Hi,

Viral disease free plants can be obtained from virus infected plants by the technique of meristem culture. Tissue culture is another method to obtain disease free plants.

Meristem culture is a process in which an already existing shoot meristem grows in the meristem culture and adventitious roots regenerate from these shoots which makes the generated plant disease free.

In tissue culture, plants regenerated from tissue culture are called somaclones. This technique is used to generate resistance to diseases where the resistance sources is not identified.

Hope this was helpful