Blueberries Mycorrhizal Symbiosis Outside of the Boundaries of Natural Dispersion for Ericaceous Plants in Chile

Abstract

Blueberry culture in Chile has been expanding its acreage from suitable edaphoclimatic conditions to environments in which some soil characteristics depart from blueberries’ requirements, among others, to calcareous soils with pH over 7.5. Under these conditions, specific technological field management is required to keep plants producing fruits; however, little attention has been given to mycorrhizal symbiosis. Several studies have been carried out since 2000 in order to assess the importance of the mycorrhizal symbiosis for cultivated blueberry plants in Mediterranean agroecosystems that do not have native Ericaceous plants. Survey of the mycorrhizal status of commercial blueberry fields and directed inoculation assays with commercial and native mycorrhizal inocula have been conducted. It was observed that under these conditions, field blueberry plants form mycorrhizae with native arbuscular and ectomycorrhizal fungi with a lower infection percentage. In some samples, only arbuscular mycorrhizae were observed. Ericoid mycorrhizae were present to a variable extent, probably as a consequence of contamination at the nursery level. No differences in field plants performance were observed. However, when blueberry plants growing in containers, are inoculated with mycorrhizal fungi at the nursery, the symbiosis performs with different levels of efficiency, from positive to negative when compared to non-inoculated plants, but having native mycorrhizal fungi. In some experiments, ericoid mycorrhiza produced by Hymenosyphus ericae had lower plants’ biomass (dwt) compared with native mycorrhiza, but in others, they had the highest. The significance of the fungal edaphic adaptation is discussed.