Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2004
Publication Date: 6/1/2005
Citation: Scagel, C.F. 2005. Inoculation with ericoid mycorrhizal fungi alters fertilizer use of highbush blueberry cultivars. Hortscience. 40:786-94.
Interpretive Summary: We investigated the potential role ericoid mycorrhizal fungi (EMF) play in container-grown blueberry production. Specifically, we determined whether growth and nutrition of highbush blueberry is influenced by inoculation with various EMF isolates and whether the response to EMF is altered by the type of fertilizer used. Rooted tissue culture plantlets of seven highbush blueberry cultivars were inoculated with one of three isolates of ericoid mycorrhizal fungi and grown for two years with either inorganic or organic fertilizer. Growth of four cultivars was greater when plants were grown with inorganic fertilizer than when plants were grown with organic fertilizer; plants generally partitioned more biomass to roots and less to stems and leaves when grown with organic fertilizer. Regardless of fertilizer type, inoculation with any of the three EMF increased biomass of six cultivars, and inoculated plants partitioned less biomass to roots and more to stems. In all cases, inoculation of plants with EMF alleviated any nutrient limitation to growth; nutrient use was either similar to plants grown with inorganic fertilizer or plants exhibited a more efficient use of nutrients. Results suggest that nutrient availability may influence colonization and growth responses to EMF, however, aspects of fungus-host specificity and inoculum availability also play a role in EMF colonization of roots in container production.
Technical Abstract: Seven highbush blueberry cultivars were inoculated with one of three isolates of ericoid mycorrhizal fungi (EMF) and grown in pots for two years with either inorganic or organic fertilizer. Root colonization of non-inoculated plants was low (<15%) regardless of fertilizer source; root colonization of inoculated plants was 15-30%. Colonization was typically higher when plants were grown with organic fertilizer. Inoculation generally increased plant growth, but decreased root:shoot biomass ratios regardless of the type of fertilizer used. Inoculation also increased nutrient uptake and/or nutrient use efficiency in several cultivars, particularly when plants were fertilized with organic fertilizer. Without inoculum, however, some cultivars fertilized with organic fertilizer had less growth and lower concentrations of N, K, S, and Cu than those fertilized with inorganic fertilizer. Cultivars that were genetically close in ancestry showed a high degree of variability in response to mycorrhizal fungi, while responses to fertilizer type were similar. Results suggest that nutrient availability may influence colonization and growth responses to EMF, however aspects of fungus-host specificity and inoculum availability also play a role in EMF colonization of roots in container production.