Increase of rooting ability in the woody species kiwi (Actinidia deliciosa A. Chev.) by transformation with Agrobacterium rhizogenes rol genes.

The woody species kiwi (Actinidia deliciosa A. Chev.), a male and late flowering clone of the cv Hayward, has been transformed by a T-DNA fragment encompassing rol A, B, C genes of A. rhizogenes. Transgenic plants, regenerated from leaf disc callus, showed the typical "hairy root" phenotype as described in herbaceous species. Explants from these plants (both leaf discs or 3 to 4 node leafy microcuttings) showed an increased ability to produce roots. Since root formation is one of the limiting factors in the vegetative propagation of woody species, the results have been discussed in relation to the use of A. rhizogenes rol genes in improving root morphogenesis in trees.