MOLECULAR BREEDING IN THE GENUS MUSA - A STRONG CASE FOR STMS MARKER TECHNOLOGY

Musa species are among the tallest monocotyledons and include major fo od-producing species. The principal cultivars, derived from two major species Musa acuminata ('A' genome) and Musa balbisiana ('B' genome), are polyploid hybrids (mainly AAA, AAB and ABB triploids), medium to h ighly sterile, parthenocarpic and clonally propagated. Bananas and pla ntains are crops to which molecular breeding is expected to have a pos itive impact. In order to better understand banana genetics, more know ledge has to be accumulated about the complex genome structure of hybr ids and cultivars. Therefore, the aim of our work is to develop molecu lar markers that are codominant, reliable, universal, highly polymorph ic and that are applicable to collaborative Musa germplasm genotyping and mapping. Two size-selected genomic libraries have been screened fo r the presence of simple sequence repeats (SSR). Our data demonstrate that SSR are readily applicable to the study of Musa genetics. Our com prehensive analyses of a significant number of banana sequence tagged microsatellite sites (STMS) will add to our knowledge on the structure and phylogeny of genomes of the Musa species, and suggest that micros atellites be used as anchor markers for a banana genetic core map. Add itional markers, such as e.g. CAPS have also been tested in order to i ncrease the detection of polymorphisms exceeding that revealed by STMS technology. The utility of PCR-derived markers for collaborative gene tic analyses of the banana genome, and the transferability of 'streaml ined' laboratory techniques and data analysis to Developing Countries are discussed.