Explain the relevance of “totipotency” and “somaclones” in raising healthy banana plants from virus infected banana plants.

Totipotency is the process of generating an entire plant from stem cell.  Even if the plant is infected with a virus, the meristem (apical and axillary) is free of virus. Hence, one can remove the meristem and grow it in vitro to obtain virus-free plants. So the callus from the meristematic tissue of infected banana plant can give rise to a healthy banana plant. Therefore, we can notice that the method of totipotency can be used to develop healthy plants. 

"Somaclones" are clones that are produced from somatic (body) cells, as opposed to germ cells (eggs and sperm) and produce genetically and morphologically identical plants are formed. Hence several disease free plants can be generated.