In vitro mass propagation of flowering plant Torenia (Torenia fournieri Lind.) through nodal segment

Torenia fournieri is an important ornamental plant in Bangladesh that can grow in a variety of soils in moist areas. It is an extensively studied plant species to investigate fertilization and movement of chromosome. This investigation was carried out to establish a suitable protocol for large scale in vitro regeneration. In vitro mass propagation is one of the best biotechnological methods that can be ensured rapid multiplication of disease-free propagules and genetically identical plant production for plant breeding. In vitro plant regeneration in Torenia was obtained on MS medium supplemented with 2.0 mg/l BA using nodal segments as explants. Maximum 95% of the explants were produced multiple shoots in this medium. The maximum number (12) of shoot per explant and the maximum shoot length of 5.5 cm were observed after 60 days of culture. The well-rooted were found when strong and healthy shoots were transferred into half strength of MS+ 1.0 mg/l IBA. The maximum number (18) of root per shoot and the maximum root length of 4.83 cm were recorded in this medium after 30 days of culture whilst 90% of shoots induced root. In vitro raised plantlets did not show any morphological variation and 90% of plantlets was survived in the natural environment. In this study, rapid multiplication of planting material in Torenia through in vitro propagation techniques such as shoot initiation, multiplication, rooting, hardening and optimizing the concentrations and combinations of plant growth regulators is developed. This regeneration protocol will be helpful in in vitro mutagenesis technique to create new variation of this plant within short time cycle.