Seeds of domesticated squash found by scientists on the western slopes of the Andes in northern Peru are almost 10,000 years old, about twice the age of previously discovered cultivated crops in the region, new, more precise dating techniques have revealed.

The findings about Peru and recent research in Mexico, anthropologists say, are evidence that some farming developed in parts of the Americas nearly as early as in the Middle East, which is considered the birthplace of the earliest agriculture.

Digging under house floors and grinding stones and in stone-lined storage bins, the archaeologist Tom D. Dillehay of Vanderbilt University, in Nashville, uncovered the squash seeds at several places in the Ñanchoc Valley, near the Pacific coast about 400 miles north of Lima. The excavations also yielded peanut hulls and cotton fibers  about 8,500 and 6,000 years old, respectively.

The new, more precise dating of the plant remains, some of which were collected two decades ago, is being reported by Dr. Dillehay and colleagues in today’s issue of the journal Science.