Barley (Hordeum vulgare L.) has been second to wheat as the most important cash crop in Canada for many years but recently has been challenged for that position. In 1998, canola surpassed barley in hectares planted but not in total yield (BMBRI Barley Briefs, #400, 1998). Annually, about five million hectares are planted to barley, mainly for livestock feed. However, since barley with malting quality commands a premium price, seeking to improve this quality has been a major influence, up to now, in breeding and growing of barley cultivars. Presently, feed quality is also receiving much attention. Thus, the major traits of inter?st for barley transformation research in Canada are related to quality and stress tolerance. Stresses include disease and insect resistance as well as drought and cold tolerance.
While gene transformation is still in its infancy relative to technology development and knowledge of the process of DNA incorporation and gene expression, work on crop improvement has progressed with many species. This push of applications has been spurred by the speed with which genes can potentially be incorporated into elite lines. Transformation of barley requires the development of a complete system. It requires a totipotent cell or tissue culture system, the identification, isolation and econstruction of genes into vectors, and the efficient delivery of the vector into target cells where the desired genes are incorporated into the host cell DNA. The successful methods of delivery, and target tissues and genes utilized will be briefly reviewed prior to summarizing barley transformation research in Canada.