Rice (Oryza sativa L.) is one of the most important cereals in the world, and extensive studies have been carried out on tissue culture and transformation (see Hasezawa et al. 1989; Bajaj 1991; Uchimiya and Toriyama 1991). However, transformation of rice by Agrobacterium-mediated gene transfer has not been successful until recently, and gene transfer methods developed for rice were restricted to direct gene transfer into protoplasts or particle bombardment methods of direct DNA transfer into intact cells of embryogenic callus or suspension cells (Table 1).