'International Society for Horticultural Science (ISHS)'
Abstract
In the wild, most of the Ericaceae are mycorrhized by typical ericoid
endomycorrhizae thus overcoming the absence of root hairs and the difficulty of
absorption of some nutrients in low pH soils. Many authors studied the relationship
between root colonization and soil composition but only a few of them took in
consideration the species of the fungi mycorrhizing the roots. Our previous works on
Vaccinium pointed out the effects of different fungal strains on rooting and growth
of in vitro produced plants. The aim of this research was to study the effect of the
inoculum with different fungal strains on rooting, acclimatization and growth of the
deciduous Azalea mollis cv. Glowing Embers (Rhododendron japonicum),
micropropagated in vitro. Sterile microcuttings, planted on a sterilized turf
substrate, were inoculated with Hymenoschiphus ericae, seven different strains of
Oidiodendron maius, and some unidentified sterile mycelia, by superimposing the
rooting medium on a pure fungal culture in agar. Rooting time and percentage was
checked. Plant height and rosette diameter, leaf and shoot number of each plant
were measured one year after transferring to ex vitro conditions. All tested strains
were able to infect the roots of the azalea, but different effects were shown on
microcutting rooting time and percentage. Oidiodendron strains were generally more
effective than Hymenoschiphus on growth of established plantlets
