THE PRODUCTION AND DISTRIBUTION OF VIRUS-TESTED ORNAMENTAL BULB CROPS IN ENGLAND: PRINCIPLES, PRACTICE AND PROGNOSIS

During the past decade or so, the viruses and virus diseases of commercially-important ornamental bulb crops (especially Narcissus, Iris and Lilium have been studied intensively in Britain. Most of the viruses infecting these crops have now been identified or characterised, and methods developed for their rapid detection and identification.

Preliminary surveys indicated that older cultivars of ornamental bulb crops were often totally infected with one or more debilitating viruses. Methods developed for the selection or production of virus-free bulbs are reviewed, and the efficacy of methods ("chipping", "twin-scaling" and micropropagation) devised for their rapid multiplication are evaluated.

During the past five years, virus-free stocks of the three major crops have been released to the Nuclear Stock Association (Bulbs) Ltd. and/or the Nuclear Stock Association (Ornamentals) Ltd. The establishment of viable nuclear stock schemes, their progress and future prospects are discussed.