Production of Virus Free Plants
In certain crops, and particularly in ornamentals, it has become possible to produce virus free plants through tissue culture at the commercial level. This can be done by regenerating plants from cultured tissues derived from (i) virus free plants, (ii) meristems which are generally free of infection, (iii) meristems treated with heat shocks (34-36°C) to inactivate the virus (iv) callus, which is usually virus free like meristems. Further, in callus or suspension culture, virus infection can be completely eliminated through repeated subculturing. During production of virus free plants, highly sensitive tests like ELISA (enzyme linked immunosorbent assay) can be employed to monitor virus free plants.

Viruses have been eliminated from a number of economically important plant species (atleast in 75 species) including the following: mottle virus has been eliminated from strawberry; potato virus X from cassava, and cauliflower mosaic virus from cauliflower. In all these cases, significant increase in yield has been obtained through production of virus free plants. These virus free plants, however, are not disease resistant, so that one will have to maintain stock to multiply virus free plants, whenever required.