Fertilisation of Quercus seedlings inoculated with Tuber melanosporum: effects on growth and mycorrhization of two host species and two inoculation methods

Abstract

Modern truffle cultivation is based on use of inoculated seedlings, which
\nshould exhibit highly colonised roots as well as a vegetative quality enhancing
\nfield plant performance. However, poor shoot and fine root growth has been a
\nfrequent issue in inoculated Quercus seedlings production. Fertilisation is a
\ncommon solution in forest nurseries, but high fertilisation levels have been
\nfound to inhibit the formation of ectomycorrhizas of many fungal species. The
\ninfluence of slow-release fertilisation (52 mg N, 26 mg P and 36 mg K per
\nseedling) on growth and ectomycorrhizal status of Tuber melanosporum-inoculated
\nseedlings was evaluated. Host species Quercus ilex and Quercus faginea
\nand inoculation methods involving root-dipping and root-powdering were
\ntested. Fertilisation increased weight of both host species without significant
\ndetrimental effects on ectomycorrhizal colonisation, showing that it can be
\neffectively used in inoculated seedlings production. Both host species showed
\nsimilar response to fertilisation. The inoculation method affected seedling
\nweight and ectomycorrhizal status, suggesting that some inoculant carriers are
\nable to damage Quercus development and T. melanosporum colonisation. The
\nstudy provided an important basis for fine-tuning the use of fertilisers in truffle-
\ninoculated seedling production.