Mycorrhizal synthesis between Tuber borchii and Arbutus unedo L. seedlings and micropropagated plants

F. Plácito, I. Ferreira, M. Clemente, P. Figueiredo, M.J. Barrento, H. Machado, F. Gomes
Arbutus unedo L. is a Mediterranean species for which the main income is linked to fruit production. The interest for high-quality plant material increased due to its drought tolerance and regeneration ability following forest fires. Previous field trials showed that micropropagated clones have higher production and anticipation of the fructification age compared to seedlings. Mycorrhizal plants with Tuber borchii allow to obtain a value-added product (edible mushrooms production). The objective of this study was to compare the mycorrhization with spores of T. borchii, between seedlings and micropropagated plants (during ex vitro rooting and acclimatization). Clones for micropropagation and seeds were collected in adult plants preselected for fruit production and quality. Perlite was used as substrate for inoculation. The mycorrhization rate, after 8 months, was 84.6%, when micropropagated plants were tested compared to 73.4% observed with seedlings. Seedlings showed lower number of secondary roots, and consequently, a later mycorrhization was observed compared to micropropagated plants. The multiple regression analysis indicated that the number of mycorrhizal branches increased with the concomitant increase of the number of mycorrhized secondary roots (P<0.05; R2=0.77). The principal component analysis (PCA, multivariate analyses) shows that the first principal component (i.e., describes the major variability in the data) explains 52% of the total variance and shows the following significant variables (directly related): the number of mycorrhizal branches, the number of mycorrhized secondary roots and the number of primary and secondary roots. Further, the number of mycorrhizal branches varied inversely to the length of the longest primary root. The mycorrhizal plants were established in a field trial to confirm long-term persistence of mycorrhizae and to evaluate the fungal colonization level required to guarantee mushroom production.
Plácito, F., Ferreira, I., Clemente, M., Figueiredo, P., Barrento, M.J., Machado, H. and Gomes, F. (2018). Mycorrhizal synthesis between Tuber borchii and Arbutus unedo L. seedlings and micropropagated plants. Acta Hortic. 1224, 91-100
DOI: 10.17660/ActaHortic.2018.1224.13
arbutoid mycorrhizae, ex vitro rooting inoculation, nursery persistence, strawberry tree, micropropagation

Acta Horticulturae