But biotechnology's most novel contribution will probably be in adding alien genes to the rice gene pool through genetic engineering. Genetic engineering also allows the re-introduction of rice genes that have been extracted and modified to give altered properties. Such gene transfers are impossible with conventional breeding methods. Further, genetic engineering allows introducing one or two well-characterized genes at a time. There is no need for the extensive backcrossing done in conventional hybridization to remove undesirable genes.
Several methods are now available to transfer genes into rice.
So far, the protoplast system, and biolistic and Agrobacterium -mediated gene transfer are noteworthy. All three methods have produced transgenic fertile rice. A few laboratories have produced transgenic rice plants via the uptake of DNA into protoplasts, which are plant cells freed of their cell wall by enzymatic digestion. DNA uptake through the protoplast membrane is achieved either by adding the neutral polymer polyethyleneglycol or by electroporation, in which the membrane is made briefly permeable by application of an electric current. Rice is the first agronomically important monocot to be transformed from protoplasts to yield viable fertile plants.