A brilliant sea of fruits and vegetables filled a hall at the Sonoma County fairgrounds last week, where grotesquely oversized pumpkins lurked like sumo wrestlers along a far wall. Table after table was dedicated to a rainbow of produce: fluorescent pink dragonfruit, mahogany-colored eggs and hundred of apples.
One long display appeared to be a grab-bag of species: persimmons, tomatoes, squash, eggplant and peppers. A closer look revealed that each of these fruits—the round red…