The puzzle of the precious white truffle finally yields to science | Food

They give off intense aromas of garlic and fermented cheese and are so rare they can fetch up to £9,000 a kilogram. Now the puzzle that has confounded experts for more than half a century about how to grow the elusive white truffle on a commercial scale seems to have been solved.

This week, scientists from the National Research Institute for Agriculture, Food and the Environment (INRAE) will reveal that, in an undisclosed location in Nouvelle-Aquitaine, western France, they have grown 26 white truffles.

While more than 90% of the highly prized Périgord black truffles are cultivated, previous attempts to cultivate their rarer white cousins ​​have failed. This bumper crop follows two productive years at the experimental plantation in which barely a handful were grown.

“This significant increase in production is very promising,” said Dr Claude Murat, mycologist and project leader, from INRAE ​​and the University of Lorraine in Nancy. “This confirms that the truffle is well established.

“With black truffles, it’s usual to have just a few truffles at first, then a rapid increase, and it seems the white truffle behaves the same way, which is good news for future cultivation.”

Truffles, like many other fungi, form symbiotic relationships with certain tree species by bonding to their roots. They provide trees with additional water and minerals in exchange for carbon-based nutrients.

Scientists developed a way to inoculate trees with Périgord truffles in the 1970s, leading to the creation of thousands of plantations in France, Italy and later Spain. The same technique failed with Italian white truffles (magnum tuber), despite the planting of more than 500,000 seedlings in Italy.

A few truffles were found in plantations 15 to 20 years after planting, but because they were in areas where T. magnatum occurs naturally, researchers believe they come from native fungi.

As early as 1999, researchers from INRAE ​​and the Pépinières Robin nursery in France produced oak trees genetically confirmed to be partners of the Italian white truffle. These were planted in a number of truffle orchards from 2008.

Tests on soil samples from five sites, all outside the part of the country where the species occurs naturally, showed the fungus was present at four of them.

Three truffles were found at the New Aquitaine orchard in 2019 and four were found in 2020. The 26 found in 2021 weighed around 900g in total. To date, 12 of the 52 oak trees planted in 2015 have produced truffles.

“It’s the first time magnum tuber fruiting bodies have been grown in significant numbers outside of its native range, so this is a very exciting development,” said Professor Paul Thomas, a Scotland-based mycologist whose company Mycorrhizal Systems works with commercial partners to develop plantations of black truffles. “Many previous attempts have failed, so we still need to know more about how they did it and how to replicate that.”

Murat and his fellow INRAE ​​mycologist, Dr. Cyrille Bach, provided details on the growing conditions of truffles, in research to be published in The truffle growerthe magazine of the French Federation of Trufficulteurs this week.

“We need to see the results of other experiments, but this opens up what could be an interesting opportunity for truffle growers to diversify into a new market,” said Alain Ambialet, president of the French Federation of Truffle Growers.

Rising temperatures and reduced water availability in Spain, Italy and southern France are, some say, opening up opportunities for truffle entrepreneurs further north, including in the UK. “With acres of limestone soil and less water stress, there is good potential for growing truffles, including white truffles in the UK,” Murat said.

This article was amended on July 24, 2022 to remove the suggestion that white truffles smell like methane, which is an odorless gas.