PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Orchids due to their extremely beautiful fascinating flowers occupy a significant position in the international floricultural trade of cut flower and pot plants. India, especially the north-eastern region of the country harboring 650 orchid species is a rich storehouse of orchids and offers great potential for commercial floriculture. However, natural populations of these inherently slow growing plants are receding under commercial selection and habitat destruction pressures and many of them are threatened of survival. Rapid multiplication through tissue culture has emerged as an important strategy to release their natural population from commercial collection pressures. Tissue culture offers a rapid means of multiplying orchid stocks with the advantage that the young plants are disease free. The utility of synthetic seeds as an efficient delivery and storage system for germplasm has also been positively tested for several taxa. Molecular markers are being used for analyzing genetic variability, confirmation of hybrids and resolution of phylogenetic problems. Due to their high commercial importance, attempts are being made to develop varieties with novel forms, colours and shades and also resistant to disease, pest and stress, having reduced flowering time and longer vase life. Since improvement by conventional methods is limited due to their long reproductive cycles and slow seed maturation, genetic engineering techniques are being used to provide plants with desired traits. Both direct and indirect methods are used for genetic transformation of orchids. Compared to Agrobacterium-mediated genetic transformation, use of particle bombardment is more successful tool in genetic manipulation of orchid species. The present review highlights the current approaches of molecular biology and biotechnology aimed at improving and conserving orchids.