Relative quantification of DNA from Tuber melanosporum mycelia was performed by conventional and real-time PCR in soil from trees in three truffle orchards of different ages to determine: (1) whether burn appearance is related to the amount of T. melanosporum mycelium in soil, and (2) whether productivity onset and truffle production are related to (a) the amount of T. melanosporum mycelium in soil, (b) tree height and diameter, (c) burn extension and (d) surface rock cover. The burn seems to appear only after a certain amount of mycelium has formed. Precociously productive trees presented higher quantities of mycelium than nonproductive trees in the productivity onset study, while highly productive trees presented less quantities of mycelium than nonproductive trees in the productivity study. Trees with high but not excessive surface rock cover showed greater truffle production. Larger trees tended to display a burn earlier than smaller trees.

No abstract

Climate change affects the distribution of many species, including Burgundy and Périgord truffles in central and southern Europe, respectively. The cultivation potential of these high-prized cash crops under future warming, however, remains highly uncertain. Here we perform a literature review to define the ecological requirements for the growth of both truffle species. This information is used to develop niche models, and to estimate their cultivation potential in the Czech Republic under current (2020) and future (2050) climate conditions. The Burgundy truffle is already highly suitable for cultivation on ~ 14% of agricultural land in the Czech Republic (8486 km2), whereas only ~ 8% of the warmest part of southern Moravia are currently characterised by a low suitability for Périgord truffles (6418 km2). Though rising temperatures under RCP8.5 will reduce the highly suitable cultivation areas by 7%, the 250 km2 (3%) expansion under low-emission scenarios will stimulate Burgundy truffles to benefit from future warming. Doubling the moderate and expanding the highly suitable land by 352 km2 in 2050, the overall cultivation potential for Périgord truffles will rise substantially. Our findings suggest that Burgundy and Périgord truffles could become important high-value crops for many regions in central Europe with alkaline soils. Although associated with uncertainty, long-term investments in truffle cultivation could generate a wide range of ecological and economic benefits.

Està subjecte a una llicència de Reconeixement-NoComercial-SenseObraDerivada 4.

Background: The objective of this study was to analyze the current situation of the truffle sector in the main producing countries of the Mediterranean area. Additionally, we identified the challenges for the future and the priority actions to develop the truffle sector in the region. Methods: We used a Delphi process approach, and we selected a total of 17 expert panelists in different positions within the supply chain of the target countries (Spain, France, Italy, Croatia, and Greece). Results: The results obtained allowed us to have a complete description of the current truffle supply chain. We confirmed an evolution of the sector due to the cultivation success of several Tuber species. The maturity of the sector has produced shifts in the roles that form the traditional truffle supply chain operators. We confirmed the trend of a decrease of collectors that hunt truffles in the wild and sell to small travelling buyers, whilst truffle hunters that collect for farmers and specialty wholesalers are emerging. However, a trend of truffle price decrease in the last few years has alerted the sector. Conclusions: As production increases due to truffle cultivation, it will be necessary to promote truffle consumption. We identified actions to develop the truffle sector: (a) strengthen the link between truffles, tourism, and gastronomy; (b) increase the effort at European level for the recognition of truffle production, helping to develop truffle culture and marketing; (c) increase the awareness and consumption of truffles among consumers; and (d) develop tourism workshops for truffle farmers.

The unprecedented price inflation of Black truffles, recently exceeding 5000 Euro kg −1 (in Zurich), is a combined result of increasing global demands and decreasing Mediterranean harvests. Since the effects of long-term irrigation and climate variation on symbiotic fungus-host interaction and the development of belowground microbes are poorly understood, the establishment and maintenance of truffle plantations remains a risky venture. Using 49 years of continuous harvest and climate data from Spain, France and Italy, we demonstrate how truffle production rates, between November and March, significantly rely on previous June-August precipitation totals, whereas too much autumnal rainfall affects the subsequent winter harvest negatively. Despite a complex climate-host-fungus relationship, our findings show that southern European truffle yields can be predicted at highest probability (r=0.78, t-stat=5.645, prob=0.000 01). Moreover, we demonstrate the reliability of national truffle inventories since 1970, and question the timing and dose of many of the currently operating irrigation systems. Finally, our results suggest that Black truffle mycorrhizal colonization of host fine roots, the sexualisation of mycelium, and the formation of peridium are strongly controlled by natural summer rainfall. Recognising the drought-vulnerability of southern Europe's rapidly growing truffle sector, we encourage a stronger liaison between farmers, politicians and scientists to maintain ecological and economic sustainability under predicted climate change in the Mediterranean basin.

No abstract

In Mediterranean climate, young truffle-oak orchards are subjected to drought episodes that can compromise the development of Tuber melanosporum. We investigated the responses of T. melanosporum to water supply in three periods: May to July, August to October, and May to October. In each period, five water doses were established: 0, 25, 50, 75, and 100% of the reference evapotranspiration (ETo). Five orchards were planted with Quercus ilex inoculated with T. melanosporum, and in each orchard, we arranged a two-factorial design with irrigation period and irrigation dose as main factors to test their combined effects on the development of both T. melanosporum and Q. ilex after 3 years in the field. Irrigation period significantly interacted with irrigation doses for the absolute presence per seedling of T. melanosporum mycorrhizae. Irrigation in May-July increased significantly T. melanosporum colonization in seedlings irrigated with 50% ETo dose compared to the 0% ETo dose. A similar pattern with smaller differences in means was observed in August-October period, but the irrigation doses did not change T. melanosporum colonization when we watered from May to October. We found ectomycorrhizae different from T. melanosporum in 51% of the seedlings studied, but their presence was marginal. Our results suggest that a moderate irrigation dose promotes seedling growth and number of fine root tips per unit of fine root length, which may be potentially colonized by T. melanosporum.