Molecular cytogenetics and cytometry of bananas (Musa spp.)

This work focused on the development of flow cytometry and molecular cytogenetics for Musa, and on the use of new tools for detailed and more efficient characterisation and analysis of its genome at the nuclear and chromosomal levels. Using flow cytometry, genome size of Musa was determined for the first time, and the extent of its variation was assessed. The method was invaluable for the rapid estimation of ploidy levels and detection of mixoploidy. While the method remains an important research tool, it is being increasingly used in Musa breeding programmes. Molecular cytogenetical methods that permit physical mapping of DNA sequences to Musa chromosomes were developed and used first to obtain physical chromosome landmarks and to characterise various repetitive DNA sequences. A novel method for preparation of high molecular weight DNA has been developed, and work is under way to construct the first Musa B-genome BAC library. The results obtained represent major steps forward in our quest to understand chromosome structure and evolution in Musa. They provide a sound basis for more targeted application of mutation techniques for the breeding of improved cultivars of bananas and plantains.