PRODUCTION FOR VIRUS FREEDOM OF SOME PRINCIPAL BULBOUS CROPS IN THE NETHERLANDS
The outcome of the production of virus-tested material per se is determined by a complexity of factors, e.g., a. incidence of viruses in the different crops; b. detection of the virus infection by visual and/or serological means; c. qualitative impact of the viruses; d. quantitative effect of virus infection on the bulb yield in weight and assortment; e. control of virus spread by the elimination of virus sources and the reduction of vector activity; and f. propagation under natural and/or adapted sophisticated conditions, e.g., by the chipping of the bulbs and the application of tissue culture in the end. The complexity of the factors in relation to the different crops is described.
The aim to produce virus-tested crops is successful in tulip, hyacinth, and crocus, but also in lily and seemingly so in bulbous iris. This ultimate aim failed in gladiolus and dahlia. The project in narcissus is in its initial stage.
The ultimate aim to produce virus-tested crops will presistently be pursed in the future in order to furtherly improve the overall quality of the Dutch ornamental bulb industry in the long-term commitment of the people involved in research, inspection, extension, and last but not least the growers.