(i) Plant tissue culture It is a technique of producing entire plants from a few plant cells or tissues by growing them in an artificial medium. The method used for micro- propagation or tissue culture is as given below:
(ii) The process of fusion of protoplast of somatic cells obtained from different varieties or species of plant on a suitable nutrient medium in vitro to develop a hybrid is known as somatic hybridisation and the hybrids so, produced are called somatic hybrids. It is carried out in the following main steps:
(i) Single cells are isolated from selected plants.
(ii) Cell walls of these single cells are digested by the enzymes like pectinase and cellulose to expose the marked protoplasts.
(iii) Naked protoplasts are then isolated from the plasma membrane.
(iv) After that the isolated protoplasts are fused together in order to obtain the hybrid protoplasts in a special nutrient medium under sterile conditions. The fusion of parent protoplasts is induced by Polyethylene Glycol (PEG) solution
(v) Hybrid protoplasts thus, obtained are cultured in a suitable medium to form new plants.
Pomato is a somatic hybrid produced by the fusion of tomato and potato protoplasts. Unfortunately, this plant do not have all the desired characteristics for its commercial utilisation.