm poses hazards for crop production worldwide (Karpati 1981, 1983). In germ plasm collections in the United States alone, some 17 crop species have been found to harbor seed-borne viruses (Doyle 1985). Worldwide, seed-borne viruses have been found in germ plasm collections of barley (Hordeum spp.), cherries (Prunus spp.), beans (Phaseolus spp.), peas (Pisum sativum), and lentils (Lens culinaris) (Hampton 1983, Mandahar 1981). Flexibility is essential for successful