Plant tissue culture-A new tool for vegetable improvement (Indian scenario): A review

In vitro culture of plant cells/tissues is now routine using a range of explant types from many of the important vegetable and fruit crops. Successful technologies include isolation, culture of tissues, cells, protoplasts, organs, embryos, ovules, anthers and microspores and regeneration from them of complete plantlets. The development of plant tissue culture technology represents one of the most exciting advances in plant sciences. For example, the prospect of being able to introduce, develop, produce, transfer and conserve the existing gene pool of plant sciences by using tissue culture methods opens up new opportunities for researches and entrepreneurs. The term plant tissue culture should denote in vitro cultivation of plant cells or tissues in an unorganized mass, i.e., callus culture. Plant tissue culture techniques, in combination with recombinant DNA technology, are the essential requirements for the development of transgenic plants. However, culture techniques like anther/pollen/ovule culture, meristem culture can themselves be utilized for crop improvement or may serve as an aid to conventional breeding. In recent, isolated microspore culture has developed as a breeding tool and an experimental system for various genetic manipulations. The inherent potentiality of a plant cell to give rise to a whole plant, a capacity which is often retained even after a cell has undergone final differentiation in the plant body, is described as ‘cellular totipotency'. On the other hand, production of virus-free plants via meristem culture can reduce losses caused by phyto-pathogens. Embryo culture has many potential uses ranging from overcoming seed dormancy to facilitation of inter-specific hybridization. Protoplast fusion technique can be used for the transfer of cytoplasmic male sterility from one species to another in a short period of time. In cabbage, male sterile cybrids are being utilized by seed companies to produce hybrid seeds on commercial scale and at competitive rates. Plant tissue culture and cell culture are providing useful methods for germplasm storage either by low temperature storage of organized tissue, or cryopreservation of cell or embryo culture.