Rapid multiplication of plant material suitable for agriculture, horticulture and forestry through tissue culture is called micro propagation. The main advantages of plant production through micro propagation are as follows:
(1) Multiple Shootlet Production: By culturing the shoot apex, multiple copies of a single plant or hybrid can be obtained. As a result of special treatments, instead of callus, many buds are formed, which can be grown to obtain shoots. In which, with the help of hormones can stimulate the formation of roots. It has helped a lot in the propagation of potato, cardamom, banana, chrysanthemum etc.
(2) Somatic Embryogenesis: Vegetative embryos or embryoids are embryos that develop from vegetative cells in tissue culture. They pass through all the stages through which embryos pass in sexual reproduction. Thousands of carrot embryos can be obtained with a little culture medium, from which plants can be grown.
(3) In the production of disease-free plants: In vegetatively propagating plants, the transmission of pathogens and viruses occurs easily through propagules. It has been found that the cells of the meristem of the shoot tip of diseased plants do not contain germs. By culturing these cells, many plants like potato, sugarcane, strawberry etc. are obtained in disease free state.
(4) Production of Androgenic Haploids: Haploid plants have great importance in plant breeding programs. You know that obtaining pure (homologous) plants is a very difficult task. Self-pollination has to take place for several generations. But this has become quite simple through tissue culture. You know each anther contains several thousand haploid cells (pollen grains). By culturing them, haploid plants are obtained. Homozygous diploid plants can also be obtained by doubling their chromosomes with the help of colchicine. In this way, one does not have to wait for a long time to obtain homogeneous variations. For the first time, Guha and Maheshwari (1965) had obtained mass haploid plants of Datura inoxia.
(5) Embryo Rescue: The embryo produced as a result of interspecies hybridization usually dies and the seed becomes useless. The newly born embryo can be saved by removing it and culturing it.
(6) Induction and Selection of Mutants: Cells are grown in liquid culture medium and shaken well so that the cells become suspended in the medium. Thereafter, these cells are transferred to different culture media in different petri dishes which contain mutagenic inducing chemicals. Beneficial variants are selected from the obtained mutants.
Similarly, adding herbicides, salts etc. to the medium will cause death of all the cells. Only those who can resist them will survive. From them, resistant varieties of plants can be developed.
(7) Protoplast Fusion: By this method, hybrids of such plants can be prepared, between which sexual reproduction is not possible. The cell wall is removed from plant cells with the help of enzymes and the protoplasm is grown in culture medium. Before the cell wall is re-formed, the protoplasms of both species and subspecies are fused with the help of polyethylene glycol (PEG) or other suitable substances. By culturing these hybrid protoplasms, hybrid plants are obtained. Pomato, a hybrid of potato and tomato, is good example for this.