MYCORRHIZAL INOCULATION OF CHESTNUT SEEDLINGS: EFFECT ON SURVIVAL AND GROWTH AFTER TRANSPLANTATION

Abstract

Trees of several species cannot develop without mycorrhizas. The first trials of controlled mycorrhization were made in Australia early in the twentieth century. Mycorrhizal inoculation is based on the main findings: (1) any mycorrhiza is better than none for plants produced in greenhouses/nurseries; (2) some species are more beneficial than others under specific environmental conditions. Building on mycorrhizal studies on chestnut (Castanea sativa Mill.) inoculated plants, work was started on inoculum production in order to inoculate chestnut plants in greenhouse/nursery and evaluate its effects. A consortium programme was started with the production of inoculum and mycorrhization of seedlings in greenhouse, followed by transference to nurseries. We report the methodology and results obtained in three year long trials with chestnut tree seedlings mycorrhization with Pisolithus tinctorius. Mycorrhizal effects were analyzed through germination rates, survival and growth along the germination, and weaning processes. Inoculation of the germination substrate did not influence germination rates, bpt affected plant growth: mycorrhizal plants are thicker than non-mycorrhizal ones. Inoculation of the substrate at sowing followed by previous acclimation revealed more favourable for plant survival and growth than inoculation and direct transfer to the nursery. When in contact with soils infected by Phytophthora cinnamomi mycorrhizal plants revealed higher survival capacity than non-mycorrhizal plants although this survival is dependent on the time of mycorrhization.