Department of Botany, University of Calcutta, Calcutta.
The present communication deals with the various in-vitro techniques attempted to conserve the germplasm of banana. The major aspects included are rapid clonal propagation through meristem culture of several cultivars belonging to different genomic constitutions, their medium-term storage under minimal growth condition and finally somatic embryogenesis. Rapid in-vitro multiplication of banana has been achieved by culturing the explants in Murashige and Skoog's semi-solid basal medium supplemented with low concentration of indole acetic acid and a fairly high level of benzyl amino purine. The genomic constitution of the cultivar on one hand as well as the concentration of benzyl amino purine in the medium on the other hand seem to control the rate of multiplication of shoot cuds. Eventually, the multiplication rate was greatly accelerated by increasing the concentration of benzyl amino purine in the medium. However, the presence of one or two ‘B’ genomes which came from Musa balbisiana causes an increase in the rate of multiplication as compared to the cultivars possessing only ‘A’ genome, from Musa acuminata. Regarding the in-vitro conservation of banana germplasm, established shoot tip cultures could be successfully stored for over two years in the same container without any transfer to fresh medium by simply reducing the incubation temperature and light intensity from 30° to 15°C and 1000 lux respectively. The survival percentage of various cultivars at different stages of conservation have been critically analysed. The regeneration of somatic embryos through the induction of callus and their further studies have been briefly described in the last phase of the paper. The somatic embryos, when carefully analysed histologically, exhibited striking similarities with their zygotic counterparts.
