Improvement of ornamental characters and fragrance and production in lemon-scented geranium through genetic transformation by Agrobacterium rhizogenes

We obtained transformed root cultures for the scented, “lemon geranium ( Pelargonium sp.) by inoculating stem and leaf fragments with Agrobacterium rhizogenes . Shoots regenerated spontaneously from transformed roots and contained the TL– and TR–DNAs (left–hand and right–hand transferred DNAs) from the Ri (root–inducing) plasmid. The transformed phenotype included shorter stature, increased leaf and branch production, accelerated rooting of cuttings, altered root system architecture, inhibition of ftowering and increased production of geraniol and other aromatic substances. We discuss applications of this phenotype in improving the ornamental quality of scented geraniums and increasing the production of their essential oils.