Gino Boscherini's neat two-story house -- the one with the lawn furniture and old men playing cards out front -- does not look like a repository for precious genetic material.
And with his missing teeth, worn sweater and weathered face, Boscherini, 84, seems an unlikely hero in the quest to preserve biodiversity in the face of climate change.
But his backyard garden contains unusual variants of several plants: a bean grown only here in the hills overlooking Lake Trasimeno, a special tomato that can be stored for months, a type of pulpy squash that is good for pig feed. Such variants, called landraces, possess unique traits encoded in their genes.
Scientists may need to borrow these traits -- the ability to thrive in hotter weather or to resist a particular pest, for example -- to safeguard the global food supply in response to a changing climate. As farms have become more commercialized in recent decades and have moved toward growing one or two high-yield crops, the number of varieties globally is quickly diminishing, erasing plant genes at the very moment in history when they may be most needed.
That has left Europe's backyard gardeners and small farmers, like Boscherini, as the de facto guardians of disappearing fruits, grains and vegetables. Time is working against them.
Most of them are very old, and as they die their plants are dying with them. Most of their children and grandchildren have little interest in maintaining the crops, holdovers from Europe's more agrarian past.
"Central Italy has 500 landraces, mostly maintained by aged farmers and gardeners, and that is a big problem since there is a chance these crops will be lost within a generation," said Valeria Negri, a plant scientist at the University of Perugia.
Negri takes in orphaned seeds and raises them behind her home, the way a pet lover might take in stray dogs or cats.
About 10 years ago, Negri and her students went door to door in nearby Tuscany asking households what crops each grew. When they returned several years later to request sample seeds, one third of the plants were no longer being cultivated.
The attrition of crop types has alarmed scientists, who are trying to catalog the variants as well as their special traits, and figuring out how to preserve them.
Three-quarters of the biodiversity in crops has been lost in the last century, according to the UN Food and Agriculture Organization. In Mexico, only 20 percent of the corn types that existed in the 1930s exist today. In the US, 95 percent of cabbage varieties and 94 percent of pea types are gone.
While a few private and local government programs are evolving to conserve these special crops, they are scattershot and the main actors remain the "farmers or the families" themselves, Negri said.
Here in rural Italy, the drama of ebbing biodiversity is playing out in nearly every family, as children move to the cities and farmers who remain turn to easier-to-use store-bought seeds rather than processing their own.
Boscherini's son Carlo, 57, a railroad worker, was taught as a child to propagate and care for the family crop lines, which had been handed down like heirlooms from generation to generation. Since his retirement, he has been helping his father pick seeds, preserving them for storage and replanting them in spring. But the younger generation of Boscherinis will not continue the tradition.