The plant tissue culture techniques are recognized as a creative, promising and feasible option for the multiplication and genetic modification of plant worldwide. As a tool of genetic engineering for plant, in vitro plant regeneration systems are taken a key part. Tissue culture systems are also used as alternative methods of vegetative plant propagation. While one cutting produces one plant by cutting propagation method and one seed produces one plant. In contrast, one explant (a piece of stem, leaf, bud, root, anther, or etc.) can produce an infinity number of plants using tissue culture system within a relatively short period. Somaclonal variation can be occurred in regenerated plant when plant regenerated from callus, which needs to be screened out of breeding programmes. Tissue culture systems have been now important and valuable for propagation and modification genetically in many plant species with immense potential in agriculture, horticulture and forestry. In this book, micropropagation, shoot organogenesis from callus and cell suspension culture are described in detailed, which are essential for improvement of watermelon.