They emit intense aromas of garlic, fermented cheese and methane and are so rare that they can cost up to £9,000 a kilogram. Now, the mystery of how to grow the elusive white truffle on a commercial scale that has baffled experts for more than half a century appears to have been solved.
This week, researchers at France’s National Research Institute for Agriculture, Food and the Environment (INRAE) reveal that they have grown 26 white truffles at a secret location in Nouvelle-Aquitaine, western France.
While more than 90% of the black, highly prized Périgord truffles sold are cultivated, previous attempts to cultivate their rarer white relatives have failed. This bumper crop follows two prolific years at the test plantation, during which barely a handful were grown.
“This significant increase in production is very promising,” said mycologist and project leader Dr Claude Murat of INRAE and the University of Lorraine in Nancy. “This confirms that the truffle is well established.
“It’s common for the black truffle to start with just a few truffles and then a rapid increase, and the white truffle seems to be behaving the same way, which is good news for future breeding.”
Truffles, like many other mushrooms, form symbiotic relationships with certain types of trees, connecting with their roots. They supply the trees with extra water and minerals in exchange for carbon-based nutrients.
Scientists developed a way to infect trees with Périgord truffles in the 1970s, leading to thousands of plantations in France, Italy and later Spain. The same technique failed for Italian white truffles (Tuber magnatum), despite more than 500,000 seedlings being planted in Italy.
A few truffles were found in the plantations 15 to 20 years after planting, but because they were in areas where T. magnatum occurs naturally, the researchers believe they came from native fungi.
Since 1999, researchers from INRAE and the Pépinières Robin Nursery in France have been producing oak trees that have been genetically linked with Italian white truffles. Since 2008, they have been planted in several truffle gardens.
Tests of soil samples from five sites, all outside the part of the country where the species occurs naturally, showed that the fungus was present in four of them.
Three truffles were found in the Nouvelle-Aquitaine orchard in 2019 and four in 2020. The 26 found in 2021 weighed a total of about 900 g. Of the 52 oak trees planted in 2015, 12 have produced truffles so far.
“This is the first time Tuber magnatum fruiting bodies have been grown in significant numbers outside of its natural range, so it’s a very exciting development,” said Scotland-based mycologist Prof Paul Thomas, whose company Mycorrhizal Systems is working with commercial partners to develop the black truffle. plantations. “Many previous attempts have failed, so we still need to know more about how they’ve done it and how to replicate it.”
Murat and fellow INRAE mycologist Dr. Cyrille Bach have provided details of the truffle growing conditions in a research paper to be published this week in Le Trufficulteur, the journal of the French Truffle Growers Federation.
“We need to see the results of further tests, but this opens up an attractive opportunity for truffle growers to diversify into a new market,” said Alain Ambialet, president of the French Truffle Growers Federation.
Some say rising temperatures and reduced water availability in Spain, Italy and southern France are opening up opportunities for truffle farmers further north, including the UK. “With acres of calcareous soil and less water pressure, the UK has good potential for growing truffles, including white truffles,” Murat said.
