Plant Tissue Culture (PTC) 

PTC is in-vitro cultivation of plant cell or tissue  under the aseptic conditions & controlled environmental condition in liquid or semisolid nutrient medium.
Apart from mass multiplication of elites, it also provides the means to multiply and regenerate novel plants from genetically engineered cells.

Why PTC:
For growth of pri, & Sec. Metabolites High Yield or Disease free plant or New plant development.