14 Procedures to Increase Virus Yield from Infected Plants

This chapter discusses the procedures to increase virus yield from infected plants. Working efficiently with viruses requires both the production of virus in its host and its recovery in a form suitable for the purpose. Virus yield is based on work with tobacco mosaic virus (TMV). TMV is easy to produce and work with; is subject to every type of virus assay that has been used; and the results with TMV also to apply to other viruses. The yield of virus depends on the number of successful inoculations, the eclipse period, the latent period, the rate of increase or decrease of virus, and the migration of the virus from the site of inoculation, each of which is separately decisive. The ideal criteria of virus yield are weight of virus or number of virus particles per unit of infected host tissue. The weight of a virus particle is known if its size and specific gravity are known.