Long Term Effects of Ericoid Endomycorrhizae on the Growth of Micropropagated Plants of Vaccinium corymbosum L. in the Field.

Previous studies on mycorrhization procedures and the effect of inoculation of 10 selected mycorrhizal fungi (Hymenoscyphus ericae, two isolates of Oidiodendron maius, 6 sterile non-classified mycelia isolated in Italy on Calluna spp., and one sterile mycelium isolated on Vaccinium spp. in France) on rooting and growth of micropropagated plants of 9 cultivars of Vaccinium corymbosum, had shown that the growth and habit of plants and their root development depended on the interaction between the fungus strain and the cultivar. The effect of the interaction between cultivar and fungus strain was maintained, in the first years of field growth, on the size of plants, on the number and length of shoots, and also on the number and length of basal shoots. In the present contribution, the results of eight years of cultivation of the same plants in three different fields are reported. The performance of mycorrhized plants in different soils and environments is compared for plant growth and development. The long term interaction of fungal strain and blueberry cultivar was confirmed: some of the strains that increased the growth of a cultivar were ineffective or even decreased the growth of another one. Moreover, within cultivar, differences in plant growth among fields showed a significant interaction between fungal strain and environmental and soil conditions.