Root induction using Agrobacterium rhizogenes was conducted in
hypocotyl explants, intact seedlings, de-rooted seedling cuttings and
adventitious shoots of radiata pine ( Pinus radiata D. Don). Use of
two A. rhizogenes strains (A4T and LB9402), with or without application
of IBA, can trigger root formation in different explants. Strain
LBA9402 was more effective than A4T in increasing rooting percentage
and root number. Addition of 4.4 uMIBA to the medium further enhanced
rooting from the cultured hypocotyl segments inoculated with the two A.
rhizogenes strains. Strain LBA9402+IBA induced in about 75% of the
cultured hypocotyl segments to form roots. In contrast the controls
failed to initiate roots on intact seedlings or cultured segments in
presence or absence of IBA. Rooting of adventitious shoots from 3
year-old radiata pine was improved following inoculation with LBA9402,
suggesting that this rooting treatment has potential to aid clonal
propagation of radiata pine