Quality assessment of truffle-inoculated seedlings in Italy: proposing revised parameters for certification

Domizia Donnini,Leonardo Baciarelli-Falini,Gian M N Benucci,Mattia Bencivenga

doi:10.5424/fs/2014232-05029

Domizia Donnini, Leonardo Baciarelli-Falini + Show 2 more

Open Access

https://doi.org/10.5424/fs/2014232-05029

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Journal: Forest Systems	Publication Date: Aug 1, 2014
Citations: 27	License type: cc-by

Affiliation: University of Perugia

Abstract

Aim of study: the main aims of this study were to evaluate the quality of truffle-inoculated seedlings produced by commercial nurseries in Italy and to identify their minimum requisites in terms of plant age, health, homogeneity, and cut-off percentage of inoculated Tuber and non-Tuber ectomycorrhizae, based on the analysis of an extensive sample of seedlings subjected to quality control and certification.Area of study: truffle-inoculated seedlings produced by Italian commercial nurseries.Material and Methods: analysis of truffle-inoculated seedlings for health and quality standards; recording of presence of inoculated Tuber spp. and other concurrent fungi according to the official Italian method for certification; selective amplification of ectomycorrhizal DNA by PCR species-specific primers.Main results: We showed that mycorrhization levels in truffle-inoculated seedlings increased with time after truffle-spore inoculation. The highest mean percentage of the inoculated Tuber spp., but also the highest presence of contaminants, were recorded after three years. The mycorrhization level of Tuber melanosporum and T. aestivum was higher in Corylus and Ostrya seedlings than in Q. ilex and Q. pubescens, but the latter two host species showed the lowest presence of other ectomycorrhizal fungi. Mycorrhization level distribution in truffle-inoculated seedlings of suitable batches differed very little from the distribution in only all suitable seedlings. Truffle seedlings with other Tuber spp. were very few and even absent after three years. The general quality of Italian truffle-inoculated seedlings is high but can be improved even further by revising the parameters used for their certification.Research highlights: Mycorrhization assessment in truffle-inoculated seedlings produced by commercial nurseries and a revision of the parameters of quality standards following several years of certification in Italy.Keywords: Truffle cultivation; truffle seedlings; mycorrhization level; Tuber; commercial nursery; certification methods.

Highlights

Hypogeous fungi of the genus Tuber (Pezizales) are globally considered delicacies, sold for high prices in markets, and served in the most prestigious restaurants, especially in Italy and France (Hall et al, 2007)
Seedling samples belonged to different plant species: Quercus pubescens Willd., Quercus ilex L., Quercus cerris L., Quercus robur L., Corylus avellana L., Tilia cordata Mill., Ostrya carpinifolia Scop., Pinus pinea L., Pinus halepensis L., Cistus incanus L. and were mycorrhized with Tuber melanospourm Vittad., Tuber magnatum Pico, Tuber aestivum Vittad., Tuber brumale Vittad., Tuber macrosporum Vittad., and Tuber borchii Vittad
Truffle-inoculated seedling samples belonging to Quercus pubescens Willd., Quercus ilex L., Quercus cerris L., Quercus robur L., Corylus avellana L., Tilia cordata Mill., Ostrya carpinifolia Scop., Pinus pinea L., Pinus halepensis L., Cistus incanus L. species were of good quality with regard to health, stem height and diameter, lignification and number of shots and branches

Summary

Introduction

Hypogeous fungi of the genus Tuber (Pezizales) are globally considered delicacies, sold for high prices in markets, and served in the most prestigious restaurants, especially in Italy and France (Hall et al, 2007). In one of the first attempts at cultivation, Frank (2005) discovered that these fungi are ectomycorrhizal (EM) and live in close association with trees. The selection of plantation sites and the quality of the truffle-inoculated seedlings are two fundamental prerequisites to allow these fungi to complete their life cycle and produce truffles. The good quality of truffle-inoculated seedlings alone does not guarantee the production of truffles, because there are many factors that affect the truffle life cycle (Granetti et al, 2005; Bencivenga and Baciarelli Falini, 2012). When soil and climate conditions are ideal for the specific truffle-plant combination, a high mycorrhization level becomes critical to guarantee the advantage of the inoculated truffle over other soil-resident EM fungal competitors (Kennedy, 2010)

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