325 Principles and practices in transgenic cereal production.

M. BÅGA and R. N. Chibbar. Plant Biotechnology Institute, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK., Canada S7N 0W9.

Production of transgenic plants is a complex process. It requires an efficient in vitro regeneration system that is compatible with the strategies chosen for gene delivery and selection of transformants. So far, transgenic wheat has been produced by micro-projectile bombardment of immature zygotic embryos or isolated scutellar tissues. However, the transformation frequencies for wheat are generally low and regenerated plants often carry multiple copies of inserted genes and frequently lack the desired phenotype. We will in this presentation address some of the approaches to decrease these problems. To allow for a faster production of explant material, there is great interest in using mature embryos or leaf- bases as starting material for plant regeneration. The biolistic technique to deliver the gene expression cassettes to the plant is gradually being replaced with Agrobacterium-mediated transformation protocols, which are expected to increase the transformation frequencies. Strategies used to allow a higher consistency in transgene expression will also be presented.