In vitro colonization of micropropagated Pieris floribunda by ericoid mycorrhizae. I. Establishment of mycorrhizae on microshoots

Selected isolates of Hymenoscyphus ericae (Read) Korf and Kernan, Oidiodend ron griseum Robak, O. maius Barron, and a second O. Robak species were eval uated as inocula for in vitro establishment of micropropagated plantlets of Pieris floribunda (Pursh ex Sims) Benth. and Hook. Severity of shoot necro sis on microshoots differed for each isolate of Oidiodendron. Inoculation o f micropropagated plantlets with isolates of H. ericae benefited initial sh oot and root development on agar-solidified Woody Plant Medium (WPM) supple mented with sucrose and covered by a layer of autoclaved 1 peat : 1 vermicu lite (v/v). Inoculation of microshoots with H. ericae or isolates of Oidiod endron did not stimulate production of adventitious roots.