Ectomycorrhizal status of a mature productive black truffle plantation

The truffle-plantation “Los Quejigares” was planted in 1971 by AROTZ-CATESA company. It is a 600 ha plot of Quercus ilex mycorrhizated with Tuber melanosporum at 1250 m a.s.l. on calcareous soil. This plantation is the largest of the world and one of the eldest truffle-plantations of Spain and it is in full production. Knowledge of the mycorrhizal status of a mature black truffle plantation is significant for the improvement of truffle cultivation. Ectomycorrhizae were studied for knowing T. melanosporum persistence and diversity and abundance of other ectomycorrhizal types. Roots of 16 holmoaks were sampled, 12 trees produce truffle sporocarps and four did not. It was found a mean of about 70% of T. melanosporum ectomycorrhizae in all the studied trees, independently of their capacity to produce or not sporocarps. Also, 105 more different ectomycorrhizal types were found. In spite of the high number of morphotypes found, it seems that they do not replace T. melanosporum, showing that there is a coexistence between species in the fungal community associated to the roots.