In a small shed nestled in a grove here, Kevin Severns dipped a long, thin instrument into a test tube filled with fresh-squeezed orange juice.

The general manager of a citrus-growing cooperative smiled after getting a reading of the juice's sugar content: "It's off the chart," said the 52-year-old Mr. Severns.

California farmers such Mr. Severns have made a new discovery: Consumers prefer sweeter oranges. The notion, obvious to some fruit connoisseurs, is driving radical changes in the nearly $1.5 billion U.S. market for fresh oranges, as farmers try to reverse years of falling sales and persuade consumers not to switch to other citrus fruit.

A revival in California orange sales could even boost the market for orange juice, which is squeezed mostly from oranges grown in Florida.

For the first time in almost 100 years, California, the nation's No. 1 grower of oranges for fresh consumption, has changed regulations that dictate when an orange is ready to be picked.

For more, see: In Orange Trade, Success Never Tasted So Sweet

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