Comparative analysis of different methods for evaluating quality of Quercus ilex seedlings inoculated with Tuber melanosporum

Abstract

The quality of seedlings colonized by Tuber melanosporum is one of the main factors that contributes to the success or failure of a truffle crop. Truffle cultivation has quickly grown in European countries and elsewhere, so a commonly shared seedling evaluation method is needed. Five evaluation methods are currently published in the literature: three are used in Spain and two in France and Italy. Although all estimate the percentage colonization by T. melanosporum mycorrhizae, they do it in different ways. Two methods also estimate total number of mycorrhizae per seedling. Most are destructive. In this work, ten batches of holm oak seedlings inoculated with T. melanosporum from two different nurseries were evaluated by means of the five methods noted above. Some similarity was detected between the percentages of T. melanosporum mycorrhizae estimated by each method but not in their ability to assess the suitability of each batch. We discuss the advantages and disadvantages for each method and suggest approaches to reach consensus within the truffle culture industry for certifying mycorrhizal colonization by T. melanosporum and seedling quality.

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

“…All seedlings bore T. melanosporum mycorrhizas, with all treatments showing mean colonisation levels analogous to those in commercial nurseries (Andres-Alpuente et al 2014 …”

“…High quality inoculated seedlings must exhibit a root system abundantly colonised by T. melanosporum (Andres-Alpuente et al 2014, Murat 2015. The commercial production of these seedlings is customarily done with spore inoculum, either concentrating inoculum onto fine roots or incorporating it into substrate (Chevalier & Grente 1978, Palazón & Barriuso 2007.…”

Edaphic and temporal patterns of Tuber melanosporum fruitbody traits and effect of localised peat-based amendment

“…ballota and Quercus faginea seedlings inoculated with T. melanosporum. The seedlings were produced in a commercial nursery and controlled by public authorities following the INIA-Aragón method 29 . They were planted at a density of 278 trees ha −1 (6 × 6 m), and the two host species were arranged in rows with a 2:1 proportion in the entire experimental site.…”

Root‐tip cutting and uniconazole treatment improve the colonization rate of Tuber indicum on Pinus armandii seedlings in the greenhouse

“…Although 30 mg l −1 uniconazole treatment further increased the root–shoot ratio, the significant decrease in host plant height and biomass limited the increase in truffle colonization rate, as ectomycorrhizae rely on the host plant as a carbon source. According to previous research, the colonization rate and the quality of the host plant constitute the primary factors contributing to the success or failure of a truffle crop (Andres‐Alpuente et al , ).…”

“…The root segments colonized by T. indicum were counted under a stereoscope based on the mycorrhizal fungal structures. A total of 30 root segments (each segment was about 1 cm long) were randomly selected and observed for each seedling (Andres‐Alpuente et al , ). Mycorrhizal colonization rate was expressed as: mycorrhizal colonization rate (%) = (root segments colonized by T. indicum /total root segments observed) × 100 (Benucci et al , ).…”