GENOMIC ANALYSIS OF TRANSGENIC SUGARCANE (Saccharurn spp.) POPULATIONS: ANOTHER LINK BETWEEN BIOTECHNOLOGY AND BREEDING

DIFFERENT sources of sornaclonal variation in transgenic sugarcane populations have been studied at the geno~nic level. AFLP analysis showed both polymorphic bands and variations in the relative intensity of the amplified DNA-products within plants froin the donor genotypes, providing lnolecular evidence of pre-existing variability in sugarcane. Genolnic analysis of transgenic populations showed the presence of polymorphic bands ainong transgenic genotypes, as well as between in vitro plants without transformation and plants froin the germplasm collection. Thus polymorphisms among transgenic lines can include preexisting variability, tissue-culture induced variability, and the effect of the transgene insertions. Promising transgenic individuals for colnmercial use should be selected for transgene expression, the occurrence of DNA changes and the maintenance of desired phenotypic characteristics. The role of somaclonal variation in a sugarcane genetic engineering program is discussed, and a selection scheme, including genomic analysis, is suggested for genetic modified (GM) sugarcane plants.